Power
Battery energy, hover power, flight time, and reserves.
Battery energy, multirotor hover power, flight time, return-to-home reserves, and payload limits, worked out from the battery label and the aircraft's mass. It is for pilots and builders estimating how long a drone can fly and what a payload costs. Start with battery energy, then flight time. The estimates are only as good as the power figure: wind, climbs, cold, and aging packs all shorten real flight time, so calibrate hover power from your own test flight when you can.
Planning and education aid. Not for primary navigation. Full disclaimer
I want to turn a battery's mAh and voltage into watt-hours
- Battery energy (mAh to Wh)
Battery energy in watt-hours from capacity and voltage (or cell count), usable energy after a discharge limit and landing reserve, and the current and C-rate for a power draw.
I want to estimate flight time
- Drone flight time
Hover and cruise flight time from usable battery energy and power draw, with the landing reserve and cold-battery derating shown, and range at a groundspeed.
- Multirotor hover power
Electrical hover power for a multirotor from its mass, rotors, and air density, by momentum theory with a figure of merit and motor efficiency, never the ideal power alone.
I want to keep enough energy to come home
- Return-to-home energy budget
Whether the battery can bring the drone home against the wind: return groundspeed, time, energy, the margin left, and the farthest round trip that keeps the reserve.
I want to find how much payload I can carry
- Maximum payload for a flight time
The most payload a multirotor can carry and still hover for a target time, from its mass, rotors, battery energy, and air density by momentum theory.
I want to see what a payload costs in flight time
- What a payload costs in flight time
The extra hover power and the flight time lost when a multirotor carries a payload, from its mass and any electrical draw, by momentum theory.
I want to tune the power estimate to my own aircraft
- Calibrate hover power from a test flight
Back-solve a multirotor's real figure of merit × efficiency from a measured hover: the energy it drew and for how long, so the hover-power and flight-time tools match your aircraft.
From battery label to flight time
- A battery's capacity in mAh times its voltage is its energy in watt-hours. Battery energy (mAh to Wh)
- Hover power depends on weight and rotor area; flight time is usable energy over power. Drone flight time
- Hold back what the return leg needs, against the wind. Return-to-home energy budget
Guides that use these tools
- Lidar bid: The size of the site, the flight lines and flight time, the batteries it takes, and the accuracy you can state.