Panel to Solar Controller Wire Size

pianotuna wrote:
Hi mena,

You are a member of the PWM controller world. Ask yourself what is the maximum voltage you ever want coming out of the controller.

Since fridge boards (and others) "fry" at 15.4, that is one number to consider.

Your panels are 18 volts?

15.4/18 ~= 15% voltage clipping.

23Voc

Shadow Catcher wrote:
The Morningstar manual spells out their recommendations for wire size etc. http://www.morningstarcorp.com/en/support/product.cfm?ProductId=1
One recommendation I would make is Install a battery monitor, either Bogart Engineering or Victron, it is the ONLY way to accurately tell you battery(s) state of charge.

Thanks for the link. I have a Victron batt monitor but I use a hydrometer to determine SOC. And I only care about that when I'm recharging after a camping trip.

BFL13 wrote:
My 130w array on roof to front of trailer where the PWM controller is wiring runs about 35 ft (so that's 70ft) It is #8 "pre-wired for solar." I have a couple feet each wire of #8 from controller to battery. That's a 2.69% drop (0.35v) array-controller

Sound like #8 is the way to go. Thanks all for the replies.