I use several Nikon SB-900 and SB-700 strobes for my photography work. Both these units use four AA batteries and the batteries drain like crazy. I was using your typically brand-named batteries for a while… and, well… they sucked. They wouldn’t hold a charge over time and they would drain rapidly when in use. I got so frustrated I jumped online and started looking for a new brand. I did most of my research on Amazon.com and came across two brands: PowerEx and Eneloope. Both brands received positive ratings and, for whatever reason at the time, I decided to go with the PowerEx. That was a year ago, and I have to report, they haven’t let me down since. They are reliable, hold almost a full charge after sitting around for weeks in a camera bag, and in a pinch you can charge them to full capacity in one hour.
I can usually snap over 350 frames on variable power levels with the SB-900 and the batteries don’t even break a sweat. At times I’ve exceeded 400 frames before they need to be replaced. In comparison, my old, off the shelf popular brand gave me just over 100 frames. They also work great in kids electronic toys. I use them in my kids InnoTab and WiiMotes.
I have the MH-C801D Eight Cell Charger. It will charge eight batteries in one hour. The manufacture recommends that every 12 charges or so, you should use the “soft charge” button on the unit to help extend the batteries life. This charge mode takes about 14 hours.
I should also note that I know several folks using the Sanyo Eneloope brand of rechargeable batteries and they also rave about their performance.