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      Abbreviated rules   07/28/2017

      Underdawg did an excellent job of explaining the rules.  Here's the simplified version: Don't insinuate Pedo.  Warning and or timeout for a first offense.  PermaFlick for any subsequent offenses Don't out members.  See above for penalties.  Caveat:  if you have ever used your own real name or personal information here on the forums since, like, ever - it doesn't count and you are fair game. If you see spam posts, report it to the mods.  We do not hang out in every thread 24/7 If you see any of the above, report it to the mods by hitting the Report button in the offending post.   We do not take action for foul language, off-subject content, or abusive behavior unless it escalates to persistent stalking.  There may be times that we might warn someone or flick someone for something particularly egregious.  There is no standard, we will know it when we see it.  If you continually report things that do not fall into rules #1 or 2 above, you may very well get a timeout yourself for annoying the Mods with repeated whining.  Use your best judgement. Warnings, timeouts, suspensions and flicks are arbitrary and capricious.  Deal with it.  Welcome to anarchy.   If you are a newbie, there are unwritten rules to adhere to.  They will be explained to you soon enough.  
kent_island_sailor

Bye Bye to AGM

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  Statements I've read from various AGM batt manufacturers says that undercharging continuously lowers the batt capacity - and nothing will raise it back to original spec once it's down.. I recently worked on a boat with a 2 yr bank of Lifeline AGM. The owner admitted to abusing them, down to 9 vdc. We tried 'equalizing' charging them twice, as per Ll spec, with no change. Only fix was new batts.

You never buy batt capability, you only rent it short term.

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7 hours ago, longy said:

  OK, you have series/parallel groups of batts. Are the 3 groups wired in a 'balanced' fashion?

Guys...the AGMs are going away. I'm completely replacing my chargers and redesigning the whole system.

There is ZERO value trying to diagnose what went wrong with the old ones since I'm basically starting from scratch.

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4 hours ago, kent_island_sailor said:

East Penn Deka white papers describe their gels as deep cycle.

http://www.dekabatteries.com/assets/base/0139.pdf

Their gels seem to have at least twice the cycle life of their AGMs too. Actually, from this table, BJ may be getting about all their is to get from typical AGM batteries.

 

 

gel_AGM.gif

That looks nothing like the curve for the batteries I have now.

http://discoverbattery.com/product-search/view/EVGC6A-A

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Nevertheless, in a rare moment of lucidity Jack is right - spend more on charge capacity and less on battery capacity if you are going to LFP. The 100A you have is too little for everything - doesn't charge the batteries, doesn't load the motor, doesn't use the fuel efficiently. 100A at 28V is only 4 hp, maybe 7 when inefficiencies are added in. The largest alternators are around 300A @28V continuous, that's what I would be looking for. 

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3 hours ago, jack_sparrow said:

The absence of very regular 100% SOC is BJ's problem with AGM's. He has no real estate for solar other than something nominal to take the sting out of 24/7 loads like refrigeration.

Solar's ability to top off at 100% and float LA is its strong point particularly when unattended and on the hook. That float feature is of no benefit to LFP and in fact will kill them, so no need to increase solar capacity if going LFP.

BJ if there is a weakness with your LFP plan it is that your not really taking advantage of them by having your AC generator being your principal charge source. The increase in AC charger capacity that you need is also doing nothing  for you dockside. You would know full well the amount of motor sailing one does from time to time. Your better off having large capacity alternator(s) say around 200A+ at 24v as your principal charge source, even on the hook as they will load up the engine nicely. With that arrangement you should also save a lot of fuel as well as have a good charging redundancy platform.

Having said that changing over to HD alternators and or going for dual alternators with their associated drive belt upgrade is a project in itself and with some engine and engine room layouts, sometimes an impossibility.

If your using around 150 Ah / day at 24v your planned total LFP storage capacity of around 1000 Ah appears not just overkill in terms of usage but more importantly too large for your charge capacity with regard to economics when diesel fuel is your principal charge source. Your better off financially reducing storage capacity and putting the savings towards increasing charge capacity.

 

I've done the latter in my plan. The bank size is at 720 Ah now, which is 576 usable at 80% DoD, 504 at 70%.

Huge ass alternators do nothing for me while at anchor, and that is where the vast majority of time is spent. I completely disagree with your assessment that this charge source is anything more than incidental. My engine has run for about an hour in the last two weeks. That is not uncommon in this lifestyle - you get somewhere, and you stay a bit. Or you move, but you tend to do so when conditions are more optimal. I've got a 70A or so alternator on it now, though it rarely seems to throw off more than 45A or so.

My boat is never "unattended" to speak of. If it is, it's tied to something while we fly to the states. My plan is to bump my charge capability up to around 160A - 200A when running the generator to cut charge time to about 4 hours every 3 days or so.

Anyway...I can't talk about this now, we're setting out this AM for a move up the coast. I'll start a new thread when we get in on Saturday.

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8 minutes ago, DDW said:

Nevertheless, in a rare moment of lucidity Jack is right - spend more on charge capacity and less on battery capacity if you are going to LFP. The 100A you have is too little for everything - doesn't charge the batteries, doesn't load the motor, doesn't use the fuel efficiently. 100A at 28V is only 4 hp, maybe 7 when inefficiencies are added in. The largest alternators are around 300A @28V continuous, that's what I would be looking for. 

As mentioned multiple times...I'm working on the design off line. I'll put together my plan in a new thread and we can pick it apart then. But yeah, changes to the charge system will cost almost as much as the cells.

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2 hours ago, B.J. Porter said:

Guys...the AGMs are going away. I'm completely replacing my chargers and redesigning the whole system.

There is ZERO value trying to diagnose what went wrong with the old ones since I'm basically starting from scratch.

Value is for the other people still stuck with AGMs ;)

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2 minutes ago, kent_island_sailor said:

Value is for the other people still stuck with AGMs ;)

Yes. I will still be asked to install big AGM banks. Very few cruisers are smart/observant enuff to understand why their batt banks don't last very long. So any knowledge/details you pass along help the next yacht owner who buys AGM.

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5 hours ago, B.J. Porter said:

Huge ass alternators do nothing for me while at anchor, and that is where the vast majority of time is spent. I completely disagree with your assessment that this charge source is anything more than incidental. My engine has run for about an hour in the last two weeks. That is not uncommon in this lifestyle - you get somewhere, and you stay a bit. Or you move, but you tend to do so when conditions are more optimal. I've got a 70A or so alternator on it now, though it rarely seems to throw off more than 45A or so.

BJ I understand you have been largely on the pick in recent times so absence  of engine use when you have a 7kVa generator is not unexpected. Cruising outside the tradewind belt, engine usage on a cruiser can change enormously as I'm sure you know.

That aside the point was AC charging is not a very cost efficient use of diesel and to get sufficient AC charge capacity a lot of capital is invested in charging that isn't used if shore power is available. It also tends to make the generator work pretty hard, particularly if it is of the high reving variety. I'm a diesel miser and like redundancy so hence bit of a alternator fanboy.

Your 70A alternator is only producing 45A because it is running red hot when your AGM's are in bulk mode. I would suggest with LFP that will be platinum hot and you will shortly have an expensive door stop. That is on account LFP will take everything you can throw at them and for extended periods with no breather due to only a small mount of absorption at the tail. 

On account you will have to externally regulate this alternator anyway to both lower the set point to < 28.4v and provide a means to shut the alternator down in the case of a high voltage event to protect rectifier diodes, most people in your position take the opportunity to upgrade to a HD alternator that will handle the beating that LFP hands out. Budget and room permitting this should ideally be a large frame alt with better cooling than auto style small frames, though the latter can be improved by utilising a remote bridge rectifier, rather than the standard internal one.

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11 hours ago, B.J. Porter said:

As mentioned multiple times...I'm working on the design off line. I'll put together my plan in a new thread and we can pick it apart then. But yeah, changes to the charge system will cost almost as much as the cells.

BJ, possibly rethink your "BJ here this is my LFP project and I need advice thread"... my guess is you will be a bit underwhelmed by the response and that what you get will be largely blowing it out of their arse.

This is a fine thread for looking what you want and I can assure you no one with any real LFP knowledge will be interested in your "one off thread" unless the wider community pondering about LFP are watching with interest on an appropriate thread like this. There are actually not many out there who are willing to invest the time in advice, unlike a few years ago. Many don't bother anymore because no one listens to their advice.

First rid your brain of LA, be circumspect about your knowledge, then get your LFP design/budget from what you know and availability to hardware etc sorted where you are on the planet, then construct design questions, then post.

If not you will be quickly put into the time waster basket by those with the knowledge of LFP and those that are willing to help. Just saying.

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OTOH why append a thread on lithium batteries to a thread about crappy AGM batteries that is three years old?

Also, I am betting the number of lithium battery experts on here is less than 4 and they surely will notice a thread about them ;)

In other news, the Sears Platinum AGMs that were really Odyssey batteries seem to be no more. Not sure if they were shit or Sears can't get them at half price or ?????

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1 hour ago, kent_island_sailor said:

OTOH why append a thread on lithium batteries to a thread about crappy AGM batteries that is three years old?

Kent this thread you started is some 3 years old now but is it out of date??? For instance it is titled  "Bye Bye AGM"..I don't recall too many threads on battery chemistry  on SA that have lasted  that long as this one you started.

May I suggest it is because many out there have no imediate desire to to get into alternative stuff like LFP etc unless pushed...however they do take notice of a thread title that suggests their current battery chemistry is not cutting the mustard and they are potentially retarded for not rethinking.

As for LFP experts sitting in the wings waiting to post...I haven't seen say Maine Sail, OP or Moon etc here recently.. probably for the reasons I suggest in that they are worn out by it all, untill the discussion gets serious.

Your a pioneer Kent with starting this thread but didn't know it....lap up the accolades.

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Speaking of lithium charge acceptance.

I have two Balmar 70-110 110 amp alternators with a MC-612 smart charger with temperature sensors. I've had occasion when my AGM bank accepted close to full output, around 200 amps for about an hour.

The outcome was not good in that both alternators fried themselves. This leads me to believe that a lithium bank would have the same effect. Anyone have similar experiences? If so what's the solution other than using different alternators that can handle full output?

 

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I'm reading this thread with interest although understanding very little of it. Please don't stop the conversation because dumbf--ks like me ask stupid questions. I'm trying to learn all I can, it just takes me longer to "get it".

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2 hours ago, kdh said:

Speaking of lithium charge acceptance.

I have two Balmar 70-110 110 amp alternators with a MC-612 smart charger with temperature sensors. I've had occasion when my AGM bank accepted close to full output, around 200 amps for about an hour.

The outcome was not good in that both alternators fried themselves. This leads me to believe that a lithium bank would have the same effect. Anyone have similar experiences? If so what's the solution other than using different alternators that can handle full output?

 

A lithium bank would have the same effect but the 200 amp phase would last a lot longer, right up until the last 5% or so of recharge. Are the temp sensors you're using for the batteries, the alternators, or both? An alt temp sensor should cut the field current enough to prevent this. You can also use the "belt manager" function of your MC-612. Each increment in the belt manager cuts max alternator output by about 7%. I'd use a setting of at least 3. 

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3 hours ago, kdh said:

This leads me to believe that a lithium bank would have the same effect. Anyone have similar experiences? If so what's the solution other than using different alternators that can handle full output?

 

All small case alternators will burn up charging at full output for any length of time irrespective of battery chemistry, though I'm surprised your 7 series did with AGM at less than full output. Temperature is the issue so the easy way is to de-rate output by around 20% as IStream says using your MC-612 regulators and utilising alternator temp sensor as a precaution. Improving cool air supply to the back of the alternator will also help.

The only solution to lowering temperature and maintaining close to full output is by pulling the rectifier out of the alternator and mounting it externally with its own best sink and fan. It's removal also improves airflow at the back of the case. 

If your serious about taking advantage of LFP a large case alternator(s) is the easiest solution, subject to mounting room, ability for engines front end to take the load and drive belt design/capacity.

 

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Here are two alternator remote rectifiers that are available commercialy that will remove around 50% of the heat from your alternator, thus allowing it to work harder and for longer at maximising output.

This first one is from Mark Grasser in Maine who also happens to make a selection of very fine alternators.

Rated at 300A+ using a single module bridge rectifier, it is a very elegant and well engineered solution with the external heat sink fan self powered via the 3 phase AC inputs from stator so it automatically turns on and off with the alternator. It also has a thermal switch to wire the regulators field connection through (or for Balmar Regs it's power wire) so if the fan was to malfunction and rectifier starts to overheat, the alternator will automatically turn off. 

The second which is a bit agricultural in comparison is from alternatorparts.com in the US which they call the Quicktifier.

It is far less elegant and I'm not sure really how effective it is at getting heat out the alt as it retains the alternators existing internal rectifier and simply parallels the 3 phase AC from the stator, thus doubling the total number of diodes in play for the 210A version that comes with 3 x 70A diode pairs or tripling for the 420A version that has 6 pairs. Heat sinks  are integrated, not external and the fan is powered externally and has no overheat protection in the event of fan failure. If using this offering I would modify the approach by removing the internal rectifier and the concept of paralleling the 3 phase AC from the stator.

For the skilled DIY it would also be relatively easy to make your own as the component parts are not expensive.

 

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images (70).jpg

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Even the so called large frame alternators have heat problems. I have not seen a problem with the Electrodyne I am using, rated at 7KW. It is actually two pretty large alternators built back to back. I've never been able to run it at 280 amps longer than about an hour, but the claim is continuous duty. the recommended maintenance is repacking the bearings every 20,000 hours. It is way too large to mount to the engine and run off a belt. 

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1 hour ago, DDW said:

Even the so called large frame alternators have heat problems. I have not seen a problem with the Electrodyne I am using, rated at 7KW. It is actually two pretty large alternators built back to back. I've never been able to run it at 280 amps longer than about an hour, but the claim is continuous duty. the recommended maintenance is repacking the bearings every 20,000 hours. It is way too large to mount to the engine and run off a belt. 

My 24V alternator is a large frame high capacity - remember that 75A translates to 150A in 12V land.

I have a hell of time getting the belts tight enough. For some reason the 12V alternator (also a large thing) has two pulleys, and there was only one for the 24V. We looked at a lof of ways to increase that but didn't find one we liked.

As mentioned, alternator charging is largely incidental. If I am motor sailing because there is no wind...I don't need 200A. On a trip like this last one, 36 hours motor sailing over a two day trip where the wind didn't crack 10 knots until the last day, I'd be plenty charged with 75A, or even 40A.

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6 hours ago, B.J. Porter said:

My 24V alternator is a large frame high capacity - remember that 75A translates to 150A in 12V land.

I have a hell of time getting the belts tight enough. For some reason the 12V alternator (also a large thing) has two pulleys, and there was only one for the 24V. We looked at a lof of ways to increase that but didn't find one we liked.

As mentioned, alternator charging is largely incidental. If I am motor sailing because there is no wind...I don't need 200A. On a trip like this last one, 36 hours motor sailing over a two day trip where the wind didn't crack 10 knots until the last day, I'd be plenty charged with 75A, or even 40A.

BJ I don't think you appreciate what you have is a bit out of the norm being a 7kVa generator and obviously oodles of fuel tankage courtesy I suspect of having a deck farm of jerries and a cheque book as well as regular fuel access to fill them and the tanks.

One of the principal benefits of LFP combined with a good balance of charge sources incl large capacity auxiliary driven alternators is that you can get rid of your fuel storage farm.

If you don't want to do that and rely on principally a AC charge source and with no meaningful redundancy, then the changeover benefits to LFP simply become less compelling under that scenario. In fact ignoring operating costs, the capital cost of sticking with a lot of LA batts and putting up with their life cycle shortcomings would be less than going LFP.

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52 minutes ago, jack_sparrow said:

BJ I don't think you appreciate what you have is a bit out of the norm being a 7kVa generator and obviously oodles of fuel tankage courtesy I suspect of having a deck farm of jerries and a cheque book as well as regular fuel access to fill them and the tanks.

One of the principal benefits of LFP combined with a good balance of charge sources incl large capacity auxiliary driven alternators is that you can get rid of your fuel storage farm.

If you don't want to do that and rely on principally a AC charge source and with no meaningful redundancy, then the changeover benefits to LFP simply become less compelling under that scenario. In fact ignoring operating costs, the capital cost of sticking with a lot of LA batts and putting up with their life cycle shortcomings would be less than going LFP.

Alternators do fuck-all for you if you aren't moving the boat.

Most cruisers I know do NOT move every two or three days. We just don't. Every week or two...or three...is a lot more common. If I rely on huge-ass alternators to charge my batteries and don't move my boat...how do they get charged? You have to run the generator. The ratio of generator hours run to engine hours for a liveaboard cruiser is about 5 or 10:1, at least in my case it has been, historically. If I use 180 Ah/Day and my battery bank has 264Ah usable capacity, I'm either moving every other day, or I'm running the generator. You can guess which it is.

I disagree completely with what you are suggesting. It makes zero sense.

I spent almost $6,000 and a week or two of my life dicking around changing batteries in 2015. And I paid for a slip for a couple of days to do it in, and didn't go anywhere cool or do anything but work on getting the god damned batteries swapped out for a week+ (including time to identify the batteries, talk to vendors, arrange for delivery, etc. etc.). And we swapped the batteries out in 2012 (though we weren't cruising yet, and I paid someone else to make the swap for me).

You are suggesting I should do the same in 2017 - drop $6,000+ on new batteries that will last 2-3 years (while also dicking around for a weeks+ arranging the batteries, paying for a slip, and doing the install. A 4D AGM deep cycle 200Ah battery runs around $1,000 AUD...I need eight). And will STILL require me to run my generator something like four hours every day, since for the physical space, weight (>1,000 lbs) and volume you can't put more than 1.5 days worth of working capacity with lead acid batteries in my boat. You just can't do it - the tech isn't there to get more than about 280Ah of usuable capacity with AGM's for under 1,000lbs and $500+/battery (more like $750/battery here in Oz).

I've literally spent $2,300/year on AGM's since I've gone cruising.

So let's say right now I run the genset four hours per day - at 50% load that's 1.4 L/Hour. 5.6 L/day. And I burn 1100-1200 hours per year off my Genset's life, and 1,540 liters of fuel.

Now put in 720Ah of 24V LiFePO4 batteries and a serious charge system.

Estimated cost: $17-19,000 USD. (Cells: ~$11,022, BMS: $2,500, 200A Charge capabilities + inversion: $4,060, plus a brackets, wiring, etc.)

Estimated life of Batteries: 2000-3000 cycles

Cycles/year: ~130

Generator hours/year @ 4 hours/cycle: 520

Estimated life of system: 15-23 years.

Cost / Year @ $20K for the system:  $1,300 - $1,150/year - Half the cost of AGMs.

And that cost doesn't account for:

  • Reduced hours on the genset = longer genset lifespan. If it's good for 10,000 hours, it will last me 8-9 years with AGMs. That's a $20K+ replacement; if I cut genset time by 50-60% it lasts me twice as long.
  • Fuel costs. Literally half the fuel costs - 728L of fuel versus 1,500+ - that's close to $1,000/year in savings in fuel alone.
  • Other incidentals. My Genset has a 200 hour oil change cycle. Right now that's 5-6 oil changes (and other filter changes...) per year. Cut that in half with LFP. 3.6L of oil and a new filter adds up over time.

I will not move the boat to charge batteries - that's not how it works. And a high output alternator isn't going to charge the engine idling at anchor, nor will it do any good at all for the engine to idle for hours laboring to run a large alternator.

At $2,300 per year just for the cost of the AGMs the break even on this is 8.7 years. If you factor in 700L of fuel saved per year @ $1.65/L AUD = $866/year (current price @ Newcastle, NSW), the break even drops to 6.3 years.

The only way this is not financially better for me is if I sell the boat in a couple of years and don't realize any increased value at sale time for the better battery tech.

 

Check this guy's numbers. He did a DIY battery install, and analyzed his costs of wonign and using different battery types. The Lithium solution turns out to be a bit more expensive than wet cells, but WAY cheaper than AGM.

Lithium with BMS - $1433/year (includes shipping, customs fees, BMS)
Lead Acid - $1200/year
AGM - $3192/year

https://marazuladventures.files.wordpress.com/2013/01/diy-lithium-iron-phosphate-batteries8.pdf

 

Admittedly, if I pay someone else to do all the work, and/or if I buy insanely expensive pre-made batteries...it won't make sense. When I talked to the guys at Victron about their chargers, they tried to convince me to buy their batteries too. Yeah, it wold have cost almost $30,000 AUD to get the equivalent Ah depth in Victron batteries that I am getting for $12,500 AUD in individual cells from CALB. I've sure they are very nice, they come in a snazzy case all wired together in 12V batteries with cell monitoring right in the pretty blue box. For $3,452.70 AUD for ONE 12V, 160Ah battery. I'd need eight of those to make a 640Ah bank - that's $27,621.60.  CALB 180Ah cells are costing me $380/each for 32 to make a 720Ah bank.

From what I can see though, this total project is going to come in under $20K USD, likely by a few $thousand under. And that makes the numbers work just fine.

I don't plan to upgrade my alternator from what I have. 75A capability with an external Balmar alternator will do just fine for the way I use my boat on a daily basis. That's the key - the rules you see for weekenders and boats that plug in every week don't apply.

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Sorry BJ but your wrong. For instance you don't have to move your boat to load up the engine, large alternator(s) provide more than enough load, in fact in some cases too much. The amount of fuel carried and consumed is where you should start your comparative calcs on determining the best and most cost effective charging regime for a boat on the go like yours. Why do you think Round the World Racers use diesel powered large alternators as their primary charge source for LFP? Anyway I'm sure you will work it all out.

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BJ,

If you put that $4K charger upgrade in and forego the lithiums, chances are very good that you'd get a lot more life out of a properly charged set of AGMs or FLAs than you have been, probably a minimum of 5 years.

"The only way this is not financially better for me is if I sell the boat in a couple of years and don't realize any increased value at sale time for the better battery tech." I wouldn't underestimate the likelihood of this. Li is still novel enough and scary enough that many folks will be suspicious of it and unwilling to pay a premium for someone's roll-your-own solution. Remember, the perceived downside is that it could burn the boat down.

IMHO, your problems with AGM have been the result of poor charging rather than the batteries themselves. Nothing wrong with switching over but I don't think they'll pencil out financially unless:

1. Implementation costs are as expected
2. You own the boat for 20 more years and everything works fine over that entire time period, or
3. You sell the boat in N years and recover (20-N)/20% of the initial cost of the system 

I'm a big fan of Li and there's no doubt you'd be happier with them but I wouldn't try to justify it financially. 

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Why use agm's?  Why not just use FLA for $100 a battery?  If you want more amperage when charging with your genset add more chargers, it'll load the genset better.  Six 8 volt batteries and four six volt batteries make up our 12 and 24 volt systems and can be had for $1,000 total. We charge with Sterling chargers and a 5 kw genset.   I understand the benefits of lithium but they are ungodly expensive. 

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BJ - I feel your pain on a smaller scale. Until recently, one use for my boat is as housing for my son and friends at sailing class for 2 weeks. Several kids using power for their devices and not moving at all. Charging from the main engine at anchor basically sucks. No one wants to run the engine at 2500 RPM in neutral and running just off idle gives you less power - and much worse - the alternator is essentially full-field with low RPMs which equals limited airflow. This is the worst possible use case for an alternator. On top of that, once you get to a big boat with a big diesel, you run the danger of carbon fouling the engine.

Using the AC generator and good big chargers is a much better way to charge while at anchor and you spend $$ on genset hours instead of $$$$ on main engine hours.

I am also interested in lithium because I have no space, but it still seems to be a very expensive experiment at this point that might go badly wrong. I would be double-triple and quadruple checking everything before I spent the cash. I am as cheap as all the other dumpster divers, but even I would think about maybe some consulting work from MaineSail or the equivalent on your project.

* a thought - you really need to see how multiple charging sources interact. You may well have them all trip each other into float mode. We *used to* have a totally integrated system that controlled charging from multiple sources in the mid 90s, but it was never 100% reliable and AFAIK no one has done it since.

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12 hours ago, B.J. Porter said:

My 24V alternator is a large frame high capacity - remember that 75A translates to 150A in 12V land.

My alternator is 280A @ 24V - remember that 280A translates to 560A in 12V land :). 

The so-called 'large frame' automotive alternators aren't really very large. They are a little bigger than a 'small frame'. Mine is driven directly from the damper pulley with a drive shaft. It weighs about 1/4 what the main propulsion engine weights. I have enough trouble keeping the little 50A Balmar belt tight, no way the big one is going to be belt driven.

BJ's - and most live aboard cruisers - problem with AGMs is the long tail of the charge curve, which has to be satisfied periodically or you will ruin them. There is no good solution to this unless you have a long duration, low current charge source. Solar or wind might qualify, but it needs to be higher than the ambient draw or it does no good, and BJ is not there. A large alternator (whether on the main or aux engine) does no good unless you are willing to run it for the 6-8 hours required once a week. If there is no way to add that charge source, then AGMs are going to die an early death. That makes BJ a prime customer for a battery technology that either can be brought to 100% quickly, or tolerates a partial SOC long term. In an ideal world, you would shit can the AC gen set and build one with a large direct driven DC alternator. Any AC requirements reasonably needed on a boat can be supplied with an inverter. 

I have the long duration, low current charge source in 450W of solar, combined with a system designed to have low ambient draw during the day. That let's me bulk charge with the large alternator, and finish to 100% with the solar frequently, which is why I am on my 9th year on the current AGMs. 

 

Alternator_zpsrg7kq2cz.jpg

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The idea behind the large alternator(s) on the engine is that there is often no dedicated generator. (Ok, you have one.) 
Next up is that a leading cause of engine death in sail boats is disuse. If it does not run regularly it will die sooner or latter. (Almost the same story for non liveabord stinkpots too.)
Another reason is that the generator may be much more difficult to maintain (even less access) and/or more expensive in consumables. This is especially true on stinkpots that need to run the main engine(s) to move in the first place. Some of them have retrofitted really large alternators occasionally with external rectifiers (+battery capacity, +inverters) to solve this issue. 
Low engine loading can be an problem, less so with large alternators driving into large battery banks. The alternator can take up a sizable portion of the (smallish) engine power and it becomes more a thermal limit on the alternator side.

Anyway. At the end of the day the big issue has been identified right away: The charging system needs a complete makeover if the new battery system is to last any longer than the previous one. All components of it need to be looked at. Not to replace them out of hand but to find out if they'll work as intended with the new system..

Thermal limits is one of the funny things. There is no reason for any alternator to burn up, other than being too cheap for a temperature sensor... Same for the external rectifiers. It makes no sense whatsoever to go external and then leave out temperature monitoring.

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When I was building my boat, the genset salesmen kept telling me I didn't want to wear out my expensive main engine charging the batteries.  The quotes for a good quality DC genset were $12K, while the main propulsion engine was $8K. I put the alternator on the main engine.

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7 hours ago, Bryanjb said:

Why use agm's?  Why not just use FLA for $100 a battery?  If you want more amperage when charging with your genset add more chargers, it'll load the genset better.  Six 8 volt batteries and four six volt batteries make up our 12 and 24 volt systems and can be had for $1,000 total. We charge with Sterling chargers and a 5 kw genset.   I understand the benefits of lithium but they are ungodly expensive. 

I agree. Everything I have read and experienced say that AGMs hate being partially charged.  I went back to flooded lead acid and have been much happier and saved a lot of money. 

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31 minutes ago, olaf hart said:

What sort of removable coupling is that DDW?

It's one you remove when its busted :). 

Actually it is a Vetus Bulflex rubber buffered prop coupling. It is disconnected in the picture because the Spicer U joint on the alternator side began to come loose on the shaft, and the way I built it it could not be tightened after pressing together :wacko:. It started making a little noise coming into an anchorage in Maine, so I disconnected the Bulflex end to stop the noise. Cut the U joint off in the anchorage with a dremel grinding wheel. During the next break back home, modified it with Bulflex couplings at both ends. No trouble since. A 4 banger diesel has some serious torsional vibration in the crank, this had made its way through to the U joint and loosened the connection to the alternator shaft. No belt to isolate the vibration. One of the few attributes of a belt. 

Normally the alternator runs 100% of the time, but I shut off the regulator when that alternator is not in use. The Electrodyne is an interesting design, the only rotating component is a toothed steel disk (and the shaft and fans at the ends), so it doesn't bother it to spin all the time. There aren't any brushes or slip rings to wear, and no rotating coils at all. The only wearing part are the ball bearings, which have a spring loaded grease reservoir with a recommended repacking interval of 20,000 hours. I'm at about 1000 hours after 9 years cruising, so I'm not too worried about that burden. I switch the alternator regulator off when we aren't charging heavy as it makes a bit of a whine, and run on the small one.

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8 hours ago, kent_island_sailor said:

No one wants to run the engine at 2500 RPM in neutral and running just off idle gives you less power - and much worse - the alternator is essentially full-field with low RPMs which equals limited airflow. This is the worst possible use case for an alternator. On top of that, once you get to a big boat with a big diesel, you run the danger of carbon fouling the engine..

Kent charging at 2500 RPM on the hook equals something is very wrong, whether it be alternator selection, pulley ratios etc. Yes any engine will die prematurely if it is not loaded up, hense high output alternator(s) with a properly engineered multi rib/serpentine belt or alternative drive arrangement that will induce a pto load of nearly 4HP per 100A. BJ already has a big arse generator so less compelling for him to consider that. 

Roll your own LFP is not for the faint hearted and you need to be prepared to invest a lot of time in design and implementation otherwise it will end up in tears. 

LFP is tailor made for the full time cruiser that has trouble ever getting to 100% SOC. My choice if LFP was out of reach either financially or DIY skillset wise would be from the opposite ends of the drop-in LA spectrum. Namely carbon foam Fireflys or flooded LA provided the latter cells can be properly installed and orientated. AGM's are the domain of the weekend warrior where they regularly get to 100% SOC either via shore power or if unattended on the hook, solar etc. 

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10 hours ago, jack_sparrow said:

Sorry BJ but your wrong. For instance you don't have to move your boat to load up the engine, large alternator(s) provide more than enough load, in fact in some cases too much. The amount of fuel carried and consumed is where you should start your comparative calcs on determining the best and most cost effective charging regime for a boat on the go like yours. Why do you think Round the World Racers use diesel powered large alternators as their primary charge source for LFP? Anyway I'm sure you will work it all out.

So what you are suggesting is that it's wiser and more efficient to run a 20 year old 1,100 lb turbo charged six cylinder 145HP engine that uses 2-3 times the fuel as my genset at a heavy idle (against any and all wisdom on diesel engines), than to run the purpose-engineered two year old 1,500 RPM (12 HP) Northern Lights generator?

I'm not buying it.

The lowest end of the fuel curve for a TAMD41 H-A...check it. It's not 1.4L/hour.  It's going to be more like double that or more.

I can buy a Balmar large frame 24V 140A alternator here in Oz for $2,671.40 AUD (about $2,000 USD). To run that, I'd need to put a new pair of disks on the front of my engine, which may or may not put undue and unknown stress on the crank shaft. I explored this option years ago, that particular modification was not a pretty picture. I doubt I can do it for less that $1,000. Probably more.   If running at 100% (which it can't do...) it would need 4.11 hours to charge. Or, if money (and physical space in my engine room) is no object, I could put on a Balmar 98 series 220A alternator...for $6,553.10 AUD ($4,900 USD).

I'm not sure how any of that is an improvement. Especially since I have a perfectly serviceable 75A alternator on the engine, and another spare under the floor boards.

And I'm still not sold that spinning 1,100 pounds of engine to do the charging is going to be more efficient that running the generator that is less than half it's size and 1/3 of it's swept volume.

RTW racers have VERY different requirements than I do for charging. Not the least of which is that they don't want the extra 600lbs of weight added by a generator. It is also my understanding that most of those racers have moved to high performance hydrogenerators as well, which can provide a large amount of power (600W @ 12 knots for the racing version, or double my power needs while sailing) for little weight and drag at the speeds they are sailing at and can compensate for most of their electrical needs. Like me, alternator charging would be more ancillary than primary if they were using these.

RTW racers also don't stop for days and weeks at a time to smell the roses and look at things.

You seem to be making a lot of assumptions on how my boat should be configured for charging by how other people use their boats. Those assumptions seem to be quite wrong for me. What RTW racers to do charge is of little interest to me, nor weekenders, racers, or pretty much anyone but the other cruisers I frequently share anchorages with.

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11 hours ago, IStream said:

BJ,

If you put that $4K charger upgrade in and forego the lithiums, chances are very good that you'd get a lot more life out of a properly charged set of AGMs or FLAs than you have been, probably a minimum of 5 years.

"The only way this is not financially better for me is if I sell the boat in a couple of years and don't realize any increased value at sale time for the better battery tech." I wouldn't underestimate the likelihood of this. Li is still novel enough and scary enough that many folks will be suspicious of it and unwilling to pay a premium for someone's roll-your-own solution. Remember, the perceived downside is that it could burn the boat down.

IMHO, your problems with AGM have been the result of poor charging rather than the batteries themselves. Nothing wrong with switching over but I don't think they'll pencil out financially unless:

1. Implementation costs are as expected
2. You own the boat for 20 more years and everything works fine over that entire time period, or
3. You sell the boat in N years and recover (20-N)/20% of the initial cost of the system 

I'm a big fan of Li and there's no doubt you'd be happier with them but I wouldn't try to justify it financially. 

Everything I have read and experienced with AGMs tells me they are great...if you can plug them into the grid a couple of times per month, or run your generator for hours and hours to get them full.

I've dealt with three sets of AGM's since 2006, and I've had quite enough of them.

I could put 200A of charge capacity and just drop $6K on AGMs. Again. And it STILL wouldn't do anything about taper charging or the need to bring the damned things up to full.

 

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10 hours ago, Bryanjb said:

Why use agm's?  Why not just use FLA for $100 a battery?  If you want more amperage when charging with your genset add more chargers, it'll load the genset better.  Six 8 volt batteries and four six volt batteries make up our 12 and 24 volt systems and can be had for $1,000 total. We charge with Sterling chargers and a 5 kw genset.   I understand the benefits of lithium but they are ungodly expensive. 

There are a number of reasons I don't want FLAs under my bed. Outgassing, spill risks, maintenance, etc. etc. Yeah, if my batteries get wet where they're installed I have much larger problems than a poison gas cloud in my bedroom, true. But I'm really, really not into the idea of ripping my bed apart once a month to top up 48 cells with distilled water...

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9 hours ago, DDW said:

My alternator is 280A @ 24V - remember that 280A translates to 560A in 12V land :). 

The so-called 'large frame' automotive alternators aren't really very large. They are a little bigger than a 'small frame'. Mine is driven directly from the damper pulley with a drive shaft. It weighs about 1/4 what the main propulsion engine weights. I have enough trouble keeping the little 50A Balmar belt tight, no way the big one is going to be belt driven.

BJ's - and most live aboard cruisers - problem with AGMs is the long tail of the charge curve, which has to be satisfied periodically or you will ruin them. There is no good solution to this unless you have a long duration, low current charge source. Solar or wind might qualify, but it needs to be higher than the ambient draw or it does no good, and BJ is not there. A large alternator (whether on the main or aux engine) does no good unless you are willing to run it for the 6-8 hours required once a week. If there is no way to add that charge source, then AGMs are going to die an early death. That makes BJ a prime customer for a battery technology that either can be brought to 100% quickly, or tolerates a partial SOC long term. In an ideal world, you would shit can the AC gen set and build one with a large direct driven DC alternator. Any AC requirements reasonably needed on a boat can be supplied with an inverter. 

I have the long duration, low current charge source in 450W of solar, combined with a system designed to have low ambient draw during the day. That let's me bulk charge with the large alternator, and finish to 100% with the solar frequently, which is why I am on my 9th year on the current AGMs. 

 

Alternator_zpsrg7kq2cz.jpg

You get it...

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BJ Hydro in racing is backup generation. Alts are primary. A Open 60 going around the world non stop with large loads like 24/7 AP and comms for three months is probably the closest equivalent there is to a full time cruiser and that is limiting fuel tankage and consumption. I don't think Alt should be your primary source when you already have a big arse generator. My comment was more general and solely directed at LFP,  no other chemistry. With the relatively short bulk charge time of LA and normally weight/space restrictions on battery capacity large charge sources are a waste of time and money without renewables to finish off.

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9 hours ago, kent_island_sailor said:

* a thought - you really need to see how multiple charging sources interact. You may well have them all trip each other into float mode. We *used to* have a totally integrated system that controlled charging from multiple sources in the mid 90s, but it was never 100% reliable and AFAIK no one has done it since.

In theory, a decent BMS will control the charge sources, less than the charge sources making their own decisions about voltage. In the best world, the BMS I am planning to use (EMUS) would be installed with a compliant CAN charger. Then the BMS can take complete control of the charger, change voltages, shut it down etc. For this BMS, non CAN charging sources can be controlled as well. But it is done with a signal sent to a relay that will cut out the charge source when the BMS is done with it. Some smart but non-compliant chargers (like the Victron Skylla-i) can also be programmed to take a signal from a BMS that will shut them down or put them to "float", which you can configure to a noncharge voltage. There is a reason to do that which involves completing a cycle count, as well as cell balancing.

The idea is to have the BMS take responsibility for maintaining the charge level and the sources, and not allow the devices their own discretion about stopping and charging.

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5 minutes ago, jack_sparrow said:

BJ Hydro in racing is backup generation. Alts are primary. A Open 60 going around the world non stop with large loads like 24/7 AP and comms for three months is probably the closest equivalent there is to a full time cruiser and that is limiting fuel tankage and consumption. I don't think Alt should be your primary source when you already have a big arse generator. My comment was more general and solely directed at LFP,  no other chemistry.

I don't know enough about the daily operation of RTW race boats to argue the point. But unless they are running canting hydraulics, I can't imagine they are using THAT much more power that we would while off shore unless their Satcomm stuff is really piggy. We tend to draw around 280-300W while sailing while running the autopilot (we're WAY heavier than any race boat), MFD's, instruments, etc. Obviously we spike that when we run the hydraulic furlers or winches, but the average isn't much higher with those since once the sails are out they tend to stay out and those bursts are all pretty short.

It certainly sounded like you were speaking specifically to me and my configuration, that by not adding a whacking huge alternator I'd not really be reaping the benefits of LFP tech.

I've got about 1,000L of fuel capacity, not including my four 20L jerry jugs (that my son despises because he's right, they are ugly). At cruising RPM, my TAMD41H-A is rated for 10L/Hr fuel consumption. We rarely run at that speed, so our consumption is closer to 50-70% of that when motor sailing in regular conditions.

While those jugs may give me a few more hours of motoring range, they give me over 50 more hours of generator time...or almost two weeks more sailing time with full power with my current configuration of 4-5 hours of genset time/day. So unless we run out of fuel within forty miles or so of land...

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5 minutes ago, B.J. Porter said:

In theory, a decent BMS will control the charge sources, less than the charge sources making their own decisions about voltage....

..The idea is to have the BMS take responsibility for maintaining the charge level and the sources, and not allow the devices their own discretion about stopping and charging.

LFP BMS's are protection devices not control devices. The battery's SOC determines the amount of current and at what voltage a charge source can deliver and the charge source delivers the selected setpoint voltage. A BMS can do none of this. All it can do is monitor cell voltage and temperature and in the case of low voltage or temperature or high voltage or temperature event at best tell a charge or load source to stop before shutting down the charge or load buss.

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1 minute ago, jack_sparrow said:

LFP BMS's are protection devices not control devices. The battery's SOC determines the amount of current and at what voltage a charge source can deliver and the charge source delivers the selected setpoint voltage. A BMS can do none of this. All it can do is monitor cell voltage and temperature and in the case of low voltage or temperature or high voltage or temperature event at best tell a charge or load source to stop before shutting down the charge or load buss.

That's not the way the manual for the BMS I am planning to install reads.

https://www.elektromotus.lt/files/bms/docs/Emus_BMS_User_Manual_v.1.1.pdf

 

Quote

3.2.4 Charging process and charging device control
Emus BMS controls the charging process and regulates the output current of the charging
device according to the feedback of various measured battery parameters. This ensures that
the battery is charged safely and the cell voltages are correctly balanced after the charging
process is finished, and is one of the most important functions of Emus BMS. Various thirdparty
charging devices are supported for that purpose, which can be categorized into three
distinct types based on how they are controlled:

1. Basic charging devices that do not have any Emus BMS compatible interface for controlling
their output current and voltage (also referred to as non-CAN charging devices) are
controlled by utilizing a special algorithm to turn them on an off using a switching device
that is driven by a general purpose output pin mapped with ”PF10 Charger Enable Output”
pin function. The Control Unit acknowledges the connection and disconnection of
such charging device whenever a corresponding high/low signal is detected on a general
purpose input pin mapped with ”PF3 Charger Mains AC Sense Input” function;
2. Charging devices that are equipped with a CAN interface (or simply CAN chargers) are
controlled by sending the requested output voltage and current values to them in a CAN
message using a protocol that is specific to a particular charger. In this case the ”PF10
Charger Enable Output” pin function is used only for disconnecting the charger from the
battery in case of a critical condition, and should drive a corresponding contactor that is
separate from the main contactor. Currently Emus BMS officially supports the following
CAN chargers:
• TC or Elcon HF/PFC chargers with CAN interface;
• Eltek Valere EV Power Chargers;
• Zivan NG and SG series chargers with CAN interface;
• Powerfinn Robust and PAP3200 chargers with CAN interface.
Up to 16 identical CAN chargers connected in parallel can be controlled by Emus BMS
if each individual charger is set up to use a unique CAN identifier. The Control Unit
detects each charger automatically and relies on the ”Number of Chargers” parameter in
order to correctly distribute the charging current amongst all connected chargers. This
means it expects that the number of connected chargers will be equal to or less than
this parameter, and determines the output current of each connected charger using the
following formula:
In = IRequested
”Number of Chargers” (2)
where IRequested is the requested charging current, and ”Number of Chargers” is the
value of the corresponding parameter. Naturally, the charging will we stopped if the
number of connected chargers exceed the ”Number of Charger” parameter value to avoid
overloading the chargers.
The Control Unit acknowledges that a CAN charger is connected when it receives a
particular CAN message from at least one charger. Depending on the charger model,
the charger transmits this message either by itself (periodically), or as a response to
a request CAN message from the Control Unit. Disconnection is acknowledged if the
Control Unit does not receive any CAN message from the charger(s) for more than 15
seconds. Consequently, the ”PF3 Charger Mains AC Sense Input” pin function has no
meaning when using this type of charging device.
3. Charging devices of which the output current is proportional to the control signal voltage
level (also reffered to as analog signal controlled chargers) are controlled by a corresponding
PWM signal generated on the ”SOC OUT” pin of the Control Unit, which has to
be mapped with ”PF18 Analog Charger Control Output” pin function for that matter.
The resultant minimum and maximum voltage levels of such signal can be adjusted in
between 0V to 5V range by changing the values of the corresponding ”Min PWM Output”
and ”Max PWM Output” parameters in order to match the requirements of the charging
device.
The role of the ”PF10 Charger Enable Output” pin function when using an analog signal
controlled charger is identical to when a CAN charger is used, while the connection and
disconnection is acknowledged the same way as for the non-CAN charging devices.

 

 

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1 hour ago, B.J. Porter said:

That's not the way the manual for the BMS I am planning to install reads.

https://www.elektromotus.lt/files/bms/docs/Emus_BMS_User_Manual_v.1.1.pdf

 

 

BJ that BMS is primarily designed for the DIY large C electric motor vehicles and not for fractional C house power applications, particularly marine despite what may be indicated to the contrary. For instance there is no means to either manage or monitor a alternator as a charge source so something would need to be designed and constructed to shut off alternator when there was a high voltage event to protect rectifier diodes. It also appears to be only capable of driving a single charge/discharge bus. 

Apart from looking more at home in a space ship it then effectively makes all aspects of your installation proprietary, from cell boards through to high current contactors. It is therefore a proprietary system without the batteries or the benefits of any intergated design. It may not even be too much different in price once all the bits are added up. I'm not sure even how long it would survive the marine environment and if there was a malfunction where you would start trying to fix it or override it as an emergency measure. Even wiring up a spare in the vicinity of all that energy density in a seaway would be a nightmare.

LFP installations on a boat should simple, idiot proof and effective. LFP BMS's should have conservative cell voltage trigger thresholds and be treated like an ejector seat you don't want to come into play other than to protect your investment.

By the way BMS charge control started years ago when computers in cars starting overriding/monitoring alternator regulators to improve engine fuel consumption. I have never heard of it being contemplated for sailing vessels using LFP.

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35 minutes ago, jack_sparrow said:

BJ that BMS is primarily designed for the DIY large C electric motor vehicles and not for fractional C house power applications, particularly marine despite what may be indicated to the contrary. For instance there is no means to either manage or monitor a alternator as a charge source so something would need to be designed and constructed to shut off alternator when there was a high voltage event to protect rectifier diodes. It also appears to be only capable of driving a single charge/discharge bus. 

Apart from looking more at home in a space ship it then effectively makes all aspects of your installation proprietary, from cell boards through to high current contactors. It is therefore a proprietary system without the batteries or the benefits of any intergated design. It may not even be too much different in price once all the bits are added up. I'm not sure even how long it would survive the marine environment and if there was a malfunction where you would start trying to fix it or override it as an emergency measure. Even wiring up a spare in the vicinity of all that energy density in a seaway would be a nightmare.

LFP installations on a boat should simple, idiot proof and effective. LFP BMS's should have conservative cell voltage trigger thresholds and be treated like an ejector seat you don't want to come into play other than to protect your investment.

By the way BMS charge control started years ago when computers in cars starting overriding/monitoring alternator regulators to improve engine fuel consumption. I have never heard of it being contemplated for sailing vessels using LFP.

I've got a friend using this exact BMS on his boat successfully so far, I'll have to ask him what he did about his alternator.

My understanding from my reading is that with an external regulator like my Balmar MC-624, it is reprogrammed with a fairly low voltage charge level, and set to float pretty aggressively at a voltage that won't harm the batteries. I'll have to dig that bit up, I think it was out on Panbo. One guy who did a DIY mentioned he downscaled his alternator's single stage regulator, so essentially he got enough power to cover house needs while motoring, but not enough to really risk a problem with the LFP batteries burning up the alternator. The voltage is low enough so it only charges when the voltage is low.

The distributor for this BMS in Australia does a lot of solar installations with this unit.

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BJ remember a LFP BMS is looking out for individual cell voltages falling outside charge and discharge thresholds, not at pack voltages. The difference between 100% SOC and 20% SOC is a OCV range of only 0.25v at 12v. Therefore simply using conservative pack charging voltages like those you indicate won't provide any protection against an individual cell rising (or falling) beyond its life ending voltage limit. 

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40 minutes ago, jack_sparrow said:

BJ remember a LFP BMS is looking out for individual cell voltages falling outside charge and discharge thresholds, not at pack voltages. The difference between 100% SOC and 20% SOC is a OCV range of only 0.25v at 12v. Therefore simply using conservative pack charging voltages like those you indicate won't provide any protection against an individual cell rising (or falling) beyond its life ending voltage limit. 

Maine Sail has great info on this stuff, how to configure it for safety and protection of the cells, etc.

 

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13 minutes ago, B.J. Porter said:

Maine Sail has great info on this stuff, how to configure it for safety and protection of the cells, etc.

 

You need to reread it closely. He doesn't lower charge pack voltage for cell protection, he has a BMS that does that.

He uses a lower pack set point for charging than some others because he wants to keep the cell pack balanced, rather chase a few extra Ahrs, and knowing full well that daisy chained cell boards have very little ability to shunt off any meaningful over voltage, despite what many think.

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5 hours ago, jack_sparrow said:

DDW that is bad arse alt you have there. Have you got a gear box or is it driven at 1:1?

It is driven at crank speed, but one of the features of the Electrodyne is it is up to full output at around 2000 rpm. It will put out over 200A at 1700. At 1300 the field is drawing more than it produces. 

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Cool DDW. I have a similiar arrangement driving a high pressure watermaker pump but the shaft is in line so vibration not an issue. Drop prop boxes in race boats have similiar drive angles and issues to yours so your not alone.

With their brushless and low power/rpm input design and stator wiring the size of a fence post you can see how they are the industrial/emergency vehicle/workboat alternator of choice. Also one of the few large brushless that are marinised and good value for money. I wanted to put one in but couldn't fit it.

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Quote

The outcome was not good in that both alternators fried themselves. This leads me to believe that a lithium bank would have the same effect. Anyone have similar experiences?

Using a Balmar regulator and alternator you need to adjust the belt-load manager setting (like 3) so the alternators put out less than max. to prevent overheating.   

 

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1 hour ago, solosailor said:
Quote

The outcome was not good in that both alternators fried themselves. This leads me to believe that a lithium bank would have the same effect. Anyone have similar experiences?

Using a Balmar regulator and alternator you need to adjust the belt-load manager setting (like 3) so the alternators put out less than max. to prevent overheating.   

That's what I've read too - even a large frame alternator you need to knock it down by 30-40% of max output.

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With the external regulators you must use the remote alt temp sensor. And make sure the cheezy (Balmar) thing does not fall off less all the smoke leaks out of the alternator. Ask me how I know.

Or severely de-tune the system, as mentioned above, which makes no sense at all as one might then simply use a generic alternator.

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1 hour ago, B.J. Porter said:

That's what I've read too - even a large frame alternator you need to knock it down by 30-40% of max output.

BJ with all due respect de-rate a large frame by 30-40% hot and for AGM/LFP?? .. WTF that is absolute nonsence unless of course it is a piece of rubbish to start with and or gets no half decent air. Your anti big Alt bias on account of having the luxury of a large AC charge source and downside of a fuel hungry auxiliary is getting the better of you. 

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3 hours ago, jack_sparrow said:

BJ with all due respect de-rate a large frame by 30-40% hot and for AGM/LFP?? .. WTF that is absolute nonsence unless of course it is a piece of rubbish to start with and or gets no half decent air. Your anti big Alt bias on account of having the luxury of a large AC charge source and downside of a fuel hungry auxiliary is getting the better of you. 

Talk to Maine Sail. He wrote it, not me.

http://www.pbase.com/mainecruising/lifepo4_on_boats&page=3

 

You seem to think I'm pulling this stuff out of my ass or making it up or something. I'm not a moron, I am researching this thoroughly.

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6 hours ago, B.J. Porter said:

That's what I've read too - even a large frame alternator you need to knock it down by 30-40% of max output.

Well I am an expert at this: I can't count the alternators I have trashed on my boat. Small frame - low RPMs* - external regulator - this is made to wreck them and it does. It used to be cheap to have the local shop rebuild them, usually the diodes were the problem, but that guy retired :( I usually had a spare and just swapped out and sent the bad one to the shop. * if I ever buy a diesel engine, the #1 reason will be the A4 engine has such a crap setup for the alternator. The engine side pulley is barely bigger than the alternator pulley and there is no way to enlarge it :angry:

Things that help:

1. A regulator with a temperature sensor on the alternator. Now my rebuilder is no more, this is on order.

2. Moving the diodes out.

3. A regulator with separate voltage and amperage controls. We used to have these, not sure if they exist anymore.

4. Some kind of forced air cooling.

BJ - IMHO you have got yourself in an uncomfortable spot above the requirements of the typical sailboat and too small for the usual large yacht/ship routine of 24/7 generator use. I used to wonder WTF anyone would want a genset running all the time for, but after working on a couple of 100+ foot boats, you realize it is actually cheaper to just use normal 120/240 volt gear and have a couple generators instead of trying to have a huge battery bank, manage said batteries, and try for the ultimate $$$$ efficiency with all your gear. YMMV and all, but do look at anything to attack the demand side as well if you have not.

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17 minutes ago, kent_island_sailor said:

Well I am an expert at this: I can't count the alternators I have trashed on my boat. Small frame - low RPMs* - external regulator - this is made to wreck them and it does. It used to be cheap to have the local shop rebuild them, usually the diodes were the problem, but that guy retired :( I usually had a spare and just swapped out and sent the bad one to the shop. * if I ever buy a diesel engine, the #1 reason will be the A4 engine has such a crap setup for the alternator. The engine side pulley is barely bigger than the alternator pulley and there is no way to enlarge it :angry:

Things that help:

1. A regulator with a temperature sensor on the alternator. Now my rebuilder is no more, this is on order.

2. Moving the diodes out.

3. A regulator with separate voltage and amperage controls. We used to have these, not sure if they exist anymore.

4. Some kind of forced air cooling.

BJ - IMHO you have got yourself in an uncomfortable spot above the requirements of the typical sailboat and too small for the usual large yacht/ship routine of 24/7 generator use. I used to wonder WTF anyone would want a genset running all the time for, but after working on a couple of 100+ foot boats, you realize it is actually cheaper to just use normal 120/240 volt gear and have a couple generators instead of trying to have a huge battery bank, manage said batteries, and try for the ultimate $$$$ efficiency with all your gear. YMMV and all, but do look at anything to attack the demand side as well if you have not.

The demand side has been pretty beat to death. It basically comes down to the refrigeration for the vast majority of my power use at anchor. The freezer takes a lot of juice. But...we like to be able to provision well when we can, and we like the flexibility of being able to take a lot of decent quality provisions with us when we go more remote places. We have no interest in living without refrigeration. We run the water maker when the water is clean enough, that takes some juice too.

The rest...all the lights we use regularly are LEDs, as are the anchor lights, etc. Computers & tech device are the other larger drain, though still less than the fridge. A laptop for school, my PC when I am doing things on it, sometimes charging my wife's laptop, etc. The only way to reduce those things is to turn them off, which is often not an option. When at anchor the N2K network is often for the drag alarm, with most of the units off. Non zero, but not huge.

Under way we use more, with the sailing equipment, instruments, autopilot, etc.

There's not actually a lot of usage we can cut out that would not also affect our quality of life one way or another. Yes there are optional things - but we want them.

Honestly, from talking to other full time cruisers, I don't think our spot is that odd at all. Most of the cruisers I've talked to want to make the move to better battery tech. We ALL hate tapered charging, limited life cycles, and the stupid stuff you have to do to baby lead-acid batteries. Some have the budget for the upgrade and can weather costs out, some don't. The guy I'm getting a lot of my information from upgraded his own boat to LFP - it is smaller and less power demanding than mine, not larger. Batteries are a daily pain in the ass for most of us, especially if boat layouts don't easily afford space for a ton of solar. Every full time cruiser I know perks up and listens in when people start talking about LFP batteries, because this is something that all of us have to deal with.

I don't think we're actually in a unique or odd situation at all. We will be the new norm for full time cruisers as the tech becomes more approachable and the time to recoup your costs gets shorter.

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I read Stan Honey's notes on his DIY bank and MaineSail's notes. 

I suddenly realize that storing the batteries at less than 60% state-of-charge is a major inconvenience for my coastal cruising use. In short, the batteries shouldn't be topped up when unattended. 

I think I'll stick to my AGMs with high capacity alternators for most charging, with periodic top-up using the A/C charger when plugged in at a slip.

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BJ - let me rephrase a little. You are big enough to have a lot of stuff, but not big enough to have 2 or 3 generators. Thus you are not an Alberg 30 with an icebox and a solar cell that hardly has a way to use much power if you tried and also not a 120 foot Feadship with 3 gensets and an engineer to mess with them. You landed in the most demanding spot on the power use and supply spectrum ;)

I'll admit this was long ago, but I engineered a couple of dual-circuit fridges with holding plates. Once circuit was either AC or high-amp DC and the other was an engine driven compressor. Back in the 90s at least we could "generate" a lot more cold in an hour with a compressor than an alternator and you could use the electrical side when no one was around to run the engine and/or on shorepower. Just an FYI

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2 minutes ago, kent_island_sailor said:

BJ - let me rephrase a little. You are big enough to have a lot of stuff, but not big enough to have 2 or 3 generators. Thus you are not an Alberg 30 with an icebox and a solar cell that hardly has a way to use much power if you tried and also not a 120 foot Feadship with 3 gensets and an engineer to mess with them. You landed in the most demanding spot on the power use and supply spectrum ;)

I'll admit this was long ago, but I engineered a couple of dual-circuit fridges with holding plates. Once circuit was either AC or high-amp DC and the other was an engine driven compressor. Back in the 90s at least we could "generate" a lot more cold in an hour with a compressor than an alternator and you could use the electrical side when no one was around to run the engine and/or on shorepower. Just an FYI

Yeah, I've really thought the damned refrigeration over many times. I deeply despise the raw water cooled evaporation plate system we have now. It is woefully inadequate to the task, and a total hog on power. The through hulls are a pain in the ass since critters grow in there, the system always seems to be on, and the stupid little water pumps are over priced and wear out. The plates freeze up and need to be defrosted, etc. etc. There's a LOT to hate about it. It's a simple system for a weekender boat, but really it's not the right thing for full time use. I'd really rather have something with holding plates and a compressor.

But...the current shitty, sub-optimal setup works.

So with everything else that needs addressing, that particular thing was a pretty large and expensive project we did not want to tackle with all the other things we've done of late.

Keep in mind since 2015 I've...

  • Replaced the generator
  • Replaced the chain rode
  • Replaced a leaking compressor on the freezer with a larger, more powerful compressor (in theory should suck more power, but for less time...tough to see a change)
  • Replaced all the standing rigging except the backstay (which I did in 2012)
  • Hauled the engine out of the boat and had it serviced (as long as we were taking the generator out, why not? We prevented a major failure in our near future when we discovered the oil pan was almost rotter out)
  • Painted the bottom and other routine stuff.
  • Ordered a new main sail (still not here yet)
  • Replaced the batteries once
  • Sent a kid to college for two years...

This battery project is a horker, it's unexpected, and I'd rather not spend the cash. But...I also don't want to toss another $6-8K down the drain on the wrong battery tech for another 2-3 years. So we make that investment now and realize it's a capital expense that will take 6-8 years to hit the break even point on.

In light of everything we've had to do in the last few years - including two battery replacements in a much shorter time than expected - the refrigeration has been WAY off the radar screen. Maybe in a few years, or if this setup fails irretrievably, then we'll address it. If we do, maybe all of a sudden I'll find myself with an extra 80-100Ah/day.

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2 hours ago, B.J. Porter said:

Talk to Maine Sail. He wrote it, not me.

http://www.pbase.com/mainecruising/lifepo4_on_boats&page=3

 

You seem to think I'm pulling this stuff out of my ass or making it up or something. I'm not a moron, I am researching this thoroughly.

Sorry BJ but it seems you are pulling all your opinions out of your arse as it pleases you and your more interested in telling us all what you know.

That approach leads to you maybe inadvertantly  misquoting, but certainly challenging and or ignoring the advise posted here simply to disguise the fact it seems that your knowledge of and research into battery storage and charging basics is pretty limited. I'm not sure how you will learn anything with that approach.

With all due respect you have been murdering a number of AGM banks for years untill now, and only just twigged to why. In the meantime you have got by running a 7 kVa generator (and your now on your second one ) for 4/5 hours per day and with 1000 litres of diesel tankage, luxuries that have disguised your charging/storage problem. That is lunacy yet you regard that as your benchmark for improvement? Are you really ready right now for taking advice on the demands of doing a roll  your own LFP installation and taking the advantages of that capital investment without the necessary knowledge? I suggest not at this juncture.

For instance:

You quote Maine Sail here on de-rating alternator output by around 20% using a Balmar Reg for LFP. Myself and a few others here have already outlined that as being essential for any small case alternator and exactly  what Maine Sail suggests in your link. That de-rating applies just as equally to AGM for small case alts. Putting aside the mindless repetition that is a far cry from your earlier post today being that a large frame won't survive unless de-rated  by 30-40% which is total bullshit.

As you keep quoting Maine Sail (who I put in the top 20 on planet earth on their knowledge of LFP in sailboats) and whose advice you clearly know about , but it seems are not a across by your commentary. You might be surprised to learn on his small sailboat which I believe sits on the hook and obviously not a full time cruiser has a single 400Ah 12v LFP pack where his principal charge source is a small case CS130 HD alternator on account he has no room for his preference of a large case and that he de-rated using a Balmar reg. He has just recently installed a remote rectifier over winter to get the output up by 20A and as close as possible to its hot rating. If I'm wrong about that I'm sure he will chime in.

When you first posted about going LFP here and knowing you were in Australia I sent you a number of unsolicited PM's providing you with my experience/knowledge of LFP cell vendors there, their quirks and suggestions on rethinking your capacity ideas, to the extent of a quick cell configuration for 24v consistent with your daily discharge regime. Your response was not a thank you or even a question but pages telling me all what you knew about LFP and your plans. I found that quite amusing, but not unexpected from  LFP dreamers. That amusement continued when my cell configuration suggestion appears in one of earlier posts here as what your plan is.

There are many other examples of your misunderstanding here like auxiliary/alternator charging being limited to when underway etc.

In short BJ if you are seriously contemplating LFP you might need to reconsider your approach to less talking/typing and more listening. If not your forthcoming roll your own experience with LFP will not end well, that is guaranteed.

By the way I don't have a mortgage on intelligence in the LFP department despite years now of mucking around with them. The stimulating thing I find is when you converse with knowlegeable people in this space, something new crops up everyday to add to your knowledge bank. There is actually not that many around who have the time and interest to share their knowledge on LFP.

Please don't take this post as a critisim. It is just a warning shot as your not the first to make this mistake when seeking advice. Many people with experience with LFP are a bit worn out in the education department. For instance Maine Sail no longer consults for a fee on LFP I believe as he got sick of people not listening to his consultancy advice on account they thought they knew better.

Cheers and please take this post in the spirit of me wanting you to succeed with your asperations.

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19 minutes ago, B.J. Porter said:

Yeah, I've really thought the damned refrigeration over many times. I deeply despise the raw water cooled evaporation plate system we have now. It is woefully inadequate to the task, and a total hog on power. The through hulls are a pain in the ass since critters grow in there, the system always seems to be on, and the stupid little water pumps are over priced and wear out. The plates freeze up and need to be defrosted, etc. etc. There's a LOT to hate about it. It's a simple system for a weekender boat, but really it's not the right thing for full time use. I'd really rather have something with holding plates and a compressor.

But...the current shitty, sub-optimal setup works.

So with everything else that needs addressing, that particular thing was a pretty large and expensive project we did not want to tackle with all the other things we've done of late.

Keep in mind since 2015 I've...

  • Replaced the generator
  • Replaced the chain rode
  • Replaced a leaking compressor on the freezer with a larger, more powerful compressor (in theory should suck more power, but for less time...tough to see a change)
  • Replaced all the standing rigging except the backstay (which I did in 2012)
  • Hauled the engine out of the boat and had it serviced (as long as we were taking the generator out, why not? We prevented a major failure in our near future when we discovered the oil pan was almost rotter out)
  • Painted the bottom and other routine stuff.
  • Ordered a new main sail (still not here yet)
  • Replaced the batteries once
  • Sent a kid to college for two years...

This battery project is a horker, it's unexpected, and I'd rather not spend the cash. But...I also don't want to toss another $6-8K down the drain on the wrong battery tech for another 2-3 years. So we make that investment now and realize it's a capital expense that will take 6-8 years to hit the break even point on.

In light of everything we've had to do in the last few years - including two battery replacements in a much shorter time than expected - the refrigeration has been WAY off the radar screen. Maybe in a few years, or if this setup fails irretrievably, then we'll address it. If we do, maybe all of a sudden I'll find myself with an extra 80-100Ah/day.

I would REALLY REALLY REALLY think about fixing your refrigeration issue. Despite having been in the position to buy the stuff wholesale and have "free" labor to install it, I never did it because I knew if I did not rebuild my crappy icebox too I would be in dead battery hell like all the "I got a fridge and now my batteries are shot please help" customers were. You might cut your needed battery bank size quite a bit and save there, save diesel, save wear and tear on engines, etc. etc. One tidbit - On a big cat with both electrical and engine driven fridges, we totally gave up on the electrical one and put all the food in the engine driven one. That one was COLD :D

* I used to write little white papers for my customers and I had a cost multiplier formula in one of them. Solar cells were like 0.5x, they saved a lot elsewhere. A fridge was like 3x, it frequently drove total re-engineering of the boat.

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6 hours ago, kent_island_sailor said:

I would REALLY REALLY REALLY think about fixing your refrigeration issue. Despite having been in the position to buy the stuff wholesale and have "free" labor to install it, I never did it because I knew if I did not rebuild my crappy icebox too I would be in dead battery hell like all the "I got a fridge and now my batteries are shot please help" customers were. You might cut your needed battery bank size quite a bit and save there, save diesel, save wear and tear on engines, etc. etc. One tidbit - On a big cat with both electrical and engine driven fridges, we totally gave up on the electrical one and put all the food in the engine driven one. That one was COLD :D

* I used to write little white papers for my customers and I had a cost multiplier formula in one of them. Solar cells were like 0.5x, they saved a lot elsewhere. A fridge was like 3x, it frequently drove total re-engineering of the boat.

I agree it needs to be fixed and I get what you are saying...but it works for now.

If I replace the refrigeration, I will STILL need to replace the batteries.

If looked into the refrigeration, it is a HUGE project to redo it properly. And it's not something I'd 1) feel comfortable doing my self and 2) even be likely to be able to do legally by myself in Oz if there is any regassing involved. I don't know the laws for sure, but like NZ I don't think you can go buy R-134a in an auto parts store here. So take the material costs to buy the equipment, upgrade the mounts on the engine (or genset) to run a compressor, and add a few days of days professional licensed labor for the fridge stuff.

The cost will be far, far in excess of what I'd save by doing something like cutting from a 720Ah LFP bank to a 540Ah LFP bank.

There seems to be a perception that I have unlimited funds and resources to tap...this is not actually the case, though I wish it was!

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8 hours ago, kent_island_sailor said:

I would REALLY REALLY REALLY think about fixing your refrigeration issue. Despite having been in the position to buy the stuff wholesale and have "free" labor to install it, I never did it because I knew if I did not rebuild my crappy icebox too I would be in dead battery hell like all the "I got a fridge and now my batteries are shot please help" customers were. You might cut your needed battery bank size quite a bit and save there, save diesel, save wear and tear on engines, etc. etc. One tidbit - On a big cat with both electrical and engine driven fridges, we totally gave up on the electrical one and put all the food in the engine driven one. That one was COLD :D

* I used to write little white papers for my customers and I had a cost multiplier formula in one of them. Solar cells were like 0.5x, they saved a lot elsewhere. A fridge was like 3x, it frequently drove total re-engineering of the boat.

Though you bring up an excellent point.

One of the big problems with AGMs is simply getting enough power so you don't have to be charging every day.

Right now we use 180-200Ah/day, with about 120-130 of that going to refrigeration.

If we can cut that out, or down dramatically it would mean the 264 Ah of usable capacity in an AGM bank would last a lot longer. Two days, even. Which cuts my charging cycles a lot.

Replacing a constant cycling evaporator system with an intermittent cold plate system could cut that dramatically. The question is what type of system.

If you can turn that 120-130Ah/Day into 30 or 40 Ah/day or less (e.g. with a plate system with an engine/genset driven compressor and an electric backup), the numbers work better. The could even work better for AGMs, if you could get the time between charges to two days all of a sudden Lifeline's claim for 1,000 cycles might get you to five years.

 

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58 minutes ago, kent_island_sailor said:

Cutting demand is the gift that keeps on giving B)

You can look around here for ideas: http://www.seafrost.com/

http://www.seafrost.com/pdfs/LITERATURE/SF Brochure 2010pdf.pdf

 

Yup...we've been having lengthy discussions all day about this stuff.

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59 minutes ago, kent_island_sailor said:

Cutting demand is the gift that keeps on giving B)

You can look around here for ideas: http://www.seafrost.com/

http://www.seafrost.com/pdfs/LITERATURE/SF Brochure 2010pdf.pdf

 

This setup still has some appeal, too.

http://www.ozefridge.com.au/

It's NOT engine or alternator driven, it's electric. But it will freeze eutectic plates off the generator, or keep them topped off of DC. And it need not be raw water cooled.

There are a LOT of different ways to skin the refrigeration cat.

But...in the short term, replacing in the fridge is great. And we can replace the fridge and throw in a set of Lifelines for about $7K less than putting in LFP batteries. And maybe it's possible those Lifelines last five years, if I can cut my power consumption enough to get two days from a charge and am militant about designating the 15th of the month as "Run the damned generator all day day" to get 100% charge in once a month.

It seems to come down to the charge cycles. Lifeline suggests they can get 1,000 at 50% DoD.  So if you can cut cycles to 200 per year...it STILLS feels like throwing good money after bad because I'm going to be replacing the damned things in five years.

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39 minutes ago, NOCALSAILOR said:

Is the charging requirements of traction batteries any different form flooded lead acid. Or just the DoD that the bank can handle?

Traction batteries usually ARE flooded lead acid. They can tolerate some overcharging because you can add water to them. They will die early if not equalized every now and again. They are essentially just deep cycle batteries designed for golf carts and fork lifts.

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15 minutes ago, B.J. Porter said:

This setup still has some appeal, too.

http://www.ozefridge.com.au/

It's NOT engine or alternator driven, it's electric. But it will freeze eutectic plates off the generator, or keep them topped off of DC. And it need not be raw water cooled.

There are a LOT of different ways to skin the refrigeration cat.

But...in the short term, replacing in the fridge is great. And we can replace the fridge and throw in a set of Lifelines for about $7K less than putting in LFP batteries. And maybe it's possible those Lifelines last five years, if I can cut my power consumption enough to get two days from a charge and am militant about designating the 15th of the month as "Run the damned generator all day day" to get 100% charge in once a month.

It seems to come down to the charge cycles. Lifeline suggests they can get 1,000 at 50% DoD.  So if you can cut cycles to 200 per year...it STILLS feels like throwing good money after bad because I'm going to be replacing the damned things in five years.

FYI - a big compressor driven by your generator at 120/240 volts that can freeze the plates in an hour is the functional equivalent of belting the compressor off the generator engine with no belts to worry about and still does not cut into the charging budget  ;)

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11 minutes ago, kent_island_sailor said:

FYI - a big compressor driven by your generator at 120/240 volts that can freeze the plates in an hour is the functional equivalent of belting the compressor off the generator engine with no belts to worry about and still does not cut into the charging budget  ;)

Yup, it's all just power, fundamentally. It's just a matter of which device is being spun and rectified and whether it's being by belts or gears.

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On 2017-6-19 at 11:15 AM, B.J. Porter said:

There are a number of reasons I don't want FLAs under my bed. Outgassing, spill risks, maintenance, etc. etc. Yeah, if my batteries get wet where they're installed I have much larger problems than a poison gas cloud in my bedroom, true. But I'm really, really not into the idea of ripping my bed apart once a month to top up 48 cells with distilled water...

BJ, I understand the advantages of sealed batteries, but if you do decide to go the significantly cheaper and less temperamental FLA route, you can at least make the watering process much easier with something like this: https://flow-rite.com/battery-watering/pro-fill

Despite my temptation to switch to LFP for the same charging reasons as you plus weight, I ended up staying with golf cart batteries with a watering system, and think it was the the right choice for us. I'm not sure which way I'd decide now if we still had the boat. Ours were under the saloon settee, so access was pretty easy, and being a cat we could vent them easily through the bridge deck, so we had no issues with fumes or smells. I understand under your berth in a monohull will be harder to vent.

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So to summarize.

BJ has mid to large consumption needs for his set up and has an undersized alternator and not enough solar/wind/hydro to top up his AGM batteries that he's been torching by not topping up but needs more deisel to fuel all the laptops and anchor alarms and inefficient refrigeration that he can consume.

In an effort to remedy the undercharge and over consume he's going li but hold on, maybe if he revisits and rebalances his battery system, it's no longer bye bye AGM?

-in listening... Kent Islands suggestions on reducing heat loss(not sure if he was saying that but insulation insulation insulation) and increasing effeciency (compressor) w refrigeration make a whole lotta sense.

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37 minutes ago, fufkin said:

So to summarize.

BJ has mid to large consumption needs for his set up and has an undersized alternator and not enough solar/wind/hydro to top up his AGM batteries that he's been torching by not topping up but needs more deisel to fuel all the laptops and anchor alarms and inefficient refrigeration that he can consume.

In an effort to remedy the undercharge and over consume he's going li but hold on, maybe if he revisits and rebalances his battery system, it's no longer bye bye AGM?

-in listening... Kent Islands suggestions on reducing heat loss(not sure if he was saying that but insulation insulation insulation) and increasing effeciency (compressor) w refrigeration make a whole lotta sense.

It's not quite accurate...

  • My consumption is higher than it could be. We're not the Pardys and never will be. Freezing food will always likely be in my future.
  • In spite of what some people insist, my alternator is largely irrelevant to my charging since I spend a lot more time anchored, not motoring, than I do motoring around. To make my alternator relevant would mean charging my batteries by idling a 20 year old 145HP engine at anchor and a truckload of cash. That ain't happening.
  • I've likely caused sulfation in my current bank by not charging to 100% often enough. I typically charge to 90%.
  • That being said...this current crop of batteries has 650+ cycles on them, which isn't awful for AGM's. The lab tested chart from this battery company suggests 800 is a good life for 50% discharge, which is more than most AGMs. I'd hoped for more, but realistically, AGM's in a liveaboard world of daily charging are two - three year throwaways (which is why reducing power consumption is desirable - I do see that). You rarely get results that match the lab derived cycle charts.
  • My refrigeration uses too damned much power.
  • My wife and I discussed it and think sticking with AGMs in any format is penny wise and pound foolish. It's another crap shoot that will probably put us back where we are now in another three years. Maybe with higher quality (and more $$$) Lifeline AGMs, a rigidly maintained schedule for 100% charging once a month, new refrigeration, and some luck we get five years.
  • The batteries are screwed now and need replacement in the short term, but the fridge works OK, but is really inadequate for a liveaboard even though it functions the way we want to.
  • Fridge may or may not happen - we've been discussing it. It's a fair chunk of money for something we've not budgeted for...while doing a much larger project we've not budgeted for. And buying a new main that we HAD planned for.
  • In theory, a new fridge would decrease the needed size of the LFP banks. In practice, dropping eight cells out of the banks isn't going to dramatically decrease the costs, and I don't want to find myself underpowered if whatever gee-whiz fridge idea we come up with doesn't work out as expected.
  • Moving to LFP batteries while upgrading the chargers appropriately will have me charging ~4 hours every three days or so. This will cut my annual genset time and fuel consumption by about 60%, saving money and extending the life of my generator.
  • BTW we're keeping the 12V AGM Start and House Banks. Those are hit lightly and rarely drawn down and are healthier than the 24V bank.
  • I am really sick of talking and thinking about this on this forum.

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2 hours ago, morwood said:

BJ, I understand the advantages of sealed batteries, but if you do decide to go the significantly cheaper and less temperamental FLA route, you can at least make the watering process much easier with something like this: https://flow-rite.com/battery-watering/pro-fill

Despite my temptation to switch to LFP for the same charging reasons as you plus weight, I ended up staying with golf cart batteries with a watering system, and think it was the the right choice for us. I'm not sure which way I'd decide now if we still had the boat. Ours were under the saloon settee, so access was pretty easy, and being a cat we could vent them easily through the bridge deck, so we had no issues with fumes or smells. I understand under your berth in a monohull will be harder to vent.

A filler would help. But yeah, those batteries are right under our feet at night. It's not a big deal to get to them, but it's a nuisance to rip up the bed.

With a shorter horizon swallowing the anchor, yeah, T-105s work out well. We're rather hoping to be doing this for a fair amount longer.

When the Gels that came with the boat started dying, ten minutes after starting to charge the aft cabin smelled like Beelzebub had just taken up residence under the bed, without all the flies.

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