This is my 10s4p battery rebuild for the build I posted a couple days ago. That battery used cell level fusing, but I was careless and didn’t check for faulty cells, two parallel packs won’t charge above 4.1 on two separate BMS’s (also when charging each pack individually with an 18650 charger. So, I built a new one with cells that I checked individually, and I will recycle the cells in the original pack for another build.
This one doesn’t use cell level fusing, as it requires a bit more room the way I did it than I prefer (my Hummie deck cutout is the older narrower one). My future packs will use cell level fusing and will take up less horizontal and vertical space than even this pack. I did my best to make sure that the nickel strips wouldn’t be able to make their way under the positive terminals. The series connections are flat braided copper for flexibility purposes. I’ve had bad experiences back when I used nickel strips for the series connections so I moved away from that.
This is a gluing jig I made from laser cut plywood when I had access to my uni’s laser cutter.
Gluing in action
Repeated this for both sides.
All parallel packs glued up
Kapton tape insulation. I tried to mimic the way @Deckoz did his insulations on his 13s evo.
Top spot welds plus solder points (I scratched up the nickel under each solder point. How do these welds look? They seemed pretty strong, but I don’t have a frame of reference that isn’t my own. My other battery’s spot welds used the same settings or ever so slightly shorter pulses, and have held.
Negative terminal welds
Soldered the flat copper braid to each solder point. I wrapped the ends of each braid with kapton tape. I think the fraying would get worse with vibrations and make their way into the cells. Balance cables were then soldered, and connections were covered with adhesive back fish paper.
Here is the battery installed in the board. The cabling is messy, but balance cables are secured with kapton tape to the battery. Also I think soldering and heat shrinking balance cables to jst connectors is one of the worst parts about building batteries.