Size DC solar cable for current capacity and acceptable voltage drop.
Solar DC circuits are held to a tighter voltage drop budget than AC because every lost volt is lost generation for the system’s whole life. Two per cent is the usual design target. Cable is a one-time cost while the energy loss recurs for 25 years, which is why solar DC cable is usually sized generously.
Solar Cable Size
Area = 2 I ρ L ÷ permitted volt drop, using the loop length
Area = 2 I ρ L ÷ permitted volt drop, using the loop length Solar DC circuits are held to a tighter voltage drop budget than AC because every lost volt is lost generation for the system’s whole life. Two per cent is the usual design target.
Cable is a one-time cost while the energy loss recurs for 25 years, which is why solar DC cable is usually sized generously.
This calculator takes 4 inputs: Array current, One-way cable length, System voltage, Permitted voltage drop. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.