Sanyo "Eneloop" rechargeable batteries
If you're like me and have been using regular Ni-mh rechargeable batteries, you've probably noticed that they tend to discharge significantly even if not being used. They'll "self-discharge" at a rate of about 1% per day so after 3 months, they're done and need recharging.
So, I recently got some of those new "Eneloop" rechargeable batteries from Amazon.com and they worked great in my Garmin 60CSx GPS and Canon A640 camera over the weekend.
The big deal about these batteries is that they
1) come pre-charged (although only up to about 75%)
2) they have a very low "self-drain" rate... the Eneloop's keep their charge up to 85% over a year, so once you charge them, they stay charged until you use them up.
3) high discharge current. While they're rated at "only" 2000 mA-hours, this is deceptive because they're able to supply a high rate of discharge for demanding applications like digital cameras.
4) they're supposed work great at low temperatures too!
So what's not to like? Well, the price, I guess: $20 + shipping for a pack of 8 (from one of Amazon's partners, I forget which).
Still, considering how well they work and that you can expect to recharge them maybe 1,000 times you save a big bundle over using regular alkaline batteries
I put them into my GPS (2 batts) and camera (4 batts) and after 8 hours of use, the power meter on the Garmin has dropped one segment. With the camera, I've taken over a hundred pictures so far and there's no sign of them dying yet.
I'm really impressed with these so far... maybe I'll even give up my habit of packing a bunch of spare alkalines whenever I head out with the GPS or camera.