I plan to post a follow up to my solar PV post with a few more things you probably didn’t know about solar but that’s not this post. Instead, I want to rant if I may on one particular piece of my solar setup that annoys me.

It should seem pretty obvious that shade is the enemy of a Solar PV installation. That’s fine, you might say, but what if my panels are only partially shaded? Well, in an array of panels a few shaded cells can muck up the power supply far more drastically than it would at first seem. This paper sums up what happens:

In a series connected solar photovoltaic module, performance is adversely affected if all its cells are not equally illuminated. All the cells in a series array are forced to carry the same current even though a few cells under shade produce less photon current. The shaded cells may get reverse biased, acting as loads, draining power from fully illuminated cells. If the system is not appropriately protected, hot-spot problem can arise and in several cases, the system can be irreversibly damaged.

Irreversible damage? To my expensive solar installation? Yikes! What can we do?
Continue reading →