How to get the best battery life from your retro handheld game console

Engadget 

For most people, a set of nickel-metal hydride (NiMH) rechargeable batteries is the way to go. Panasonic Eneloop is an Engadget staff favorite. It's consistent and tends to hold up over time better than cheaper options. If you want to save a few bucks, IKEA LADDA is a good budget alternative. Both are sold in the AA and AAA sizes you need for these systems.