Hi Bigboat;

6 Hours on a 2 Ah battery means an average current of 333 mA. On 6 volts 330 mA is 2 Watts right? This seems to be a decade lower than the value I figured before. Did I make a mistake on the math? Joules = wattsxseconds. 12000 rpm would be one spark every 5 msec. 90 mJ per spark means that 0.09 J / 0.005 sec = 18 W?? What did I miss here?

J