Battery Mixing integrating Lithium Lifepo4 AGM or Gel

[Screen Saver]

Ok, I know Im out on a limb here with the general consensus.
What I’m looking for here is a technical explanation as to why not, or how to, run a mix of AGM/Gell and Lithium
The attached shows my current setup, and my thinking of how I will integrate lithium.

So firstly some information:

My existing Gells have a max charge .equalization of 14.4 to 14.6
The Lithium’s Im looking at are LifePo4 192ah Max charge voltage 14.6 (3.65 x4) So same
My Max charge amp can not exceed its 120amps, so also within spec

I have 2 x Rita 260amp Gells ( had 3 one swelled prompting this)

Let us assume a staring point where Gells and Lithium are in parallel and fully charged So 14.6 to 14.8v on house
This is within Gell and Lithium spec. for say equilzation
Charger is removed and load applied say 10 amp for the sake of discussion.(in my case reality is around 14amps)
The whole bank will drop quickly to 13 and then to 12.8 and its likely that the Gells will carry most of that load initially.
Perhaps even a little will trickle from Gell to Lithium. ( so some loss as Gells try to put a bit into Lithium, at a guess well under 0.5amps for a few minutes)
As the load continues, Gells will drop to around 12.8 and Lithium will start to pick up more load.
Eventually because lithium tends to hold its position (approx. 12.8), Gells will do less as the voltage is dragged down and Lithium will do more.
At this point lithium will start to pickup more of the load and gells will see a voltage that is being maintained by Lithium that does not cause a drag on the Gells, because its being held up by Lithium.. So yes now some trickle from Lithium to Gell will occur.
If one continues with the load, eventually the lithium will begin to collapse and shut of as it approaches fully discharged.
Given we are not supposed to take Lithium below 70 or 80% to keep a good life cycle we should have stopped the discharge before fully discharging lithium, which would be well before we risk damaging the Gells.

If we now apply a 120AMP 3 stage charger and don’t breach the peak charge values (volts or current) they will suck up whatever they need..
Presumably the Gells being not fully discharged would suck up little and reach peak voltage before the Lithium. But in any event the set that has not reached 14.6 for example will beholding down the voltage sucking up the current.
When the bank as whole reach fully charged, the charger would return to float .

So given the Lithium would have a BMS (Battery Management system of its own to protect it, and accepting there is some disparity between the two types of batteries, I don’t see a major issue or major losses.

Given so many people have pondered lithium and I’m sure I’m not the only one to think like this, someone please give me a good technical answer as to why I’m wrong. Better still if anyone has tried this. ? Cause I think I will try it.
My fall back if I completely stuff this up is to put a DC to DC charger between Gell bank and lithium bank and move the load to Lithium

All input welcome

 

[Will Gilmore]

So given the Lithium would have a BMS (Battery Management system of its own to protect it, and accepting there is some disparity between the two types of batteries, I don’t see a major issue or major losses.

It is practically hammered into us by all the literature, that you don't mix battery types or sizes. I think you have the answer to your problem right here. Separate individual controllers. I don't see the problem except as having to do with the dangers of uneven discharge and poor supply over inadequate conduits, possibly causing overheating with over draw on one battery or another.
Great question. I can't wait for an informed answer.

-Will (Dragonfly)

 

[dLj]

I'm no expert in this. But it's a subject I'm very interested in. I'd suggest you read this before moving forward:

Marine lithium batteries in operation | Nordkyn Design

This article details the relations between voltage, state of charge, current and temperature for lithium iron phosphate (LFP or LiFePO4) battery banks.

nordkyndesign.com

It would be my guess that most of your assumptions above as to how these two battery types would interact are not quite right. I think you would have to put the two seperate battery systems essentially on their own circuits and not allow them to interact with each other. Charging your LifePo4 batteries requires monitoring both voltage and current. Overcharging of them is very bad. This is not at all the same as your lead acid batteries. I just don't see how these two can play well together. For sure, keep us posted as to what you do and what you find out. I, for one, am very interested.

dj

 

[capta]

It has been explained to me that LifePo4 batteries are not to be charged to full capacity, but operated in a range below full charge. As LifePo4 batteries are a completely different technology, I think you need to do a lot more research before you jump into using them in conjunction with conventional batteries. You do not seem to understand the technology.
You are pretty much the first person I think I've heard of who is using gel and LA batteries and if the swollen gel is an indication, it isn't going very well for you. But dropping a LifePo4 cell into a bank of other tech batteries sounds extremely dangerous to me. You certainly are not going to be equalizing the bank if you do.
Maine Sail has a lot of good info on his site RE: LifePO4 Batteries On Boats. I suggest you read that before proceeding any further.

 

[SG]

Screen Saver,

In response to your question, I'll relate what I was told and what I've done to utilize Lithium Ion Batteries which we decided to install after I'd have enough of my AGM woes -- but that's another story that I've related here before.

The simple explanation is it's not the Lithium Ion's cell functions that are a concern, it's the "on-top" electronic controls and monitoring system that are built-in to each battery that don't like variable loads imposed between batteries in a bank. Anyway, below is what we did, and why.

Steve

We have two large Relion Lithium Ion batteries for our house loads from which is Bank 1. We have a separate "emergency" AGM battery on a back-up, second circuit ("Bank 2 - Emergency").

We also have separate, dedicated engine and generator start batteries which are Optima spiral AGMS.

Our Mastervolt inverter/charger system allows us to monitor and charge the two house banks separately. We charge our batteries off the generator or from shorepower with the AC through the Mastervolt system. When we are under way and using the main engine from the main engine, we have a 250 amp Balmar which has a smart regulator which charges the "real" House batteries on Bank 1 and the "emergency" or back-up Bank 2.

If we are running the engine and the generator we can be dumping a LOT of amps back into the Lithium Ion Batteries. The Mastervolt monitors AC charging independently going to the "real" or main house Bank 1 (Lithium Ion) and the "emergency or back-up" Bank 2 (AGM). The

The Relion Lithium Ion batteries (like most of the batteries that I looked at) have their own protection system built on-top of EACH of the batteries. Among the things this "on-top" system of electronics does it to protect each battery from overcharging or over-heating. It measures each cell and other components which make up each battery. It the battery and its components go out of range, the "on-top" electronics shuts the battery OFF and locks it out. If this happens for some reason that is simply overheating. I'm told the system will reset automatically when things cool off.

I was told that the Lithium Ion batteries in a bank do not like to have one battery which is dramatically different than the same level as others. They don't like to either have on battery taking more charge coming in, or providing differ loads going out. I believe this may because of the "on-top" systems built-in to each of the batteries; or if might have to do with the concerns with individual cells within the battery.

This would especially be a concern if we used one-battery and then loaded-them on together. (e.g., ran on "Battery 1" instead of "Both", then after the Battery 1 was run-down, then switch to "Both"). I was told it wouldn't be catastrophic, but it might cause the system to have false shutdowns; and that there was no reason to cause unnecessary complications. T

The reason that I added the "back-up" AGM for a second bank was the following:

If for some reason the Lithium Ion controllers shut-down one of the batteries, then the other battery in the "Real House Bank also shuts down, then, they would both be disconnected.​

​

If your Balmar 250 Amp alternator is trying to charge the batteries, it would see NO battery and it's diodes could get fried.​

​

By having an single "Emergency" AGM sitting as Battery 2, then the Alternator would have a place for the smart voltage regulator to send the current to. The diodes would be protected.​

​

Also, if for any reason I don't like what's happening with the Lithium Ion batteries, I can simply switch from Battery 1 to my Battery 2 ("Emergency") House bank. In normal situations, I never intend to use the banks in "BOTH" in normal situations.​

​

We cruise from Annapolis to Maine each summer. I don't want to stuck without instruments or power for a variety of reasons. I can alter our electrical loads within reason, but I've built redundancy into our systems.​

I have done this with a assistance of a experience marine electrical group and certified marine electrician. I've had our electronics installer and (when in Maine) had other really competent groups look things over. I'd caution you to consider that your batteries and electrical system has a variety of situations which are interactive. There are multiple sources and combinations of situations of charging, regulating, loading your systems.

 

[Screen Saver]

The response below are not for a minute suggesting I’m right, they are my thinking out loud and answers to some of the comments, in the hope that someone with better technical knowledge than I will agree or shoot it down technically.

Yes it is hammered into us for sure that one shouldn’t mix battery types., but many (not all) of these things are manufactures design spes in there closed world. I run 4 different charging systems, this was said to be a no no as well, due to equalization /float and while a completely different subject, I carry one !!! oil. This oil goes everywhere, Main engine (turbo), genset(std Diesel) outboard which is 2stroke again said to be no.. All have been fine for over 10 years now. If there is a good technical reason (which is what Im seeking) then yep I will do as I’m told, ie Yanmar oil filters, anyone not using the original yanmar oil filter would be just about the same as leaving it out completely, and there are sound technical reasons for this not just Yanmar trying to suck us dry. Your local shop where you buy your third party oil filter won’t have a clue, and will tell you it’s compatible and your Yanmar dealer wont be able to tell you why or what the difference is.

LifePo4 now days with BMS seems to be heading towards drop in replacement for most situation, even to the extent that as stated above don’t charge them to 100% which of course a car or standard alternator cant do, and many of the BMS systems are trying to make it idiot proof.

In regards to cable sizes over heating disparate discharges. All cables sizes are large (0 or 00)already in order to carry 150amp DC adequately, Uneven discharge at some level is a given, but unless it gets substantially out from some catastrophic failure this happens within any battery internally and again with in any bank of batteries. and as within conventional battery banks any dead or lazy cell or battery will have a knock on effect.

Charging for LifePo4 has only minor differences between say Gell or AGM and that difference is around threshold levels. All battery types should have charge current monitored and my system cannot exceed any of these specs especially Lithium. . All should have voltage monitored and the top end voltage recommended for LifePo4 seems to be around 14.4v ( 4x 3.6v cells) but there are suggestions that damage will not occur till around 16.2v. and also that you should not fully charge Lithium to 100% So the voltage range is quite wide.. In terms of float voltage unless your vessels sits on a marina for much of its life, which in my case its not liable to get the opportunity to sit a float voltages for long LifePo4 doesn't care. One cloud, another beer from the fridge, the ice maker or any of the systems will soon nock the float voltage off.

Yes my technical knowledge is lacking there is little doubt and as suggested and this is why Im asking. Differences in technology or internals are not that relevant so long as one follows the rules or meets the requirements of the batteries in question.. My swollen Gel is only 1 of 5 I have ,that are now 4 years old. Perhaps I am naïve but I do not put this down to my configuration. I put it down to a Gell failure. The others are running around 70% efficient which given their use and age is probably fair ware and tare.

It was suggested I was not going to be able to equalize in my proposed config. I would be interested to know why not. LifePo4 wont care. AGM is the highest at around 15.5 to 16v and in theory Lithium wouldn’t care until it exceeds 16.2, plus the BMS should shut off Lithium before it gets that high, Gels Equalization is much lower around 14.4 and in my case the manufacture says 14.6, so I think should be able to equalize.

SG/Steve; I appreciate your feedback and input. A quick look at the Relion website would suggest that in your case the ontop electronics which I assume is the BMS is packaged into the battery case. At this point I am looking at basically starting with 4 separate cells to make up the 12v (200amp) and a BMS system as all individual items. Essentially so 1 cell failure, or a BMS failure does not cause me to toss out the lot and the price is of course considerably cheaper, which may or may not be smart. Because Im looking at integrating these with Gells (if possible) as a bit of a test even if the BMS disconnects the Lithium, my Balmar alternator will still see a Gell load and hence not damage the diodes. I think I have only once run Main and Genset together. While I have the capacity to probably supply 350-400amps if I add all the charging systems together only in the event of Multiple Catastrophic failures resulting in a low resistance, hence very high current draw can I see any cause for concern.

Yes I believe in your case the joining of both banks could be a problem. Mainly because they did not start together, and or there could be a significant difference in the banks states, resulting in a lot power/current going one way or the other. However if the joining was planned, when batteries were floating at very near the same point. I do not envisage you would have a problem if you joined them.. I have done this between AGM and Gell, but not Lithium.

 

[SG]

Screen Saver,

Are you from Sydney, Australia? If so, my condolences to all of you, your fauna and flora.

Beyond that, I believe that LiPo batteries are really made up of a number of assembled cells. I appreciate your view that the range of tolerance is supposedly going to allow you to ignore the general admonition not to do what you are contemplating. As with propane stoves on boats, into powered race car engines, and nitro glycerine, sometimes over thinking and circumventin admonitions can lead to disasters.

I have known diabetics that drink alchohol and thing they can work their through their desire for alchohol, desire to live dangerously, and their imbalanced systems by creative pharmacology. Sadly, they passed early and not well.

At the very least, why screw win it over either sticking with AGM's only, or just bit the bullet and do it "right". If you're wrong, you might lose your boat, hurt others close to you (or those collaterally around), or hurt yourself.

Sorry if you think I pontificating, but it concerns me.

 

[Screen Saver]

Yes Sydney is or was my home. Left there 10 years ago to go cruising, so family friends etc still there, thanks for yuor thoughts.
No problem with any views expressed. Im not the only mad one here looking at this just so you know, and it in fact it wasn't my idea, but I tend to agree with them this should be doable. We have a few variations on the design/implementation and I think we are each gong to try a slightly different variation perhaps even slightly different products, pending anyone coming up with a flat-out technical show stopper or risks getting higher. The risk of fire or explosion with this technology is not like phones etc, its vastly different and in fact arguably no more dangerous than an AGM or Gell which can also suffer thermal runaway, internal shorts, load dumps etc.
Here is the replacement to current LifePo4... next generation. Next gen Lithium

 

[dlochner]

Yanmar oil filters, anyone not using the original yanmar oil filter would be just about the same as leaving it out completely, and there are sound technical reasons for this not just Yanmar trying to suck us dry. Your local shop where you buy your third party oil filter won’t have a clue, and will tell you it’s compatible and your Yanmar dealer wont be able to tell you why or what the difference is.

Yanmar oil filters are rebranded Racor filters. Look at the model numbers, 4230 Yanmar filters are Racor 230 or 20 filters.

 

[Screen Saver]

It looks to me as though those numbers are fuel filter numbers. I was referring to oil filters. If you believe you have an equivalent oil filter to Yanmars send me the specifications as I have yet to find any out of about 15 I have looked at.

 

[dLj]

I'm rather looking forward to new technologies in batteries:

IBM Blog

News and thought leadership from IBM on business topics including AI, cloud, sustainability and digital transformation.

www.ibm.com

Unfortunately this likely won't be ready for prime time when I'm ready to build my system, so I imagine I'll still be looking at the same battery systems you are, but here's to hoping!

dj

 

[dlochner]

It looks to me as though those numbers are fuel filter numbers. I was referring to oil filters. If you believe you have an equivalent oil filter to Yanmars send me the specifications as I have yet to find any out of about 15 I have looked at.

Check with Wix. The number for a 3JH2E is 5138. Wix has a good cross reference chart. They are also better than Fram and other brands. In the US, Wix makes filters for NAPA.

 

[Screen Saver]

Hi Dave, Yea, been there done that as they say. This is exactly my point. Im sorry to say the one they show as compatible for my 4JHTE (and your 3JH2E) is no where near it. Yes it fits, but that all you can say about it. Its NOT compatible.
Short story version; I go to buy new oil filter, tell the guy I want one of these (non original after market) , he says yep here ya go and whats it for. For Yanmar, he takes the filter back, says which model. 4HJTE, he says that's not compatible, and more over he says none you buy here will be (same in Ozy by the way). He says I can sell you anything anyone one can, but it wont be right and they wont know or tell you. He explains 99% of oil filters have a filter by pass built into it, so if the filter blocks, the engine at least still gets oil. Weeeee news to me but makes sense. He says modern day diesels run a much higher oil pressure than they did years ago. After I provided him a number of alternatives I had used in the past, he said all of those were a waste of time you need not have bothered, they all have a relief valve that is under 40psi and hence it will be in bypass mode as soon as the motor starts. Stunned I checked up my self, he was right all had the pressure relief valves well under 40psi ( about 11psi in the case of Wix where you pointed me) and all would have been doing nothing. I then check the Yanmar one and yep it was up around 55 as I recall. Many do not believe my story and live on the fact they have always used x y z. Check it yourself, Oh and its not just the 4JHTE by the way, I checked yours too, bypass is 11-14 your engine should be running at greater than 25 PSI, possibly as high as 65, so if your using there filter I suggest its doing nothing for you.

 

[Screen Saver]

Update:
Well I have just approved an order for 2 banks of 200amp Lithium Phosphate batteries, so 8 cells @ 3.2v.
It was not my intention to jump in this deep given there are some obvious risks and I thought I was on the bleeding edge trying to do and go where no man had been before.

However given there is a bunch of us the price is right down with only about $50USD difference between Lithium and AGM on dollar terms alone, let alone life expectancies, and available amp hour calculations and cycle factor, it seemed silly not to move forward.

So the purest will tell you the concept will never work, however some have done this or variations and the numbers, theory and logic (well my logic anyway) still seem to stack up.

Just a small example where Im headed.

AGM is fully charged at around 14.4/14.6 and will likely suffer irreputable damage at 14.8 (equalization for long periods)
Lifepo4 is the same, although you may be able to go higher without damage, but 14.6 is typical cut off and if you put Lithium through 14.8 AGM equalization cycle, the BMS for Lithium should cut it off, and if no BMS the battery should still be fine at 14.8, although not ideal.

AGM float depending on your desire to run the battery near its limits etc or slightly below to extend its life, is around 13.5 – 13.8. which in Lithium terms that's 3.45/cell. However at that Lithium is not full, perhaps around 80-90%, so in theory less stressed.

AGM discharged to 50% will still be above Lithium cut off. So if we have managed our AGM’s properly it wont be a problem for Lithium cause it should never approach cut off. AGM will pick up the initial load after charging stops, soon followed by Lithium. Lithium cut off 2.5v/cell or 10V should never be reached if we manage or AGM’s to say 50%

On the charging phase, given we have not discharged below AGM 50% range Lithium will be well cable of dealing with anything most of our charges can throw at it. So my 120amp charger will be fine. It will set it to stop at 14.5 which is roughly 0.1 above what AGM likes and 0.1 below the cur off for Lithium

As for imbalance between the AGM and Lithium, or to stop significant draining of one to the other, 40amp Shotkey diodes have been used, or DC to DC chargers.

In regards to imbalance within Lithium, this is essentially not different to AGM. It happens as cells change over aging. If you think your AGM don’t have this problem trying running a digital laser thermometer across the top of your AGMS, and you will find and see the cell temperature differences. It would seem less aggressive charging promotes less imbalance..

The risk of Lithium going open circuit due to a high cut off, and then blowing your diodes in your alternator is also reduced by retaining AGM (or some other load). But again when Lithium cuts of at say 14.6, your alternator wont be doing much and probably your instruments, chart plotter etc which would also be cut off without AGM or in that event this would be enough to stop the diodes blowing.

As to fire explosion or other such things. Lithium Phosphate is said to be no more risky from thermal runaway than other technologies we use, and in my case said to be good to 130c and my AGM’s good for roughly the same.. The Lithium’s I have bought are short circuit tested, that they do not explode or catch fire. I cant find this information for my AGM’s

So I will not update this post further until I actually start to build it in around 21 days.

Happy to answer and consider any comments of course good bad critical or otherwise and I know there are many skeptics out there, but this is where I’m headed..

Happy sailing off to Taiwan and Japan soon, so if you see a glow in the sky, I got wrong and you can say I told you so.

Take care
Alan

 

[Ron20324]

Happy sailing off to Taiwan and Japan soon, so if you see a glow in the sky, I got wrong and you can say I told you so.

Sorry to say, mate, we're already seeing a glow in the sky from your direction. Best of luck.

 

[dLj]

I am very much looking forward to you not exploding, and reporting back on how it worked, both good and bad...

dj

 

[Maine Sail]

Happy to answer and consider any comments of course good bad critical or otherwise and I know there are many skeptics out there, but this is where I’m headed..

Did you take the time to read the two links shared with you in this thread? Based on your statements it does not seem as if you did?

LiFePO4 Batteries on Boats

Nordkyn Design LiFePO4


.

 

[thinwater]

The only situation that makes sense to me is if the boat is fundamentally powered by Li, but must support a sump pump in below freezing conditions. This is a tricky one, because you can't change Li when below freezing, so a separate LA system is needed. You can store Li below freezing and the self-discharge rate is low, so this would only be challenge if the boat were in the water during seriously sub-freezing weather.

But that's an oddball.

 

[dlochner]

Happy to answer and consider any comments of course good bad critical or otherwise and I know there are many skeptics out there, but this is where I’m headed..

Happy sailing off to Taiwan and Japan soon, so if you see a glow in the sky, I got wrong and you can say I told you so.

I can't speak to the mixing of AGM and LiFePo batteries in one bank, perhaps you are on to something, perhaps not. I do trust @Maine Sail's opinion and knowledge.

Whether it is a viable system or not, it is clear that this is not a mainstream, well-tested system. Setting off on a trans Pacific crossing without having spent many hours, days, and months actually using the system seems particularly poorly advised.

Be sure to have all your affairs in order before departing and do not tell your life insurance company or your creditors of your plans.

 

[Screen Saver]

Main sail:
Yes I did re read the links , not much sense in asking questions and then not bothering to read what responses are.

In fact based on your prompt I have spent the morning re reading. So some short response overall is below. But if something specific that sticks out, feel free to be specific or ask how I will address X perhaps I have missed something.

Perhaps its worth understanding, that I have fairly good control over all my charging systems, and was neither looking or considering for a moment I would just put in a “drop in” Battery, let a loan in parallel to AGM/Gell and expect not to change any settings. That for sure would light up the sky rather quick I expect and if not at least burn my pocket. The other point to remember is I will make the settings fit LifePo4, not the other way around. So in theory any suffering should be slanted to wards ageing AGM's which I am prepared to lose.

I have also just backed up on the BMS system, because I had no control over it, it was not pro-active and had no audioable warning systems. So my BMS I will have control over, it will have visual display and it will have alarms.

Insurance: in my case not applicable anymore. Given recent market happenings I have cancelled mine.

LifePro Drop in verse single cell.. A lot of the article negative comments are pointed at drop in solution, which mine is not. The drop in solution I personally do not believe meets cursing boats requirements, plus there no way to monitor individual cells (essential in my view), balance cells, and to be able to replace just one cell, reconfigure the setup. So I have chosen single cell config in packs.

LifePo4 chemistry. Is in my view the only lithium chemistry to be used, and I have yet to read or hear of any LifePo4’s catching fire, or exploding from thermal runaway. The significant amount of current they can deliver should be respected and in my case I believe the weak link is my 00 AWG wiring. If due to some failure that sat with say a 200amp load for continuous for 30 min, then I suspect these wires would get extremely hot.

BMS ratings. Short comings: Yes I agree with the article in regards to BMS. As stated above I will obtain control, so I can shut it down, be warned before a risk of damage (ie lower thresholds) and with alarms so I know.
In my case load or charges are contained to 100amp 90% of the time. Loads or charges above that are for very short periods only. The other point made is any warning auditable alarms etc, are hard to find and Bluetooth is fine for the technical geek, but I need something that warns beforehand, while I’m sailing or drinking my scotch and the phone is off or flat.

Alternators Diodes: Yep I believe I understand this one and have a number solutions, not the least of which is retaining an AGM. However there are many way to address this. In my case I will set my Balmar with external ARS ( regulator) not to exceed 14.6v, and I will see that a load is maintained in the event for some reason (solar perhaps) does exceed 14.6. Interestingly the article actual says…” is to keep a buffer “load” on the charge bus at all times (load = a battery on the systems charge bus) “ in effect almost exactly what Im doing, or DC to DC charger my backup plan if my design doesn’t work.

Charging speeds: The article is promoting high or fast charging speeds, ie .3C or .5c, (120amp or greater) I have no idea if this is right or wrong. However there is a body of evidence suggesting the opposite from those who have 6-9 years up on there Lithium and running at much lower charging speeds. While I can do .3C (almost from Sola) I wont be doing that. My batteries are rated below that and I believe based on my own research 0.2c charge is better.

Weight:: For a mono its irrelevant in fact probably Im better off with the weight, given they are below water line.

Steady Voltage: The fact that LifePo4 should maintain 13.2 approximately for most of its discharge is both beneficial and important to me, as this is what my AGM in parallel will see. While not ideal for AGM (to low) my priority is to Lithium. I do not expect the lower 13.2 volt will be a problem for AGM. So in my system Lithium will be programed to disconnect before the Knee and AGM will take over. Of course the proof is in the pudding as this is pretty much uncharted ground.

Using GEL Charging profile on LifePo4. The example quoted in the article holding Gels up at 14.2v for 4 hours and thus risk damaging his LifePo4 using that profile I do understand. I would have thought any half responsible multistage charger would not do this. Mine is xantrex, not top of the line, but in simple terms as stated LifePo4 hitting this voltage is not detrimental, unless its sustained and the battery is already full, in which case it could be argued its verging on float voltage . In my case 3 factors are examined in deciding whether to hold the absorption cycle.. Have I put back the AMPhrs I took out, if I haven’t it can not be full. Is it still soaking up more than 2,5,or 10 amps, has the current been (+ or -_) stable for 30,sec, 1min, 2min. My charger will not reset absorption phase unless 20% of the amphs have been consumed. So the event described would not happen in my case, unless I screw up the programing.

Floating LifePo4’s: Yes I agree with the article and in fact have two friends that have lost 4 cells from floating quality LifePo4 cells at traditional levels. In my case as a continuous cruiser hardly ever on shore power, floating is not something that is typically maintained for long periods, plus there seems no clear answer to this question..

I think his maijor points should be the objective. Get it balanced, don’t run it at 100%, monitor individual cells and keep them in spec, don’t run traditional floats, don’t run absorption based on time.

Thinwater: I have no intention to go to freezing waters, so I do not need heaters to charge my Lithium. Im a tropical cruiser… well Japan perhaps is not but, we will see.