I get the replacement cell at Batteries+. You will need a heavy duty soldering iron so you can solder the new battery on quickly and not apply a lot of heat using to small soldering iron. It is also a good idea to "tin" to negative end of the battery. After soldering the positive wire to the battery, slip the orange covers back on the battery. I then apply a return address label over the joint and then seal the whole thing with clear shipping tape. If you happen to forget your ignitor at the flying site, anyone finding it can return it to you.