My Bestech BMS seems to have shorted and caught fire while soldering.
In shock right now… The fire extinguisher failed (fell out of charge…). Had to use a damp rag to put out the fire. Quite the disaster. Burnt BMS. Possibly burnt battery pack… Hundreds of dollars of damage… But all else is well, thank God.
My 8s4p li-ion battery pack had been finished earlier, and I was on to soldering the very last wire to the BMS… A black negative lead (from the load / anti-spark switch / VESC) to the “P-”… Everything was connected except for P-. I’m really not sure how it all burst into flames?
The P- wasn’t even hooked up to anything, apart from an unplugged XT90! There was fire before I even connected the negative wire to the P-.
The last thing I vaguely recall doing was putting a droplet of flux onto the P- connection. I think so anyway, as I did that to prep the C- and B- the same way. It’s all hazy right now. Next thing I see is smoke and flames… Maybe the droplet was too big? Maybe it seeped through the PCB, connecting the C- (red positive lead) to the P- (black negative lead). – Looking at the underside of the PCB, these two connections are really close, like 1-2mm. So, maybe the flux seeped through?
It’s a sticky mess right now. Hot glue has melted everywhere. Even small melted solder puddles. A couple of nickel tabs came off the 1st series connection. Heatshrink has melted everywhere, both the original layer and the 2nd layer I added. But somehow the battery is still registering 25.7v (was ~26.2 earlier before the fire), so 3.21v per cell.
Is the battery ruined? What should I do? What went wrong? Should I try again and connect my 2nd BMS? I’m shocked and confused, uncertain how this happened. I thought I was doing everything right.Uploading…
- BMS Model: HCX-D223V1LI10S80A-06
- Battery: 10s4p Li-ion, cardboard ring sealed, shrink wrapped each cell, soldered nickel strips
- Load: NA. Nothing connected.
Please help if you can. Thank you.