RC Motor Efficiency Calculator

Compare RC motor efficiency under propeller load with peak efficiency. View current, RPM and input/output power for supported motor presets.

01 Configuration

1400 KV58 g28 mm · case

S = series · P = parallel. Wire lengths: battery / motor, one way.

Example setup. Check against your hardware.

Key specs

Cell open-circuit voltage
3.81 V
Cell resistance
0.006 Ω
ESC resistance
0.003 Ω
Motor resistance
0.0592 Ω
Battery wire area
1.5 mm²
Motor wire area
1.5 mm²
All electrical specs Read only
Series cells
2 S
Parallel cells
1 P
Cell open-circuit voltage
3.81 V
Cell resistance
0.006 Ω
ESC resistance
0.003 Ω
Motor resistance
0.0592 Ω
Motor KV
1400 rpm/V
No-load current
1.14 A
No-load reference voltage
15 V
Motor count
1
Battery wire, one way
0.02 m
Battery wire area
1.5 mm²
Motor wire, one way
0.04 m
Motor wire area
1.5 mm²

Preset · sii2212-fresh-2s1p-soft

02 Thermal time constant

Optional

Time scale of the motor’s temperature response.

Per-motor results

Best-efficiency point

Per motor

Ready to calculate

Select a motor and power setup.

EfficiencyCurrent & voltageSpeed & power
Model & validation

2 motor models, 24 fixed setups.

Software comparison passed 144 efficiency fields and 120 thermal cases.

Verify estimates against actual hardware. This model covers motor efficiency and thermal response time.

fanCalc Motor Analysis 1.0.0 · validated-electrical-configurations-only

How to compare motor efficiency under propeller load

Open Propeller load to compare the loaded operating point of a fixed-wing motor with its best-efficiency point. Read efficiency alongside current and input/output power for the same setup. Change the motor, battery or propeller and recalculate to see whether the operating point changes; a peak efficiency figure alone cannot describe that combination.

Electrical outputs for supported motor presets

Presets calculates the electrical best-efficiency point for two supported motor identities and 24 exact motor/circuit combinations. Results include motor-terminal current and voltage, RPM, input power, shaft output power and efficiency. Each result is per motor, including twin-motor presets.

What does the thermal time constant tell me?

The optional preset thermal result is a time constant in seconds. It is not a maximum temperature or a complete warm-up curve. Preset best-efficiency outputs are also not maximum-power ratings or predictions of an installed ducted fan's operating point.

Frequently asked questions

Does peak efficiency describe my motor under propeller load?

No. Peak efficiency describes a best-efficiency operating point, while the selected battery and propeller determine a loaded operating point. Use Propeller load to compare the two for the modeled fixed-wing setup instead of applying the peak value to every configuration.

Are preset outputs per motor or for both motors?

Preset electrical results are per motor, including twin-motor presets. Read motor-terminal current, voltage and shaft power on that basis; do not interpret them as the complete aircraft’s combined power or thrust.

Does the thermal time constant give a maximum temperature?

No. The optional preset thermal result is a time constant measured in seconds, not a temperature or full warm-up curve. The preset analysis also does not predict the installed operating point or thrust of a complete EDF system.