Calculate starter motor current draw, cable sizing, and voltage drop during cranking for reliable engine starting.
Input Parameters
Results
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Cranking Current
A
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Min Cable Gauge
AWG
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Cable Voltage Drop
V
--
Min Battery CCA
A
Note: Diesel engines require 40-50% more cranking current than gasoline. At 0°F, battery capacity drops ~40%. Keep cable voltage drop under 0.5V for reliable starting.
Reference
Cranking Amps ≈ Displacement × Draw/L
Gas: 35A/L, Diesel: 50A/L, High-Comp: 45A/L
Cold correction: +1% per °C below 20°C
Cable V_drop = I × R_cable × 2 × Length / 1000
Min CCA = Cranking Amps × 1.5