If the kids play inside the house, they should just plug the AC adapter in.
And you can turn it as much as you want, playing more than 4 hours per day on a regular basis is just way too much. (I stated that on another thread already.) I see that sometimes people play 4 hours or longer, but really, how often is that the case? How often do you go on 16 hour flights every year? How often is there no power outlet somewhere near? For the vast majority of people a battery life of 4 hours is totally enough. And if you're really that desperate, just get an external charger, I'm sure there will be one to fit both 3DS and PSP2.
BTW, of course I'd love longer battery life, too, but thinking about it realistically, that will be quite difficult in the future with handhelds always getting stronger and stronger. 4-5 hours will probably be the upper cap from now on.
Need something off Play-Asia? http://www.play-asia.com/
