Hi guys,
I’m working on a battery repair. I won’t name the builder, because its irrelevant right now, but wanted to go over what my plans are to attempt to repair this battery and see what you all think.
For starters, I had to open the build multiple times to check the P group voltages since it wouldn’t charge. On 3 occasions now, I’ve found multiple groups way out of range. I’ve now opened up the pack, and found one P group that had a cell with obvious signs of distress. It was corroded on the + terminal big time, and the shrink wrap had been compromised. Image of the compromised cell with wrap removed for posterity included. On those multiple occasions, I simply “manually rebalanced” the P groups in question.
Opening the pack I realized I wasn’t fond of many things about the pack, but I don’t want to completely disassemble/reassemble the pack for many reasons.
First, I do want to replace the balance wires and connector once my replacement BMS gets here, ordered from LiTech Power, I’m hoping it comes with the connectors and heatsink, but please let me know if you know otherwise. The balance wires will be made to be all the same length, using silicone wire, and completely replace the existing wires. I will be soldering onto the same existing pads.
Second, I plan to replace the serial connection between P groups 1 and 2 using copper plate sandwich method. I plan on spot welding a manually cut out shape, image included, of .2mm copper sheet to fold in half using nickel strip to provide resistance as described on endless sphere. I want to do this to avoid the hodge-podge of overlaying nickel strips and folds for serial connections, as they have shown to be a major cause of concern on this pack. Among many things, I don’t like that the discharge wires were coming out the skinny ends of the P-group, instead of at the very least the middle.
Third, I plan on replacing the + and - collector ends with the same described sandwich method, except here I plan to make the “solder pad” in the middle of the P-group.
Fourth, I’ve added fish paper running down the middle of the pack as there was nothing there, and I don’t want to become the Lithium Surfer.
Does anyone think that the other gajillion joints/serial connections need to be revisited anyways? At this point I feel like repairing the things I’ve pointed out are going to be good enough.
Thanks in advance everyone.