# Forum Home Renovation Solar Electrical Systems  For the Solar Electricity Experts

## cyclic

Has anyone ever been in a position where they have tested a Solar Installation as to output, cleaned the Panels, then tested again in as close as possible circumstances, to show up any gain. 
Reason I ask is, I clean my own Panels about twice a year and there are people getting around charging to clean Solar Panels at rates from $100 to $175, and while I understand clean Panels will put out more power, I cannot help but wonder if the outlay for cleaning is justified. 
I would think only someone who installs but does not clean Panels for a living, and has done the exercise/testing would give an honest answer, so, any people done the test and come up with the numbers ?

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## BRADFORD

My brother has been in the Solar Electricity game for over 30 years, and I don't know if he has ever tested it, but he has never bothered to clean panels unless they are installed in an environment where it is necessary.
Most of his work has been in the outback where dust is the main problem, this washes off quite well with normal rainfall.
If you are near the ocean, in the city or other areas where there is pollution, your panels would need cleaning on a regular basis.
However unless the panels were extremely dirty it would be a long time before you regained your $100 - $175 in improved performance.

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## notvery

^+1. no statistical evidence but from people in the know its not the killer solution. certainly 100+ bucks a year is not to be saved domestically. better off spending that money using the elecy produced more effectively.

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## SilentButDeadly

The rare occasions I have cleaned my panels...we have noticed no massive gains in output (no more than a couple of percent if I recall).  I only clean them now in the winter when I'm up there anyway to clean the solar hot water panels. 
The big limiter in our case is the capacity/willingness of the grid to accept the power being generated.  We often get significant load dumping due to not having many neighbours and being at the end of a long single wire line.

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## Smurf

I measure and record the output of my system daily (on the basis of total energy produced per day from sunrise to sunset). The logging is automatic but I just manually transfer the figures to an Excel spreadsheet. 
Given that output of the system isn't measurably declining without the panels being cleaned, there would seem to be little if anything to gain by cleaning them. Therefore I don't intend cleaning them. 
At work we have a large number of small standalone solar systems (not grid connected). Suffice to say that we sure don't pay someone to go around cleaning panels, indeed we've only ever cleaned one that I know of and that was due to attack by birds (who left "deposits" all over the panels - problem identified when the batteries started discharging and so someone was sent out to investigate).

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## Uncle Bob

The Mars rovers Spirit and Curiosity noticed big losses once their panels became dusty. And IIRC correctly wind storms helped clean them off. https://en.wikipedia.org/wiki/Spirit...and_Home_Plate 
So yeah, I'd say a clean now and then should help, but I do doubt that paying someone to do so would be that beneficial, especially since wind and rain would probably keep them fairly clean anyways.

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## UseByDate

The writer of that article does not know the difference between power and energy. The units used are energy but the word used is power. No wonder the general population gets confused. :Doh:

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## Bloss

No need to clean - the weather will do the job. The formula is simple - is the additional output (paid by the kWh) after cleaning gaining you more revenue (or offset costs) than any cost involved in cleaning. If you are paying someone the answer is almost certainly no. 
Look at how much revenue or offset (since both equate to the total income - if you are on a premium FiT then it is the amount you get for the gross output)  the PV system is giving you over a year and see what proportion of that is any charge being asked to clean your system. 
It would be rare that there is a likelihood to save any money at all - you are simply reducing your income stream from the PV. If you get a really and dust storm or they look dirty a hosedown is all they need, but generally rain will wash them off regularly enough. 
As said above - if you want to spend money buy energy efficient lighting or a more efficient fridge or get and induction cooktop instead of gas or get a heat pump HWS or a high efficiency heat pump reverse A/C  - or shades and heavy curtains with pelmets for windows. All of those will guarantee a lower cost on your bill!

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## SilentButDeadly

> ...if you want to spend money buy energy efficient lighting or a more efficient fridge or get and induction cooktop instead of gas or get a heat pump HWS or a high efficiency heat pump reverse A/C  - or shades and heavy curtains with pelmets for windows. All of those will guarantee a lower cost on your bill!

  Bloss...you'd have to hope that most punters would be smart enough to do those things before they even fitted solar panels. Hope is a very strange concept... :Doh:

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## Bloss

> Bloss...you'd have to hope that most punters would be smart enough to do those things before they even fitted solar panels. Hope is a very strange concept...

  Nah - saving energy isn't sexy, solar is . . . but I am an old tight ar*e so I like the idea of not spending money when I don't have to . . .

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## cyclic

Well, thanks for all the replies, and as I expected, paying someone to clean the Panels is not financially viable.

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## Brian7886

Its financially viable for the reason that it will help extend the life of the panels.  
Output wise, yes, dust drops efficiency of panels. And depending on what sort of panel you have, a covered over (say in a huge bird @@@@) cell could render 1 whole panel useless. You wont gain $100 a year in output, but its another home maintenance thing that does need to be done

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## FrodoOne

> The writer of that article does not know the difference between power and energy. The units used are energy but the word used is power. No wonder the general population gets confused.

  There is no single writer of Wikipedia articles. (Click on "View History" to see that.) 
You (or anyone) can go to Wikipedia and "correct" any article.
If your correction is valid (and you give a brief explanation in the "Edit summary") it is likely that your correction will not be "Undone" by anyone else. 
So, I suggest that you register with Wikipedia and then go ahead and make the corrections which you consider to be necessary.

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## Bloss

> Its financially viable for the reason that it will help extend the life of the panels.  
> Output wise, yes, dust drops efficiency of panels. And depending on what sort of panel you have, a covered over (say in a huge bird @@@@) cell could render 1 whole panel useless. You wont gain $100 a year in output, but its another home maintenance thing that does need to be done

  Nope - will make no difference to panel life and not enough difference in output (over and above the natural washing from rainfall in most locations in Australia) to warrant bothering. That means cleaning is not financially viable - except to the business offering the survice! Of course if there is build up of dirt, or moss or lichen etc - as can happen at the bottom edge in some locations that should be cleaned off. If an owner feels comfortable and can hose off their panels DIY then no harm, but at the rates charged by most of these offering cleaning services it is  waste of money. Ditto those offering 'maintenance' programs - PV systems are set and forget for the most part as are most solid state systems - at some point older inverters are going to fail - but that is generally after 10 years or so - so checking every month to make sure the inverter indicators are all looking normal is a useful practice so you don't lose a a full billing cycle off the system stops working. Newer systems can send a warning SMS or email when they fail and many have web of or pc based monitoring.

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## UseByDate

> There is no single writer of Wikipedia articles. (Click on "View History" to see that.) 
> You (or anyone) can go to Wikipedia and "correct" any article.
> If your correction is valid (and you give a brief explanation in the "Edit summary") it is likely that your correction will not be "Undone" by anyone else. 
> So, I suggest that you register with Wikipedia and then go ahead and make the corrections which you consider to be necessary.

  Maybe I should have written the writer or writers ..............
 I think that to merely correct ubiquitous errors by attempting to correct one example is futile. A much more successful tactic is draw attention to the error. The more people become aware of the errors the quicker the errors will be eliminated. Although I don't expect it to happen in my lifetime. 
 You are quite free to follow your own advice and read the article and correct any errors you deem necessary. Indeed not to follow your own advice would be seen as hypocritical. 
 I have included the following quote from the article so you don't have to read it all. 
 Normally the solar arrays on the rovers are able to generate up to 700 watt-hours (2,500 kJ) of power per Martian day. After the storms, the amount of power generated was greatly reduced to 128 watt-hours (460 kJ).

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## FrodoOne

> I think that to merely correct ubiquitous errors by attempting to correct one example is futile. A much more successful tactic is draw attention to the error. The more people become aware of the errors the quicker the errors will be eliminated. Although I don't expect it to happen in my lifetime. 
>  You are quite free to follow your own advice and read the article and correct any errors you deem necessary. Indeed not to follow your own advice would be seen as hypocritical. 
>  I have included the following quote from the article so you don't have to read it all. 
>  Normally the solar arrays on the rovers are able to generate up to 700 watt-hours (2,500 kJ) of power per Martian day. After the storms, the amount of power generated was greatly reduced to 128 watt-hours (460 kJ).

  Done - about 15 changes in all, with the note "_Changed the term "power" to "energy" - "Watts" refer to power (or the rate at which energy is produced/used), "Watt-hours" (Joules) refer to energy.)"_ 
It is interesting to note that the seemingly "precise" watt-hours figures seem to have been derived from quite "rounded" figures in "Joules".- For example, when using Wikipedia's device of {{Convert|223|Wh}}, the result is "223 watt-hours (800 kJ)"

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## UseByDate

> Done - about 15 changes in all, with the note "_Changed the term "power" to "energy" - "Watts" refer to power (or the rate at which energy is produced/used), "Watt-hours" (Joules) refer to energy.)"_ 
> It is interesting to note that the seemingly "precise" watt-hours figures seem to have been derived from quite "rounded" figures in "Joules".- For example, when using Wikipedia's device of {{Convert|223|Wh}}, the result is "223 watt-hours (800 kJ)"

  RESPECT  :2thumbsup:

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