Wiring - Doing it Right

electricity from the sun by John Drake II | home

First off, do not go on the cheap.

If you use too small of a wire size you system will under-perform, and in some cases

won't work at all.

A good example.

One of our customers has been living off-grid for many years in Michigian.

His pv array is some distance from the house and the incoming wires are buried in conduit.

When he was setting up his system he got a "deal" on some wire that turned out to be undersized

for his 1,200 watt system.

In the summer time it usually worked well but in the winter he would have to change back to propane

lighting and sometimes run a generator to bring his batteries back.

A few winters back we were on the telephone and he was saying that the system just would not keep

up.

I asked him to take a note pad, check the voltage at the array and at the charge controller input.

This was a 12 volt system and there was a 1-1/2 volt difference due to voltage drop (wire loss).

He wound up replacing the incoming wire with the proper gauge of wire for his array and his batteries

were much happier.

The propane dealer was not quite as happy.

Please use this link to determine the wire size you need between the solar panels and your charge

controller: