Estimate hovering and active flight times for quadcopters and multirotors based on all-up weight, motor efficiency, battery capacity, and safety reserves.
Your drone's takeoff weight is the single most critical factor in flight times. Every extra gram forces the motors to generate corresponding thrust. A heavy camera or oversized battery increases the current draw exponentially, often yielding negative returns.
Motor efficiency defines how many grams of thrust a motor produces per watt of power (g/W). Efficient setups (large props, low Kv motors) can reach 9-13 g/W. High-speed racing quads operating on small, aggressive props typically drop to 4.5-6 g/W.
Never discharge your LiPo battery packs completely. Keep at least a 20% safety reserve (discharging to 80% capacity). Cruising below this drops cell voltages below 3.5V, degrading the chemistry, puffing the pack, and risking sudden power collapse.
Calculations are based on the standard multirotor thrust equation. The power needed for hover is estimated by:
Hover Power (Watts) = All-Up Weight (grams) / Propulsion Efficiency (g/W)The usable energy (in Watt-hours, Wh) is calculated by multiplying the battery capacity (Ah) by nominal pack voltage (V), factored by the safety margin:
Usable Energy (Wh) = [Capacity (mAh) / 1000] * Nom Voltage (V) * [1 - Safety Margin / 100]Finally, flight time is computed as:
Flight Time (Minutes) = [Usable Energy (Wh) / Average Power (Watts)] * 60