AA battery powered mp3 player?

I agree that for normal use the larger capacity mp3 players that I can just plug into the wall or pc are much better, however I’m about to deploy for Haiti next week and am looking for a battery operated mp3 player that I can buy to bring with me.  I really don’t care about a sleek design and just want something that I can use to listen to music while i’m there.  Since I will be in an environment where there really is no power, except for our own generators (which isn’t to be used for charging personal electronics) it really would be much easier to bring extra batteries, and not have to worry about the internal battery going dead after 12-15 hrs.  I will be there for 2 weeks so something that only gives me 12-15 hrs there is not even worth bringing there if I can’t charge it afterwords.