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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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So my AGM house battery is pretty much beat after 5 years. The one before - a gel cell - lasted 9 and worked better too.

My choices:

Get another AGM and hope it works better.

Go back to gels.

Try the new thin plate AGMs. Odyssey makes there and also lets Sears sell them as Marine Platinum Diehards.

Get a golf cart battery and see if it fits - it might, the height is very close.

 

 

 

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That is a "how long is a string" type question - what do you use it for and how well do you take care of it?

 

I've got a pair of 6v Trojans as my house bank, wet batteries, they do me fine and are reasonably tolerant of abuse thus far.

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I have the exact opposite view..

On the ships I work on gels have sucked. AGM has been flawless.

On my sailboat, had the yard change the batteries, they installed gels instead of AGM (think they made more money).. and the gel cells have been OK but its only one year.

Having said that not all AGM batteries are created equal. (For that mater neither are gel or lead acid).

Lifeline has been the worst in the cost vs lifetime. Would stay away from them.

Oceaneer

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I have enough 6V Trojan's to arc weld or light a small stadium. Second big bank after 20 years five years ago and still going strong. Keep 'em watered and charged with no issues. I've known people (their charger) has "cooked" their batteries for what reason - there is no going back. Lead/acid not so much.

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If all AGMs are as bad as mine I cannot see why anyone would buy them. Deka's own white papes show the AGM line lasting about half as long as their gel batteries in deep cycle applications. I wish I had seen that when I got my battery, but the gel had finally died after 8 years of great service and one year of decline and I needed one that day and AGM was the only thing in stock. One thing I have found out the hard way is that you need to hit AGMs hard when charging or they lose capacity quickly. An Atomic 4 drives the alternator about 1:1 ratio with engine RPM, so even putting on the biggest alternator ever made still will rarely get you more than 40-50 amps charge running flat out and less at low cruise RPM. The battery wasn't even a month old when I noticed it sure didn't hold voltage as long as the gel did.

I really wish my storage space was better for wet cells. Nothing beats the life cycle cost of golf cart batteries IMHO.

 

BTW - to the poster with the ship batteries - gel and AGM charge differently. Gel batteries CANNOT be overcharged or they lose capacity that will never ever return. I had my alternator set to 14.1 volts in summer and 14.2 volts in winter and it worked fantastic that way. A bigger alternator or big charger needs to drop back to a float voltage for gels. AGMs need higher charge voltage and they need to be pushed all the way to 100% full pretty often. I did not know this latter bit when I got my battery and I think that helped with it not being very good.

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Yes,, Charging voltage has the be adjusted.. And it was done.

I thought Deka made decent batteries buy have never had any.

Odessey AGMs were amazing.

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Odessey sells batteries to Sears and they get sold as "Platinum" AGM marine batteries. I also have heard good things about these.

Deka sells a TON of batteries and they get labeled a lot of different ways. West Marine AGMs are Dekas. From what I can gather and from my own experience, it is possible to get a bad one now and again. Way back in the day we worked on a big powerboat with new gels that seemed dead brand new. We had to zap them with 15 volts for 30 seconds or so to get them to start working for some reason.

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I have 2 Odessey AGM batteries...I have had nothing but good things to say about them.

 

For us the fact that they hold their charge much better over the winter means I can leave them aboard and with a small 5 watt solar panel I can keep them fully able.

 

The big bonus is they are safer and won't gas off. I sleep better knowing that.

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I'm with Maxx and Sculpin on this one. Eight years and still going strong.

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No point in paying for AGMs if you don't have the installation to charge them properly.

 

I have a bank of Lifelines purchased in 2006. Still working well in 2014. But I do charge them properly.

 

If you don't like the price of AGMs, you wouldn't like LiFePO4 either, but a couple of the big advantages of these are sometimes overlooked: They are not damaged by partial charges or by being left partially charged. That has longevity benefits and operational benefits. To me these are more important than any weight or life cost advantages.

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And what installation is required to charge AGM's properly?

 

No point in paying for AGMs if you don't have the installation to charge them properly.

 

I have a bank of Lifelines purchased in 2006. Still working well in 2014. But I do charge them properly.

 

If you don't like the price of AGMs, you wouldn't like LiFePO4 either, but a couple of the big advantages of these are sometimes overlooked: They are not damaged by partial charges or by being left partially charged. That has longevity benefits and operational benefits. To me these are more important than any weight or life cost advantages.

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The best luck with batteries I ever had were 6V deep cycle golf cart batteries from Sam's Club... $39 each... Kept them topped up with distilled water only and kept charged above 50%. They were nearly 10 years old when I sold the boat, still functioning well. Heck they could have lasted only two years and I would have been cheaper than any of those called High tech gels or ATM ones cost per year basis!

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I have a 20 amp 3 stage charger and a 50 amp alternator with an adjustable set-point external regulator plus 20 watts solar. That apparently was never enough.

 

And what installation is required to charge AGM's properly?

 

No point in paying for AGMs if you don't have the installation to charge them properly.

 

I have a bank of Lifelines purchased in 2006. Still working well in 2014. But I do charge them properly.

 

If you don't like the price of AGMs, you wouldn't like LiFePO4 either, but a couple of the big advantages of these are sometimes overlooked: They are not damaged by partial charges or by being left partially charged. That has longevity benefits and operational benefits. To me these are more important than any weight or life cost advantages.

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AGMs seem to be particular about float voltages and recharge intervals. You need a temperature compensated charger for anything doing the float (line charger or solar) or your float voltages will be off unless you can guarantee the batteries are always at the nominally rated temperature. Second, they seem to need to be brought to 100% state of charge at regular intervals, not sure how often but lets say once a week or so. If you have a continuous source of charge like solar or line or wind, you can do this, keeping in mind that since they are continuous they will switch to float and must be temp compensated. Many cruisers don't bring their batteries to 100% because it takes a very long time: the acceptance rate drops off so the last little bit takes many hours of engine or genset run time if that is how you are trying to do it. There is an argument that efficient use of Pb batteries is to run them between 50 and 80% charge (because the last 20% takes too long). That works for flooded cells which can take that sort of abuse (and you can equalize them aggressively), but in my opinion won't work with AGMs.

 

On cruises about once a week I charge to 95% or so in the morning with the large engine alternator, then let solar finish them off the rest of the day. The alternator provides the bulk of the charge and the solar the long tail of low current. The idea is to achieve 100% SOC.

 

Kent Island, you kept your boat plugged in? And is the line charger properly temp compensated?

 

I have had four sets of Lifeline batteries in the boat and various RVs. Boat is going on 8 years, still good. Sold the motorhome with batteries going on 7 years, still good. One in the truck camper died at about year 11. Got new ones in new truck camper, only about a year old, still good. I did kill the Lifeline engine start battery on the boat (or rather the yard did) by running it down and leaving it dead for 8 months. It was recharged and survived another two seasons but was never really the same and finally gave up.

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I say go cheap flooded gold carts or get the lead out and go LiFePO4. I only had two seasons of full time cruising on my lithiums before I sold the boat, but they were still at 100% or original spec. They had a warranty for 5 or 7 years (can't remember) and expected life was > 5000 cycles at 70% DOD. They were 25% smaller, 25% ligher and you could run them to 70%, even 80% DOD, so you bank is actually much larger that you would calculate for any lead battery staying less than 50% DOD. And they were only about 25% more expensive than AGM's when I bought them.

 

I know some fellow cruisers that went the TPPL (Thin plate, pure lead) route and didn't have great experiances. They were also full time cruisers, and they set was getting tired after about 2.5 years. Like AGM's, they NEED to come to 100% on a regular basis, which is you don't plug in, or have an inordinate amount of renewable energy, you wont have.

 

That being said, we did have a large amount of solar and were 100% full nearly every day, but theoretically we didn't need to as the chemistry in LiFePO4 is much more stable long term.

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Rolls batteries are made an hour drive from my house, and I can't afford them... :(

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No point in paying for AGMs if you don't have the installation to charge them properly.

 

I have a bank of Lifelines purchased in 2006. Still working well in 2014. But I do charge them properly.

 

If you don't like the price of AGMs, you wouldn't like LiFePO4 either, but a couple of the big advantages of these are sometimes overlooked: They are not damaged by partial charges or by being left partially charged. That has longevity benefits and operational benefits. To me these are more important than any weight or life cost advantages.

How about the whole bursting into flames issue?

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No point in paying for AGMs if you don't have the installation to charge them properly.

 

I have a bank of Lifelines purchased in 2006. Still working well in 2014. But I do charge them properly.

 

If you don't like the price of AGMs, you wouldn't like LiFePO4 either, but a couple of the big advantages of these are sometimes overlooked: They are not damaged by partial charges or by being left partially charged. That has longevity benefits and operational benefits. To me these are more important than any weight or life cost advantages.

How about the whole bursting into flames issue?

 

Ahhh... doesn't happen that often. :rolleyes:

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Less than reassuring. Even the occasional burst into flames (no matter how it happens) is just not something I want on a boat.

 

So you're giving up on internal-combustion (and occasionally external-combustion) engines as well?

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^^^ My guess is that "bursts into flames" is not a popular feature. Strangely enough we tolerate it in lead acid batteries, diesel engines and so on. To make an informed decision I like to have a feel for the absolute risk of the various systems. The theory guys say lithium-iron should be low risk and there don't seem to be a lot of reports of fire yet. But the number of installations with hours on them is still small.

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Less than reassuring. Even the occasional burst into flames (no matter how it happens) is just not something I want on a boat.

 

So you're giving up on internal-combustion (and occasionally external-combustion) engines as well?

 

At least there's a really good chance I'm awake and paying attention when an engine does it.

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I'm way over on one side of the spectrum with only a 4 amp alternator on my outboard and two 48w solar panels. I've used a Mastervolt Group 31 AGM since install in 2008 with no issues and fine performance. A couple of times each winter I put a charger on it to keep it dropping too low (my battery monitor is the only drain, go figure), but otherwise its 95% solar. I have a controller to keep from overcharging, but it never gets a real blast of energy. If I go on an overnight race where radar is used or a cruise in fog I can drain it pretty hard, but I only do that once or twice a year.

 

So AGM has worked for me. I'll probably go lithium next time- weight vs. capacity is important to me. I just need to make certain it will like my charging style. It doesn't scare me.

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My batteries are under the quarterberth. Judging from the results of the Boeing 787, NFW would I rest my head on lithium batteries and go to sleep :o

 

Any deep cycle battery used on a boat large enough to stand up in has plenty of energy to start it on fire. Just drop a wrench across the terminals of one if you don't believe it. The concern is that LiFePO4 might have extra failure modes causing fires.

 

The Boeing problems always seem to get raised in these kinds of threads, but the Boeing batteries are Lithium Cobalt rather than Lithium Iron Phosphate. It is unfortunate that the media and public have taken to referring to all batteries containing lithium as "Lithium" even though there are quite different chemistries with quite different characteristics. LiFePO4 batteries seem to be about as safe as ordinary Pb, and do not have the self immolation modes seen in Boeing, laptops, Chevy Volts, etc., all of which use different materials and chemistries.

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I have a 20 amp 3 stage charger and a 50 amp alternator with an adjustable set-point external regulator plus 20 watts solar. That apparently was never enough.

 

And what installation is required to charge AGM's properly?

 

No point in paying for AGMs if you don't have the installation to charge them properly.

 

I have a bank of Lifelines purchased in 2006. Still working well in 2014. But I do charge them properly.

 

If you don't like the price of AGMs, you wouldn't like LiFePO4 either, but a couple of the big advantages of these are sometimes overlooked: They are not damaged by partial charges or by being left partially charged. That has longevity benefits and operational benefits. To me these are more important than any weight or life cost advantages.

The more I read this thread the more I realize I am clueless when it comes to this stuff! Can you help me out?

 

What does a 3 stage charger mean? 20 amp seems small for a shore power charger no??? Mine is a heart interface 75 amp and the factory 30 amp is still installed that I am told is still functional but I just use the 75 amp. Have no idea on how many 'stages' it has?

 

WTF is an "adjustable set-point external regulator" on your alternator? You can adjust it? I think my alternator is 30 amp on my Yanmar 3GM30F. Don't see anyplace to 'adjust' it?

 

I have a solar charger as well but have no idea on the specs. And why is everything else listed as amps yet with solar you go to watts?

 

Shit I am confused! And I can't even track down a simple fresh water leak in my forward tank! :lol:

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I have a 20 amp 3 stage charger and a 50 amp alternator with an adjustable set-point external regulator plus 20 watts solar. That apparently was never enough.

 

And what installation is required to charge AGM's properly?

 

No point in paying for AGMs if you don't have the installation to charge them properly.

 

I have a bank of Lifelines purchased in 2006. Still working well in 2014. But I do charge them properly.

 

If you don't like the price of AGMs, you wouldn't like LiFePO4 either, but a couple of the big advantages of these are sometimes overlooked: They are not damaged by partial charges or by being left partially charged. That has longevity benefits and operational benefits. To me these are more important than any weight or life cost advantages.

The more I read this thread the more I realize I am clueless when it comes to this stuff! Can you help me out?

 

What does a 3 stage charger mean? 20 amp seems small for a shore power charger no??? Mine is a heart interface 75 amp and the factory 30 amp is still installed that I am told is still functional but I just use the 75 amp. Have no idea on how many 'stages' it has?

 

WTF is an "adjustable set-point external regulator" on your alternator? You can adjust it? I think my alternator is 30 amp on my Yanmar 3GM30F. Don't see anyplace to 'adjust' it?

 

I have a solar charger as well but have no idea on the specs. And why is everything else listed as amps yet with solar you go to watts?

 

Shit I am confused! And I can't even track down a simple fresh water leak in my forward tank! :lol:

http://www.batterystuff.com/blog/3-stages-of-smart-chargers.html

 

and you though racing an Antrim was hard. You are a cruiser now.

 

Basically, lead acid batteries are limited by how fast they can accept a charge. Any faster and they do things like overheat, boil, gas off excessively and the like. It's why temperature compensation is important.

 

It would be nice to say a 100 amp charger can charge your 400 AH battery bank in 4 hours but it's not so. I have a 520 AH bank of flooded 6V batteries (4-T145+ batteries) and a 100 amp Mastervolt charger, temp compensated. A certain young lady pulled shore power to go swimming off the dock (a wise safety move) but forgot to turn it back on (plug it in and turn the switch to the ON position....) and I ended up with a deep (nearly full) discharge before I caught it several days later as I keep the refrigerator on at the dock. Turned on the charger (that darned ON-OFF switch again) and went to bulk phase at about 90 amps input that tapered quickly to about 75 for an hour or so. Then t went to acceptance at 50-55 amps for a longer period before switching to float so it took about 8 hours to get back to "fully charged".

 

Your Heart Interface should be a 3 stage charger and also have an "Equalize" setting. Your alternator was internally regulated when new and probably still is. It will taper off amperage as voltage rises so it will take a long time to top off a big bank. Not it's fault The tech is automotive and designed to replace what it took to start the engine and then have your entire trip to finish off the charging. An external regulator will allow you to control bulk, absorption and float stages in a manner similar to the Heart charger but it will work the alternator harder. Some (often small frame) alternators in poorly ventilated engine compartments can overheat and die an early death.

 

What difference does it make? As DDW points out, AGMS don't like partial charges and a full charge on a big bank takes a long time with the aux engine or generator running so many cruisers work a 40%-80% state of charge range where they can pump in replacement amps quickly and shut off the engine. That approach kills AGMs.

 

Pros and cons to all battery chemistry and construction and how their charging systems work (or don't) . In my mind, most folks get best value from flooded LA batteries because they will abuse them at some point and simple flooded batteries tolerate abuse and are cheap to replace when you screw up. You can argue the charge efficiency and utility of LiFePO4 batteries but they are very expensive at the moment. If you kill a battery on a cruise, you can buy a GC or truck battery pretty much anywhere in the world (first to third). If you need an LiFePO4 and BMS in Polynesia, good luck. Same with external regulators. Seems they are one of teh "high failure items" for long range cruisers while the lightly stressed, internal regulators tend to go forever.

 

All depends on what your expectations and use profile are.

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Thanks IB that cleared up a lot!!!

 

For the record I am still a dingy racer, occasional keel boat racer and a cruiser (was a cruiser before a racer anyways).

 

1) Hike your ass off when blowing and maintain great sail trim.

2) Sit your ass still when light and maintain great sail trim.

3) Accomplish 1 and 2 you will have speed and point on the fleet.

4) Then it's as simple as getting to the right side of the course and finding shifts.

5) Oh and keep the pointy end up on the runs.

 

See very simple! Well not really! :lol:

 

 

Sorry back to cruising!

 

Yes I recall reading that my Heart Interface is a 3 stage charger and I had no idea what that all meant, now it all makes sense. And yes I have an "Equalize" setting as well.

 

I have AGM's, not sure on total AH, have not looked at them that closely yet. I do know I have 3 for house and one starter. Sounds like AGM's are good for weekend cruising or when getting to shore power every couple of days but not so much for being on the hook for weeks at a time. Starting battery is probably fine as an AGM.

 

Now to figure out how the solar panel works, keeps banks at full charge with not much running but with the frig on not so much.

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Basically, lead acid batteries are limited by how fast they can accept a charge. Any faster and they do things like overheat, boil, gas off excessively and the like. It's why temperature compensation is important.

 

Temperature comp is important for that reason on flooded cells, however it is also important to maintain proper float voltages on both gel and AGM chemistry batteries. These are particularly sensitive to incorrect float voltage (which changes with temperature). Most small solar chargers are not temp compensated, and even a small solar array is capable of overcharging a fairly large AGM bank with no load.

 

The advantage of flooded cells beyond their low cost is that when they are abused, they loose water. The water can be replaced. The same thing happens to AGM and gel cells, but the water cannot be replaced, rather the battery must be.

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My experience with batteries (and a lot of other boat systems and maintenance items) is that boat usage patterns and dedication to maintenance are the variables that shred the spec sheets and manufacturers recommendations. When you're able and willing to pay close attention and follow the correct regimen finicky stuff is fine (usually the first part of the ownership cycle), but if at some point you get caught up in something else (work/love/health/other hobbies, etc.) and let things sit untended for awhile the payback is shortened lifespans and/or lots of work to get it right again. I find golf cart batteries better able to tolerate the occasional abuse/neglect many/most of us sooner or later wind up throwing at our boats.

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Basically, lead acid batteries are limited by how fast they can accept a charge. Any faster and they do things like overheat, boil, gas off excessively and the like. It's why temperature compensation is important.

 

Temperature comp is important for that reason on flooded cells, however it is also important to maintain proper float voltages on both gel and AGM chemistry batteries. These are particularly sensitive to incorrect float voltage (which changes with temperature). Most small solar chargers are not temp compensated, and even a small solar array is capable of overcharging a fairly large AGM bank with no load.

 

The advantage of flooded cells beyond their low cost is that when they are abused, they loose water. The water can be replaced. The same thing happens to AGM and gel cells, but the water cannot be replaced, rather the battery must be.

Yep. I agree with all that.

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My experience with batteries (and a lot of other boat systems and maintenance items) is that boat usage patterns and dedication to maintenance are the variables that shred the spec sheets and manufacturers recommendations. When you're able and willing to pay close attention and follow the correct regimen finicky stuff is fine (usually the first part of the ownership cycle), but if at some point you get caught up in something else (work/love/health/other hobbies, etc.) and let things sit untended for awhile the payback is shortened lifespans and/or lots of work to get it right again. I find golf cart batteries better able to tolerate the occasional abuse/neglect many/most of us sooner or later wind up throwing at our boats.

And that's why my position is that flooded batteries, particularly GCs are the best option for most casual cruisers. Races who cut handles off toothbrushes may justify newer tech. Long range cruisers may justify ROlls or teh like batteries but I've long held that batteries don't die. They are murdered by owner abuse and you can kill an expensive as easily (or easier than) a cheap one.

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I DID buy a Rolls battery. The battery shop said it was really good and would outlast the Diehards we had been replacing every two years.

It also lasted two years and cost a LOT more money :angry:

At the time I bought it I was not yet working in the marine industry and had a more basic level of electrical knowledge. If I had known better, I would have realized a 35 amp alternator set to 13.8 volts and no shore power would sulfate that thing to death just as quick as the Diehards. If only I had known then that a better regulator and some equalizing from a good charger could have kept it going a long time.

 

I also have noted what is known NOW about AGMS is not what was commonly known a few years ago about them. I pretty much thought they would act like gels and they do NOT. AGMS were pretty new when I got out of the business and we dealt mainly with gels and had a very good idea of what they liked and didn't like.

 

btw - my solar controller is temperature compensated.

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I DID buy a Rolls battery. The battery shop said it was really good and would outlast the Diehards we had been replacing every two years.

It also lasted two years and cost a LOT more money :angry:

At the time I bought it I was not yet working in the marine industry and had a more basic level of electrical knowledge. If I had known better, I would have realized a 35 amp alternator set to 13.8 volts and no shore power would sulfate that thing to death just as quick as the Diehards. If only I had known then that a better regulator and some equalizing from a good charger could have kept it going a long time.

 

I also have noted what is known NOW about AGMS is not what was commonly known a few years ago about them. I pretty much thought they would act like gels and they do NOT. AGMS were pretty new when I got out of the business and we dealt mainly with gels and had a very good idea of what they liked and didn't like.

 

btw - my solar controller is temperature compensated.

I was all over AGMs as a great replacement for flooded without the voltage sensitivity of gels until I started hearing about the early deaths due to chronic undercharging (like a cruiser normally does) so I stayed with flooded for my latest set.

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I'm on my second set of AGMs (440 ah total) in 9 years. I killed the first by drawing them down too much, also destroyed both of my 100 amp alternators by using them to charge the bank from a deep discharge. Balmars won't run for long at full charging current without self-immolating.

 

I also see now the benefit of letting the batteries get to full charge. I monitor just with voltage and charging/load currents.

 

Live and learn, but I'm reluctant to live and learn with another bunch of technology now that I've learned this one.

 

To me the critical variable is charge acceptance. I see 150 amps at 40% discharge. I don't want to plug in (corrosion) or run the engine just to charge the batteries.

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I was all over AGMs as a great replacement for flooded without the voltage sensitivity of gels until I started hearing about the early deaths due to chronic undercharging (like a cruiser normally does) so I stayed with flooded for my latest set.

"like a cruiser normally does" If he doesn't have solar panels or wind generator aboard. I have 4- 4D AGM's and find that the best way to care for them while cruising is to get them to within about 30 amps of full using either the engine (underway) or genset (on the hook) and make sure I finish doing that with at least several hours of strong daylight or wind left so the solar panels or wind generator can finish the job. That way I don't waste diesel fuel for an extra hour and a half to pack in that last 30amps to fill my AGM's back up. Almost every day I manage to fill them up to capacity and am hopeful that they will last quite awhile.

 

On my last boat I also had AGM's but without wind or solar capability and it was very tough to always have the patience to run the genset long enough to keep them full. One technique I used was to start the genset and battery charger alone to have max amps available for the battery charger while the acceptance rate was still high, and as the battery started to fill up and the acceptance rate started to drop, I'd add the hot water heater and DC refrigeration to the gensets load. So, the highest DC load item (refrigeration) was almost never powered by the batteries, but rather was powered by the alternator or battery charger, which reduced the amount the AGM's would be drawn down over the rest of the day, requiring less of an uphill battle getting them back to full. I also would equalize my AGM's once a year near the end of the season and it didn't seem to do them any harm but I can't definitively say it did them any great good either. They were 5 years old and going strong when I sold the boat though.

 

If my current AGM's died, I'd be tempted by good 6V wet cells, but for the safety factor of never spilling acid and no gasses being emitted and less chance of explosion, I think I'd replace them with more AGM'$.

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jtsailjt, it's a tough situation, as we use AGMs for their charge acceptance but we don't see that benefit if they're always between 90% and 100% full in order to get a long life out of them. My attitude is I'll do what I can, but am willing to accept just replacing the batteries more often.

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Just to be clear, you don't need to have them always between 90 and 100%. I discharge mine to 50% somewhat regularly, and further occasionally. You just need to get them back to 100% periodically. As mentioned above, 100% is hard to achieve away from the dock unless you have wind or solar. I like them for the charge acceptance rate (my 440 AH bank routinely accepts 220 amps at 50% SOC and still around 100A as they cross 90%). Also because they don't spew acid and corrosion. Also because the self-discharge rate is very low.

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How often is "periodically"?

 

I've killed several sets of batteries, Gels, AGMs, and floodded, by undercharging them. The AGMs were the worst in terms of lifespan so I can attest to this effect. Obviously I had an undersized charging system. The question is, what should I be doing?

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How often is "periodically"?

 

I've killed several sets of batteries, Gels, AGMs, and floodded, by undercharging them. The AGMs were the worst in terms of lifespan so I can attest to this effect. Obviously I had an undersized charging system. The question is, what should I be doing?

 

Good question, and I don't have an exact answer. I take it to mean once a week or so, and try to do that - and I have gotten very good life from them.

 

It isn't an undersized charging system that is usually the culprit. It is inadequate charging time. The nature of lead acid batteries are that the acceptance rate goes down as the state of charge goes up, resulting in a very long, almost asymptotic tail to the charge, at low currents. This is true weather you discharge them to 50% or 90%. The top 10% takes several hours at least, a high capacity charger doesn't make any difference because the acceptance rate is low. Very few people are going to do that running the main engine or even the genset, unless you are motoring all day or overnight for other reasons. That's why solar is so compelling: it provides the low current, long hours charge that lead acids (and AGM in particular) want.

 

If you live aboard you need either a shore plug, or a large solar array along with good management. That means bulk charging with the engine in the morning, so the solar can finish the charge in the 8 hours of sunlight left to achieve 100%. If you don't live aboard, a medium sized array will work because it will catch up during the week even if you leave the batteries depleted from the weekend, again achieving 100%.

 

And this again points to the advantages of LiFePO4. Most comparisons are between Li and Pb charge cycles under lab conditions. The problem is, Pb cells suffer more from real conditions vs. lab conditions: they are less often returned to the full charge they need and so die a death much earlier than the lab results may predict. LiFePO4 on the other hand, do not need to be recharged fully, or kept anywhere near a full charge and still live a long life. So the actual differences in charge cycles may be far more than the comparison charts you typically see.

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DDW, and of course LiFePO4 has much better charge acceptance in the first place. What do you know of charge management for them? Is it practical to use a standard alternator/3-stage regulator arrangement?

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I DID buy a Rolls battery. The battery shop said it was really good and would outlast the Diehards we had been replacing every two years.

It also lasted two years and cost a LOT more money :angry:

At the time I bought it I was not yet working in the marine industry and had a more basic level of electrical knowledge. If I had known better, I would have realized a 35 amp alternator set to 13.8 volts and no shore power would sulfate that thing to death just as quick as the Diehards. If only I had known then that a better regulator and some equalizing from a good charger could have kept it going a long time.

 

I also have noted what is known NOW about AGMS is not what was commonly known a few years ago about them. I pretty much thought they would act like gels and they do NOT. AGMS were pretty new when I got out of the business and we dealt mainly with gels and had a very good idea of what they liked and didn't like.

 

btw - my solar controller is temperature compensated.

 

 

GEL's are the longest lasting of the VRLA type of battery I have installed or come across. This is of course if they are properly charged. Far too many people expected to be able to charge GEL at flooded voltages and GEL got a grossly undeserved bad rap. I have multiple GEL's banks exceeding 10 years and one into it's 15th year all of them on boats that are cruised / used quite heavily..

 

AGM's can give equal life to flooded but ONLY if charged and cared for properly. You will however need a "premium" AGM in order to accomplish equaling the life of a FLA deep cycle. The two premium AGM's are Lifeline and Odyssey.

 

Lifeline's CAN be equalized "conditioned" so the argument of "maintence free" is blown out the window. Odyssey wants to see a minimum of .4C charge current for the longest life and Lifeline wants .2C.. Lower charge rates will affect cycle life though Lifeline and Odyssey will not qualtify how much. With both brands charging MUST be temp compensated and this is NOT ambient monitoring it is a physical temp sensor mounted directly to the battery with the most propensity to get hot. Odyssey has superior acceptance rates to Lifleine but Lifeline is far superior in CAR to flooded batteries. The reality is that most sailors can't physically take advange of these high acceptance rates and both of these brands still taper so getting back to 100% is still not a short process as it is with LFP for example.

 

One issue with solar & AGM people often overlook is that every day you begin with a new absorptiuon cycle. Most charge controllers are pretty darn stoopid and use an egg timer approach. When your AGM's get full you do not want a daily absorption for very long, especially not multiple hours.

 

In order to get the most out of AGM's you really need to treat it as a system and start from the ground up.. Not all "smart chargers" are smart, and many are smart in label only.....

 

FLA's definitely tollerate more abuse for the average boater... I regularly see AGM's, including Lifeline and Odyssey, destroyed by year three. Two weeks ago I replaced two Lifeline 4D's that could not be recovered. They were 3 years old.. No solar, improper charge voltages (dumb dip switches with just three settings AGM, GEL, WET and no temp compensation on anything. The previous bank of wet 4D's on this very boat, treated identically (according to the owner) lasted 5 years. The yard who installed the AGM's failed to treat the installation as a system...

 

Anyone even considering AGM technology should read John Harries (Morgan's Cloud) wealth of info on getting the most life out of AGM's. This should be AGM 101 and a prerequisite for every AGM owner. I have known this stuff for a long time as I was one of the Pioneers who jumped on AGM early and then began having horrible cycle life. Thankfully John wrote this stuff so I did not have to..

 

 

This was back when we were told it is "OK to cycle to 80% DOD", "AGM's don't sulfate" and "charge them as you would a flooded battery", "just drop them in and they will outlast flooded deep cycle" oh and "AGM's can't be equalized."......... boy how times have changed... What happens in aviation is not representative of the abuse the marine market can dish out....

 

 

AGM Batteries Making The Choice

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Re aviation - outside of a glider an airplane battery is a car battery or a powerboat battery. As long as they can live in a float environment they last a long time. I got almost 10 years out of a cheap wet cell in a plane with a *generator* it was so old.

As for what I am doing - I have to decide today pretty much. The AGM got down to dropping to 10.9 volts right after engine shutdown. It is dead as a Monty Python's parrot. I have an idea to avoid a Deka sourced AGM because I think their AGM line may have issues. My current AGM is a Deka and from day 1 was not as good as the Deka gel it replaced.

So it is going to be either a Deka gel and then I'll have to swap the AGM start for a gel start or I'll get an Odyssey (or the Sears labeled verison of it). i am avoiding wet cells because of the issues with containing spilled liquids and space needed for the containers. I had a wet cell break open during a hurricane and the acid got into a locker that had our spare food which turned into a smelly mess.

 

I kind of like the Odyssey idea just to try something new. It also sound slike I need a temp sensor lead for my charger.

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DDW, and of course LiFePO4 has much better charge acceptance in the first place. What do you know of charge management for them? Is it practical to use a standard alternator/3-stage regulator arrangement?

 

Yeah, the near constant (and high) charge acceptance is very attractive.

 

I don't know a great deal about them, but I am learning. I have a couple in my glider now which are very deep cycled as they power the instruments all day. They seem not to need the 3-stage lead acid regimen, but rather: current limited (very high limit, but still) bulk charge until about 14.0V is reached, then constant voltage voltage until current tapers, then shut off (no float). The second phase seems very short, maybe too short to consider separately at least in the smaller batteries I have. They seem to accept the max charge from the charger and then taper to zero in just a few minutes. It also seems to be that short periods of float at a well regulated voltage (for example while motoring) will not do them harm.

 

The fancier external alternator regulators seem to have enough programmability to make that happen (though you MUST reprogram them). Some seem to think an additional step is necessary, that is the de-energization of the alternator field if/when the BMS in the battery disconnects due to overcharge. That shouldn't happen, but if it does, the BMS will remove the battery from the charge system, which will then go crazy because no battery load which it depends on for regulation. That would require the BMS output, and a relay in the power or on signal to the regulator. The Genasun system goes further, with a load disconnect at the low end too but that seems unnecessary to me.

 

I think on solar you would need a controller programmable enough to do the same thing, including either no float or a low enough float voltage.

 

I had originally thought I would need to replace everything in the boat to go to LiFePO4, but after studying it a bit I think it would only require minor modifications, using existing line charger, alternator regulators, and solar charge. But I already have highly programmable versions of those installed. My large alternator has 280 amps continuous output capability, I need about 200 AH useable capacity (this is all at 24V) so the idea of going from discharged to charged in less than an hours run is attractive. As is not needing to worry about keeping them full or returning them to full.

 

Perhaps Main Sail will jump in here, he has much more experience with these than I.

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You don't need any special charging regimin for LiFePO4 batteries. The prismatic cells everyone uses like charge voltages VERY similar to flooded batteries. I think the float voltage they like may be slightly higher, but the company I bought them from did not have any reported issues from people using standard chargers. In my case, I was able to set both the shore side and solar chargers voltage points to exactly what the batteries wanted.

 

I also installed a small simple BMS for them. Again, the company I bought the batteries from didn't say it was required, but I figured it gave me some extra protection and minimal cost. They did say that is you build large packs (mine was just 300Ah 2.6C cells * 4 for a single bank) that a BMS became more necessary.

 

http://minibms.mybigcommerce.com/products/HousePower-BMS.html

 

Is the system I used. It both allowed cell balancing in the pack to keep all at the same exact voltage, and also allowed for low and high voltage disconnect and alarms.

 

A complete discharge is something you REALLY want to avoid with these batteries as if you take a pack down to 0%, you could ruin them.

 

There is a lot of information about these in reality because electric car enthusiasts have been using them extensively, as well as the normal off grid use like we use them on boats. Sure the electric cars hammer the packs a little more since they use a much higher C rate that we do on boats. I read an article on electric car blog, which I can't find at the moment that showed actual testing of these packs show better #'s than the specs even say, I think they had put like 10k 80% DOD cycles on a small pack and it was down only like 15% capacity from new. We had 2+ years of full time cruising on them before leaving the boat, and at 2 years, they were indistinguishable from new as far as performance goes.

 

That all being said, I did put a pair of 6V flooded batteries in my new boat. It came with 100% toasted batteries and we will only be sitting at the dock and weekend cruises for the next year or three, so $200 for a set of batteries seemed about right. We will definitely be putting LiFePO4 back in (or something batter maybe) before we head back out full time cruising again though...

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You don't need any special charging regimin for LiFePO4 batteries. The prismatic cells everyone uses like charge voltages VERY similar to flooded batteries. I think the float voltage they like may be slightly higher, but the company I bought them from did not have any reported issues from people using standard chargers. In my case, I was able to set both the shore side and solar chargers voltage points to exactly what the batteries wanted.

 

I also installed a small simple BMS for them. Again, the company I bought the batteries from didn't say it was required, but I figured it gave me some extra protection and minimal cost. They did say that is you build large packs (mine was just 300Ah 2.6C cells * 4 for a single bank) that a BMS became more necessary.

 

http://minibms.mybigcommerce.com/products/HousePower-BMS.html

 

Is the system I used. It both allowed cell balancing in the pack to keep all at the same exact voltage, and also allowed for low and high voltage disconnect and alarms.

 

A complete discharge is something you REALLY want to avoid with these batteries as if you take a pack down to 0%, you could ruin them.

 

There is a lot of information about these in reality because electric car enthusiasts have been using them extensively, as well as the normal off grid use like we use them on boats. Sure the electric cars hammer the packs a little more since they use a much higher C rate that we do on boats. I read an article on electric car blog, which I can't find at the moment that showed actual testing of these packs show better #'s than the specs even say, I think they had put like 10k 80% DOD cycles on a small pack and it was down only like 15% capacity from new. We had 2+ years of full time cruising on them before leaving the boat, and at 2 years, they were indistinguishable from new as far as performance goes.

 

That all being said, I did put a pair of 6V flooded batteries in my new boat. It came with 100% toasted batteries and we will only be sitting at the dock and weekend cruises for the next year or three, so $200 for a set of batteries seemed about right. We will definitely be putting LiFePO4 back in (or something batter maybe) before we head back out full time cruising again though...

 

 

Sadly you were fed a bunch of BS by an opportunistic company trying to make a buck off you and not have you run off when they told you the real truth, or perhaps they were really that ignorant........ LFP's DO NOT FLOAT. Or perhaps you misunderstood what they said? Can't say was not there....

 

There is not a single reputable prismatic cell maker I know of that does not recommend a BMS for cell protection.

 

The HPBMS DOES NOT do cell balancing unless you manaully opt to do that by physically bypassing the HVC circuit. HVC occurs well before cell balancing so it is impossible with the HPBMS to cell balance automatically because your charge sources would already be disconnected. This is by design because cell balancing is one of the more problematic areas of a BMS.. If someone else installed this system you were likely charging at 14.0V and not automatically balancing. Going higher than 14.0V on the HPBMS can trigger the HVC relays when high loads drop off the system and regulation can't react fast enough. 14.1V is just too close so 14.0V is about the best you can do.

 

If your HPBMS was allowing cell balancing then you were already well past the HVC (14.2V) and the BMS was wired wrong. The HPBMS will allow manual cell balancing but this should always be done at the lowest possible C rate to achieve the shunting, & no more. Course this is only after you have manually bypassed the HVC alarm and relay in order to push the cell voltage to shunting levels..

 

Genasun and Mastervolt, IMHO, are the only two companies with solid engineering for marine use, at this point, yet Mastervolt has their charging voltages off in lala land. This leaves Genasun as the only pre-made pack company that actually gets it.

 

One of the larger LFP pack makers recently woke up to the realities of LFP by dropping their recommended charge voltage from 14.6V to 14.0V... Guess why....???? Hmmm, I am sure it had nothing to do with those insane upper voltages hitting them in the pocket... They simply spent too much time building pretty "drop in" boxes and a spin marketing campaign to go along with "drop in LFP" and apparently forgot about the actual engineering.. Ooops.... Not so "drop in" anymore when you need a custom charge profile to get down to 14.0V.....

 

LFP's for marine use need not be charged any further than 14.0V and just now some compnaies are starting to wake up to this reality. For some it is a tad too late (can't disclose all I know about this because some of it is still under investigation).

 

It is the continual push into the upper knee range that CREATES the need for automated balancing and is what will lead to destroyed batteries in considerably shorter than expected cycle life. Add floating LFP to this and we are now cutting into expected cycle life even more. Anyone who tells you LFP's can be charged at the same or similar profiles to LA batteries, for fractional C use, is smoking something goofy and is completely and utterly clueless.

 

A BMS should be an insurance policy to protect the cells not a device used daily, as many companies try, and owners insist on, because they refuse to build the proper system around the LFP bank due to the financial constraints. Can this be done? Absolutely, and it is not entirely difficult, but it needs to be done with good engineering not a hip shoot guess from reading a Chinese smoky back room manual that fails to fully explain all you really need to know to get the most out of your investment....

 

Properly charged (13.7V - 14.0V and NO FLOAT) these batteries will rarely need to be rebalanced but you should still have a BMS/insurance, in case something goes awry...

 

There is zero benefit to pushing LFP's to any more than 13.8V to 14.0V for fractional C use. Doing so only creates problems for a "auto balancing BMS" to fix, where there does not need to be any problem at all....

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Well then - I think the gel was a good choice!

In other news the charge controller that would solve many issues does not - AFAIK - exist any more.
In ideal-world the alternator regulator and battery charger have 2 shunts and can tell when the battery is full and can tell if the current is going into the battery or going to house loads. Imagine motoring 24 hours with totally topped up batteries but people keep using heavy DC loads. The charging system "thinks" these damn batteries must be really low, I keep having to shove 100 amps in them :o

Back in the 90s we sold a system that did this and tracked the total AH in and out of the bank. It was sadly made before the tech was all there and ended up being very tempermental. The alternator part of it died so often it even came with a switch to the backup regulator and the total AH keep drifting off from reality.

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Well then - I thinkt the gel was a good choice!

Very good choice just use temp corrected charging and do not go beyond 14.1V in your charge settings. Ignore Deka's latest claim that you can charge them higher. This is simply an attempt to gain more market share afgter a major drop in sales to to AGM's being able to be charged at FLA voltages.. All the GEL banks I've seen that exceed 10 years have been properly charged at 14.1V absorb and 13.8V float (both temp corrected)...

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Sorry, I was incorrect on the float voltages, I did set this up over 2.5 years ago now, and hearing you say that I do remember disabling the float stage on my Tristar-MPPT solar charge controller. I also set it up to use the Bulk and Absorb voltages I got from Sinopoly's tech support when I installed the pack. Sinopoly at the same time said that for a single four cells in series 12V pack that a BMS was NOT required. So maybe what they told me was wrong, I can't say.

 

My personal experience is using the BMS, like you said, as an insurance policy. I disagree that the cell level shut balancing does not work on the BMS I had though. The unit itself shows a LED when shut balancing is turned up and you could feel the resistor get warm when in action. If you look at the charge curves for these batteries, the single cell voltages go high reasonably quickly as they approach 100%, so as long as the charger voltage points are set correctly, I was able to get a cell voltage to go to the shunt level before the entire pack gets to the high voltage level.

 

Maybe my experiences are different because of using a reasonably fast MPPT tracking algorithm in my charge controller which was looking at pack voltage/current more often than a standard shore charger.

 

I think some of this is a red herring as I don't think many people that will spend $2k in batteries is going to use a $150 dumb charger, but I guess that must be the experience you are dealing with. I am surprised that have a 13.something float stage would damaged them, but if that is your experience, I can't deny that...

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Yes the House Power BMS will shunt, it is designed to. It is just not designed to automatically shunt. If it was doing so on every cycle your BMS was simply installed and wired wrong and was not doing the job it was designed to do because of the incorrect installation.

 

HVC is at 14.2V/3.55VPC this means all charge sources should be broken away/disconnected, via a relay, at preciscely 14.2V or if any individual cell hits 3.55V. Of course HVC only works if the BMS was wired correctly, yours was not.

 

You simply can not charge beyond 14.2V unless you manually over-ride HVC because teh HPBMS will not allow it.. This mean all your charge sources should have been set to 14.0V or less in order for the HPBMS to work correctly, and do the job you paid for.

 

Dimitri designed this product with both warning level actions and emergency actions. HVC is a warning level event to prevent you from ever getting to an emergency level pack disconnect.

 

Shunt balancing begins at a higher voltage than HVC, by design, because if you charge these cells SAFELY at SAFE charging voltages balancing is very, very rarely required. Balancing with high "C" rates can also be dangerous as the resistors can only disipate so much heat. This is why it is designed to be a manual/observed event just like equalizing flooded batteries...

 

Prismatics are full at below 14.0V and need not be charged any higher. Doing so just causes undue stress, balance issues and places you into the dangerous upper knee, which is exactly where you were. It is okay to do this occasionally but certainly not every charge cycle.

 

So yes, you were shunting, but only because your HPBMS was installed and wired incorrectly and you were using charge voltages set far to high for the BMS's design and for prismatics......

 

 

My personal experience is using the BMS, like you said, as an insurance policy. I disagree that the cell level shut balancing does not work on the BMS I had though. The unit itself shows a LED when shut balancing is turned up and you could feel the resistor get warm when in action. If you look at the charge curves for these batteries, the single cell voltages go high reasonably quickly as they approach 100%, so as long as the charger voltage points are set correctly, I was able to get a cell voltage to go to the shunt level before the entire pack gets to the high voltage level.

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<sigh>

 

threads like this just reinforce that

 

1) i admittedly haven't a clue about the details of 12v charging systems

 

and

 

2) my boat's 12v system doesn't seem to be setup correctly

 

Mainesail - do you ever make house calls to WLIS?

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Has anyone got experience or opinions with/on the Mastervolt 5kW Li ion battery pack and it's built in BMS? Any comparisons to the Genasun equivalent? I'm currently in the Mediterranean so the pricing on Mastervolt is a bit more attractive. When I last looked at Li ion batteries I thought I would want to put the pieces together myself, but now I'm not so sure.

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<sigh>

 

threads like this just reinforce that

 

1) i admittedly haven't a clue about the details of 12v charging systems

 

and

 

2) my boat's 12v system doesn't seem to be setup correctly

 

Mainesail - do you ever make house calls to WLIS?

1) +1

2) I think mine is setup correctly but still trying to figure it out and how all the pieces work together. I have AGM batteries.

 

I have learned A LOT in this thread but some of it is still all "Charlie Brown teacher speak" to me!

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Lifeline has been the worst in the cost vs lifetime. Would stay away from them.

Oceaneer

Got to dis agree with that one.. I've got 5 of the 4ds , lifeline AGM in for the last 11 years and still running strong... But, my batteries have never seen a 110 battery charger .. have always been on solar and wind with a deep charge by from my motor every 6 months or so.. They have never been discharged lower than 12.6 ..

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Anyone even considering AGM technology should read John Harries (Morgan's Cloud) wealth of info on getting the most life out of AGM's. This should be AGM 101 and a prerequisite for every AGM owner. I have known this stuff for a long time as I was one of the Pioneers who jumped on AGM early and then began having horrible cycle life. Thankfully John wrote this stuff so I did not have to..

 

 

 

 

AGM Batteries Making The Choice

Maine Sail, I checked out Morgan Clouds site and even managed to pry the $20 out of my wallet to become a subscriber. Lots of good info on a variety of subjects, including batteries and charging.

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Golf cart batteries are best for cruising because you can replace them anywhere in the world where they play golf. They are cheap. You can look into them and see if they are fully charged or not, or whether they are overcharging. As long as they get a charge into them every day they last for many years. I have a 24 Amp solar system and a 40A regulator which can be adjusted. AT $400 for 4 6V units, they last 5 years.

 

I am a power systems engineer and have helped many yachties who had problems with Gel batteries drying out through overcharging. Unless you plan to roll the boat, there isn't any benefit from Gel.

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I am a power systems engineer and have helped many yachties who had problems with Gel batteries drying out through overcharging. Unless you plan to roll the boat, there isn't any benefit from Gel.

I am guessing though, you don't understand the finer points of DC storage technology. Flooded, AGM, Gel, LFP, all have pros and cons. If one was hands down better than the others, the others would not exist. In fact there are many advantages of other chemistries, to go along with the disadvantages. Among them higher acceptance rate, lower self discharge rate, no outgassing of noxious gasses, no terminal corrosion.

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Golf cart batteries are best for cruising because you can replace them anywhere in the world where they play golf. They are cheap. You can look into them and see if they are fully charged or not, or whether they are overcharging. As long as they get a charge into them every day they last for many years. I have a 24 Amp solar system and a 40A regulator which can be adjusted. AT $400 for 4 6V units, they last 5 years.

 

I am a power systems engineer and have helped many yachties who had problems with Gel batteries drying out through overcharging. Unless you plan to roll the boat, there isn't any benefit from Gel.

No one plans to roll the boat, but battery acid is about the last thing you want when downstairs takes a big gulp of water

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Golf cart batteries are best for cruising because you can replace them anywhere in the world where they play golf. They are cheap. You can look into them and see if they are fully charged or not, or whether they are overcharging. As long as they get a charge into them every day they last for many years. I have a 24 Amp solar system and a 40A regulator which can be adjusted. AT $400 for 4 6V units, they last 5 years.

 

I am a power systems engineer and have helped many yachties who had problems with Gel batteries drying out through overcharging. Unless you plan to roll the boat, there isn't any benefit from Gel.

No one plans to roll the boat, but battery acid is about the last thing you want when downstairs takes a big gulp of water
With a proper box and the right flooded batteries, you would need to stay inverted for an uncomfortable period of time for the battery acid to be a major problem. By your criteria, you don't want a ballasted monohull because it might sink or an unballasted multi because it might invert. It's always safe to sit home on the porch.

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Golf cart batteries are best for cruising because you can replace them anywhere in the world where they play golf. They are cheap. You can look into them and see if they are fully charged or not, or whether they are overcharging. As long as they get a charge into them every day they last for many years. I have a 24 Amp solar system and a 40A regulator which can be adjusted. AT $400 for 4 6V units, they last 5 years.

 

I am a power systems engineer and have helped many yachties who had problems with Gel batteries drying out through overcharging. Unless you plan to roll the boat, there isn't any benefit from Gel.

No one plans to roll the boat, but battery acid is about the last thing you want when downstairs takes a big gulp of water
With a proper box and the right flooded batteries, you would need to stay inverted for an uncomfortable period of time for the battery acid to be a major problem. By your criteria, you don't want a ballasted monohull because it might sink or an unballasted multi because it might invert. It's always safe to sit home on the porch.

Not saying you should sit on the porch, but I know many cruisers in my area don't have proper battery boxes, shit some of them needed to be told to tie their batteries down after a safety inspection! Would you say golf cart batteries would constitute the right flooded batteries?

2 race boats swamped their batteries in a race from our club a few years back, both basically gutted the boat as everything inside was rooted.

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Golf cart batteries are best for cruising because you can replace them anywhere in the world where they play golf. They are cheap. You can look into them and see if they are fully charged or not, or whether they are overcharging. As long as they get a charge into them every day they last for many years. I have a 24 Amp solar system and a 40A regulator which can be adjusted. AT $400 for 4 6V units, they last 5 years.

 

I am a power systems engineer and have helped many yachties who had problems with Gel batteries drying out through overcharging. Unless you plan to roll the boat, there isn't any benefit from Gel.

 

No one plans to roll the boat, but battery acid is about the last thing you want when downstairs takes a big gulp of water
With a proper box and the right flooded batteries, you would need to stay inverted for an uncomfortable period of time for the battery acid to be a major problem. By your criteria, you don't want a ballasted monohull because it might sink or an unballasted multi because it might invert. It's always safe to sit home on the porch.
Not saying you should sit on the porch, but I know many cruisers in my area don't have proper battery boxes, shit some of them needed to be told to tie their batteries down after a safety inspection! Would you say golf cart batteries would constitute the right flooded batteries?

2 race boats swamped their batteries in a race from our club a few years back, both basically gutted the boat as everything inside was rooted.

Actually, I do believe that flooded batteries, such as golf cart batteries are adequate for the vast majority of cruisers.

 

As to your mates, if their batteries were situated and installed such that they got flooded in anything less than a major emergency, it would seem a self inflicted wound. I've found many racers with little care about deck leaks, down flooding and anything more than filling out the equipment list for the race category. If your boat takes that much water in anything less than survival conditions, you need to plan accordingly.

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Not so relevant for this discussion, but for those reading. Sealed batteries (ie. not flooded, not golf cart) are required for all Cat 0,1,2, & 3 offshore races. Lots of coastal races are Cat 3. Hawaii & Bermuda races are Cat 1.

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I did have a wet battery break open in a hurricane and the acid got into a locker with all our canned food and dissolved the cans. Besides for having to feed everyone with a coffee cake it was VERY stinky - not to mention the lack of electricity :(:o

Nothing beats golf carts for $ per AH over the life of the battery. In my case they just don't fit where my batteries are now. It would have been a major construction project to make a place for them that was safe and acid proof, and then I would have to run big $$$ wire to the new spot.

My previous set of gels lasted for a very long time - 9 years - and worked very well. If you look at East-Penn Deka white papers their gels have around TWICE the cycle life of their AGM batteries at deep discharges. They seem much more tolerant of not being topped to 100% then my crap-tastic AGM battery from Deka was. Speaking of which, the last couple weeks it was in it got really hot and had my battery charger at constant full output. I checked it the other day before hauling it off to the recycler and it read a whole 25 millivolts. I think it internally shorted out somehow.

 

The new gel seems settled in nicely after a few cycles. I don't even have the shore power on right now, the solar is keeping it going at the dock. The gel starting battery that I bought around 2002 or so took up where it left off and fired the engine right up B)

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Lithium NO float? Why? I understand why you don't need float, but I don't understand why you cant just set your cheap shitty solar charger to never go above 14v and disable temp comp.

 

Finding a controller that actually shuts off will be hard and expensive. Why will it be bad to just have it hovering at 14V? Chances are the fridge will come on, some other things will be running etc. What's the problem?

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Wouldn't be the first time the sales people and engineers had different opinions. "Drop in replacement" seems to be not written by the engineering side of the house over in lithium battery land.

As for my new gel, I let it run down some and then charged it a couple of times. It seemd to like the excercise and is doing a good job holding a charge. I love how I have to load it up a bit to get it down to 12.8-9 volts. The defective AGM would dive on down to 12.2 if you turned on one light :(

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Not so relevant for this discussion, but for those reading. Sealed batteries (ie. not flooded, not golf cart) are required for all Cat 0,1,2, & 3 offshore races. Lots of coastal races are Cat 3. Hawaii & Bermuda races are Cat 1.

Actually very relevant. Some of us cruisers also do Cat 1 and Cat 2 races with our varnish hogs. I'm doing one more set of AGM for just this reason, by time these are cooked I figure the LiPO will be much more accepted.

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For what it's worth, the Lifeline AGMs in VALIS were installed in 2002, and they are still going strong. Most of this time they've been float-charging from the solar panels, but every year I do a capacity test under a 24 or 48-hour load and they haven't lost much if any capacity. The only heavy use is a month or two per year, so if I were cycling them daily they might not be holding up as well.

 

I've got four 8D batteries (plus an engine-start battery), and my alternator is only a 90A unit. On the hook, the solar keeps it charged (main load is the refrigerator), but at sea I need to engine-charge about one hour per day (depending on cloud-cover). I can go three days or so without charging, but eventually I have to put the juice back.

 

Anyway, I've been quite pleased with the AGMs.

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FWIW, I have gone through a LOT of batteries in cars & boats in my life and found that Interstates were far and away the best of the lot - a definite difference in quality from other brands. They make gel's but I don't know if they do AGM's.

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Lifelines are quite a bit more expensive than the cheaper AGMs and also more than gels. I could see no reason to buy Lifelines when the gel battery is just a little bit more than the cheaper AGM and is much much better. If you have a really big alternator the formula might change, but I don't.

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If I lived in the USA I would by buying those $39 golf cart batteries. Seems a no brainer really.

 

Also I managed to get 3 x 100AH 12V AGMs for now very cheap (I want lithium in the future). What is the max charge voltage I should use for them? I have it on 14.1V. They get cycled a little as we have a fridge running since the boat is down town in the Bris River and when we go there a few times a week I demand cold beer :D

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FWIW, I have gone through a LOT of batteries in cars & boats in my life and found that Interstates were far and away the best of the lot - a definite difference in quality from other brands. They make gel's but I don't know if they do AGM's.

I have had good luck with Interstates as well but application is in cars and powerboats so basic wet cell batteries and simple altenators.

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Where are you seeing $39 golf cart batteries? I think you can get some that are under $100 at costco, but I have never seen anything under $50

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If all AGMs are as bad as mine I cannot see why anyone would buy them. Deka's own white papes show the AGM line lasting about half as long as their gel batteries in deep cycle applications. I wish I had seen that when I got my battery, but the gel had finally died after 8 years of great service and one year of decline and I needed one that day and AGM was the only thing in stock. One thing I have found out the hard way is that you need to hit AGMs hard when charging or they lose capacity quickly. An Atomic 4 drives the alternator about 1:1 ratio with engine RPM, so even putting on the biggest alternator ever made still will rarely get you more than 40-50 amps charge running flat out and less at low cruise RPM. The battery wasn't even a month old when I noticed it sure didn't hold voltage as long as the gel did.

I really wish my storage space was better for wet cells. Nothing beats the life cycle cost of golf cart batteries IMHO.

 

BTW - to the poster with the ship batteries - gel and AGM charge differently. Gel batteries CANNOT be overcharged or they lose capacity that will never ever return. I had my alternator set to 14.1 volts in summer and 14.2 volts in winter and it worked fantastic that way. A bigger alternator or big charger needs to drop back to a float voltage for gels. AGMs need higher charge voltage and they need to be pushed all the way to 100% full pretty often. I did not know this latter bit when I got my battery and I think that helped with it not being very good.

I'm ready to buy batteries for my new (old) boat. I have a lot of conveniences I would like to run with an inverter. I have seen Rolls batteries mentioned in other venues, but I don't understand how to make them work. They sell many batteries but only 6V marine AGM batteries and they are advertised to last 15 years. They have 250 amp. hours. However, the 6V battery wieghs 79 pounds, so four of them would weigh 316 pounds and that's a lot of weight! Can someone tell me what size I should use and why? Weight is certainly a consideration but, since I have a 12 volt system and need either two or four of them, I'm confused: If I go with two, the system goes down if one of them fails. If I go with four and one fails, I can unhook another one and run just fine on two. Plus, I will get 500 amp. hours out of two and 1,000 amp hours out of four. I don't think I need 1,000, but 500 might be a little light.

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Make sure you know how to combine batteries and figure the amp-hour capacity. If you use the 6V / 250Ah batteries, you have to put two of them in series to get 12V, and you now have a 12V / 250 Ah battery bank. If you series / parallel connect four of them you get a 12V / 500Ah bank.

 

What I would do first is figure out your power needs. Look at the power (amps) consumed by all your loads in 24 hours. Consider how you will be using this stuff, for example on my boat I burn significantly more power when at sea than when at anchor. You will end up with a 24-hour Amp-hour number. On my boat I consume about 200 Ah per day (with computers and refrigerator running 24/7, etc). If I start with a fully-charged 500Ah battery bank, over 24 hours this 200Ah load will drain the battery to about 60% capacity. You generally don't want to drain the battery below 50%. (We're talking about lead-acid batteries, such as wet-cell, gell, or AGM. Lithium batteries have different characteristics). Also, you generally won't be charging the batteries all the way to 100%. That takes a long time and you usually stop before 90%, only occasionally going all the way.

 

As Kent Island Sailor mentioned, figure out how you will be charging the batteries. This will help determine how much Ah capacity you need.

 

And Rolls makes many different styles of batteries. They're not the only reliable battery brand, either.

 

If you want to do this yourself I recommend that you get a book, or do a lot of online research. Nigel Calder's book is good: http://www.amazon.com/Boatowners-Mechanical-Electrical-Manual-Essential/dp/0071432388

 

Finally, wherever possible, reduce your power consumption. This is much easier than increasing your charging / storage capacity.

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