Walking on Solar Modules – Is It Really That Bad? Let’s Take a Look!

Don’t scrape the backsheet. 

Don’t step on the panels. 

Don’t drop the panels. 

And don’t scrape up the frames. 

Aside from safety and how to properly use ratchet straps, those were some of the very first things I was taught when I started working in solar installation. Of course, accidents happen. Sometimes, you may even have to step on the panels during installation with the configuration of the design. 

Is it really that big of a deal? 

Let’s tune into an excerpt from Dr. James Rand’s free course 5 Things You Should Know About Silicon PV Panels to find out! 

 Okay, walking on panels can hurt them. We are going to head right back out to the field, where we’re going to catch a new guy coming off break. Let’s see how he does this time. 

Hey Rand, let’s get back to work. Alright, can you grab my water for a minute? Sure. 

Okay, not so good. Probably not the right thing to do there, new guy. 

Many of you know that walking on panels in some installations virtually require you to walk on them. It’s almost unavoidable. So this can occur and does occur in real life. 

So what happened in this case? Well, I’ll tell you what happened in this case.

The power dropped. 

The power dropped 4%, all in fill factor. And certainly there were no visual signs of damage.

So we’re going to take a look at the EL [Electro-Luminescence] images before.

We’ll start with the before image here on the left – lots of cracks here. And again, I used a beginning of life module that hasn’t been in the field, but was subjected to some transportation damage. 

So let me just back up and show you one thing. This module, before we dropped it, was putting out 300 watts, which is the rated power. So here is a module full of crack cells that was working at rated power. Even if you had a sophisticated tester, you would call this a prime module. Short of having the electroluminescence image to look at, you would call that a prime module. 

To the right, we have the EL image after we’ve stepped on it. Well, to a first order, much like the visual, it appears nothing happened.  Now, perhaps the darker, poor performing areas got a little bit darker and the lighter areas got a little bit lighter. That may signify that the existing cracks were disrupted. I may have broken a little bit of metal that was holding the cells together or at least broke some of the metal lines, making it more resistive.  

Let’s take a closer look at exactly where the footfall was. You can see it. It’s right there  So we’re going to be looking in this area right here. So let’s zoom in on that. Sure enough lots of hairline cracks appearing that didn’t exist beforehand. You can see another crack here. I understand that this might be difficult for you to see on your media, so I’ve included a high res EL image of the module after it’s been stepped on and that’s shown here on the right.

So you can just see the two cells affected before and after they were stepped on.  Lots of new cracks right where the footfall occurred. But you can tell by the uniformity of the brightness here that these cracks are not very active. They’re not really causing much degradation, so it’s highly likely that the 4 percent drop in power that we saw on testing this module occurred from disrupting cracks that were already in place, like in existence here and here. You can see two cracks that the contrast may have increased on those. So that may have been me just disrupting existing cracks. 

In this case, at beginning of life, we added new cracks to this module by stepping on it, but it’s unclear whether those new cracks really contributed to the 4 percent power loss. 

What we can say is that those cracks will probably continue to move and cause degradation in the future going forward. Not only have we cracked this cell, we’ve cracked it in such a way that it’s virtually impossible to tell by testing it alone, at least by IV testing it alone.  

So what can you conclude from this?

Really, the only thing you can take away is that you really shouldn’t walk on a panel.