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I have Sunpower Maxeon3 400W (SPR-MAX3-400-COM) panels for installation on a yacht. Partial and fast moving shading will always an issue. I could connect 2 panels in parallel to a SmartSolar 150/70 or connect each panel to a SmartSolar 100/50. Which option would produce the most power after losses from the controllers, wiring, etc and how much of a difference might there be?
With my pair of 410w panels I went for 2 separate controllers. In my case, I went for the 100/30 units. They're just about maxed out, but the highest peak I've recorded is 29.6 amps output on a controller, so they've yet to limit my output. The extra cost for the 100/50 isn't worth it with 400w panels.
In my case, the panels are mounted to a cabin top, so the deck has some arch to it, leading to the panels being angled slightly differently. That, combined with the cost of 1 big controller vs 2 smaller ones being very close led me to 2 controllers for the 2 panels.
If it's not only a shading issue, but also the panels are facing into different directions, then two solar chargers.
Panels will be mounted side by side facing the same direction on the stern with long edge running parallel to the hull centerline. They will be aft (behind) the boom.
I think you are usually better having each panel on it's own controller.
Most panels are internally wired with from one to several strings of series-connected cells connected in parallel through isolation diodes. Shade on one cell within a string essentially shuts down that string because that string's voltage will be less than the other string(s). The panel's current would be that provided by the unshaded strings.
Paralleling panels essentially puts strings from all panels in parallel, so one cell shaded will shut down only one string.
Current through series connected panels will be limited to the panel with the least current provided by any single panel. So losses from a single shaded cell would technically be more than a parallel configuration. In my tests however I found series connection of 4 100 watt panels had a slight edge over all in parallel.
Your best option would be to experiment with your specific panels.
Controller and wiring losses will be minimal in any case.
