Small solar charger system...
I am interested in using a basic solar panel with my camper to charge one or two 12V batteries. I would want to be able to run the water pump, a light or two and a 12V fan. Any suggestions of how to a...
Forum Discussion
pianotuna wrote:
Hi barntt,
No, so long as the wire is able to legally carry the number of amps and is using a PWM controller voltage drop is a NON factor. That's just one of the mistakes at the page you suggested folks read.
If it is MPPT then wire size is important and should be as big as can be accommodated with the shortest possible run.
Handy Bob tends to err on the side of caution. Still, he is living generator free, one of very few solar users that can.
Yes, with PWM the wire size from panel doesn't matter as long as the voltage on the battery end is over 15V, and as long as the wire ampacity is adequate for the current.
No, with MPPT it doesn't have to be the thickest possible and the shortest possible cable run from the panel. When doing calculations for my 490W system, I found that at 60V that despite pretty long 70ft total wire run from panel, the difference between wire gauge 10 and gauge 8 was 0.7% of power loss at the very peak (which happens less than 1/3 of the time, daily). This is roughly 0.2 AH or 2.4W loss daily. With MPPT it's all about lost watts, nothing else. Considering much easier installation with #10, and the fact that people have 750W system with #10 wire, the choice was obvious.
Yes, wire from controller to battery is very important, there should be no more than 1%-2% voltage loss.
