Formula Used
Nominal voltage = Series cells × nominal cell voltage.
Rated energy = Capacity Ah × nominal voltage.
Base current = Motor current + FPV current + servo current.
Effective current = Base current × loss factor × wind factor.
Mission capacity = Capacity Ah × usable percent × health percent × reserve factor.
Flight time = Mission capacity ÷ effective current × 60.
Required capacity = Target current demand ÷ usable battery factors.
Current limit = Capacity Ah × C rating.
How To Use This Calculator
Choose the battery chemistry first. Enter the series cell count and pack capacity. Add the current used by the motor, FPV system, and flight controls. Enter safety reserve, battery health, and wind margin. Add C rating and burst current to check current safety. Press calculate to view the result above the form.
Example Data Table
| Mission Type | Pack | Average Current | Reserve | Likely Use |
|---|---|---|---|---|
| Long range cruise | 4S 5000 mAh Li-ion | 8 A | 25% | Efficient calm flight |
| General FPV wing | 4S 5200 mAh LiPo | 13 A | 20% | Mixed throttle flying |
| Fast fixed wing | 6S 3300 mAh LiPo | 24 A | 20% | High power passes |
| Training flight | 3S 4000 mAh LiPo | 9 A | 30% | Safe short sessions |
Battery Planning for FPV Wings
A fixed wing FPV aircraft needs a balanced battery. The pack must feed the motor, receiver, servos, camera, video system, and autopilot. It also must stay light enough for stable launch and efficient cruise. A larger pack gives more energy. It also adds mass. Extra mass can raise stall speed and landing distance.
Why Capacity Is Not Enough
Many pilots choose packs by capacity only. That can hide several limits. Voltage changes motor speed and wattage. C rating limits safe current. Old cells may deliver less energy. Wind can increase throttle demand during the same route. This calculator joins those factors into one estimate. It shows usable amp hours, watt hours, current headroom, and estimated flight time.
How The Estimate Helps
The tool is useful before a new build, maiden flight, or long range mission. Enter your normal cruise current from a watt meter or flight log. Add FPV and control loads. Then add a reserve for landing, climb outs, and unexpected headwind. The result shows whether the selected pack can meet the target time. It also shows the required capacity for that target.
Safe Use Notes
Use conservative numbers for first flights. Real endurance changes with propeller choice, airframe drag, altitude, temperature, and throttle style. Cold cells sag sooner. Poor connectors waste power. A damaged pack should not be trusted for long flights. Always test on the ground before flying far away. Check voltage after landing. Adjust the reserve if the pack comes down too low.
Better Battery Choices
A Li-ion pack often gives high energy for calm cruising. A LiPo pack usually gives stronger current for fast climbs. LiFe packs offer stable voltage and long cycle life. The best choice depends on the aircraft. Long range wings favor energy density. Racing wings need current headroom. Mapping aircraft need predictable reserves. This calculator helps compare those tradeoffs before parts are ordered.
Reading The Outputs
Flight time is only an estimate. Treat it as a planning number, not a guarantee. Current headroom should stay above burst demand. Required capacity helps size a pack for a target duration. Pack weight percentage helps you avoid a heavy wing. Endurance per watt hour helps compare different batteries fairly.
FAQs
What is an FPV fixed wing battery calculator?
It estimates flight time, voltage, usable energy, current safety, and required capacity for an FPV fixed wing aircraft battery setup.
Which current value should I enter?
Use average cruise current from a watt meter, telemetry log, or bench test. Do not use only peak current for endurance planning.
How much reserve should I keep?
Many pilots keep 20% to 30% reserve. Use more reserve for cold weather, long range routes, old packs, or unknown airframes.
Is LiPo or Li-ion better for fixed wing FPV?
Li-ion often suits long range cruising. LiPo suits higher current climbs and faster wings. Choose by current demand, energy need, and weight.
Why does C rating matter?
C rating estimates safe current output. A weak rating can cause voltage sag, heat, poor climb power, or battery damage during high load.
Can this predict exact flight time?
No calculator can predict exact endurance. Wind, propeller choice, throttle use, temperature, and airframe drag can change real flight time.
What happens if voltage sags?
Voltage sag reduces power and may trigger low voltage warnings early. Use better cells, reduce current, or increase capacity safely.
What do the CSV and PDF buttons do?
They download the entered values and calculated results. Use them for build notes, mission planning, or battery comparisons.