I use two 1200ma batteries in series to drive the two glow plugs on my Saito 130 twin. The glow plugs are connected in series to the battery thru a Radio Shack micro switch controled by a servo so I can turn it on or off at will. It comes in handy to start and when you lose a jug in flight. I have been flying this engine since 1994. Its a bit tired now and needs to be stimulated now and then