So this happened today
- Thread starter plaidcabin
- Start date
mrzed001
Voice of reason
You know why you need fuses if you parallel more solar panels/strings ?
It is the same with cells.
And this is only the tip of the iceberg why not to parallel cell ... but to parallel batteries (we can write pages about it).
How can you tell those are copper bus bars? I'm not saying you're wrong, but they could be aluminum. I can't tell.
Last edited:
mrzed001
Voice of reason
It is a universal check list
Just guessing.But manufacturers usually give Nickel plated copper busbars to cells.
And aluminium is a bit more sallow/matt. Like the ones that make the series connection here.
It is a universal check list
But manufacturers usually give Nickel plated copper busbars to cells.
And aluminium is a bit more sallow/matt. Like the ones that make the series connection here.
The bus bars between the cells and the bus bars between the parallel sets are different. Different metals? Who knows. But I do wonder if the bus bars were up to the number of amps that the battery bank could produce.
mrzed001
Voice of reason
We have very limited information in this case.
I could not identify even the cells. No info on the manufacturer. Capacity 80Ah.
The cells look like an older (3+ years old) model.
The series busbars are aluminium. I am pretty sure on that.
The parallel busbars are shiny so I guess nickel plated copper (hope not stainless steel).
The busbars placement is ... lets say not ideal.
Also we do not know if the battery was the cause of the fire.
The pack remained in one block. Even there was no compression.
And there is no brutal bloating. Pack did not open like a flower.
I will bet the first and last bank RAPIDLY became dramatically over charged, bloated and count the entire bank on fire…
It looks like bank one and 16 are 1P, with the other 4 in that bundle disconnected…
Wow… look close at the before picture… notice main positive and main negative are NOT connected to the parallel set… a fire from the omission of two bussbars…
EVERYBODY BUILDING THEIR OWN SETS… PLEASE PLEASE PLEASE… take close up pictures of everything you are building, and post them to the beginner diy forum… BEFORE YOU POWER ANYTHING UP!!!!!
this simple mistake would have been spotted by us, and we would have cautioned you not to begin charging without a BMS… we would have saved this house.
I can see it in my head… cell 1 &16 the voltage must have hit 5 or 6V when charging that big a bank capacity difference… man… what a terrible mistake.
this simple mistake would have been spotted by us, and we would have cautioned you not to begin charging without a BMS… we would have saved this house.
I can see it in my head… cell 1 &16 the voltage must have hit 5 or 6V when charging that big a bank capacity difference… man… what a terrible mistake.
mrzed001
Voice of reason
The pic is so bad, I had to open it in program to be able to zoom in on the left centre part
Good catch
That is a terrible mistake.
Hedges
I See Electromagnetic Fields!
- Joined
- Mar 28, 2020
- Messages
- 20,761
So they should have swelled. And yet, those aren't the ones ripped out of the pack.
They are however the ones with the ends of the case burned out…
The missing ones from the pack are likely the result of firemen’s axe…
I'm having trouble seeing what the issue is, could you draw on the image itself to point out exactly what the issue is?
Also seems like it would be wise to not pack parallel banks directly up against each other simply to reduce chances of an issue physically spreading to all the banks.
Look at the before picture… notice where he has the cables connected to the cells… there is a space between the terminal with the wire and the rest of the paralleled cells…
So his 5P set is 5P on all the cells in the pack, except the first set in series and the last set in series… meaning the main pack is 400Ah, and the first and last cells in the pack are 80Ah… they didn’t stand a chance of surviving without a BMS…
mrzed001
Voice of reason
Main + and Main - terminals (where the cables connect) not connected to the parallel bars (up and down)
It kind of looks like he started out making 4p and then switched to 5p. Notice that a single bus bar covers four cells and then another bus bar is used to extend to a fifth cell.
I am wondering if the other 8 cells got any charge at all, so maybe those survived the fire? It looks like they didn’t swell at all, the ones closest to the main ones got toasted bad, but maybe a few survived?
mrzed001
Voice of reason
And he had an extra 16 cells (set in serial in the bottom of the pic)
So could have build a 6p16s
The real issue here is no BMS, and if someone is too cheap and/or stupid to skip a BMS they likely did not have adequate other safety systems in place.
A bucket of gasoline is dangerous as well, that same gasoline in a fuel tank in a car becomes a non-issue because of the safety systems around it.
I don't see the 8S in the "post fire" picture at all do you?
