Originally Posted by
05forfun
I've got some information from other forum. They told me to use higher watt soldering gun(higher than 80 W). It makes sense to use high watt because the negatives generally have larger surface so the heat will dissipate quicker. I think I will buy 100 watt soldering gun to see if it works. But one guy told me he can use 40W to solder cells. well I don't know how he did it
Using a higher wattage soldering iron makes it easier to make a mistake and damage the cells. A hotter iron means you have to work quicker, and if you don't know what you're doing you're asking for trouble.
I've been using a 40w iron for years and years and never had trouble putting together packs. But if you're not using flux and pre-tinning the cells and tabs before beginning I can see how you're having problems.