plus four AA size rechargeable NiCad batteries to supply the receiver.
The main battery also provides useful ballast weight.
I originally used two 6 volt, 4 amp batteries, but found they did not quite give me
a long enough 'on the water time'.
Changing to 12 amp, gives me enough power for three rounds of competition steering.
This would work out at approximately Two Hours running if the boat is run at scale speed,
(not flat out all the time).