First time cleaning the panels

+SpiceWare · May 2, 2021

Was a rainy day yesterday so my folks came over and helped me clean my solar panels as you're not supposed to clean them on a bright sunny day.

I bought this soft bristle extension brush, solar panel cleaner concentrate sprayer, and concentrate refill for the cleaning. Was a good thing I got the refill as the initial quantity included with the sprayer ran out towards the end.

The lower section of each panel had a bit of a buildup, the metal lines were hidden by a black residue. The residue is now gone.

I did not have my phone on me as I didn't want to risk damaging it, so no before and after closeups of the panels. My mom did take some photos from ground level:

Thomas Jentzsch · May 2, 2021

Were you able to detect a difference in efficiency?

+SpiceWare · May 2, 2021

Not on a rainy day as production fluctuates so much as the cloud coverage changes. I plan to download the data next week to see if I can spot a difference.

This is what it's done so far today - sunny in the morning with some cloud coverage in the afternoon:

+SpiceWare · May 8, 2021

On 5/2/2021 at 3:16 PM, Thomas Jentzsch said:

Were you able to detect a difference in efficiency?

Sure did, about 5% more energy. Here's a few sunny days before the cleaning^*:

And the one good sunny day after the cleaning:

52.5 * 1.057 = 55.49
53.5 * 1.038 = 55.53

So a 3.8% to 5.7% improvement. Based on yesterday with some clouds:

I suspect the 55.5 kWh is close to the limit of what I can generate per day for this time of year. Summer might produce more as the days are longer, though higher temperatures reduce the efficiency of the panels. I'll try to remember to follow up on this over the next few months.

^*The 20th and 24th produced the same, but the graph for the 24th looks smaller. This is because the kW scale changed due to the home usage spike from charging the car. The "ears" on the spike are due to the AC turning on while the car was charging: