A Wee Bit of Dust Buildup Since Last Cleaning End of April...

[Ian S]

But still about 44 kWh production today with high temperature of 103F. Not sure what animal took a dump - either a feral cat or roof rat perhaps.

dirty solar cropped.jpg

[J.P.M.]

But still about 44 kWh production today with high temperature of 103F. Not sure what animal took a dump - either a feral cat or roof rat perhaps.

[ATTACH=CONFIG]4355[/ATTACH]

It wasn't me ! Honest !

FWIW, I'll be washing and measuring input/output diff. on my stuff around the solstice before and after cleaning. Last cleaning 04/15/14. Lite rain 04/26/14. Some morning dew once in a while. Other experiments underway. I'll abstract the results if anyone's interested.

[HX_Guy]

Wow, did you clean them off? I'm curious to see how your production looks like the next couple of days.

It must be solar panel cleaning season, I know a guy here in Peoria who also got up on the roof a couple days ago to clean his panels off.
Looking at his production numbers, I think it helped (he cleaned them off on the 12th)...it reversed the decline he was having the last few days for some reason.



He was just saying how it sucked getting up on the roof though and that he needs to find a company that does this as a service. I'm sure there are some, if not, business idea?

[J.P.M.]

Wow, did you clean them off? I'm curious to see how your production looks like the next couple of days.

It must be solar panel cleaning season, I know a guy here in Peoria who also got up on the roof a couple days ago to clean his panels off.
Looking at his production numbers, I think it helped (he cleaned them off on the 12th)...it reversed the decline he was having the last few days for some reason.



He was just saying how it sucked getting up on the roof though and that he needs to find a company that does this as a service. I'm sure there are some, if not, business idea?

Lots of folks do panel cleaning around here, including some installers. Call a few where you are and see.

[J.P.M.]

Wow, did you clean them off? I'm curious to see how your production looks like the next couple of days.

It must be solar panel cleaning season, I know a guy here in Peoria who also got up on the roof a couple days ago to clean his panels off.
Looking at his production numbers, I think it helped (he cleaned them off on the 12th)...it reversed the decline he was having the last few days for some reason.



He was just saying how it sucked getting up on the roof though and that he needs to find a company that does this as a service. I'm sure there are some, if not, business idea?

At the risk of starting WWIII, unless you have a reliable, quantitative way to measure solar input and plate temps., usually with a pyranometer and an IR thermometer or more sophisticated instruments, it is not possible to get reliable information as to how much difference a panel cleaning makes. What is being measured dirty to clean will be of approximately the same order of magnitude of that induced by a 2% variation in the solar irradiance which happens as a random and often common event. That same 2% diff. can also be induced by something like an 8 to 10 deg. F. diff in panel temps., pre vs. post measurement. That much diff. in temp. one day to the next, even under "clear" skies and similar ambient temps. is an easily attained and likely difference due to the wind and also the very fact that the panels are cleaner and absorb sunlight differently. The synergistic combination of all the variables, irradiance variation, wind, wind direction, etc. means that the input diff. one condition to the next will be about the same magnitude or greater than any effect any cleaning will have. That state of affairs makes the pyranometer essential along with some way to measure plate temps. almost or equally as important.

Have fun measuring output, but without some way to measure input and panel temps. don't expect much more than a difference in output, one day to the next without knowing or even being able to guess the reasons causing the difference. To call that diff. the result of cleaning is not correct.

I didn't make the rules, I just know what they are.

[Ian S]

I haven't cleaned them yet. I just went up to see how bad they were. I had an AC maintenance visit on Thursday and the tech said they were pretty dirty and offered to clean them for me. I said thanks but no thanks. Maybe tomorrow I'll go back up. It has to be very early or late in the day to avoid hot panels although at this time of year, the "cold" water supply is quite warm i.e. comfortable enough to shower in. So there really isn't any risk of thermal shock. But I prefer to go up there when the sun is low in the sky.

Interestingly, today was a much better day for production than yesterday: 43.75 kWh vs. 40.29 kWh. The sky today was bluer and it was more breezy with a drop of about 5F in temperature although both days would be considered "clear." Just shows how subtle haze/faint clouds can make quite a difference.

Oh and as for my AC: last year it iced up at the end of June and required 3 lbs. refrigerant to be added. This time it was working OK but took 1 lb. So the leak is about 1 lb a year. Not too shabby for 17 years old but time to think about new system.

[quicksilver8907]

Whats the best way to clean them? Do I need to turn them off first?

[J.P.M.]

Whats the best way to clean them? Do I need to turn them off first?

Since you ask:

Opinions on cleaning methods and fluids vary. Water is one choice, but may streak/leave hard H2O residue. Mild soap/squeegee after rinsing seems to work for me. Some use D.I. rise after. That may be a good idea. Avoid organic or other solvents that can eat seals and plastics.

I don't turn my system off and I'm still alive.

Make sure the panel surface temp. is as close as possible to the cleaning fluid temp, and try not to thermally shock anything by dumping buckets of water or fire hose rate applications of H2O.

[Mike90250]

I wash mine early in the AM, while the dew is still on them (softening deposits overnight) and before the sun heats them up. And I just blast with water. If I had DI water for a rinse, I would use it.

[slopoke]

My panels are a little dusty, but since we are in a severe drought, I'll hold off on the cleaning. My luck a passer by will see me using water and report me, no need for any drama.

[mapmaker]

I wash mine early in the AM, while the dew is still on them (softening deposits overnight) and before the sun heats them up. And I just blast with water. If I had DI water for a rinse, I would use it.

That's good advice to clean them when the dew is still on them. I only use distilled water (and no soap) for cleaning my panels.

--mapmaker

[HX_Guy]

This stuff looks pretty good, not sure if it's necessary though.

http://www.titanlabs.net/glass-gleam-solar.htm

[Ian S]

This stuff looks pretty good, not sure if it's necessary though.

http://www.titanlabs.net/glass-gleam-solar.htm

That looks interesting. I might get some just to try.

[bando]

It wasn't me ! Honest !

FWIW, I'll be washing and measuring input/output diff. on my stuff around the solstice before and after cleaning. Last cleaning 04/15/14. Lite rain 04/26/14. Some morning dew once in a while. Other experiments underway. I'll abstract the results if anyone's interested.

i'd be interested. our panels are disgusting right now. max outut hasn't touched 10 in a long time. a little disappointing. haven't attempted to clean at all with the drought and just praying that some rain comes and washes them off.

would you be interested in seeing a ratio between your system and mine before/after?

last 4 days:

6/11 75.02
6/12 72.56
6/13 74.34
6/14 73.81


only "cleaning" (hose) was in Jan 2014 and that was only one array. could not get the other one. we have not had the time or energy to do anything since. and the rain did such a nice job on its own, we have just been trying to leave it alone (not to mention water now costs $8.xx/HCF). but i think it's about time to call someone to clean.

[AMC]

Funny this thread came up. I recieved a flyer in the mail advertising a PV cleaning service. They advertise it at $99 though, so I'd rather do it myself.