I used 8AWG, but maybe 10AWG would have sufficed, since my run was around 20ft with 435 watts of solar power. I would look at the wiring
gage recommended by the solar panel manufacturer. I doubt anyone would tell you 8AWG was a mistake. Maybe thinner would work
, but I don't think 8AWG is a mistake and you must rip it out to 'fix it'. I used my inverter
to check my max amps from the panels. I ran a mini shop vac. It would seem that at midday in Chicago in late May, I was getting 20 amps of input. That was the reduction in the number of amps being pulled by the shop vac, the battery voltage being the same in both runs. The voltage over the wires from the panels is higher, so the amps over that wire run would be less.