Formula
- KE lost = ½ m (v₁² − v₂²)
- Recovered = KE × regen efficiency
- Range added ≈ recovered kWh × 5 km/kWh
About this calculator
Part of our EV & Renewable Calculators collection. Battery sizing, solar panel tilt, wind turbine performance, and EV drivetrain estimates.
How it works
Kinetic energy lost equals one half times mass times the speed change squared. Recovered energy applies your regen efficiency percentage. Range added uses a simple 5 km per kWh vehicle efficiency assumption for quick comparison.
Enter your values in the inputs above and click CALCULATE. Results appear on the right without a page reload. No login and no server upload.
Worked example
1500 kg vehicle slowing from 80 to 10 km/h, 70% regen efficiency.
- Speed change releases ~101 Wh kinetic energy
- Recovered ≈ 0.071 kWh
- Range added ≈ 0.35 km (at 5 km/kWh)
Result: 0.07 kWh recovered, ~0.35 km range added.
When to use
- Estimating regen energy from a speed drop
- Comparing regen efficiency scenarios
- Quick EV energy recovery screening
Limitations
- 5 km/kWh range factor is a rough vehicle average
- Ignores rotational inertia, grade, and aerodynamic drag during brake
- Assumes single deceleration event
FAQ
- Why 5 km/kWh for range?
- It is a simple 200 Wh/km vehicle efficiency proxy for quick comparisons. Enter your own Wh/km for production estimates.
Privacy and accuracy
Every calculation runs locally in your browser. Your design data never leaves your device. Results are intended for preliminary engineering work. Always verify critical designs with qualified review and applicable standards before production use.
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