If you really want a 4 channel charger, and want big power, here is another option -

Turnigy_Reaktor_QuadKore_1200W_80A_4_X_300W_20A_DC

4 channels of 20a power. You will need a healthy DC power supply. Something like This $60 Ebay unit would work, so long as you don't max out all 4 channels at the same time.