big problem with battery pack!! please help

[tc3guy]

I have started to make my own packs and i was finishing my first one yesterday, and I took it out and the hole thing fell apart. Then I tried again after scratching the ends with scissors. Some of the bars stayed on but not all. And yes I am using 60/40 rosin core solder. :confused: :( :mad:

[nsane]

How how it your iron? You are probably getting whats called a cold joint, where the metals on both sides haven't been hot enough to bind.

[Railman]

Like insane said, you need a lot of heat to build packs. I also like to clean the batts with a scotch pad or #300 or so wet/dry (autobody type) sand paper. Then you need to put a little solder paste on the batt & then tin it with a little solder. Clean & paste the connector also, & then it's a piece of cake if you have enough heat. If you don't have an iron that's hot enough , you can get by by using two smaller ones; if you can borrow another small one. What a lot of guys do is buy a cheap big iron just for packs. Let us know if this works for you.

[marvi]

youll need a very hot iron for solder to flow easily. but dont leave it on the cell too long as heat may damage it. use a battery jig to make it easier. to make my packs stronger, i individually heatshrink the cells, then assemble them using a jig. then, i CA the cells together side by side. the individual heatshrink protects the original labels of the cell. also, if you need to rematch them, you just cut through the heatshrink.