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E-Bike

E-Bike Voltage Sag Calculator

Calculate dynamic voltage sag from cell resistance, S×P pack layout, and max controller current.

WattQuick

Quality 18650 ≈ 0.03 Ω per cell

48 V pack often 13S

e.g. 13S4P

Full-throttle current

Primary result

45.6V

2.44 V sag · 5.1% of nominal

Voltage sag2.44V
Sag percentage5.1%
Pack resistance97.5mΩ
Nominal voltage48V
Max controller draw25A
Cell resistance0.03Ω
Pack layout13S4P

Note: R_total = R_cell × S ÷ P; V_sag = I × R_total. Default cell resistance is 0.03 Ω (quality 18650). Actual sag varies with temperature, SOC, and cell age.

About E-Bike Voltage Sag Calculator

Pack resistance model

R_total = R_cell × S ÷ P. Sag = I × R_total. Under-load voltage = V_nominal − V_sag.

Planning note

Estimates are for planning rides, charging, and battery health—not a substitute for manufacturer specs or professional e-bike service.

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