Fast charge at field between flights using power from car battery. Bob's Honda Odyssey's  hood is open. At left is homemade cooling tube with battery pack sticking out. Fan built into tube helps cool battery after a flight. At right is WattAge PF-12 AC/DC peak-detect charger. This eight-cell, 1100 mAh battery gets charged at maximum current of roughly 2 amps. It should take 30 minuets or slightly less to reach full charge.