i got my little brother(9) a stampede 2wd for his birthday(july 30th). i want to get him a better charger and better batterys for the truck. i gonna keep him on nimh for a while so he can learn to drive and not tear things up. im looking at the ez peak 2amp charger and a 4000+ mah batt. my question is what kind of charge times am i looking at for this?