take look at a lot of battery packs, all some of them are is aa's, take a look at you house phone,, probally 2 aaa batteries with shrink wrap. i was looking at buying a small 12v 2.0ah battery for my headlight, but then i found a 10aa battery holder for $2, i already have a ton of aa rechargables. pretty cool stuff

also 6v= 5 1.2v rechargables