wrongway rc sells an inline diode. Single diode for A123's and double diode for 2s LiPo
www.wrongwayrc.com
That's all you need, you don't need a regulator.
A123's work great on ignitions.
EDIT:
http://www.wrongwayrc.com/index.php?...product_id=154
Last edited by BarracudaHockey; 08-19-2014 at 12:24 PM.