There's lots of battery choices. I use OptiPower 50c on my EDF's, there's plenty of other choices out there.
I use an iCharger 308 Duo powered by 2 12v server power supplies wired in series to provide 24v input to the charger from a wall outlet.
More Mah increases flight time but it also adds weight so you might have CG issues, usually best to go with what they recommend unless you have a lot of room to move the battery around.