An important thing to keep in mind is that the solder tabs will not hold up of movement of the cels for very long. A good heat shrink covering is a must. If the batterys can wiggle around in the pack, the tabs are going to fail. I know from experience.

I've built a few packs, and I'll tell you, you are money ahead to purchase pre-assembled packs. There are a few companies on Ebay and the Web that sell packs very cheep. I just picked up four 2500 mah NiMh packs, the same physical size as the Futaba pack for $40 including shipping. I've had the same companys TX packs in my transmitters for several months now and they are awsome. A charge on Sunday night using the Futaba Wall Wort. is good for four days flying. The key is to NOT use a field charger and if you do limit it to less than a 1 amp charge rate. THe NiMh don't like to be overheated and I've got a dozen of the individual cells I got for my Digital camera that I basicly killed with charging them to fast. THe first charge wasn't very impressive and it went down hill from there. These last packs had tiny print saying to limite the charge rate to less than 1 amp. My field charger said to charge them at 2.5 amps. Believe the battery.

Don