If you're going to do the 2.4 get A123's for everything. That way you only carry one charger. The money you would save on a nicad for the ignition would be seriously offset by having to buy two chargers. Or you might have to charge the receiver and ignition batteries separately on one charger. The A123's field charge quite rapidly if not run down too deep.

Tom's the man to talk to since he has all the info he developed using the A123 battery. One thing he does that I have a lot of respect for. He's always looking for ways to provide the customers with the best possible product and superior performance at the lowest possible price and he's done the same again with the A123 work. Plus once he decides he wants or needs to know about something he digs deep and when the dust settles he's an expert on the subject.