My friends and I just use a multimeter to test individual batteries, and also the output from the leads on packs. It's not this model, but this is the idea of what i'm looking at.

http://www.radioshack.com/product.as...DB6FA3713323CC

If you just go to radioshack and tell them what you're looking for, they should be able to help you find one that'll do what you want.