I have the 25amp viper marine speed controllers are these any good?

I also have the drill motors off gimson robotics.Link-

http://www.gimsonrobotics.com/shop_dc-electric-motors.htmlhttp://www.gimsonrobotics.com/shop_d...ic-motors.html

For these i want ni-mhs or ni-cads what battery power will i need?

What link is best for a feather 30amp or 50 amp?

Thanks.

Dan.