How do I measure average current draw?

Use a watt meter inline between battery and ESC to measure current during flight. Alternatively, fly a timed flight and then check how many mAh the charger puts back in. Divide mAh by flight time in hours to get average amps.

Why should I only use 80% of battery capacity?

Discharging a LiPo below 3.3V per cell causes permanent damage. Stopping at 80% of capacity keeps the voltage above the safe minimum and dramatically extends battery lifespan. Some pilots use only 70% for maximum battery longevity.

How does flying style affect flight time?

Gentle cruising uses about 70% of the average current. Aggressive aerobatics can use 140% or more due to sustained high-throttle manoeuvres. Racing uses even more as throttle is nearly always at maximum. Adjust your style to match desired flight time.

What timer should I set on my transmitter?

Set your timer to 80% of the calculated flight time. This gives you a warning with enough remaining capacity to land safely. For example, if calculated flight time is 10 minutes, set the timer to 8 minutes. Always land with some reserve.

ModelCalcs

Flight Time Calculator — Battery Endurance

Estimate flight or run time from battery capacity and average current draw.

Battery Capacity (mAh)

Avg Current Draw (A)

Usable Capacity (%)

80% recommended for LiPo health

Flying Style

How We Calculate This

Calculates flight time from usable battery capacity divided by adjusted current draw.

Formula

Usable capacity = Battery mAh x Usable %
Adjusted current = Avg draw x Flying style factor
Flight time (mins) = Usable capacity / (Adjusted current x 1000) x 60
Timer setting = Flight time x 0.8 (safety margin)

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates. Always verify quantities before purchasing materials.