The battery is excellent! I can play mine a couple of hours a day and the battery wont need a charge until after about 5 days! (That's a conservative estimate - it may even last a lttle longer!) But I have never been disappointed with it. I've always been pleasantly surprised how long the battery lasts between charges. If you need to go along time with no charging, you can buy additional batteries (I saw them at Radio Shack for Gameboy which I never would have expected) for about $20. You can insert them in the Gameboy and charge them and then take them out and use them as needed later.
