http://www.3epower.com/servlet/the-9...RC-NiMH/Detail buy one of those and will be able to put in at least 12 flights on your trainer .40 trianer
I use one on a 1.20 size yak with 5 digital and 1 std servo and can fly saturday and sunday at least 8 total flights(roughly 6-8 minute flights) and the battery is still good to go....