PV panel selection? (long)
Hello, all. I’m looking for some feedback on PV panels before embarking on the next upgrade to our electrical system. To establish the background, we will be mostly boondocking, and moving frequent...
Forum Discussion
Ductape wrote:
I am planning at this point to go all series to MPPT. So the 140w panels will be 88.4 voc and 70.8 vpm.
My thinking is the controller can make sense of it and charge even if only one panel is lit and three are shaded and in bypass. From what I understand if it's partial shading across multiple panels it's a crapshoot, and the MPPT controller may struggle to figure out which of the panels it's optimizing for.
If 4*140 panels, 560W total, results in a less shading from roof A/C than 2*265, 530W total - I would go for 4*140W. A no brainer to me.
Partial shading in series can be difficult for any controller. It's all about sufficient number of diodes. I don't think MPPT will handle this any better than PWM. With this wattage you're more likely to find a decent MPPT than PWM though, not to mention #6 or #4 cable and rooftop box - in case of PWM.
Of course, there is always an argument that 4 panels in parallel will handle partial shading better than 4 panels in series - don't know how much truth there is to it ;)... Hear it from times to times.
