I was flying with my 26 gas when the engine suddendly lost power, land the plane and discovered that the ignition battery fell under 4,4 volts,that is the power loss explication. The problem is that even under 4.4 part of the charge is still avilable but completely unuseful. I suppose that the only metod to full exploit the charge of the ignition batt. is to avoid the voltage to fall under 4.4 that means 5 cells instead of four (I am using 4) comments requested.