This is used to connect a solar panel to the solar regulator. Cable length between these 2 is not critical, however it should not be longer than necessary.
10m is more than long enough to reach the regulator from the solar panel no matter where on a vehicle???s roof or roofrack the panel or where the regulator are fitted, but this longer option can also be used as a short extension cord when camping in the shade. Shorter or longer cables can be made.
The cable used is 4mm2 ripcord.