Is it safe to use normal water to clean solar panels?

choeey11

Hey!

We installed a solar panel at our home a few months back and it was one of our many steps to go green and be ecofriendly. In addition to the satisfaction of going green, while doing the utility bill tracking, we noticed significant savings in our electrical bills. 

Anyway, we have heard that solar panels are to cleaned every 6-12 months in addition to regular maintenance. It's fine, but is it fine to use normal water to clean he panels? In this article: http://solution105.com/keep-it-clean-keep-it-green-the-importance-of-solar-panel-cleaning/ it's recommended not to use normal tap water, but use pure water. What will go wrong if we do it with pipe water? Any advice on what to do without causing any issues with the panels?

littleharbor2

Depending on your location you may need to clean your panels more often than twice a year. Mine are by the sea and get a salt crust on them fairly rapidly so need bi monthly cleaning. I have always used clean tap water and a scrubby/squeegee thing on a threaded broom handle. I would think as long as you are squeeging the water off right away you wont need to worry about any mineral buildup. The panels I have mounted flat on the 5th wheel are another story. The standing water they accumulate at night which evaporates daily will cause this mineral buildup. I have had to remove it with a razor blade.

Estragon

Definitely location and tilt specific. I have never had to clean my panels. They're tilted fairly steeply (~60°), and we get enough rain to clear off what little dust there is in our remote bush location. Rainwater pretty much is pure water, so no mineral deposits.

When I was near the beach in N Florida this winter though, my car would get covered in enough sea spray and dust to need washing in less than a week. That would be enough to cut solar production quite a bit, and winters tend not to be rainy there. If I had panels there, I would wash with tap water (well sourced and likely high mineral content), but I would do it late in the day when sun wasn't hitting the panels. Same idea as not washing the car in full sun to avoid spots.

Dave Angelini

We use rainwater from 16,000 gallons of tanks. Stop by and you can have a rinse   Occasionally an Eagle, Raven, or Red Tail will 
do their business. I have been saying that I will put up some of the security wire they use for birds at airports for a very long time.

Photowhit

I've actually never read about using 'pure water'. It doesn't surprise me, as manufacturers use coatings on the glass to aid light transmission. I doubt there would be much problem with using your homes water, in time any coating is likely to wear off.

I use rain water...lol. Only time I actually clean my panels is to remove snow. This time of year I could likely increase their wattage by 10-15% as they get a nice coating of pollen, but we also have more sun and the pollen comes when we're having sunny days and leaves with rain then overcast days and I'm off grid so it works out fine.

Raj174

Pollen has been a problem here in north Florida too. I was having to spray them off every 3 or 4 days for several weeks. I did this early in the morning while the dew was still on the panels. I used tap water. Increase in array output was about 10 percent.

Estragon

Pollen won't be a big issue here for a couple of weeks. Getting up to a foot of snow today :-(

westbranch

June for Lodgeole Pine, D-Fir and Spruce's pollen loading here.... sweeping followed by a wet rinse with some vinegar due to alkalinity in lake and well water...

choeey11

Thank you guys! We get good rain, but not very often. We don't have trouble with dust or pollen, but whether there is any accumulated dust or pollen is a thing to see. If there is a lot of dust accumulated or something on it and it's not rainy time, what would you suggest me to clean it with? Are you sure pipe water will do no harm?

KeithWHare

The issue with cleaning panels is not really pipe water, it is whether or not the water you use leaves mineral deposits on the glass when it dries. If you squeegee the water off as part of the cleaning, then it doesn't really matter what water you use.

If the water you use etches the glass or even the frames, you have a much bigger problem.

mike95490

And if the panels are not really clean when you run the squeegee over them, you have scratched your panels.   I use strained pond water, early AM, before the dew has dried.

littleharbor2

mike95490 said:

And if the panels are not really clean when you run the squeegee over them, you have scratched your panels.   I use strained pond water, early AM, before the dew has dried.

Do you have any idea what goes on under water in those ponds?

Dave Angelini

littleharbor2 said:

mike95490 said:

And if the panels are not really clean when you run the squeegee over them, you have scratched your panels.   I use strained pond water, early AM, before the dew has dried.

Do you have any idea what goes on under water in those ponds?

Getting up that early to even see the dew impresses me!  

mike95490

The pond is full of life.   I strain the water when I pump it, to keep the frog parts out of the water tanks.  Pond water is naturally soft, not from an underground source where it picks up minerals.

BB.

If you have problems with water spotting (i.e., rinsing your car)--You can get de-inonizing bead filters:

https://www.amazon.com/DI-120-Cr-Spotless-Water-System/dp/B0056HDCUM

20 inch cartridge containing a mixed bed of de-ionizing resin that will produce approximately 200 gallons of mineral-free water based on an average TDS level of 200 ppm. Depending on the quality of the water where you live, you can get between 75 and 1000 gallons of deionized water from one resin cartridge.

That is $50 per refile (for this brand--Don't know anything about the produce--just FYI). There are many other brands/models out there--But similar costs. De-Ionized water is not cheap.

-Bill

isakshisinghal

Yes. It is quite safe to use normal water - neither too hot, nor too cold. For insistent stains like bird droppings you could use some soap with a clear conscience.

NANOcontrol

Rain water isn't that pure.  In the Adirondacks, the state drops lime into remote lakes with helicopters just to keep the fish alive as the rain has become so acidic.  Hard water over time will leave a film.  I know someone makes a sprayer that attaches to a garden hose for cleaning upper windows with a cleaning element.  I don't think anything you do makes much difference.  I've had to clean mine once a week due to local road construction.

softdown

mike95490 said:

The pond is full of life.   I strain the water when I pump it, to keep the frog parts out of the water tanks.  Pond water is naturally soft, not from an underground source where it picks up minerals.

Ground waters natural state is alkaline unless there are dominant factors contributing to acidity. Factors such as low turnover rates, decomposition of flora and fauna, high stocking rates, or local sewage leaks. Highly industrialized and densely populated areas may also experience "acid rain". 

The vast majority of ground water is alkaline because the earth is primarily composed of alkaline elements such as basalt and granite. Calcium, for example, is an extremely common primarily alkaline mineral that winds up in groundwater, rivers, lakes, and many ponds. We are flying through space on a giant rock with a molten iron core that provides the magnetic shield that prevents the sun from destroying life on earth as we know it. And people wonder why I worry? 

It is the decomposition of organic matter, and pollution plus periodic volcanic debris, that causes most acidic water conditions. For example, the Amazon River moves at a leisurely pace in a very biorich environment. The resulting influx of acidity creates a riverine system with pH levels well below the neutral level of 7.0.

It is also possible for naturally occurring CO2, sulfur dioxide, hydrogen sulfide and hydrogen halides to be emitted via volcanic gases or subterranean leakage.

If water is acidic, I would not drink it. It is highly likely to contain phosphates and nitrates and other byproducts of organic decomposition. It may be a "common phenomenon" when septic systems are placed too close to well water. 

A textbook could be written on the subject. This is just a few selected highlights. 

westbranch

Acidic water is common on the West Coast in areas labeled RAIN FOREST such as Vancouver, BC

softdown

Everyone knows that Canadians are not as caustic as their more southerly peers.

Rain forest type habitats were mentioned a few times in my synopsis. Such as:
"decomposition of flora and fauna".....more rain equals more flora and fauna
"It is the decomposition of organic matter, and pollution plus periodic volcanic debris, that causes most acidic water conditions. For example, the Amazon River moves at a leisurely pace in a very biorich environment. The resulting influx of acidity creates a riverine system with pH levels well below the neutral level of 7.0."

Acidic water would be preferable for the majority of window cleaning anyway. Especially solar panels. 

Most cleaning is done via pH reactions. Using acid to remove alkalinity. Alkalinity to remove acid.

Do not ever co-mingle strong acids and bases (alkaline chemicals) unless possible death or lung crystallization is sought.

westbranch

Softdown, I agree with you. I just wanted to [point out where it occurs...  and has been the reason , when in Vancouver , Victoria, Seattle, etc it is recommended to run your drinking water tap till it runs cold, that way the dissolved metals ...lead primarily. are minimized... 

softdown

There are many arguments for a carbon filter on drinking water. Though I'm not sure if dissolved lead (lead sulphate?) is removed. I would hope so and it is logical to think that lead would be removed. There are a few things that carbon fails to remove however. Minerals such as calcium and chemicals such as phosphates and nitrates for example.....

It sure seems that there are few things that the experts pretty much all agree on. For example, I did a little research on the effects of lead plumbing and and lead storage vessels in ancient Rome. Opinions varied all over the place. How could lead plumbing and lead liquid storage vessels be anything but really bad? They even found that storing wine in lead vessels created a sweeter taste. Lead tastes sweet. If one can literally taste the sweetness from the lead vessel, that is surely a bad thing.