A year ago I learned about Sanyo Eneloop batteries and bought a starter pack. Eneloops are now my prefered battery for most uses.
Eneloops are improved Nickel Metal Hydride (NiMH) rechargeable batteries with these key benefits:
- Hold a charge longer (low self discharge)
- Can be recharged more times
- Better low temperature performance
- Can be used right out of the package (pre-charged)
The Eneloops charge just fine in my NiMH battery charger. If you don't already have a charger there are bundles with a charger, and even a USB charger.
As my NiMH batteries wear out I've been replacing them with Eneloops. I have both AA and AAA Eneloops. Other companies make batteries like Eneloops: Rayovac Hybrid, Kodak Pre-Charged, and Duracell Pre Charged. I like the distinct white package of the Eneloop so I don't mistake them for Alkalines or standard NiMHs.
I bought my starter pack at Costco (I think they still stock them). Eneloops can be hard to find around town, but are widely available for purchase on-line (Amazon has them).
I still use a lot of non-rechargeable Alkaline batteries. They last a long time and work great in devices that don't use much power or are seldom used, like remotes, emergency lights, toys, etc.
Occasionally I use some lithium non-rechargeable batteries (expensive!) when I need maximum run-time and/or best performance in low temperatures.