How to use the EV Charging Cable Power Loss Calculator
The Formula
Every amp through copper creates I²R heat in the conductors. Long thin extension cords add resistance in series with the charger—energy becomes warmth in the jacket instead of kilowatt-hours in the pack. You still pay the utility for those losses.
Practical Example
Round-trip Ω ≈ 2 × (0.0175 × length m ÷ mm²). Loss W = I² × Ω. Wasted kWh = W × hours ÷ 1000. Session $ = kWh × your rate. Loss % compares to I × 230 V reference charge power.
About EV Charging Cable Power Loss Calculator
Why cable resistance wastes money
Every amp through copper creates I²R heat in the conductors. Long thin extension cords add resistance in series with the charger—energy becomes warmth in the jacket instead of kilowatt-hours in the pack. You still pay the utility for those losses.
Loss formulas
Round-trip Ω ≈ 2 × (0.0175 × length m ÷ mm²). Loss W = I² × Ω. Wasted kWh = W × hours ÷ 1000. Session $ = kWh × your rate. Loss % compares to I × 230 V reference charge power.
Pick the right gauge
Upsize mm² or shorten the run before buying a longer cord. Warm plugs after a session signal excessive loss—match OEM cable rating and avoid daisy-chained household extensions on sustained 32 A loads.
Frequently asked questions
Q: DC fast charging? A: This models AC cord I²R; DC pins have separate contact resistance. Q: Aluminum? A: Use ~1.6× copper Ω for the same mm². Q: Include charger efficiency? A: Add 5–10% on top for inverter loss in total wall-to-pack budget.