By John Slaughter WB5HSI
Recently I was faced with trying to repair a battery-operated device and had the usual problem of how to make connections to the battery. Normally a spot welder is used to weld nickel strips to the battery terminals. While it is possible to solder to a battery, it is not recommended and with Li-ion batteries there is the real risk of uncontrolled discharge and fire due to the flammable electrolyte.
I found this device on Amazon and at $72 seemed a little pricey, but I found at least one review on YouTube which was encouraging, so I ordered one. Many other similar items for less money may be found on eBay. I found the identical item on AliExpress for $40.55.
No English language instructions were provided, but between the description on the Amazon page and Google Translate, I was able to figure out how to operate the unit.
Results so far are good. I was able to weld nickel strips to an AA battery easily and to a few other items in the shack including a PL259 shell and the body of a small transformer. I was also able to weld a strip to a piece of plated steel. You cannot weld to aluminum with this device. There have been many times when I have found electrical items very difficult to solder. It is very easy to solder to the nickel strips.
Your mileage may vary!