Issues with spot welding

[justwannaweld]

I recently bought a spot welder for my 10S2P 21700 battery pack, I'm using 400A 12V car battery. Also I'm using 0.15x10mm nickel strips.

The issue is that welds are weak (0.1mm are fine), but the thing is after 4-5 welds welding "prongs" and wires get noticeably warm to the touch (wires are 12AWG, 50cm in total). My question is are the wires to thin/long i.e. should I double them (since 12AWG is all I have)?

 

[docw009]

The red/black cables on your little welder are only 12AWG? Sure. Double them. Good luck. These little welders are not very reliable. I've wasted a lot of money on then, but do have one that works.

I use this one, but had to modify it for reliablity per youtube videos. I'be done over several thousand welds with it, mostly ,15mm nickel, It works best with a RC drone battery, 5AH, 70-140C. With a 12V car battery, the welds are burned. They don't sell it on aliexpress any more, so I'm glad I have a spare,



I tried this purple one. Seemed pretty powerful, but it blew up.

 

[calab]

Heating up would be the wire but maybe the internals of the tab welder are heating up too, might have to add heat sink to the mini tab welder, see what components are getting hot. Use pure copper for the probes, be sure the connection between the copper probe and the wire looks good and solid and shiny.

 

[justwannaweld]

Ended up using 0.1mm strips (stacked 3 of them on each connection), my guess is probably the welder,T if I were to do it again I would opt for something like this