Solar wiring question
Currently I have 2 100 watt panels on top of the trailer (VOC 21.6 volts, ISC 6.34 amps, VPM 17.4 volts, IMP 5.75 amps) with a 30 foot run of 12ga wire to the charge controller. Last fall my system...
Forum Discussion
Ed_Gee wrote:BFL13 wrote:Ed_Gee wrote:
Since I did not see any previous comment on this, I thought I would point out that voltage loss on 30 feet of 12AWG is approximately 9%.....pretty high. Most professionals I have dealt with don't want to exceed 3% loss.
Is that at 20 amps?
Since the Original Poster was contemplating 300W, I used 18A which is about all that 300W would provide in full sunlight. Regardless the current, though, 9% loss at any rate is unacceptable.
Not sure 9% would matter with PWM, which he has. Have to do some math. Thing being, PWM means array voltage is battery voltage , much lower than panel voltage, so you can afford some voltage drop panel to controller. Not with MPPT though.
See earlier post on which voltage drop calculator and whether round trip or one way to do the calculation.
You are correct to raise the voltage drop issue.
