I hope you can help me with a mysterious electrical issue that has been driving me nuts. Honestly, I don't know if the problem is in any way related to your battery packs, but I don't know where else to turn. Here's the scoop:

A few months ago I bought two of your 3cell 100mAh battery packs and like them just fine. However, I'm having trouble maintaining continuity of the connectors I soldered to the leads (batteries, ESC, and charger). I've used Deans Ultras and E-flite EC3s with the same results. At first the electrical connection is just fine. However, after a few weeks, the connection becomes less and less reliable. For example, a mere 'wiggle' is all it takes to make or break the electrical connection. Eventually, the connection becomes totally unreliable. The mechanical connection looks and feels fine, but there is no electrical continuity. It's almost like there is an invisible barrier to electrical current.

For example, I am currently using E-flite EC3 connectors. When I soldered them in place a few weeks ago, they worked just fine in my model airplane and on my Hobbico Accu Cycle Elite charger. However, when I plug the batteries into my charger now, it will not even recognize the presence of the batteries. It works just fine if I remove the connectors from the circuit and hold the wires together by hand. You're probably thinking it's a soldering issue, but I respectfully disagree. I've had enough soldering training and experience to know there's nothing wrong with my soldered connections.

Is there some other chemistry issue at work here that could be degrading the quality of the connection? Could the type of solder be a contributing factor? I'm using a 60/40 tin/lead allow that was labeled especially for "fine electrical" applications.

Just a guess, but you might have one of the fragile tabs inside the pack where your leads connect that is broken or has come unsoldered.