Mike@Asheville wrote:
I confess, I don't know how you determine to wire parallel or in series. For my needs what would be best?
Probably there is already too much info on 11 pages.
I wrote this before: with PWM controller you HAVE to wire panels in parallel.
Parallel wiring is better on your small roof, but you would need a beefy cable from panels to controller. And, possibly - rooftop junction box to transition from thin panel wires to that beefy cable. The only commercially available junction box:
AM Solar. Vent-mounted box is $60, another one is $80 I think.
You might need Y-splitters for parallel wiring. 2*140W panels at Solar Blvd have 2 splitters included. This has been already mentioned before.
With your 280W it is possible - I think - to avoid rooftop box while doing parallel wiring. You use Y-splitters to transition from #10 pigtail wire of panels to #8 MC4 cable extension, run this #8 cable to inside, and install any $5 Home Depot junction box inside, to transition from #8 to #4 cable. #8 MC4 extension you can buy at Unlimited Solar, as mentioned earlier - don't remember on what page. Long threads are difficult to follow.
MPPT controllers - except for Eco 20 - give you a choice of parallel or series wiring. Series wiring allows a thinner cable, so you don't need the rooftop box.
