Solar setup input?
Hello! Thanks for all of your input; reading through these forums helps a lot. We got a '95 Winnebago Adventurer that already had a 400W system installed - 4 100W panels wired up to a PWM controll...
Forum Discussion
2oldman wrote:
Wire size depends on how things are connected. 12awg is too small to handle 400w.
all depends on the amperage.. we need to know the Vmpp of the panels to be sure.
I suspect he has "12 Volt" panels. the Voc of these is about 22 volts and Vmpp of 17 to 18 Volts.
4 of these in series would be approx 72 V at full load
so a Victron Blue 150/35 would handle this with ease
400 Watts / 72 Volts is 5.5 Amps
12 AWG is rated for 20 Amps so no problem at all.
voltage drop at max power with say 50 ft 12 AWG = 0.43 Volts
would I chose 12 AWG.. probably not if I intended to expand the array at some point in time.
It might be better to re-wire to 10 AWG for future expansion, then you could use the renogy 100/40 and connect the panels in a 2S2P string..
then the Vmpp = 36 V, Imax = 11.1 Amps
Vdrop over say 50 ft of 10 AWG = 0.55 Volts
loss approx 1.6 %
wiring from panels to MPPT would be 10 AWG, on the 12 V side you now have a max of 33 Amps, so you would need a minimum of 6 AWG for a length of no more than 20 ft inclusive or 4 AWG if you get serious and add two more panels. if you add two more of the same panels then you would connect 2 strings of 3 panels.
the renogy 100/40 will be maxed out as it can only charge at 40 Amps. if you think you will expand at a later date then you might want to consider the Victron blue 100/50
pm me if you have questions.
