A little thread necro here but I am as confused as OP and my confusion comes straight from late Amy Beaudet - The Solar Queen.
In her article on diodes she states:
So I assume this is what OP was referring to and @Hedges is offering in the previous post as a solution.
I am debating 3S vs 3P with 215watt / 22Voc. I would prefer 3S for wire size and lower transmission loss as a have a fairly long run from where the roof penetration is to where the MPPT will live. But an RV roof is an ever-changing solar surface and parking could easily change shading where one panel is partially or completely shaded while another is not. Seems like a lot of factory systems (ZAMP) only work with 2/3/4P setups - I guess because they build lower voltage PWM chargers? Or maybe because of this very issue - which running each panel in parallel ups the current but eliminates the shading concerns on an RV roof?
Will the J-Box diodes be all I need or should I also look to have full-panel bypass diodes in the event that I have sun/shade mix on my roof?
In her article on diodes she states:
Most solar panels have bypass diodes built in these days, so you typically won’t have to worry about that anymore. However, if you have multiple solar panels wired together in series, and you consistently have shading on one or more of the solar panels, wiring a bypass diode in parallel across the shaded panel can prevent the current from being forced back through the shaded panel and cause it to heat and lose power. So, it acts the same as the internal bypass diodes, but bypasses the entire panel instead of the individual cells.
So I assume this is what OP was referring to and @Hedges is offering in the previous post as a solution.
I am debating 3S vs 3P with 215watt / 22Voc. I would prefer 3S for wire size and lower transmission loss as a have a fairly long run from where the roof penetration is to where the MPPT will live. But an RV roof is an ever-changing solar surface and parking could easily change shading where one panel is partially or completely shaded while another is not. Seems like a lot of factory systems (ZAMP) only work with 2/3/4P setups - I guess because they build lower voltage PWM chargers? Or maybe because of this very issue - which running each panel in parallel ups the current but eliminates the shading concerns on an RV roof?
Will the J-Box diodes be all I need or should I also look to have full-panel bypass diodes in the event that I have sun/shade mix on my roof?
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