Well I almost burnt the house down. Time to ask for some help....

First of all, I'm new to this. I'm posting in the the beginners area hoping not to be overrun with messages about how dumb I am.

I watched dozens of Will's videos and thought I knew enough. I put up the solar panels and bought a very expensive brand new 32 cell 48v lifepo4 battery and a good solar charger.

The cells came certified fully balanced and since they were brand new all I did was check the voltage and they were all the same. Also I thought if everything is new and balanced you don't need a bms. So hooked up the charger and everything looked good.

I left it for a while and came back an hour later to find one cell with HUGE bulges on both sides and was so hot I couldn't touch it. My kids were home so thank God it didn't explode.

Obviously I shut everything down and took it outside with a pair of gloves. Now the other cells are reading different voltages too.

I'm devastated. I don't know what to do, how to fix this, or even what I did wrong and I think i ruined my $4000 battery.

I don't know what happened or what to do now. Any help would be sooo appreciated.

Never build a battery with no BMS, the bms will keep the battery for over charging and bulging on you. The solar controller will not know when to stop charging the battery that is what the BMS is for. See if you can maybe return the cells as defective, then get new cells and a BMS and try again. If you cant return them then get a BMS and see if they can be saved.

Did you change the charge parameters in the SCC for LifePO4? Might as well post what SCC you are using and what the settings were.

Might want to show your system schematic.

PsychoticEpisode said:

Never build a battery with no BMS, the bms will keep the battery for over charging and bulging on you. The solar controller will not know when to stop charging the battery that is what the BMS is for. See if you can maybe return the cells as defective, then get new cells and a BMS and try again. If you cant return them then get a BMS and see if they can be saved.

Click to expand...

Solar controller will know when to shut down or go to float, that's what the settings are for. What it won't know is what the cells are doing.

OP, what was your settings? Did you top balance the cells?

To all new folks just because the cell are matched as they sit with no load on them (either charge or discharging) doesn't mean they'll be that way in the knees when charging or discharging, as can be seen in photo all cells aren't perfectly match.

Not the end of the world it will just cost you to replace the cell or cells.

GeorgeV7 said:

The cells came certified fully balanced and since they were brand new all I did was check the voltage and they were all the same. Also I thought if everything is new and balanced you don't need a bms. So hooked up the charger and everything looked good.

Now the other cells are reading different voltages too.

Click to expand...

That cell really expanded and didn't pop it's blow hole.

Video time... put it in the middle of the yard and keep charging it for the blow hole venting. I haven't seen any aluminium cells overcharge/ venting videos.

What are the other individual cells reading now?

Thank you for the replies. The charger is the Victron Smartsolar 250/100 for 48v. The cells were 2 groups together in parallel with 16 cells in series each group. I didn't make any changes to the charge controller's settings other than to set it for 48v and lifepo4.

The cell that blew up was the 2nd one in one of the groups.

So I guess they weren't really balanced from the store then? I need to too balance them by putting the rest of them in parallel? Can I still use the battery with the cell missing?

Sojourner1 said:

That cell really expanded and didn't pop it's blow hole.

Video time... put it in the middle of the yard and keep charging it for the blow hole venting. I haven't seen any aluminium cells overcharge/ venting videos.

What are the other individual cells reading now?

Click to expand...

Some are the same voltage and some are a little different. 3.32 3.35 3.4 etc.

If they are in that range that's not bad at all. No cell deformities in the rest of the cells? If not break them down in parallel and top balance them.
You do know how from Wills video? Order a replacement cell, bms.

Sojourner1 said:

If they are in that range that's not bad at all. No cell deformities in the rest of the cells? If not break them down in parallel and top balance them.
You do know how from Wills video? Order a replacement cell, bms.

Click to expand...

Ok. What bms do I get? I'm only confused because the ones I see on his site say 16s - but I have a 32 cell battery (16 in series + 16 in series) well, 15 now.

GeorgeV7 said:

Ok. What bms do I get? I'm only confused because the ones I see on his site say 16s - but I have a 32 cell battery (16 in series + 16 in series) well, 15 now.

Click to expand...

You need one BMS for each 48 volt pack. Two 16s BMS's.
And watch this for how to top balance.

A cell that did that in an hour while the other cells stayed in the 3.3v range was either very defective or (dare I say) connected backwards.

onemorebattery said:

A cell that did that in an hour while the other cells stayed in the 3.3v range was either very defective or (dare I say) connected backwards.

Click to expand...

Oh ok, it was absolutely not backwards. I guess it was defective but it came from China so Im just out the money I guess.

GMB said:

You need one BMS for each 48 volt pack. Two 16s BMS's.
And watch this for how to top balance.

Click to expand...

Thank you

What voltage is the bulged cell reading?

From your description of the design, and the charger settings, that cell must have been near full, and others were much lower.
what voltage were all the cells at when they arrived?

Can you post the wiring and a picture of your bank?

GeorgeV7 said:

First of all, I'm new to this. I'm posting in the the beginners area hoping not to be overrun with messages about how dumb I am.

I watched dozens of Will's videos and thought I knew enough. I put up the solar panels and bought a very expensive brand new 32 cell 48v lifepo4 battery and a good solar charger.

The cells came certified fully balanced and since they were brand new all I did was check the voltage and they were all the same. Also I thought if everything is new and balanced you don't need a bms. So hooked up the charger and everything looked good.

I left it for a while and came back an hour later to find one cell with HUGE bulges on both sides and was so hot I couldn't touch it. My kids were home so thank God it didn't explode.

Obviously I shut everything down and took it outside with a pair of gloves. Now the other cells are reading different voltages too.

I'm devastated. I don't know what to do, how to fix this, or even what I did wrong and I think i ruined my $4000 battery.

I don't know what happened or what to do now. Any help would be sooo appreciated.

Click to expand...

Who did you buy from? Can you post a link?

I have a couple questions:
You referred to your 'battery' a few times, in my experience people who purchase raw cells more often refer to cells, packs, banks in this context. This (combined with your comment that the cells were 'certified fully balanced') makes me wonder if they were sold to you as a packaged battery? If so maybe you have more recourse, at least its worth a try.

What exactly do you mean 'certified fully balanced'

GeorgeV7 said:

Ok. What bms do I get? I'm only confused because the ones I see on his site say 16s - but I have a 32 cell battery (16 in series + 16 in series) well, 15 now.

Click to expand...

I would suggest 2 x 16S BMS's . Run each series bank on its own BMS. At least if you lose one bank you are still in business and you have better control over each cell. I agree , a BMS is essential and maybe this tragedy could have been mitigated by a properly set up BMS.

Affordable Solarguy said:

I love my AGM's They like being over charged ;/

Click to expand...

If you can't help with the OP question why not stay in a dead lead thread and spread your wisdom there. Unless you like to troll.

First things first. Likely you only damaged the one cell, which puffed up. More than likely it got too much charge or took too much for some reason, it could be internal failure (not that likely) or something else wrong like bad connections. Test each cell independently and write down teh voltages and resistance, mark that on a sticky note (or tape it to cell). A BMS should have disconnected though when one cell went out of spec, this is one of the key functions of the BMS to control each cell within a pack.

Terms:
Pack = a set of cells assembled to make a Battery Pack complete with it's own BMS.
Bank = a set of 2 or more Packs configured to collectively deliver more Amp Hours and Voltage depending on configuration.

You will need to split up the packs and set the cells up in Parallel. That means (+ to +) and (- to -) so they share out the voltage and balance themselves down. They will likely have to sit a couple of days till they all read the same voltage. It may be good to do that with the 16 cells in the good pack and the 15 cells in the pack that had the wonky cell. You will have to order another identical cell to replace the puffed up one of course.
‼ Forget the puffed up cell, consider it dead and dangerous, do not use it.
Once you have all the cells back to "normalised" voltages, then you'll have to do at least a Top Balance to ensure they are uniform.

BMS (Battery Management System)
A BMS is a key component that manages the cells and what happens to / with them. A basic BMS will protect from over/under charge and Over-temp conditions. Some more advanced BMS can do balancing between the cells and even more advanced ones can do more with interactivity. A BMS can cost anywhere from $75 (basic & simple) to thousands (insane gear for EV's + bigger stuff) but for < $200 USD you can get a wide variety of choices & options for BMS'.

You mention having a Victron Smartsolar 250/100 for 48v SCC (Great Stuff BTW) but not what Inverter/Charger you have. Victron is a Tier-1 product and they support LFP quite well. Their equipment can be made to interact with LFP battery packs so they can do their job most efficiently. IF you are in the "Victron Family" then I very highly recommend using two 16-S BMS' (one per pack) which can interact with Victron Systems so you can get the most from your investment. I cannot specify a particular BMS that will interact with Victron, there are several and there are threads in here discussing such in great detail. Even threads on using the Victron Software to manage it all nicely.

Once you know the status of all your cells, you will know which ones are toast, hopefully just the one which took the brunt, then you can order replacements as needed. I very highly doubt the vendor would take any responsibility, it's not their fault. If it is only one or two cells, count yourself very lucky indeed.

BTW: Personal Opinion: Some may say going without a BMS is OK... I say it's IDIOCY ! Yes you can live in a house with no fire / smoke detector or one with, which is safer @ 3am if the house catches fire ? We put thousands of dollars into battery systems and to not put failsafe protection on them is really dimwitted and risky. We install fuses & breakers for good reason and the BMS is the Last Stop should something go awry.

This thread brings up another question: What do we (responsibly) do to properly dispose of a substantially overcharged puffed up lifepo4 cell. All batteries need to be disposed of properly, but is there additional risk in its overcharged state? Should the charge be slowly bled off somehow?

I don't believe I've ever seen a discussion of end-of-life disposal before

Regardless of chemistry I always take a battery down to flat if I'm getting rid of it (for me that means taking it to the recycler, others this may mean throwing it in the bin). It wouldn't be the first time here that someone has dropped a crook but still charged car battery in the bin and caused a fire in a rubbish truck when the battery was put through the compactor.

Sojourner1 said:

If they are in that range that's not bad at all. No cell deformities in the rest of the cells? If not break them down in parallel and top balance them.
You do know how from Wills video? Order a replacement cell, bms.

Click to expand...

Has not will said 24 volt max with lithium batteries??

Freds northwoods said:

Has not will said 24 volt max with lithium batteries??

Click to expand...

I don't recall anything to that affect, what do you mean exactly and what specifically are you replying to?