Also ~ your going to want to get yourself at least 6-cells so that you can have three cells in your light and three fresh cells to swap out when needed. You don't want to buy just one 4 pack of AA's and then have to wait for the three in the light to get charged back up when they run down before you can ride again or end up having to use disposable cells in a pinch.

Before you know it you will just be buying more NiMH rechargeables every time you need AA or AAA batteries for something once you figure out that with just four or five recharges they pay for themselves and it doesn't take long for them to end up being cheaper then the old throw away alkaline for almost everything except for those few applications where alkaline still works the best like smoke detectors and such.