dewey02 wrote:
2oldman wrote:
I don't know if 30ft is enough - probably cutting it close if you're a tree camper. I'd consider putting those panels in series if you go longer to cut down on line loss. Your controller will handle it.
I don't see the need for fusing panels; some do.
If series you can eliminate #2. Size #6 to whatever an amperage chart suggests.
So can the Grape Solar 40 Amp PWM controller really handle those to 120 watt panels in series and still output to charge a 12 volt system battery? I didn't think it could, but you've said yes. If it can, then I would definitely want to wire in series. Thanks.
No. Solar controllers have a limit on total Voc in their specs. PWMs are in the 40-50 zone. Two 12v panels with 22Voc each is 44 and you need some margin for when Voc gets above rating, such as in the cold.
MPPTs have higher Voc limits but some are also only 45-60ish so you can't go serial with them either sometimes. My Tracer has 100 limit so I can put my three 100w panels (22 each) in series if I choose at 66.
The only reason to spend more on high voltage MPPT for this job is the thinner wire but fatter wire is cheaper than a big MPPT controller.
If the whole idea is to park in the shade and set out the panels where there is more sun, it is likely there will be some trees or whatever around and part of the time you will get partial shading. For that you want to be in parallel anyway, NOT series.
