PZ -

The formula for roughly estimating flight time is:

(Battery Capacity in Ah/Motor Current in A) x 60 = run time in minutes

Get the Battery Capacity by converting from mAh to Ah. Simply divide by 1000.

Get Motor Current by measuring your full throttle current on the ground with a wattmeter. A wattmeter is a required purchase. Get one!

Let's look at a few flight time examples.

Example 1:
1500 mAh battery
power system draws 12A

1500 mAh = 1.5 Ah

1.5/12 x 60 = 7.5 minutes


Example 2:
1500 mAh battery
power system draws 18A

1500 mAh = 1.5 Ah

1.5/18 x 60 = 5 minutes


Example 3:
2200 mAh battery
power system draws 10A

2200 mAh = 2.2 Ah

2.2/10 x 60 = 13.2 minutes


Example :
3200 mAh battery
power system draws 20A

3200 mAh = 3.2 Ah

3.2/20 x 60 = 9.6 minutes

These calculations assume you are flying at full throttle at all times, a worst case situation. So actual flight times should be a bit longer.

Regarding charging time: By definition, any fully depleted battery being charged at 1C should in theory take exactly one hour to charge. In reality, there is some variation from this because the battery may not be fully depleted and because charging is never going to be a 100% efficient process. You should figure on at least an hour for charging a pack and plan your bettery purchasing accordingly.

- Jeff