I just go the MZ-NHF800. I could not find anything in the manual about a built-in charger, but I see a "charging" icon on the display when I plug the unit into AC power with a non-rechargable AA battery in the unit. What's going on? Will I get longer battery life from a non-rechargable alkaline AA battery or from one of the better NiMH batteries? Will this unit charge a NiMH battery? PS - I also recommend Thomas Distributing for NiMH batteries.