DC Voltage Drop Calculator

Calculate DC voltage drop in solar cable runs using V = 2 x I x R x L for round-trip conductor loss.

DC current flowing through the cable in amperes. For solar strings, this is typically the short-circuit current (Isc) of the string.
A
Distance from the solar array to the inverter/combiner (one way). The formula doubles this for the round-trip.
Select wire gauge (AWG) or enter custom resistance. Resistance is per unit length for copper conductor at 75C.
Nominal DC system voltage at the source. Common values: 48V (battery), 300-600V (string inverter), 12/24V (small off-grid).
V

Results

Voltage Drop-V
Voltage Drop Percentage-%
Power Loss-W
Voltage at Load-V
Status-
References:
Formula: Vdrop = 2 x I x R x L, where I = current (A), R = resistance per meter (ohm/m), L = one-way length (m). Factor of 2 accounts for positive and negative conductors. NEC recommends max 3% voltage drop for branch circuits, 5% total. Resistance values for copper at 75C.