u/NJSpro

I finally decided to add a spotwelder to my toolbox of electrical doodads and testing apparatus! I'd appreciate advice on this kit I put together. The BMS says it's rated for 30 amps, but that probably needs a heatsink on the mosfets since I measured a 130mv drop across them for a 7 amp load, they were getting warm.

Should I add any more insulation before dropping it into the case? It's a tight fit and I don't want to pry it back out....

Are spicy pillows welcome here? I couldn't find anything in the rules.

I've got 105 of these pouch cells. I'm thinking of using 50 of them in a .30cal can with a 5S10P configuration. I read that these have some expansion when used. Is it significant enough to worry about? There's a couple of cells worth of space in the bottom of the can. I'm considering running each group of 10 cells into an XT60 connector for serviceability, what do you guys think? I've also got some rubber for the bottom and fish paper for the walls.

I've never built a battery before, but I am very excited for this. I would appreciate any and all advice.

What are everyone's favorite homemade tools, apparatuses, jigs, modifications, or even art?

I'm working Industrial maintenance for production lines. In the absence of issues and radio calls I have quite a bit of free time to work on custom tools or anything really that would save us time. I have access to welders, grinders, saws, lathes, mills, all the popular machines in shops. A material rack of misfit and left over steel along with a wall of 12.9 socket head Allen fasteners.

Never seen an 18650 fail like this before, looks like leaked electrolyte and corrosion.

Sidenote, I'm looking to spotweld in two replacement cells. I currently have another dewalt 5 AH that also has two bad cells model ICR18650HE2. Would it lead to an imbalanced pack if I combine 2,500mah cells in series with these 2,000mah ones? Or vice versa. It seems like a bad idea given my understanding of the tool and charger voltage cutoff