Portable panels wire size

#10 is too small. If your system is operating at 14.5 volts and your 2 panels are putting out 8 amps each you will have 27% voltage drop in 100 feet of #10. The first improvement would be to get an MPPT controller that will allow the panel output to be closer to it's Vmp of 17 volts. This would give you a 23% voltage drop. The next improvement, with an MPPT controller having a high enough input voltage, would be to run the panels in series. This would give you 34 volts at 8 amps which in 100' of #10 is about 6% voltage drop. (Isn't MPPT technology great!)
However, I normally try to design home solar systems with no more than 2% voltage drop in the DC cables. This would mean, even in series to MPPT, you need #4 wire.