Series string shading summed up in 4 pictures

[fafrd]

True. Which runs counter to harvesting the most power. I think each optimizer should draw down panel voltage to activate bypass diode for a shaded section, including for some half-cut panels.

That is how I believe Tigo optimizers work (use the bypass diodes on the back of the panel).

The point is, it that is what they do (and they don’t integrate their own more robust circuitry to bypass an entire panel), then it doesn’t change anything as far as the eventual burning out of a bypass diode in the presence of severe partial shading and the eventual burning out of the panel after that…

If they can safely bypass an entire panel then they would at least be able to protect a partially-shaded panel from damage (even if leaving a bit of potential power output on the table) while still being able to maximize output for partial shading which less severely chokes-off current as well as compensating for mismatched panels, mismatched string length, etc…

 

[fafrd]

A good post explaining the role of bypass diodes, how too much partial shading can cause them to burn out, and the hotspots created on a pet Isley-shaded solar panel that no longer has working bypass diodes:

Do solar panels ever fail because of shading?

modern solar panels are so well made (I believe) compared to earlier panels from ten plus years ago, and I can't find any reports of panels failing anywhere, when I search on Google, but perhaps I'm doing it wrong. There are lots of 40+ year old panels still out there working fine. The...

diysolarforum.com

 

[ksmithaz1]

I just saw an add on streaming for a Solar panel that is supposed to solve shading issues (OMMV). This is probably going to be a chunk of the next round of panel engineering. My preference would be to maintain current and vary voltage for serial strings, but a minimal amount of components should be able to accomplish these feats of engineering directly on the panel much more efficiently by compartmentalizing the solar cells, and running them thru a control chip of some description. Preferably with a 'Serial/Parallel' switch