For the past 8yrs, I have had exceptional luck with the Maha PowerEx batteries, available from Thomas Distributing. They last a very long time, allow hundreds of recharges. Good, reliable power. Have used primarily the AA flavor, up to 2500mAh. Buying them in blocks of 8ea, they're an exceptional value. You can also find RCR-123a LiION rechargeables there, too.