I haven't used a CD walkman in a long time, but I remember the drive always spinning/streaming data and never turning off and I don't recall ever thinking they were huge battery hogs. Don't the PCEngine and TurboGrafx drives act as portable walkman and take AA batteries? (I've only ever owned Duos) How long do the batteries last playing music as a portable? I'm just thinking that there is no way the screen bats are going to out last the CD batteries. You're going to have to charge it when the screen bats go down so you'll just be topping of the CD bats at each charge really.