I use this
http://batteryjunction.com/ch10chsmchwi1.html
The 2600mAh last wicked long, and 10 batteries is enough to cycle out the batteries for 4 controllers. Plus, since it is a smart charger, each battery is charged to the max, compared to how most wall chargers work where the charge 2 batteries in a group. The group setup causes one battery to be overcharged, and the other undercharged, which can lead to problems.








