How to determine run time with batteries.
 

Ok, Im a battery noob and I have a question. Is there a formula to determine runtime? Lets say I'm using 2- 3.7v Li-Ion 720 mAh batteries. Is there a way to determine how much power is being consumed by my motor and then somehow converting that to determing run time? Could you give me an example?

Thanks in advance.

RE: How to determine run time with batteries.
 

You can't really calculate an accurate run time, because throttle usage varies, and running at less-than-full will extend run times somewhat. A crude estimate can be done by dividing the capacity of the battery by the full-throttle current of the motor.

mAh == milliAmpere-hours
A == Amps * 1000 == milliAmperes

Divide mAh by mA, you get hours, or the run time of the motor, roughly, and only if you run full throttle the whole time.