you Can do that with all of the Hitec optima RX's as I do I am using 2 a123 battery packs in my giant p47 one is plugged into the battery port on the rx and the other is using a y harness with the a 123 battery into one side and throttle servo into the other side with the male end into switch #2 and then into the rx ch3 and I also use a good 4.8 v 2300 mah nimh on a separate switch for the engine cdi . with that set you will have no problems