TalonF4U

Practical experience with Li Batteries on raceboats?

Recommended Posts

Been looking at revamping my electrical system and am considering lithium ion batteries. NexGen has a slick website selling them. 

From the math for Group 27s, they are about 1/3 the weight of AGMs but about 3-4x the cost. The question I have has to do with discharge and cycle life. In theory, I should be able to discharge them deeper (~80%? vs 50%) and run them longer, which may make me feel better about spending three large to save a hundred pounds. Anyone tried 'em? 

Share this post


Link to post
Share on other sites

There are numerous threads Gear Anarchy on this exact subject, where LFP offerings exactly as that, being simple "drop-in" replacements for lead acid, are not treated very kindly. Numerous other modifications required incl new charging system, even then maybe not trouble free.

  • Like 1

Share this post


Link to post
Share on other sites

Lots of boats use them.   Race boats have been using them for a decade plus.    Yes, deeper discharge, faster recharge, much longer cycle life.   You must take a hard look at your charging setup.

Share this post


Link to post
Share on other sites
18 minutes ago, solosailor said:

 Lots of boats use them.   Race boats have been using them for a decade plus.  

Not this "drop in" varient (a recent invention) they haven't.

Share this post


Link to post
Share on other sites

Should've thought to check Gear Anarchy, thanks. 

I was wondering about the impact of the charging setup. I'm thinking about re-doing that, too, and getting a new charger. Sounds like that's a precondition. 

Share this post


Link to post
Share on other sites

It’s a precondition if you don’t want your boat to turn into a smoldering puddle of fiberglass at the bottom of your harbor

Share this post


Link to post
Share on other sites
42 minutes ago, toad said:

Lithionics premium marine product are not "drop-ins" and their "drop in" infinitely better than others. They have a independent BMS with alternator regulator switching etc. Their premium offering probably the best LFP system out there and one not constrained by proprietary chargers etc like Mastervolt and Victron.

Share this post


Link to post
Share on other sites

Neither Mastervolt nor Victron are constrained by proprietary chargers. Both vendors publish their charging requirements and can be matched to any quality regulator or shore power charger.

Share this post


Link to post
Share on other sites
2 hours ago, Moonduster said:

Neither Mastervolt nor Victron are constrained by proprietary chargers. Both vendors publish their charging requirements and can be matched to any quality regulator or shore power charger.

Moon that is not exactly right. Both Mastervolt and Victron LFP BMS's have no external analogue high (say charger or alternator regulator) or low (say inverter) voltage event controls only with their own proprietary digital 2k matched to their own gear.

Genasun used to have that analogue capability but no longer in the game. Lithionics (who took over Genasun's space) the only one to my knowledge who does and where small LFP BMS standalone offerings have all but disappeared (Lithionics took over the market leader that did). LFP is now being driven by price with "drop ins" by on line vendors and most are shit and will give LFP a bad name.

PS. Like you and other than race boats constrained by Offshore Regs to having sealed LA, I think vast majority of users are probably better off wallet and performance wise with flooded LA if installed properly.

  • Like 1

Share this post


Link to post
Share on other sites

The Victron BMS does - I've installed several. The Mastervolt doesn't, but the internal BMS will protect the battery just fine. In both cases, external voltage levels are sufficient to guide charging thresholds.

Share this post


Link to post
Share on other sites

either of you guys have an opinion on the ReLion batteries? supposedly drop in, with an integrated BMS.

Share this post


Link to post
Share on other sites
11 minutes ago, ryley said:

either of you guys have an opinion on the ReLion batteries? supposedly drop in, with an integrated BMS.

I just installed one for the house bank on a 40 footer. I'd recommend them.

Share this post


Link to post
Share on other sites
8 hours ago, Moonduster said:

The Victron BMS does - I've installed several. The Mastervolt doesn't, but the internal BMS will protect the battery just fine. In both cases, external voltage levels are sufficient to guide charging thresholds.

Read what I said Moon. 

Share this post


Link to post
Share on other sites

I homebrewed a bank two years ago for my cruiser using sinopoly cells, a bunch of relays and an orion JR BMS. It took about 9 months to research and set-up.

Back then the 'drop in' batteries were pretty much borderline scams, using them with your existing charging regime/voltages would destroy them pretty fast.There may be better/easier solutions out there now with actual decent BMS.

 

Share this post


Link to post
Share on other sites

I generally stay away from electical on boats,  but I'd suggest bumping up your ABC fire extinguishers if you flip over. As far as I know, they haven't burned down a boat yet, but they've torched a lot of houses.

 

 

Share this post


Link to post
Share on other sites

Not even close.

Marine applications use lithium iron phosphate battery. It is fundamentally a different chemistry.

 

  • Like 3

Share this post


Link to post
Share on other sites

So much hype, disinformation and confusion about batteries.  The best/easiest place to learn basics is to start here: https://batteryuniversity.com/learn/

The *only* safe lithium to put on a boat is LiFePO4 (aka Lithium Iron Phosphate, LFP).  Yeah, use a little LiPo pack for your drone for on-water selfies, but not fixed in the boat, please.

If you want to shave the pounds, go LiFe, and deal with cost, cell-balancing (BMS is a must) and custom charge/discharge settings.  I found in playing with LiFe (non-marine solar applications) that I had to count Coulombs (monitor Ah in and out, very carefully) to have a decent idea what the state-of-charge of the LiFe bank was.  LiFe, unlike lead-acid, has a very flat voltage/charge curve.  You find out quite suddenly that you are either full or empty if you only watch voltage.  Also, the cell voltage is very sensitive to temperature, so unless you temperature-compensate pretty well, you really can't rely much on LiFe cell voltage telling you SoC, except at the extremes.  Lead-acid open-circuit cell voltages are a much better proxy for state-of-charge.

I don't have experience with LiFe on a raceboat.  My experience with LiFe in other applications convinced me I didn't want to bother for our trimaran (which is weight-sensitive, but there are limits...).  Mea culpa - yeah, I should buy an ad, because I starting importing these into Canada after I couldn't buy them here:  I decided on a single Firefly Oasis Carbon Microcell sealed VRLA Group31 for our F-31.  In the US contact Bruce Schwab, in BC Canada: Pacific Yacht Systems, in Ontario: Total Battery.  Aussies might be able to get carbon-enhanced lead-acid, not sure... CSIRO funded some research into the "UltraBattery".  It's bulletproof technology (sealed lead-acid), an answer that hit my sweet-spot.  I don't mean to hijack a Lithium-thread, but folks should know about alternatives, too.  Silicon Dioxide is another up-and-comer technology...

@TalonF4U, I suggest you add up your loads and figure or measure how many Ah/day you really want/need.   We seem to do ok with a single 116Ah (20-hour rate) G31, running it up and down about 70-80%/day when cruising, living aboard, with no shore-power, no evening top-ups, occasional boost from motoring to/from anchor or no-wind, 200W faceplate solar (could use more).  It's always so hard to actually start with requirements, as we should...

  • Like 1

Share this post


Link to post
Share on other sites

Yeah, no.

There are an increasing number of suppliers who have moved on to NMC - Lithium Nickel Manganese Cobalt Oxide. I wouldn't be surprised to see them surpass LFP in volume within the next five years.

 

Share this post


Link to post
Share on other sites

am i looking at this too simplistically?  in our J35, i am running two 12V car batteies with the standard battery switch to choose Bat1, Bat2, All.  so i should just be able to get two of these batteries, drop them using the existing wiring?

Share this post


Link to post
Share on other sites
1 hour ago, Moonduster said:

Yeah, no.

There are an increasing number of suppliers who have moved on to NMC - Lithium Nickel Manganese Cobalt Oxide. I wouldn't be surprised to see them surpass LFP in volume within the next five years.

 

In the recreational boat business? Which?

Share this post


Link to post
Share on other sites
2 hours ago, Moonduster said:

Yeah, no.

There are an increasing number of suppliers who have moved on to NMC - Lithium Nickel Manganese Cobalt Oxide. I wouldn't be surprised to see them surpass LFP in volume within the next five years.

 

Things like Graphene and Sodium being spoken of replacing lithium, albeit no idea how safe that chemistry is for a boat, suspect not if it has a energy density and thermal runway issues greater than some Li cobalt derivatives.

Share this post


Link to post
Share on other sites
Quote

There are an increasing number of suppliers who have moved on to NMC

I've done some custom ones as far back as '13.    Use them on my boat as well.

Share this post


Link to post
Share on other sites
3 hours ago, Moonduster said:

Yeah, no.

There are an increasing number of suppliers who have moved on to NMC - Lithium Nickel Manganese Cobalt Oxide. I wouldn't be surprised to see them surpass LFP in volume within the next five years.

 

 

53 minutes ago, solosailor said:

I've done some custom ones as far back as '13.    Use them on my boat as well.

Moon that appears conservative. NMC LFP equal now but maybe not pack size availability just yet?

Solo can you get NMC in same pack dimensions and reuse LFP external BMS's voltage limits and cell boards or completely different box of  monkeys?

us-lithium-ion-battery-market.jpg

Share this post


Link to post
Share on other sites
17 hours ago, shubrook said:

I generally stay away from electical on boats,  but I'd suggest bumping up your ABC fire extinguishers if you flip over. As far as I know, they haven't burned down a boat yet, but they've torched a lot of houses.

 

 

Lithium polymer and Lithium Phosphate (LiFePO4) are very different techologies.

LiPo's don't get used on boats, not really. They may be in a few handheld devices, but that's their primary application.

LiFePO4 is a safer tech.

 

Share this post


Link to post
Share on other sites
17 hours ago, shubrook said:

You may want to check out some marine sites for information on marine appropriate batteries...not a cell phone site.

 

Share this post


Link to post
Share on other sites
22 hours ago, solosailor said:

No one uses lips on boats.....   unless they want trouble.

Use of lips on boats is the kind of trouble I could get used to:

D1061_25_824_1200.jpg

But, seriously - @Moonduster:"Yeah, no"?  Not very specific or helpful.  You put LiPo on a boat?  @Miffy asks a good question of you, above.  Maybe there are now LMC cells and systems that are suitable and safe for marine use, but could ya be just a bit more helpful with, say, a link or something, rather than just glossy flip statements to a newb-to-lithium?  I mean, if you bother to post, dude, why not be helpful instead of just contradictory?  My last look at marine product I recall there was only one battery monitor system that did any good at all at tracking LiFe state-of-charge, using an adaptive algorithm.  Might have been Victron... It sounds like you know something about this, but you really don't need to be such a tease.

Share this post


Link to post
Share on other sites
On 7/15/2019 at 12:47 PM, jack_sparrow said:

Lithionics premium marine product are not "drop-ins" and their "drop in" infinitely better than others. They have a independent BMS with alternator regulator switching etc. Their premium offering probably the best LFP system out there and one not constrained by proprietary chargers etc like Mastervolt and Victron.

Youre a clever chap, very very clever, probably the cleverest chap here but I think that what I mean by  drop in and you mean by drop in may be lost in translation.From what i can gather from their retro website lithionics are offering batteries with an integrated BMS and  batteries without. Happy to be corrected by our senior extremely clever expert on everything though.

Share this post


Link to post
Share on other sites

For a full house and start setup and not a single battery system;

Lithionics_Marine_BMS_3_Alternators_706.

 

 

Share this post


Link to post
Share on other sites

Spud,

You said "The *only* safe lithium to put on a boat is LiFePO4". I said yeah, no and then added that NMC is quickly catching up to LFP from several manufacturers. If that's not sufficient constructive, send me an IM.

 

  • Like 1

Share this post


Link to post
Share on other sites

God that's so much simpler than my setup. Are the relays built into the BMS?

 

edit: Looking at the price you certainly pay for it though, wow

Share this post


Link to post
Share on other sites
6 hours ago, toad said:

Youre a clever chap, very very clever, probably the cleverest chap here but I think that what I mean by  drop in and you mean by drop in may be lost in translation.From what i can gather from their retro website lithionics are offering batteries with an integrated BMS and  batteries without. Happy to be corrected by our senior extremely clever expert on everything though.

No translation lost. I didn't say Lithionics didn't market "drop ins" in fact said they did and rated them. You need to read before trying to be a half smart.

On 7/15/2019 at 10:47 AM, jack_sparrow said:

Lithionics premium marine product are not "drop-ins" and their "drop in" infinitely better than others....

And you have posted their "premium marine" offering that has an independant BMS incorporating analogue alternator regulator control, which is not found in their "drop in" offering. 

6 hours ago, toad said:

For a full house and start setup and not a single battery system;

Lithionics_Marine_BMS_3_Alternators_706.

 

Share this post


Link to post
Share on other sites
5 hours ago, alctel said:

. Are the relays built into the BMS?

Yes. Excellently engineered next generation up from Genasun's that accommodated a board mounted relay. 

Share this post


Link to post
Share on other sites
21 hours ago, jack_sparrow said:

...haven't a clue what you are talking about...

We were talking about batteries,  cold wanking gramps.  I think Brexit must be getting under your skin.  Don't bring it here.

main-qimg-7a982132cf43e41c499ca38b35115b18.webp

@Moonduster thanks for clarifying.  @toad thanks for the actual useful info.  @jack_sparrow, um... cheer up?

 

  • Like 1

Share this post


Link to post
Share on other sites

Lithium Manganese were used on at least two america's cup boats back in the late 80s, so they have been around for a while on race boats.

Share this post


Link to post
Share on other sites
Quote

Solo can you get NMC in same pack dimensions and reuse LFP external BMS's voltage limits and cell boards or completely different box of  monkeys?

Same pack dimension?   Every cell company has a different form factor, sometimes multiple sizes of the same capacity.    BMS settings are different but many BMS systems are programmable and many don't use cell boards so in some instances, yes but not likely for a proprietary system like Genasun BMS or such.

Share this post


Link to post
Share on other sites
Quote

Lithium Manganese were used on at least two america's cup boats back in the late 80s, so they have been around for a while on race boats.

NMC = nickel manganese cobalt oxide

Share this post


Link to post
Share on other sites

  

 

Lithium Cobalt Cells. Older legacy cells, same kind that caused so many fires in early Apple Powerbooks. Li-Cobalt doesn't scale well and has "thermal issues". Marine applications now typically use Lithium Iron Phosphate which is the safest chemistry.

Share this post


Link to post
Share on other sites

I'd still love to hear what commercially available suppliers are making units for the recreational marine market. 

Share this post


Link to post
Share on other sites
On 7/19/2019 at 2:50 AM, solosailor said:

Same pack dimension?   Every cell company has a different form factor, sometimes multiple sizes of the same capacity.

Meant pack as in 12v but should have said individual cell plan size and terminal location same as LFP Chinese cell providers so you can reuse cell boards in NMC cells.

Share this post


Link to post
Share on other sites

Almost every LFP manufacturer uses a different terminal location and NMC and LFP have slightly different settings.   If you have a BMS that is programmable you are likely good to go.   Many BMS manufacturers no longer put a full board on each cell.

Share this post


Link to post
Share on other sites
20 minutes ago, solosailor said:

Many BMS manufacturers no longer put a full board on each cell.

Yes the cell balancing bit was bullshit for those that did. The marine environment and EMI issues in boats also didn't help making some more relaxed having pack not cell voltage monitoring.

Share this post


Link to post
Share on other sites

Got two wet cells in parallel and revamped the electrics on the boat.  Moved to all LED lighting, added fans (used by crew during the race) in each bunk with the power savings.  Read up on the amperage of everything, even the lights on the electronics.  Made sure to turn things off and turn things on.

Just finished the Chicago Mackinac race.  On all boats in 42 years always had to re-charge the House set of batteries, power went down to 10.8 volts, electronics went tits up.  This year was a longer race, not only slower winds, we now own the slowest rated boat in the race.  At the finish, had 11.7 volts (started race at 12.8 volts), leaving us at least another day after 62 hours of usage, if not more to go, before we would have needed to charge the first time. This was awesome.

Reduce your power needs as much as you can.

  • Like 1

Share this post


Link to post
Share on other sites

A Watt saved is worth two in the bank.

  • Like 1

Share this post


Link to post
Share on other sites

The boat I raced in this years Marblehead to Halifax Race had a 2016 Mastervolt Li setup. A switchable, 2nd alternator allowed us to charge at 230amps at 12v. I loved the high acceptance rate and minimal charging time. It may have been an expensive setup but the benefits were obvious.

Fast forward to last weekend... The J/121 named Sarah in the NE Solo Twin race had a Li fire. I've not been able to get any additional info about cause, chemistry or battery manufacturer. I have certainly heard of other Li fires but this one feels closer to home, especially as I had been researching for my own Li upgrade. Anyone have additional details about this incident?

https://www.newportyachtclub.org/sailing/offshore/new-england-solo-twin/

Share this post


Link to post
Share on other sites
On 7/16/2019 at 9:59 PM, George Hackett said:

am i looking at this too simplistically?  in our J35, i am running two 12V car batteies with the standard battery switch to choose Bat1, Bat2, All.  so i should just be able to get two of these batteries, drop them using the existing wiring?

George,

Simple answer is yes.  You cant replace deep cycle batteries with a Lithium based alternative for one simple reason.  Lithium batteries REALLY dont like to be overcharged.  A standard car battery spends much of its life at near full charge or technically overcharged as the alternator is constantly putting some voltage into the cells.  If you do that to a Lithium based battery you will damage the cells.  That is why you need a BMS for any Lithium based marine system.

 

MS

Share this post


Link to post
Share on other sites
2 hours ago, Mr. Squirrel said:

Lithium batteries REALLY dont like to be overcharged.  A standard car battery spends much of its life at near full charge or technically overcharged as the alternator is constantly putting some voltage into the cells.  If you do that to a Lithium based battery you will damage the cells. 

That's not much of a problem for LiFePO4 normally used in boats. Normal 14-14.4 V wont overcharge it. It will keep the battery at 100%, which  is not ideal for it, but is ideal for sailboat usage (you want to have full capacity, not keep the battery around 50%, which is best for it).

Lithium batteries used in portable devices and cars have different chemistry and are much more prone to overcharging. But even those can be float charged. You just need to be careful about the voltage and should not go for 100% charge (4.2-4.3 V/cell).

  • Like 1

Share this post


Link to post
Share on other sites

Also a typical car battery is not at full charge. It is the only battery used for everything in the car. While starting doesn't take much Ah all the other use may take. It takes several hours for a lead acid battery to charge from 70% to 100%. Most cars are driven way less than that after each start. This is naturally even more true for modern cars which stop the engine at traffic lights. I typically measure 12.2-12.4 V from my car after being parked for the night. That's only 50-70% SOC. Even for a new battery, that has been used for a couple of weeks. While the engine is running, I get 14.4 V at the battery, thus there is nothing wrong with the alternator etc.

Share this post


Link to post
Share on other sites
3 hours ago, squiby said:

Fast forward to last weekend... The J/121 named Sarah in the NE Solo Twin race had a Li fire. I've not been able to get any additional info about cause, chemistry or battery manufacturer. I have certainly heard of other Li fires but this one feels closer to home, especially as I had been researching for my own Li upgrade. Anyone have additional details about this incident?

https://www.newportyachtclub.org/sailing/offshore/new-england-solo-twin/

You sure it was main battery, not phone or tablet or powerbank?

Share this post


Link to post
Share on other sites
7 hours ago, Upp3 said:

You sure it was main battery, not phone or tablet or powerbank?

I was out on Block Island sound during the incident and could hear some of the USCG side of the VHF conversation with Sarah. At the time, I did not know it was a Solo Twin competitor or that it was "Lithium" related.

It definitely could have been something other than the house bank. I have no info other than what was listed on the solo twin website. Happy to hear that help was nearby and everyone was ok.

This is from the Solo Twin site:

7/26 1900 – The fire on Sarah has been put out (I think by the Newport fire boat), Todd and Greg reboarded Sarah and SeaTow towed them back to Warwick. They are fine.
Boats are reporting in rounding both 1BI and the Southwest BI buoy. Beautiful conditions.
7/26 1400 – reports came in that Sarah had turned back then that smoke was coming out of the boat. Some power boats were around and picked the crew off the boat. There was an lithium fire on board. The coast guard were present as well as Sea Tow. All is ok.

 

Share this post


Link to post
Share on other sites
9 hours ago, Joakim said:

That's not much of a problem for LiFePO4 normally used in boats. Normal 14-14.4 V wont overcharge it..

Complete fucking nonsense.

Joakim your LFP experience promoting a car alternator sitting in vast majority of boats is OK for LFP in any of its forms is what? Your experience with LFP answer my guess is absolutely fucking zipp.

Your reply is what then Joakam..???? You read that on the internet from a likewise clueless wonder or marketing shit from a LFP on line drop in battery provider ??

  • Downvote 1

Share this post


Link to post
Share on other sites

My 100ah @ 48v LiFePO4 bank is nice. Charges using all 30A @ 120v from shore, so just over an hour if I run them flat.

I have 4 Battleborn 100ah 12v batteries, each with built in BMS. 

Battleborn is run by a CalTech PhD. So they are actually extensively tested during R&D, not simply assembled and “the specs say...”

None of my three SoC meters are worth a damn, regardless of the advertising copy. I just got a new Balmar unit specifically tuned by those excellent guys in Maine for 3years ... I hope it works! 

I really like the LiFePO4 batteries! Light!! No maintenance, so no easy access required except to terminals of course. Fast charging. Can use high power loads, boil water in two minutes, etc. 

And best: got rid of the damn diesel vibration, stench, and noise device. 

Saved 700 lbs!! Total savings getting rid of Yanmar 3GM30F, tank, filters, etc, and the 4 T105s. 

Batts + electric motor system installed (in hours of work) was $8k, less than a little Beta at the factory. Same speed under power.

Share this post


Link to post
Share on other sites
14 hours ago, jack_sparrow said:

Complete fucking nonsense.

Joakim your LFP experience promoting a car alternator sitting in vast majority of boats is OK for LFP in any of its forms is what? Your experience with LFP answer my guess is absolutely fucking zipp.

Your reply is what then Joakam..???? You read that on the internet from a likewise clueless wonder or marketing shit from a LFP on line drop in battery provider ??

I'm not promoting anything. I'm just now sailing with my friends boat, which has Yanmar with its standard alternator and LiFePO4 batteries. I think he replaced lead-acid with LiFePO4 three years ago. Overcharging has really not been a problem. More vice versa, charging has been slower than it should be. Yesterday we charged with the engine running at around 1500 rpm. First it charged about 50 A but then dropped to 20 A when the battery monitor showed 80%. Voltage was 13.8 V while charging. If this was my boat, I would increase the charging voltage to get faster charging.

Our club has handful of boats with similar setup. None have changed the charging system when switched to LiFePO4. One of them is selling these setups.

Electronics is my profession. I'm quite well aware of charging different battery chemistries.

  • Like 1

Share this post


Link to post
Share on other sites
2 hours ago, Joakim said:

Overcharging has really not been a problem. More vice versa, charging has been slower than it should be. Yesterday we charged with the engine running at around 1500 rpm. First it charged about 50 A but then dropped to 20 A when the battery monitor showed 80%. Voltage was 13.8 V while charging. If this was my boat, I would increase the charging voltage to get faster charging

Joakim overcharging is the key issue of LFP in terms of cell damage. LFP will accept everything you can throw at it with a slow taper unlike LA so the issue is small frame alternators running at max output and burning them out. Above day 90% taper rapidly falls off. The battery sets the charge voltage subject to SOC not the alternator. Increasing max output voltage doesn't increase the charge rate.

SOC on battery monitor will be out of whack unless it is either manually or automatically reset at a selected 100% SOC. If still accepting 20A at 13.8 volts that not a indercharging issue but alternator regulator may or may not be set at a safe limit of 14.1v max. Once charge voltage reaches around 13.9v individual cell voltage will start to drift and above 3.4V (pack 14.4v if all equal) those cells will be cactus along  with your investment. Most drop in LFP offerings indicate max charge voltages way above that which is bullshit to market a drop in replacement for LA.

I would be highly surprised if someone knowing what they are doing has not replaced internal OEM regulators with ones set at around 14.1 max and preferably < 14v to limit cell drift. So in essence to protect battery your charging to less than 100% SOC. You of cause can eyeball voltages and cease charging at a selected voltage to protect cells using a OEM regulator but that dangerous practise as it doesn't take long for individual cell voltages to spike beyond their safe maximum.

Looked after good quality LFP will last 10 years with capacity shrinkage not exceeding 20% further increasing the return on investment over that of LA.

I hope that makes sense.

Share this post


Link to post
Share on other sites

Winston recommends charging their 12 V LiFePO4 batteries to 14.6 V and gives 16 V as the maximum charge voltage. The current will taper down when the battery is becoming fully charged. 

We have been motoring now for about 1.5 hours after evening and night in the harbour without shore power. The battery monitor showed something over 80% when we started. Now it shows 100% and current is only 2.2 A. Voltage is 14.05 V. Do you think this will harm the battery? We will probably still be motoring for 4 hours unless we get enough wind.

Even with LiFePO4 charging current depends on voltage. There is always some voltage drop in cabling, possible diode and even a very internal resistance in the battery. These also depend on the alternator. Some have a sense wire that can be connected to different places. Even when connected to the battery terminal there will be some voltage drop in the negative path not compensated.

 

Share this post


Link to post
Share on other sites

Now after three hours of motoring we have 0.4 A and 14.08 V. So basically no current at all.

Share this post


Link to post
Share on other sites
5 hours ago, Joakim said:

Now after three hours of motoring we have 0.4 A and 14.08 V. So basically no current at all.

Which now means Joakim you don't have a OEM alternator regulator as per my post above and assuming that is with no draw. Lightbulb moment your end?? I really do doubt it and give up sometimes.

Share this post


Link to post
Share on other sites
1 hour ago, jack_sparrow said:

Which now means Joakim you don't have a OEM alternator regulator as per my post above and assuming that is with no draw. Lightbulb moment your end?? I really do doubt it and give up sometimes.

What makes you think my friends boat doesn't have the standard Yanmar alternator? It's YM30 from 2009 with 60 A alternator. Very mutch standard to see 14.1 V at the battery, which then takes as much current it takes. When the battery is full the current it takes at that voltage is about zero.

Share this post


Link to post
Share on other sites

I said OEM alternator regulator Joakim and so really given up now.. you are not into listening. You saying you increase charge voltage to increase acceptance charge into a battery (of any chemistry) and yet you say electronics is your profession really said it all. Bye.

Share this post


Link to post
Share on other sites

Standard Yanmar alternator naturally also includes the standard regulator inside the alternator. There is no external regulator. There is just a low voltage cut-off circuit that disconnects the battery from consumption.

Here are some charge curves for Winston cells:

qidwvcdb3z4i.jpg

Say you battery is at 70% SOC. If you put 3.35 V/cell (13.4 V) at the terminals you get just 0.05C, if you put 3.4 V/cell (13.6 V) you get 0.2C. To get 1 C you will need about 3.5 V/cell (14.0 V). To get more current you need even higher voltage (e.g. about 3.7 V/cell 14.8 V for 3 C). You can see the higher voltage charge curves from datasheet.

On top of that you have some voltage drop on the cabling (both plus and minus). At 60 A that might be 0.4 V dropping to 0.04 V at 6 A. If you have a Schottky diode based battery isolator, you will have 1-1.2 V or even more at rated current and 0.3 V at zero current.

Note that the charging voltage at the graph goes steeply up as the battery is full. A standard regulator in the alternator will not allow the voltage go up, thus the current will be close to zero when the battery is full.

Share this post


Link to post
Share on other sites

Using a standard alternator is very similar to using a laboratory power supply described here. Just as a this laboratory power supply set up an alternator will have maximum current (set by winding resistance) and maximum voltage (set by the regulator). It is just a case of making sure the voltage set is correct. 3.65 V/cell equals to 14.6 V. Most marine alternators have lower voltage.

Share this post


Link to post
Share on other sites
On 8/4/2019 at 12:34 PM, Joakim said:

Using a standard alternator is very similar to using a laboratory power supply described here. Just as a this laboratory power supply set up an alternator will have maximum current (set by winding resistance) and maximum voltage (set by the regulator). It is just a case of making sure the voltage set is correct. 3.65 V/cell equals to 14.6 V. Most marine alternators have lower voltage.

3.65V / cell is pretty much the "You will toast your batteries if you push much harder" voltage for my CALB LiFePO4 cells. 3.65V is where my BMS shuts down the battery bank to protect it, 3.55V is were they suggest balancing.

 

  • Like 1

Share this post


Link to post
Share on other sites

I only get about 94% charge capacity in my Li batteries when charged by the Yanmar as compared with a Li specific charger. Still gives me significantly more capacity than the old Lead acid. 

Share this post


Link to post
Share on other sites
2 hours ago, Rawhide said:

I only get about 94% charge capacity in my Li batteries when charged by the Yanmar as compared with a Li specific charger. Still gives me significantly more capacity than the old Lead acid. 

How fast charging do you get and what voltage do you see at the battery terminals while charging?

Share this post


Link to post
Share on other sites
On 8/5/2019 at 2:34 AM, Joakim said:

It is just a case of making sure the voltage set is correct. 3.65 V/cell equals to 14.6 V. Most marine alternators have lower voltage.

Joakim 3.65v/14.6v set point equals a murdered LFP battery guaranteed as BJ confirms. Set point of all marine alternators are way above what LFP can survive taking into account cell voltage drift depending on set up. That is guaranteed. Don't believe what you read on the manufacturers spec sheet. Don't change your charging set up to properly match LFP you are murdering your investment.

Then again Joakim your "actual" LFP experience may surpass mine and others, who knows.

On 8/6/2019 at 5:07 AM, B.J. Porter said:

3.65V / cell is pretty much the "You will toast your batteries if you push much harder" voltage for my CALB LiFePO4 cells. 3.65V is where my BMS shuts down the battery bank to protect it, 3.55V is were they suggest balancing.

BJ those CALB cells I'm sure you know start drifting out of balance big time at less than 3.5v or 14v pack and you are spot on at 3.55 or 14.2 the max balancing voltage. Even that is on the edge monitoring each cell. Mate hope that LFP set up you put so much time into is giving you dividends. Cheers.

Share this post


Link to post
Share on other sites
29 minutes ago, jack_sparrow said:

Joakim 3.65v/14.6v set point equals a murdered LFP battery guaranteed as BJ confirms. Set point of all marine alternators are way above what LFP can survive taking into account cell voltage drift depending on set up. That is guaranteed. Don't believe what you read on the manufacturers spec sheet. Don't change your charging set up to properly match LFP you are murdering your investment.

Then again Joakim your "actual" LFP experience may surpass mine and others, who knows.

BJ those CALB cells I'm sure you know start drifting out of balance big time at less than 3.5v or 14v pack and you are spot on at 3.55 or 14.2 the max balancing voltage. Even that is on the edge monitoring each cell. Mate hope that LFP set up you put so much time into is giving you dividends. Cheers.

It's literally been life changing.

Last time I checked my cells were all within .02V after charging. 

Share this post


Link to post
Share on other sites
1 hour ago, jack_sparrow said:

Joakim 3.65v/14.6v set point equals a murdered LFP battery guaranteed as BJ confirms. Set point of all marine alternators are way above what LFP can survive taking into account cell voltage drift depending on set up. That is guaranteed. Don't believe what you read on the manufacturers spec sheet. Don't change your charging set up to properly match LFP you are murdering your investment.

Then again Joakim your "actual" LFP experience may surpass mine and others, who knows.

I don't have LFP in my boat, but several of my friends have. They all have Winston 12 V batteries, which do not show terminals for each cell, thus it is impossible to know how balanced they are. Winston says 4.0 V/cell is the maximum charging voltage for individual cells. CALB says 3.65 V. I don't know the reason for this difference. Also Winston recommends charging to 3.55 or 3.65, but warns about potential damage when exceeding 4 V. They used to recommend balancing to 4.0 V. They even recommended charging 12 V batteries to 17 V: https://www.ev-power.eu/blog/Winston/FAQ-12V-LP-battery-balancing-and-charging.html So they are very likely not murdered by charging to 14.2-14.4 V which the most common (Yanmar and VP) marine alternators output as standard.

Now they recommend 3.65 V: https://www.ev-power.eu/blog/Winston/Initial-charge-voltage-levels-of-LiFePO4.html

BJ said 3.65 V is the limit for BMS cut off. Not that the batteries are damaged at that level.

So far I haven't heard of any battery failures. These are 3-5 years old installations.

Share this post


Link to post
Share on other sites

Yeah please don't charge your lifepo4 bank above ~14v

Winston says 14.6 is ok but that's under factory conditions and assumes charging completely stopping (which isn't how alts tend to be set up) and holding them at 100% voltage is bad for them anyway.

At 14v they are basically 98% -100% charged anyway, any higher and you are pushing into the 'knee' where the voltages starts spiking, and you'll unbalance your cells and risk damage for no gain.

I've had a bank for around 2 years I homebrewed and did a ton of reading before I installed it

  • Like 3

Share this post


Link to post
Share on other sites
1 hour ago, alctel said:

I've had a bank for around 2 years I homebrewed and did a ton of reading before I installed it

Me too.

Share this post


Link to post
Share on other sites

someone asked how fast do they charge, Mine take about 60 amps all the way up to 99% full,  but I have no idea why they do not take the full alternator capacity. (It is a balmar 125 amp alternator. Also it does not really matter. They charge pretty quickly.

We just did a 2 and half day ocean race and charged the battery once for 45 minutes and finished with 60% capacity left. That included a fridge (no freeze dried) and full instrument system. (that has a 200 amp system)

It does make a huge difference.

Share this post


Link to post
Share on other sites
2 hours ago, bushsailor said:

someone asked how fast do they charge, Mine take about 60 amps all the way up to 99% full,  but I have no idea why they do not take the full alternator capacity. (It is a balmar 125 amp alternator. Also it does not really matter. They charge pretty quickly.

Bush if still accepting 60A they are well short of 99% SOC. If acceptance starts at 60A with a 120A Alt they are already well north of say 60% SOC. They will accept every amp that small case alternator has to the extent being small case you run the risk of cooking it.

My guess is you have a columb counting Battery Monitor that has not been set up properly so no automatic reset at your selected 100% SOC capacity/alternator "set point voltage" so its SOC reading is completely out of wack and that error increases each time you discharge/charge. If monitor SOC governed by pack voltage even more inaccurate.

The nett effect is relying on your battery monitor SOC you are only using a fraction of battery capacity and that from mostly in the top half. Fix that and your charging time will plummet when you start using the full capacity range.

Leave your LA experience/knowledge on the dock as it hinders understanding LFP.

Share this post


Link to post
Share on other sites
7 hours ago, alctel said:

Yeah please don't charge your lifepo4 bank above ~14v

Winston says 14.6 is ok but that's under factory conditions and assumes charging completely stopping (which isn't how alts tend to be set up) and holding them at 100% voltage is bad for them anyway.

At 14v they are basically 98% -100% charged anyway, any higher and you are pushing into the 'knee' where the voltages starts spiking, and you'll unbalance your cells and risk damage for no gain.

I've had a bank for around 2 years I homebrewed and did a ton of reading before I installed it

^^^^ This ....yes charge and use don't float noting 14.2v is absolute max on a system with really good BMS.

Best storage voltage is 40- 50% SOC or say 3.15v per cell.

  • Like 1

Share this post


Link to post
Share on other sites

Bush,

You say your batteries are only accepting 60A charge rate - what's the voltage during that charging? In all likelihood, if you've a Balmar alternator you've got a Balmar regulator (neither are a good choice) and it's your regulator that's limiting the rate-of-charge, possibly due to alternator temperature. 

Share this post


Link to post
Share on other sites

I have a lfp bank on board and to save changing the whole charging systems I left a small LA for starting the engines and then a B2B charger as the only charge source connected to the lfp bank. This is full programmable for ALL voltages and and durations. It also has limits the charge current so alternators will not overheat. It does limit charge rate a bit to much, 50a, but main charge source is solar so no issues for me.

Set to 14v max with no absorbtion and then 13.2 float, which takes load once battery has discharged to 60 - 70 % with obviously nothing overnight!!

Share this post


Link to post
Share on other sites