Many thanks Ron and Uncle G for you replies to my query. There seems to be a wealth of knowledge and generosity in our group. Given my total lack of knowledge of things electrical I will chase up the cell purchase option and have a discussion with you prior to unleashing things that go flash bang in the night. I have the one ZOHD battery bought from Hoppy and now have rigged my charger up with 12v leads to connect to my ute battery so i shall have reasonable air time for the moment. The motor cut out on launch I experienced was resolved by Predator and Uncle G as voltage drop on the ZOHD batt and has been prevented by limiting motor to 35% max power.I believe Moose has his limited to 15% and his is flying well. Thanks again.