The battery builders club

Iv been trying out settings on cheep eBay battery and 0.3mm Nickle strip increasing then pulling it off with pliers. It started to get stronger about the 120j and I can feel the heat building guessing about 40 deg if I toutch it straight after welding heat gone after a second. I’m worried I’m using to much energy. What people’s opinions? More or less?

130j I started to rip a hole in the Nickle when pulling it off on 1 contact. 100j seemed to start to leave a little Nickle behind.