How many of you were able to activate your sun power panels on your own?

[oregon_phil]

I think Guest is right on the money. The OP has microinverters and for comparison, I calculated my % of STC of my two year old system to be 88% today. Today is a bright, clear, cold, windy day. I figured the OP had 97% efficient microinverters and ~1% accuracy on the Sunpower PVS6. I could not find any specs on the PVS6. Accuracy could be worse, who knows.

I always weigh the cost vs. benefit for cleaning my panels. Ash from last fall's wildfire season caused me to wash my panels. Other than that, I don't worry about it.

When I did wash my panels, I used a safety harness. It only takes one mistake to make all the cleaning in the world not worth it.

[J.P.M.]

now i gotta find a way to clean them, they are only producing a max of 4.5 KW at mid day and they are rated for 5.25, there has been some construction by our home for the last few months so i think they are dirty now, i wonder if its worth cleaning them to get that extra .75 kw

Take this FWIW and think 2X about hiring the cleaning out.

After more measuring than I'd care to recount and most readers wouldn't want to bother to read, one of the conclusions I've reached over the last 7 years or so is that for my array and location, my array's performance decreases approx. 2/3 to 3/4 of 1% per week if it doesn't rain. That rate seems fairly constant for about 8-10 weeks or so if it doesn't rain and then seems to stay at about 6-8 % or so performance loss due to fouling. I haven't figured that one out yet and I've not seen anything similar in the literature. I once knew something about fouling of heat transfer surfaces in heat exchangers and there is a somewhat similar mechanism of about a half dozen or so that can act on a boiler's heat transfer surfaces where the fouling becomes asymptotic after a period of time.

WHATEVER YOU DO, DO NOT SPRAY WATER ON AN ARRAY WHEN THE PANELS ARE WARM. THIS MEANS HOSING AN ARRAY NO LATER THAN 8 A.M. AND PREFERABLY ON CLOUDY DAYS. REATIVELY COLDER WATER CAN CRACK THE GLAZING.

Anyway, a decent rain (~ 1/4"-1/2") restores about 2/3 or so of the lost performance of a PV array due to fouling as does hosing the array with ~ 3l of tap water per panel and then letting it drip dry. Easy peasy.

I've got hard water full of group II chemicals and it leaves some hard water spots on the array. After comparing cleaning with soap, rinsing with distilled H2O and squeegeing vs. soap and tap water and no squeegeing, both about a dozen over the first couple of years of operation, I wasn't able to measure a benefit or improvement in performance by doing the more detailed and distilled water use over the simple hosing. Besides, after a week or 2 of no rain operation, things are about 1+% fouled and getting dirtier by the day anyhow, so just hose the array again.

While every environment is different, I live in a semi rural environment and I bet my situation is probably not that much different from a lot of others. If I ever stop measuring my array's performance and fouling rate, I've pretty much decided that I'll hose it down 1X/month or so as described if it doesn't rain and accept a 3 % performance penalty or so for fouling.

BTW, commercial cleaning is a complete rip off for what's being charged vs. what's gained by a (temporarily) cleaner array.

Take what you want of the above. Scrap the rest.

[Lil12002]

You do know that under normal operating conditions a system will rarely if ever produce it's STC rating for more than a couple of minutes. Under clear skies this time of year a shade free system will likely produce ~ 80 - 90% of STC rating or so, right ?

4.5/5.25 = 0.86 or so. Sounds about right to me. Cleaning, while always a good idea, will probably get you a few % more unless they're super fouled up.

Take this FWIW and think 2X about hiring the cleaning out.

After more measuring than I'd care to recount and most readers wouldn't want to bother to read, one of the conclusions I've reached over the last 7 years or so is that for my array and location, my array's performance decreases approx. 2/3 to 3/4 of 1% per week if it doesn't rain. That rate seems fairly constant for about 8-10 weeks or so if it doesn't rain and then seems to stay at about 6-8 % or so performance loss due to fouling. I haven't figured that one out yet and I've not seen anything similar in the literature. I once knew something about fouling of heat transfer surfaces in heat exchangers and there is a somewhat similar mechanism of about a half dozen or so that can act on a boiler's heat transfer surfaces where the fouling becomes asymptotic after a period of time.

WHATEVER YOU DO, DO NOT SPRAY WATER ON AN ARRAY WHEN THE PANELS ARE WARM. THIS MEANS HOSING AN ARRAY NO LATER THAN 8 A.M. AND PREFERABLY ON CLOUDY DAYS. REATIVELY COLDER WATER CAN CRACK THE GLAZING.

Anyway, a decent rain (~ 1/4"-1/2") restores about 2/3 or so of the lost performance of a PV array due to fouling as does hosing the array with ~ 3l of tap water per panel and then letting it drip dry. Easy peasy.

I've got hard water full of group II chemicals and it leaves some hard water spots on the array. After comparing cleaning with soap, rinsing with distilled H2O and squeegeing vs. soap and tap water and no squeegeing, both about a dozen over the first couple of years of operation, I wasn't able to measure a benefit or improvement in performance by doing the more detailed and distilled water use over the simple hosing. Besides, after a week or 2 of no rain operation, things are about 1+% fouled and getting dirtier by the day anyhow, so just hose the array again.

While every environment is different, I live in a semi rural environment and I bet my situation is probably not that much different from a lot of others. If I ever stop measuring my array's performance and fouling rate, I've pretty much decided that I'll hose it down 1X/month or so as described if it doesn't rain and accept a 3 % performance penalty or so for fouling.

BTW, commercial cleaning is a complete rip off for what's being charged vs. what's gained by a (temporarily) cleaner array.

Take what you want of the above. Scrap the rest.

Thank you for the information. I'm pretty new to this whole solar panel thing thats why i thought that maybe washing them woud improve the output. I have a FU question, I wasnt there when the sun power guy came to the house but my wife was there. he was telling her the solar panels should be producing more that each panel is capable is producing around 300 W... so thats why i was thinking of washing....

[J.P.M.]

Thank you for the information. I'm pretty new to this whole solar panel thing thats why i thought that maybe washing them woud improve the output. I have a FU question, I wasnt there when the sun power guy came to the house but my wife was there. he was telling her the solar panels should be producing more that each panel is capable is producing around 300 W... so thats why i was thinking of washing....

You're welcome.

Washing an array will improve it's output but unless they are very fouled or unless there are onsite instruments, it's very difficult to get an idea of how much improvement in output is achieved.
Panel fouling characteristics, fouling rates and fouling patterns are very site dependent as well as having likely seasonal characteristics. I believe my rates as described are perhaps typical of suburban and semi rural environments, but even if it is typical, it's only one location.

As for what the peddler said, it's a bit of a matter of interpretation. When "flash" tested immediately after manufacture, panels produce a few % more than their rated output. That's the way their designed and rated. However, because stationary panels are only normal to the beam irradiance 2X/year, about the best real world output that can be expected for mostly equator facing arrays is for arrays that have just been cleaned and are oriented at some tilt to the horizontal of maybe latitude plus or minus 10 degrees or so on a clear spring day with moderate ambient temps. and a good breeze blowing for maybe an hour or so around solar noon. That power output might be 85 or so % of the array's STC (rated) output, maybe a bit more. This is not an exact science.

Looked at another way on an annual basis, my array turns ~ 17 % of the insolation that hits it into electricity and that's pretty good as those things go.