Get a good smart charger. Sony makes a good one for $15 or $25 and they both include a set of four LSD AA Nimh batteries. Personally I'd pick the $25 one since it will ship for free if you buy off Amazon. It takes about 2 hours to charge 1-2 AA or about 3-4 hours for 3 or 4 AA on the $25 model. The $15 model takes about 6 hours to charge 1 to 4 AA. A pack of 4 AAA will probably run $10 too...
The LSD batteries will retain something like 80% of their original charge even if you leave them alone for a year so self-discharge is really a non-issue. My rear blinky in strobe consumes about 35-50% of the capacity in about a week's worth of commuting which is around 5-8 hours depending if I go on a ride after work. So even after a year, there is plenty of run time.
Personally I charge my batteries once a week so there is no doubt whether or not I have good batteries but I use mine a lot. My 18650 light, though, only goes for about two hours so I always keep a spare in my bag since I always forget how long I've had the light running.
Last edited by jsdavis; 01-02-12 at 02:28 AM.