After seeing your post I watched a video where these firemen stress tested three different battery technology, Lifepo4 being one... and in their video over charging just caused the battery to bloat and spit out acid, I assume, or some kind of liquid, but it never caught on fire.
Not saying it isn't possible, just comparing...
I use an Electrodacus SBMS0 which stops the charging when any cell goes over a preset voltage(3.55 volts). it works with 12-volt up to 24-volt battery banks.Overcharging causes heating within a cell and prolonged or extreme overcharging has the potential to cause a fire.
I don't know the specifics of how stobbie configured his system but as a general rule:
Most BMS modules are meant to be a last line of defense against over/under charging.
Typically charge control should be a separate dedicated function/system.
IE: Best not to depend on the BMS module to control charging.
Hard to do a postmortem on a pile of charcoal.
May never know the cause of his meltdown...
Stobbie did mention that he forgot to turn his charger off during top balance:
This post makes me wonder if perhaps he damaged one or more cells while top balancing.
IE: "I've done my charge at 50 amps, but forget to turn the carger off, so it kept on charging until amps dropped to zero, and it seems that one cell has developped a very very slight bulge, only a mm or so.."
Lishen 272AH thread?
I'm going to guess cutting off at 3 volts (as measure by a meter at the cell terminals, not at the cables or any other pieces of attached hardware) will net you about 5Ah less than actual capacity. So if you get 267, then I think you'd have a perfect 272Ah cell. Thanks. I'm hoping these test...diysolarforum.com
In another post - I can't put my finger on it right now - but to summarize - I think he was having some issues with the busbars making good electrical contact. That could potentially result in the BMS not seeing the actual cell voltages.
I offer that comment as a possible justification for investing in good busbars. Personally I like the CALB busbars - five thin layers of flexible copper with an arch in the middle: https://amprevolt.com/collections/battery-accessories/products/prismatic-cell-lifepo4-busbar
Perhaps the moral of the story is - "A chain is only as strong as the weakest link" - and there are a lot of links in a DIY lion system...
I'm sure it hasn't been caused by heat in a cable (except maybe the charger, charging at around 30amps). Every cable was fused, the charger as well.
4 of the cells have swollen like a balloon, one has burst open. I'll take photo's of the cells tomorrow.
The vents on top are still closed!! They obviously didn't do their job!
They can catch fire, but rarely:
I think we would have to know if the cells were overcharged and by how much. It is normal for EVE cells to expand and contract. I don't know what is normal for Lishen cells.This post makes me wonder if perhaps he damaged one or more cells while top balancing.
IE: "I've done my charge at 50 amps, but forget to turn the carger off, so it kept on charging until amps dropped to zero, and it seems that one cell has developped a very very slight bulge, only a mm or so.."
Please take a look at my thread here if you haven't already done so.Also, I don't have lishen cells yet, but how is the outer case? Is it directly connected to +? If so, damaged wrap can cause a short also.
Mine EVE cells did have + on the outer case, but I'm not sure if it's directly connected or only a leakage current (incapable of providing huge amps)
I have noticed severely bloated cells posted by other forum members and the vent did not function. I am not an expert as to what is supposed to happen to cause a cell to vent.The vents on top are still closed!! They obviously didn't do their job!
I agree but can't be 100% certain there was an internal failure of one of the cells. If there was, would the cell catch on fire? In any event I think it's very rare for a cell to fail internally...but not saying it can't happen.No, these didn't spontaneously catch fire. They put a heater on it AND a pilot light to make sure any gasses caught fire.
Can you SET LFP on fire? Yes. Will they spontaneously combust? No.
I'm relatively certain something other than your cells is responsible for the fire.
I know you are trying to forget about your loss and again I am so sorry this happened to you. But if you don't mind, please take photos of the cells at your leisure and anything in the surrounding area you think might have been the cause. While we may never know the events leading up to this, it does give me much to think about. Thank you.I'll take photo's of the cells tomorrow.
Could there have been a loose connection to a battery?That's one of the video's I was referring to. That makes me think it was heat in a cable, caused by a short or somewhat.
Charger leads can, but I'm not sure if a few amps is enough to heat the wire to a point where it could initiate a fire
Mine were mostly in the 15-25% range when they arrived, but some were higher, like 70 amp hours higher, which made balancing fun!On a side note, my batteries arrived at 3.24 and 3.25.. 25% charged.. Is there any concern there? What did everyone else batteries arrive at? I am going to allow them to warm up over the next few days before top balancing, but wonder about the soc and if thats okay
I agree but can't be 100% certain there was an internal failure of one of the cells. If there was, would the cell catch on fire? In any event I think it's very rare for a cell to fail internally...but not saying it can't happen.
Aside from that there are several things that could have happened. One possibility is the cells were overcharged, bloated and caused the terminals/busbars to fail which resulted in arcing. That in turn started a fire.
Since the cell bloated so badly I wonder if it's possible gasses were expelled from the cell, possibly through the terminals or through somewhere through the shell, and the result of arcing mixed in with the gasses started the fire. I am no expert on this and what happened here is terrible and we may never know. So I am just envisioning this in my head.
Prismatic cells are encased in an aluminum shell. I have often wondered how much they would have to heat up before they started on fire?
from the spec sheet:Does anyone know if the Lishen 272 cells can be laid only upright on their base, on the long side, or the short side?
Thanks!from the spec sheet:
c)During the course of storage or usage, keep the cells upright .