Swollen prismatic Eve, Calb alu cased prismatic cells

[Fuss]

Has anyone swollen aluminium cased prismatic cells…what was the cause? This would be very interesting to know as I don’t want this happening to mine.

[wholybee]

I haven't done it to mine, but the cause is pretty well understood. As the cell charges, pressure increases in the cell. If you want to prevent swelling, follow advice and clamp them to not allow any movement.
I have know of people that caused their cells to swell during top balancing, because they did that without clamping them.

[Ken Fry]

Yes, I agree with wholybee.

[Fuss]

I have 2 x 24v clamped cells and 1 12v x 2 unclamped batteries in series. One of the two 12v in series batteries are also used to start the 6l engine so it gets completely overloaded as it’s unclamped, I would expect this one to show signs of swelling, but so far it’s ok.

[Fuss]

So no swollen cells at all so far in the cruising forum, well I guess it’s not such a big problem as the amount of time and effort given to discussing it and warning on here.

[s/v Jedi]

Originally Posted by Fuss

So no swollen cells at all so far in the cruising forum, well I guess it’s not such a big problem as the amount of time and effort given to discussing it and warning on here.

Oh no many swollen Eve cells everywhere. When you look at the battery disposal sites in boatyards you have to cry when you see how many cells are being destroyed and thrown away because of ignorant installations.

[SoggyPaws]

Fuss,
You have drop-in 12v batteries, not individual cells? If so, they may be swelling inside the 12 enclosure.

It IS a thing. We had clamped EVE type cells that we installed ourselves in 2020. They are now 4 years old. We took them off the boat to do a capacity test and found that 2-3 of the 8 are pretty bulged. A couple more have discernable bulging, but not bad. Most of them had very weird results in the capacity test.

We had one cell "go high" quite early during daily charging during the year's cruising which we did lots of motoring in hot weather. Am assuming they didn't like that. (Even though we have a very good control system, including Electrodacus BMS, Smart Morningstar MPPT and Wakespeed 500 alternator controller). Maybe we didn't have a setting right, or a "cut off charging" relay did not work. We are re-doing the whole system will new cells and more capacity.

[s/v Jedi]

Originally Posted by SoggyPaws

Fuss,
You have drop-in 12v batteries, not individual cells? If so, they may be swelling inside the 12 enclosure.

It IS a thing. We had clamped EVE type cells that we installed ourselves in 2020. They are now 4 years old. We took them off the boat to do a capacity test and found that 2-3 of the 8 are pretty bulged. A couple more have discernable bulging, but not bad. Most of them had very weird results in the capacity test.

We had one cell "go high" quite early during daily charging during the year's cruising which we did lots of motoring in hot weather. Am assuming they didn't like that. (Even though we have a very good control system, including Electrodacus BMS, Smart Morningstar MPPT and Wakespeed 500 alternator controller). Maybe we didn't have a setting right, or a "cut off charging" relay did not work. We are re-doing the whole system will new cells and more capacity.

Charging lithium with the alternator can be very destructive. It’s fine when the battery isn’t fully charged but once it is, you’re supposed to terminate charging and long periods of motoring often cause prolonged overcharging.

The best thing is an accurate battery monitor that turns off the alternator regulator when state of charge is 98% or so and only switch it back on when lower than 90%. I still like to see a manual switch so it can be turned off during long periods of motoring.

[SoggyPaws]

Originally Posted by s/v Jedi

Charging lithium with the alternator can be very destructive. It’s fine when the battery isn’t fully charged but once it is, you’re supposed to terminate charging and long periods of motoring often cause prolonged overcharging.

The best thing is an accurate battery monitor that turns off the alternator regulator when state of charge is 98% or so and only switch it back on when lower than 90%. I still like to see a manual switch so it can be turned off during long periods of motoring.

Yes, agree. We do have manual switches, and the Wakespeed alternator controller set to a conservative profile with no float. Plus a BMS with a conservative profile and automatic cutoff. But we forgot to keep a close eye on the alternator charging, and I think the relay on the BMS cutoff for the alternator was defective.

[Fuss]

Ok, thanks, very interesting information, yes if motoring for long alternator periods that then overcharged the cells would not be good.
Do you know what the maximum voltage was when this was faulty? Do you know what the BMS high voltage cutoff setting was?
Thanks for the information

[CaptainRivet]

Originally Posted by Fuss

Has anyone swollen aluminium cased prismatic cells…what was the cause? This would be very interesting to know as I don’t want this happening to mine.

Not compressed is the one thing.
Overcharged by
a) too high Charge voltage
b) too Long Absorption times
c) overcharged by a charger emitting dc ripple eg alternator or wind gen. This can also Happen through an unisoltated and unfiltered DC2DC Charger like the Orion XS. BMS cannot detect dc ripple. To avoid that cut all Charge sources that contain ripple at 3.4V cell voltage.
D)overcharged by a defect charge source, eG Solar Panel or alternator going open voltage=>can BMS block 50V or is it Fried close=> BMV712 with Relay as last resort?

A very good Artikel to really understand lifepo4 Charging is from Eric Bertscher Nordkyn Design. If you really understand and put all into Place he suggests you are 100% Save. One of the Major points the BMS steers the Charge as it’s the only source that knows cell voltages, Contrary to many Gurus Opion here but Eric explains why.
A real eye opener that also reveals whats done bad by companies like also Victron:

https://nordkyndesign.com/charging-m...battery-banks/

[donradcliffe]

The above article is correct that almost all battery charging systems overcharge LiFePo4 batteries. However he way overestimates the amount this overcharging damages the batteries. I am on year 5 of running the RV on the salvaged cells from a 200 ahr battery. It gets daily overcharging from the 400 watts of mppt controlled solar panels when it is sitting in the driveway, and it gets charged at 14.1 volts from the alternator any time the main engine is running. My swelling constraint is a roll of electrical tape around the cells.

According to the article, the cells must be swollen and smoking remains. According to my annual load tests, I am down about 15%, and they show no signs of swelling. Maybe I am lucky, but I don't try to cook with electricity, and my maximum discharge rate is 0.05C.

I got my mate who has written 2 books on RV electrical systems, to put in LiFePo4. His solution is to build an old style solar controller with mercury switches which stop charging at 13.5 volts and resume charging at 13.0 volts. If I have to pay for my next set of batteries, I may follow his lead.

[CaptainRivet]

Originally Posted by donradcliffe

The above article is correct that almost all battery charging systems overcharge LiFePo4 batteries. However he way overestimates the amount this overcharging damages the batteries. I am on year 5 of running the RV on the salvaged cells from a 200 ahr battery. It gets daily overcharging from the 400 watts of mppt controlled solar panels when it is sitting in the driveway, and it gets charged at 14.1 volts from the alternator any time the main engine is running. My swelling constraint is a roll of electrical tape around the cells.

According to the article, the cells must be swollen and smoking remains. According to my annual load tests, I am down about 15%, and they show no signs of swelling. Maybe I am lucky, but I don't try to cook with electricity, and my maximum discharge rate is 0.05C.

I got my mate who has written 2 books on RV electrical systems, to put in LiFePo4. His solution is to build an old style solar controller with mercury switches which stop charging at 13.5 volts and resume charging at 13.0 volts. If I have to pay for my next set of batteries, I may follow his lead.

One or two sets of cells you are having doesn't proof anything, it's your spot estimation.
The damages done that Eric states are correct and even more on the conservative side. LiFePo4 doing only 10 years or less is a clear sign of that. That should run 15years and still have above 90% of nominal capacity. And good quality lufepo4 battery that regularly sees 0.3C and some peaks 0.5C does 20 years and is then at around 80% of nominal capacity. Even the first gen cells, the new gen should easily top that.
I have banks ran via electrodacus or even just a BMV712 that are 12 and 13 years old where the bank is still above nominal capacity but heavily cycled. Non of these banks saw any absorption at all, they where charged with fixed power supply or an MPPT with 14.0V and as soon cells hit 14.0V the power supply or MPPT cut off by BMS or BMV. An active balancer done balance during discharge till 3.35V cell voltage.

All the damage is done because manufacturer like victron need to have their charger "suitable" for many different chemistries and simply force it into their logic and because they also sell batteries don't care that these lost parameter game shortens life significantly as they make more turnover.
A lifepo4 is better off having no absorption at all as that causes less damage, an active balancer can still create the top balance during discharge in and at the knee. Still the best compromise that does the least damage.
And the best to regulate charge is the BMS who as only device knows cell voltages, no MPPT, no shorecharger, not any other charger knows cell voltages but should decide when to do absorption and finishes it, simply cannot work.

[AndyOz]

Another cause is low-quality cells. There's plenty of Chinese resellers who claim to be selling A grade cells, but are actually factory reject B or C grade (which is sometimes fine if capacity and longevity is not a great concern).

If you receive cells with QR codes removed or defaced, this is an indication of low quality cells. Also try looking up the QR code if legible, you may find the cell test results interesting.

[CaptainRivet]

Originally Posted by AndyOz

Another cause is low-quality cells. There's plenty of Chinese resellers who claim to be selling A grade cells, but are actually factory reject B or C grade (which is sometimes fine if capacity and longevity is not a great concern).

If you receive cells with QR codes removed or defaced, this is an indication of low quality cells. Also try looking up the QR code if legible, you may find the cell test results interesting.

Still no problem with a good active balancer like in the JK BMS that's not a problem. Even grade B and C can easily live 15years without a problem if treated right.
What do you think is all in these cheap Li-time, power queens or other Chinese surprise boxes for 159Euro?
The way we use them in boats with mostly below 0.3C is pampering these cells so even low quality can life very long.