Hi,
For the pwm controllers the wire only needs to be of the minimum ampacity required for the number of amps. Voltage drop really doesn't matter because the battery will determine the voltage. i.e. a 17 volt panel when connected to a 12.8 volt battery via a controller sends 12.8 volts--no matter what the wire size. #10 wire is going to be able to handle 400 watts of panels, #8 for 500 watts, and etc.
If you go MPPT, wire size matters a great deal, because the extra volts are put through a dc to dc converter and, like magic, are changed into extra amps. So voltage drop is an issue.
ewarnerusa wrote:
and nice fat wiring that would allow you to upgrade in the future without having to replace anything.
