Hi all, Tony_Bev has asked me to provide some information to everyone in relation to cleaning your solar panels....
My background before retiring was the owner/operator of Townsville Solar Clean, sold it in August 2016 with a clientelle of 700+ on the list...
Anyway, we utilised a water filtering system which removed all chemicals and minerals from the water, basically de-mineralised water..
We used no chemicals in the cleaning of the solar panels, just good techniques...
Most of you will not have de-mineralised water on hand, so, the easiest way to clean your solar panels is.....
Use your garden hose, a soft flock broom/brush and good squeegee, the closest item to what we would have used is the Truck/Caravan Brush with the extension pole and tap...
You can purchase these from Bunnings and other hardaware stores....
Please DO NOT USE any chemicals, car wash or products to clean your panels, these will have abrasives, chemical films and residues, all of which will hamper the output of your system....
Simplest method, wet down the panels, leave for a minute, then with the water flowing in the head of the brush, lightly brush the surface.
Then working with a little increased pressure, dependent on how dirty the panels are, brush down the panels until your are satisfied that they are sufficiently cleaned...
Here is the kicker!!!
Squeegee off the surface of the panels to remove the majority of the water...this will allow the panels to dry alot quicker.
Most standard water in cities and towns will have a percentage of chemicals and calcium, the calcium will leave a series of small rings on the surface of your panels.
The more times they are cleaned without removal of the water from the panels surface, the more calcium rings will remain, over time this will gradually diminish the
output of your system...
If you do this on a regular basis, you will maintain the potential output of your system....
If you have any questions, feel free to pick my brain
Tony Bev said
10:51 PM Apr 4, 2017
Thanks for that info Brett, it is appreciated
It has enlightened me, and I am sure that it will be of interest to others
T1 Terry said
10:08 AM Apr 5, 2017
Hi Brett. The biggest problem for solar mounted on RV's is the rain washed minerals drying on the panels, this does not wash off with plain water. I have increased the output of just washed panels by 50% by applying cut and polish after the wash. The colour of the polish cloth says it all, that is the film the water did not remove. Solar panels are toughened glass, some with a coating over that and it holds a lot more water than the plain glass ones so suffers the mineral build up much faster.
Just like a coat of polish on the paint work, only the rubbish on the outer surface is removed, glass is tougher than paint so the chances of scratching the glass enough to effect light passing through is not very likely. Those who think that polishing panels causes the sun light to be reflected, think about the car paint again, the dull white look is light being reflected, the strong colour is all light but that part of the spectrum being absorbed, only the colour reflected, so how can polishing cause more light to be reflected?
T1 Terry
Jaahn said
10:40 AM Apr 5, 2017
Hi
Terry said "I have increased the output of just washed panels by 50% by applying cut and polish after the wash."
What can you say to that ??? What a load of tosh ! Magic polish
Thanks to The Dogs House for an informative report on how to do it properly.
Jaahn
-- Edited by Jaahn on Wednesday 5th of April 2017 10:41:39 AM
T1 Terry said
12:00 PM Apr 5, 2017
Jaahn wrote:
Hi
Terry said "I have increased the output of just washed panels by 50% by applying cut and polish after the wash."
What can you say to that ??? What a load of tosh ! Magic polish
Thanks to The Dogs House for an informative report on how to do it properly.
Jaahn
-- Edited by Jaahn on Wednesday 5th of April 2017 10:41:39 AM
More than once and have had the owners witness it so your expert opinion seems to be just that, your opinion rather than reality. But hey, it's up to those reading to decide, logic plays a big part in making any decisions making so try adding some logic to your side of the argument to sway people to think you could be correct rather than snide remarks and throwing your support behind someone simply because they have an opposing view. The forums are full of those type so you can't stand out from the crowd that way
T1 Terry
The Dogs House said
03:02 PM Apr 5, 2017
Just took a photo of the brush that is ideal for cleaning your solar panels...
Best features are a telescopic shaft, soft flock brush and a tap on the end to allow easy on/off of the water supply....
Brand is Sabco
Model - Bulldozer...
There are probably a few variations out there similar and they will all do the same job, this is my preference for the job...
Interesting post T1 Terry, it may work for you, however, I have only one issue in your post (not being snide or derogatory in any way)...
Cut and polish is primarily an abrasive mixture and over time can be detrimental to your system.
Again, this is only my opinion, it is your choice to make either way.
-- Edited by The Dogs House on Wednesday 5th of April 2017 03:10:12 PM
Cruising Cruze said
07:23 PM Apr 5, 2017
I tough that glass was harder than any cut and polish car product
I might be wrong
Cheers John
Aus-Kiwi said
07:34 PM Apr 5, 2017
I just use water .. I have cleaned aging plastic headlight covers with normal tooth past on damp towel . It cleans and cuts the plastic cover as good as new . I assume this would work in dirty sections of solar ? Not too sure about doing whole panel though . House has 22 of them . 5.5 kw .
Craig1 said
08:50 PM Apr 5, 2017
Thanks Brett and Lynne and Finn,
My house panels instructions say " Correctly shut down system " prior to any maintenance including cleaning. Your thoughts on that please. cheers Craig
The Dogs House said
10:38 PM Apr 5, 2017
Hi Craig, We didn't shut down any solar panel system prior to a clean as the panels will still be active on the roof no matter whether your isolation switch is on or off.
The primary reason they state they state to isolate the system prior to maintenance is to deal with the electrical cabling side from panels to inverter etc....
Cleaning panels on an active system is fine, unless a panel has visible damage, then you would egress the roof and call your solar techs to check the system..
Over the time I ran my business, I would have personally cleaned well over 3000 individual systems, ranging from 6 panels to 250 panels in an array..
It will not hurt your system to isolate the panels prior to a clean, however, not absolutely necessary...
I would be more worried with issues of chemicals, cleaning agents when on your roof... gets nasty slippery with products...
Another helpful hint is to invest in a pair of Dunlop Volleys, we used them religiously on the roofs as they have phenominal grip
-- Edited by The Dogs House on Wednesday 5th of April 2017 10:39:07 PM
Jaahn said
10:55 AM Apr 6, 2017
Hi
I have cleaned my house panels a couple of times over the years. Mostly because of bat/bird sh*t. I always did it when overcast and used a simple detergent and mop and then hosed it off well after. A scrubbing brush if needed for the blobs As the panels are at 35deg they drain well and as the sunlight was low they did not dry quickly. I like the idea of the squeege to dry them off. Thanks. I did not notice any great change to the output either, and I look at the meter every time I walk out the door.
My several sets of portable panels are washed occasionally if I think they need it and they are near a hose. I monitor their output too and never noticed any improvement that stood out. I always keep an eye on the output to see problems that may be coming. I might look at the panels on the MH soon to see how dirty they are as they have been up there for several years now and always exposed. Still putting it out OK though. I would not use cutting polish on my panels ! But I accept that if panels have been under a tree or the like for some time they may need some more vigorous cleaning than straight water.
I am not an expert, just an old fart with common sense and plenty of technical knowledge and experience. So I see some statements on forums that in my opinion are good, or alternatively seem exaggerated, or again sometimes just BS. I make up my own mind, so can you ! That's life in the real world Sometimes I make a comment, that's life in the forums
Jaahn
-- Edited by Jaahn on Thursday 6th of April 2017 11:05:15 AM
Aus-Kiwi said
12:37 PM Apr 6, 2017
Exactly Hahhan. I've cleaned mine and hardly found any difference . Both on house and motorhome . The truck or motorhome extension handled washing brush comes in very handy ., I guess once a year or before we go on interstate trip . Usually wax the roof while at it . Maintenace saves in the long run .
The Dogs House said
03:22 PM Apr 6, 2017
Thanks Jaahn, as you said, it comes down to common sense...
Hence no chemicals on the roof, just adds to the problems on safety and also potentials for hurting the panels long term...
Hard packed on dirt and bird crap is usually handled by soaking the panels, takes time, but it is very effective.
Izabarack said
04:36 PM Apr 6, 2017
Telstra tech mate tells me that a quick lick with Truck Wash on a brush then lots of water rinse is sufficient to bring remote tower panels back to at installation performance. I remember a time I washed my van panels after coming off the dirt from Birdsville and got about an extra 6% compared to the pre-washed dusty condition.
Same Telstra tech wants to know the physics behind a 100 Watt panel suddenly putting out 150 Watts following a cut-n-polish. I'm not sure that is what was meant but if a washed panel is putting out its spec in full sun on a mild day and after a wash, why would anyone give them a cut-n-polish?
Iza
macka17 said
05:04 PM Apr 6, 2017
It varies.
I've used panels since the late '60's b4 coming to this country.
On the yachts. we cleaned whenever in port and near hrbr. Solely cause of salt build up on fixed panels. Mainly on framework at stern.
Caravans. It Rains. Mine flat. get washed. 40 yrs. I think I've touched them twice when up there doing work. Never noticed any difference to output. Always floating by 11-12 mid day.
over 10 yrs on home. Angles North and East. It and Evac Tubes water system, BOTH paid for themselves last\this yr. Electric and hot water. ALL day. FREE...
Never been touched, cleaning wise. But probably, if living in a dusty area we'd have too.
Unless you living in dirty air. City etc. I wouldn't think it would make enuff difference to be noticed.
unless you one of those who sits on Gauges measuring every minute milliamp.
Last time I looked at roof system Inv was last week. Power cuts with end of Cyclone Prev. Last Cyclone. We still getting our cash returns every yr so somethings good hey.
Down from a Grand to $576 last yr. That's how much the running cost have gone up over 9 plus yrs. Near $500 on our sized system.
On a sunny day it runs the whole house. Pool pumps. Air cond and still trickling cash into grid (2 person home 2 story)
When cold (winter coupla weeks) Heater runs 24\7 for around 5\6 weeks or so.
Warm. Aircond runs, again 24\7 for coupla months I keep a Steady 25\26deg all yr. And at that. we still get those returns. Chuffed.
Seems to be well balanced system. We "supposedly" good on this 44c per kw till '28. So I'll probably be well gone by then hey. Little jar of dust. OH. When washing van I'll point the hose over roof for a tic, that's it.Normally coupla times a yr.
-- Edited by macka17 on Thursday 6th of April 2017 05:04:56 PM
Warren-Pat_01 said
07:45 PM Apr 6, 2017
Thanks Brett for the info.
My van was christened earlier in the year by a possum living in the tree above the van when it was parked in my son's drive way. The yellow stain on the roof & the panel was removed with a rag wrapped around a broom (where I couldn't reach) & water, the rag, water & elbow grease where I could reach. The brush looks good (I'll have one for the next time I visit Canberra or anywhere else that has possums).
At home I leave it up to the rain (? - what's that in Townsville?) to clean the panels. I haven't noticed any reduction in output though.
Prior to a roof fire caused by a dodgy installation, I had decramastic tiles so the less foot traffic on the roof, the better.
Will see how things go now that the roof has been replaced.
Iza, I'm not aware of any cleaning of the solar panels that powered Telstra radio sites in north & NW Qld. Perhaps they do so in southern areas but maintenance became a dirty word in the more modern Telstra. Faulty panels were replaced from time to time & some "low lifes" saw fit to borrow some occasionally. Alarms on the arrays fixed that issue!
T1 Terry said
07:08 PM Apr 7, 2017
I have a Bushtracker in the yard at the moment with a solar charging problem that wasn't a problem 12mths ago. Progressively over the last few weeks travelling from Sydney to Mannum SA the lithium batteries have dropped from 100% SOC to 65% SOC yet in the past the solar has kept up without a problem. A trip up the ladder and the problem is self evident. When I get to that part of the job I will post photos of the panels before and the charge rate recorded on the Victron BMV and again afterwards, just so all can see the difference in the look of the panels, what the polish rag looks like even though the panels were thought to be clean and the charge rate after cleaning.
I honestly didn't believe it would make that much of a difference either so I was out to prove the improvement was negligible and solar panel cleaning companies were a bit like Australian elephant attack insurance policies, a bit of a con unless they was a decent sized bird signature on the panel. I was forced to accept that proper solar panel maintenance was a must rather than a fluffy feel good thing. Recently (within the last 12 mths) there was a paper about the damage caused by dirt film built up around the framework of fixed solar that relied on rain to clean the panels, anyone interested will probably find it with a well worded Google search. Those interested may also see there is a large number of S/H grid tie panel appearing on evil bay lately where they have been "upgraded" due to falling output so it isn't imaginary.
As far as the solar panels that power many of the Govt utility devices in outback areas, someone who has the contract to replace the panels every 5 yrs has offered them to another acquaintance for his off grid solar upgrade, it will be interesting to see just what they are and how much output they still have.
T1 Terry
macka17 said
12:45 AM Apr 8, 2017
Terry. A while ago I was commenting on some older panels I have\had. and still going.
2 x 40w on carport. One calked. BP. the date on it and it's mate put them at 34 and 35 yrs old. Then. Remainder still outputting 2.2a on multi.
Originally on stern frame of yacht. then caravan, then carport for boat batt's.
Only clean they ever got was when it rains. and salt removal while at sea.
Several 80\85w units were similar. 1 x 50w (Yacht plus the 3 x 80\85 on van. All only cleaned when wet. ALL giving within spec's. and aged up to 25 plus yrs each. ALL bought new by self.
NONE Chinese..
Same with house. My solar on roof and Evac tubes water.
(German\US.)Paid for themselves, completely.
In under 9 yrs. ($16 grand Outlay.)
As long as you live in reasonably clean air districts. or regular rain. (We get that and more thank you) There's NOT really any proven reason to clean for max output. They give enuff as is. Or have done so far in the environments I've existed in. At Sea and in Tropics. Oh and yacht based in Adel for good sailing for 30 yrs.
-- Edited by macka17 on Saturday 8th of April 2017 12:48:07 AM
T1 Terry said
01:56 AM Apr 8, 2017
What are you doing still out of bed Macka, I'm still working so I don't have a choice :lol: Just about all my solar work is with RV's and they drive them in some real dusty places, so when it rains the dirt doesn't wash off cause they are flat mounted. The layers just keep building up, a close inspection of just about any flat mounted solar panel will show the brown or black build up around the edges and an even closer inspection will show the black spots all across the panels as well. They really show up once you start polishing them.
I'm guessing that 2.2 amps from the 40w panels is short circuit, I have 11 x 70w panels that date back to before BP entered the solar arena when the company was still Solarex. They still work ok and are within the expected output range, but output to area they aren't in the hunt compared to the Chinese stuff available these days at less than $1/w.... who would have believed they would be so cheap, especially compared to what a dollar bought way back then
T1 Terry
Bagmaker said
11:30 AM Apr 9, 2017
I wonder if glueing a little wick of material onto each corner would suffice to drain water from flat mounted panels?
macka17 said
11:20 AM Apr 16, 2017
I don't sleep much Terry.
Normally catch up every coupla days.
Hoping this implant would help.
But not so far. Pain Yes. Sleeping ?????. We'll see.
Those 40w were rated 2.2A Outputs from new.
Still giving 2.1ish on reg and Multi.
Does enuff to slowly raise v in a battery read from Multi when I connect
so there's some output there.
Plus not draining boat batt's yet..
Yep Mobile\Dirty they do need cleaning.
But regularly "weather" washed like on my van and house up here.
Never touched. still full (theoretical) output showing in system.
House over 9 yrs. But we do get HEAVY rain when it does. Regularly.
Maybe I just picked the perfect spot to retire hey.
It is for everything else.
The old BP\Solarex. discs go black from centres out. b4 calking.
This second panel going that way too recently.
The old Solarex Factory wksp's were in Northern Adel in those days.
A fishing mate worked there
He the one told me about the bridging.
and through glass repairing to keep 'em going.
There were a LOT of older Solarex floating around in those days.
One side shorted. $20 ea, 6v Output.
Buy a doz or 2. Take to shack. double them up and away you go.12v system.
Area needed wasn't a problem. Good sun down there.
And make good Barby benches when dead. Completely weatherproof.
One lad made a carport frame. legs and top.
Covered completely in 6v panels over coupla yrs. Ran both shacks on it.
and kept ute under.
40\to 60w were biggest avail in those days.
My first was a 5w. ONLY ones avail.
Oh and some old Telstra units that appeared at boat club one w'end.
Spindly looking things they were hey.
handful of round discs on a blue glass plate.
Basically.
Yep. Sure have come on in technology.
and even Chinese Quality seems to be improving
with the QC in latest factory's.
It's interesting to watch them assembling on net.
Aus-Kiwi said
11:56 AM May 11, 2017
Up on roof on motor as I'm applying bees wax to protect paint and roof . Due to a few light showers of rain the panels have quite a bit of dust over them. Checked battery voltage . 13.7 and on no charge so I'd say they are well working .. I'll get up and clean them though .. possibly have a good rain when I do though !!
T1 Terry said
06:25 PM May 12, 2017
While at the Stone The Crows gathering I was asked to check why a solar set up was not keeping the batteries charged and they had dropped to 11.5v after only 2 days. A check of the panels and they were covered in dust that had been wet over night and now dried on. It was yet another chance to test the wash with water only against polishing afterwards. A wash and chamois dry improved the solar output by 50%, 1.5 amps increased to 3 amps, not very good for 2 x 150w panels. Polished the panels with Repo no2 cut and polish, no improvement on the first panel but the second panel the input went from 3 amps to 7 amps, that's better than a 50% improvement. Unbolt the panels to see why there was no improvement from one panel, wire broken off at the large BP connector join but also discovered the wiring from the roof to the controller and on to the battery was 2.5mm sq conductor.... caravan manufacturers simply don't have a clue when it comes to solar wiring. Connected the second panel and the output was now only 7.5 amps, not the expected 14 amps, disconnected the first panel and the output of the panel with the previously broken wire was 7 amps, yet both connected only 7.5 amps, that was all the 2.5mmsq cable could carry. Plugged 2 folding 100w panels (2 x 50w x 2 sets) into the Anderson plug that went to the fridge and from there to the house battery (again another example of clueless caravan manufacturers) and the output from the 200w was 12.5 amps.... because the cable was heavier.
It got them through the week as there was no power available that far out and they both had CPAP machines that ran at night off the inverter, the fridge was on gas fortunately.
This improvement from just washed compared to polished was witnessed by quite a few interested parties and they confirmed it to the group gathered for the solar and wiring talk a few days later, so it's not something I just made up, it has been verified more than once to a lot of different interested parties, it really does make a difference.
T1 Terry
oldtrack123 said
08:34 PM May 13, 2017
Perhaps what you should have said that while the 2.5 mm Cross sectional area cable could carry up to up to around 26A without overheating, due to run length & perhaps some other factors , [such as panel output voltage] VOLTAGE drop was the problem!!!
It would be interesting to know just what the voltage drop was in the circuits
Especially if you are giving a talk on electrical matters ,wiring etc
-
-- Edited by oldtrack123 on Saturday 13th of May 2017 08:53:24 PM
T1 Terry said
01:43 PM May 14, 2017
oldtrack123 wrote:
Perhaps what you should have said that while the 2.5 mm Cross sectional area cable could carry up to up to around 26A without overheating, due to run length & perhaps some other factors , [such as panel output voltage] VOLTAGE drop was the problem!!!
It would be interesting to know just what the voltage drop was in the circuits
Especially if you are giving a talk on electrical matters ,wiring etc
-
-- Edited by oldtrack123 on Saturday 13th of May 2017 08:53:24 PM
I'll let you do your own testing Peter The thing most people including those electrically trained fail to keep in mind is solar panels do not have to put out any current, so it is not really voltage drop that is the problem, it is how high the voltage is held at the solar panel. The Vmp at the solar panel for the average 12v nom. cell is between 16v and 18v @ 25*C, solar panels in the Aust sun are unlikely to remain at 25*C so the Vmp must be derated to match the internal temp of the solar panel.
This graph from Kyocera shows the effect temp has on output
From the chart you can see that at 25*C the current output starts to drop off at roughly 17v, but at 50*C the current starts to drop off at just below 15v. If the target voltage is 14.8v before the end of bulk charging is achieved there is only a margin of 0.2v between the point were the panel simply reduces its output. At the 17v mark with the panel's internal temp at 50*C the output has dropped by 25%, so as you can see it doesn't take much resistance in the solar wiring to seriously effect the total harvest available. It is not unusual where poor cable sizing has been use to see 16v plus at the panels, the output of the panel has already started to drop off at this point, does this make the panel get even hotter? Perhaps Peter can enlighten us, he has expressed an opinion on this subject on another forum so his response will be interesting
Quote T1"'I'll let you do your own testing Peter The thing most people including those electrically trained fail to keep in mind is solar panels do not have to put out any current, so it is not really voltage drop that is the problem, ""
So he is saying that voltage drop in the cables is not the problem, yet he says bigger cables overcome the problem
Electrical principles are the same , it does not matter if it is AC ,DC 2V or 1000V!! or what the source is!!
Electrical source can have many different characteristics but the basic electrical principle still apply ,even within those sources themselves
Clearly you should steer well away from anything to do with the technical side side of electricity.& not give advice on such matters
As usual, all you could come up with is a smoke screen I'll leave to those who have even some basic understanding of electrical principle, who can see you have totally failed to comprehend my post & the blatant failure to directly reply to those points,,to be the judges.
So, instead of a big copy & post of something that" looks" good but is virtually irrelevant ,directly answer my points
I would remind all readers ,this man is not even an ordinary electrician & has little respect for any electrical theory, for one simple reason,he does not understand it.!!
Never a truer word [quote T1]"One day I'll know it all, but till then, I'll keep learning."
perhaps should follow that????
-- Edited by oldtrack123 on Sunday 14th of May 2017 09:34:36 PM
oldtrack123 said
09:25 PM May 14, 2017
Izabarack wrote:
Same Telstra tech wants to know the physics behind a 100 Watt panel suddenly putting out 150 Watts following a cut-n-polish. I'm not sure that is what was meant but if a washed panel is putting out its spec in full sun on a mild day and after a wash, why would anyone give them a cut-n-polish?
Iza
Good question Iza.!
Of course the BAD effects of a regular cut & polish may not show up for years , and the degrading then would no doubt be claimed to be due to aging
-- Edited by oldtrack123 on Sunday 14th of May 2017 09:31:39 PM
Aus-Kiwi said
02:03 AM May 15, 2017
Oh here we go !
T1 Terry said
11:52 AM May 15, 2017
As I said else where Peter, I don't want to go into a head to head battle with you so close to loosing your wife. Please don't attack me to get over your pain but please read what was written again, it might help with your understanding of the issues involved. It is not "voltage drop" that is problem here but rather resistance within the cable that increases as the temperature of the cable rises. We all know that resistance through a cable creates heat, that is how an element type heater works, we also know energy can not be destroyed but rather converted from one form of energy to another, in this case electrical energy into heat energy.
Voltage drop is not the actual problem, the fact the solar panel can not get its output current through the wire without the output voltage increasing to a point where the output starts the steep downhill run to zero output is the problem. Yes, the same principle that causes voltage drop is causing this problem, but looking at it as voltage drop alone causing the problem masks the real cause, the panel voltage climbing higher than the temperature adjusted Vmp resulting in less output, not the output being lost in the cable, it just doesn't get out of the panel in the first place.
Hi all, Tony_Bev has asked me to provide some information to everyone in relation to cleaning your solar panels....
My background before retiring was the owner/operator of Townsville Solar Clean, sold it in August 2016 with a clientelle of 700+ on the list...
Anyway, we utilised a water filtering system which removed all chemicals and minerals from the water, basically de-mineralised water..
We used no chemicals in the cleaning of the solar panels, just good techniques...
Most of you will not have de-mineralised water on hand, so, the easiest way to clean your solar panels is.....
Use your garden hose, a soft flock broom/brush and good squeegee, the closest item to what we would have used is the Truck/Caravan Brush with the extension pole and tap...
You can purchase these from Bunnings and other hardaware stores....
Please DO NOT USE any chemicals, car wash or products to clean your panels, these will have abrasives, chemical films and residues, all of which will hamper the output of your system....
Simplest method, wet down the panels, leave for a minute, then with the water flowing in the head of the brush, lightly brush the surface.
Then working with a little increased pressure, dependent on how dirty the panels are, brush down the panels until your are satisfied that they are sufficiently cleaned...
Here is the kicker!!!
Squeegee off the surface of the panels to remove the majority of the water...this will allow the panels to dry alot quicker.
Most standard water in cities and towns will have a percentage of chemicals and calcium, the calcium will leave a series of small rings on the surface of your panels.
The more times they are cleaned without removal of the water from the panels surface, the more calcium rings will remain, over time this will gradually diminish the
output of your system...
If you do this on a regular basis, you will maintain the potential output of your system....
If you have any questions, feel free to pick my brain
It has enlightened me, and I am sure that it will be of interest to others
Just like a coat of polish on the paint work, only the rubbish on the outer surface is removed, glass is tougher than paint so the chances of scratching the glass enough to effect light passing through is not very likely. Those who think that polishing panels causes the sun light to be reflected, think about the car paint again, the dull white look is light being reflected, the strong colour is all light but that part of the spectrum being absorbed, only the colour reflected, so how can polishing cause more light to be reflected?
T1 Terry
Hi
Terry said "I have increased the output of just washed panels by 50% by applying cut and polish after the wash."
What can you say to that ??? What a load of tosh ! Magic polish
Thanks to The Dogs House for an informative report on how to do it properly.
Jaahn
-- Edited by Jaahn on Wednesday 5th of April 2017 10:41:39 AM
More than once and have had the owners witness it so your expert opinion seems to be just that, your opinion rather than reality. But hey, it's up to those reading to decide, logic plays a big part in making any decisions making so try adding some logic to your side of the argument to sway people to think you could be correct rather than snide remarks and throwing your support behind someone simply because they have an opposing view. The forums are full of those type so you can't stand out from the crowd that way
T1 Terry
Just took a photo of the brush that is ideal for cleaning your solar panels...
Best features are a telescopic shaft, soft flock brush and a tap on the end to allow easy on/off of the water supply....
Brand is Sabco
Model - Bulldozer...
There are probably a few variations out there similar and they will all do the same job, this is my preference for the job...
Interesting post T1 Terry, it may work for you, however, I have only one issue in your post (not being snide or derogatory in any way)...
Cut and polish is primarily an abrasive mixture and over time can be detrimental to your system.
Again, this is only my opinion, it is your choice to make either way.
-- Edited by The Dogs House on Wednesday 5th of April 2017 03:10:12 PM
I might be wrong
Cheers John
My house panels instructions say " Correctly shut down system " prior to any maintenance including cleaning. Your thoughts on that please. cheers Craig
Hi Craig, We didn't shut down any solar panel system prior to a clean as the panels will still be active on the roof no matter whether your isolation switch is on or off.
The primary reason they state they state to isolate the system prior to maintenance is to deal with the electrical cabling side from panels to inverter etc....
Cleaning panels on an active system is fine, unless a panel has visible damage, then you would egress the roof and call your solar techs to check the system..
Over the time I ran my business, I would have personally cleaned well over 3000 individual systems, ranging from 6 panels to 250 panels in an array..
It will not hurt your system to isolate the panels prior to a clean, however, not absolutely necessary...
I would be more worried with issues of chemicals, cleaning agents when on your roof... gets nasty slippery with products...
Another helpful hint is to invest in a pair of Dunlop Volleys, we used them religiously on the roofs as they have phenominal grip
-- Edited by The Dogs House on Wednesday 5th of April 2017 10:39:07 PM
Hi
I have cleaned my house panels a couple of times over the years. Mostly because of bat/bird sh*t. I always did it when overcast and used a simple detergent and mop and then hosed it off well after. A scrubbing brush if needed for the blobs
As the panels are at 35deg they drain well and as the sunlight was low they did not dry quickly. I like the idea of the squeege to dry them off. Thanks. I did not notice any great change to the output either, and I look at the meter every time I walk out the door.
My several sets of portable panels are washed occasionally if I think they need it and they are near a hose. I monitor their output too and never noticed any improvement that stood out. I always keep an eye on the output to see problems that may be coming. I might look at the panels on the MH soon to see how dirty they are as they have been up there for several years now and always exposed. Still putting it out OK though.
I would not use cutting polish on my panels ! But I accept that if panels have been under a tree or the like for some time they may need some more vigorous cleaning than straight water.
I am not an expert, just an old fart with common sense and plenty of technical knowledge and experience. So I see some statements on forums that in my opinion are good, or alternatively seem exaggerated, or again sometimes just BS. I make up my own mind, so can you ! That's life in the real world
Sometimes I make a comment, that's life in the forums 
Jaahn
-- Edited by Jaahn on Thursday 6th of April 2017 11:05:15 AM
Thanks Jaahn, as you said, it comes down to common sense...
Hence no chemicals on the roof, just adds to the problems on safety and also potentials for hurting the panels long term...
Hard packed on dirt and bird crap is usually handled by soaking the panels, takes time, but it is very effective.
Same Telstra tech wants to know the physics behind a 100 Watt panel suddenly putting out 150 Watts following a cut-n-polish. I'm not sure that is what was meant but if a washed panel is putting out its spec in full sun on a mild day and after a wash, why would anyone give them a cut-n-polish?
Iza
It varies.
I've used panels since the late '60's b4 coming to this country.
On the yachts. we cleaned whenever in port and near hrbr.
Solely cause of salt build up on fixed panels.
Mainly on framework at stern.
Caravans.
It Rains. Mine flat. get washed.
40 yrs.
I think I've touched them twice when up there doing work.
Never noticed any difference to output.
Always floating by 11-12 mid day.
over 10 yrs on home. Angles North and East.
It and Evac Tubes water system,
BOTH paid for themselves last\this yr.
Electric and hot water. ALL day. FREE...
Never been touched, cleaning wise.
But probably, if living in a dusty area we'd have too.
Unless you living in dirty air. City etc.
I wouldn't think it would make enuff difference to be noticed.
unless you one of those who sits on Gauges measuring every minute milliamp.
Last time I looked at roof system Inv was last week. Power cuts with end of Cyclone
Prev. Last Cyclone.
We still getting our cash returns every yr so somethings good hey.
Down from a Grand to $576 last yr.
That's how much the running cost have gone up over 9 plus yrs.
Near $500 on our sized system.
On a sunny day it runs the whole house. Pool pumps.
Air cond and still trickling cash into grid (2 person home 2 story)
When cold (winter coupla weeks) Heater runs 24\7 for around 5\6 weeks or so.
Warm. Aircond runs, again 24\7 for coupla months
I keep a Steady 25\26deg all yr.
And at that. we still get those returns. Chuffed.
Seems to be well balanced system.
We "supposedly" good on this 44c per kw till '28.
So I'll probably be well gone by then hey.
Little jar of dust.
OH.
When washing van I'll point the hose over roof for a tic, that's it.Normally coupla times a yr.
-- Edited by macka17 on Thursday 6th of April 2017 05:04:56 PM
My van was christened earlier in the year by a possum living in the tree above the van when it was parked in my son's drive way. The yellow stain on the roof & the panel was removed with a rag wrapped around a broom (where I couldn't reach) & water, the rag, water & elbow grease where I could reach. The brush looks good (I'll have one for the next time I visit Canberra or anywhere else that has possums).
At home I leave it up to the rain (? - what's that in Townsville?) to clean the panels. I haven't noticed any reduction in output though.
Prior to a roof fire caused by a dodgy installation, I had decramastic tiles so the less foot traffic on the roof, the better.
Will see how things go now that the roof has been replaced.
Iza, I'm not aware of any cleaning of the solar panels that powered Telstra radio sites in north & NW Qld. Perhaps they do so in southern areas but maintenance became a dirty word in the more modern Telstra. Faulty panels were replaced from time to time & some "low lifes" saw fit to borrow some occasionally. Alarms on the arrays fixed that issue!
I honestly didn't believe it would make that much of a difference either so I was out to prove the improvement was negligible and solar panel cleaning companies were a bit like Australian elephant attack insurance policies, a bit of a con unless they was a decent sized bird signature on the panel. I was forced to accept that proper solar panel maintenance was a must rather than a fluffy feel good thing. Recently (within the last 12 mths) there was a paper about the damage caused by dirt film built up around the framework of fixed solar that relied on rain to clean the panels, anyone interested will probably find it with a well worded Google search. Those interested may also see there is a large number of S/H grid tie panel appearing on evil bay lately where they have been "upgraded" due to falling output so it isn't imaginary.
As far as the solar panels that power many of the Govt utility devices in outback areas, someone who has the contract to replace the panels every 5 yrs has offered them to another acquaintance for his off grid solar upgrade, it will be interesting to see just what they are and how much output they still have.
T1 Terry
Terry.
A while ago I was commenting on some older panels I have\had. and
still going.
2 x 40w on carport.
One calked. BP.
the date on it and it's mate put them at 34 and 35 yrs old.
Then. Remainder still outputting 2.2a on multi.
Originally on stern frame of yacht. then caravan, then carport for boat batt's.
Only clean they ever got was when it rains. and salt removal while at sea.
Several 80\85w units were similar. 1 x 50w (Yacht plus the 3 x 80\85 on van.
All only cleaned when wet. ALL giving within spec's.
and aged up to 25 plus yrs each. ALL bought new by self.
NONE Chinese..
Same with house.
My solar on roof and Evac tubes water.
(German\US.)Paid for themselves, completely.
In under 9 yrs. ($16 grand Outlay.)
As long as you live in reasonably clean air districts. or regular rain.
(We get that and more thank you)
There's NOT really any proven reason to clean for max output.
They give enuff as is.
Or have done so far in the environments I've existed in.
At Sea and in Tropics.
Oh and yacht based in Adel for good sailing for 30 yrs.
-- Edited by macka17 on Saturday 8th of April 2017 12:48:07 AM
I'm guessing that 2.2 amps from the 40w panels is short circuit, I have 11 x 70w panels that date back to before BP entered the solar arena when the company was still Solarex. They still work ok and are within the expected output range, but output to area they aren't in the hunt compared to the Chinese stuff available these days at less than $1/w.... who would have believed they would be so cheap, especially compared to what a dollar bought way back then
T1 Terry
Normally catch up every coupla days.
Hoping this implant would help.
But not so far. Pain Yes. Sleeping ?????. We'll see.
Those 40w were rated 2.2A Outputs from new.
Still giving 2.1ish on reg and Multi.
Does enuff to slowly raise v in a battery read from Multi when I connect
so there's some output there.
Plus not draining boat batt's yet..
Yep Mobile\Dirty they do need cleaning.
But regularly "weather" washed like on my van and house up here.
Never touched. still full (theoretical) output showing in system.
House over 9 yrs. But we do get HEAVY rain when it does. Regularly.
Maybe I just picked the perfect spot to retire hey.
It is for everything else.
The old BP\Solarex. discs go black from centres out. b4 calking.
This second panel going that way too recently.
The old Solarex Factory wksp's were in Northern Adel in those days.
A fishing mate worked there
He the one told me about the bridging.
and through glass repairing to keep 'em going.
There were a LOT of older Solarex floating around in those days.
One side shorted. $20 ea, 6v Output.
Buy a doz or 2. Take to shack. double them up and away you go.12v system.
Area needed wasn't a problem. Good sun down there.
And make good Barby benches when dead. Completely weatherproof.
One lad made a carport frame. legs and top.
Covered completely in 6v panels over coupla yrs. Ran both shacks on it.
and kept ute under.
40\to 60w were biggest avail in those days.
My first was a 5w. ONLY ones avail.
Oh and some old Telstra units that appeared at boat club one w'end.
Spindly looking things they were hey.
handful of round discs on a blue glass plate.
Basically.
Yep. Sure have come on in technology.
and even Chinese Quality seems to be improving
with the QC in latest factory's.
It's interesting to watch them assembling on net.
It got them through the week as there was no power available that far out and they both had CPAP machines that ran at night off the inverter, the fridge was on gas fortunately.
This improvement from just washed compared to polished was witnessed by quite a few interested parties and they confirmed it to the group gathered for the solar and wiring talk a few days later, so it's not something I just made up, it has been verified more than once to a lot of different interested parties, it really does make a difference.
T1 Terry
Perhaps what you should have said that while the 2.5 mm Cross sectional area cable could carry up to up to around 26A without overheating, due to run length & perhaps some other factors , [such as panel output voltage] VOLTAGE drop was the problem!!!
It would be interesting to know just what the voltage drop was in the circuits
Especially if you are giving a talk on electrical matters ,wiring etc
-
-- Edited by oldtrack123 on Saturday 13th of May 2017 08:53:24 PM
I'll let you do your own testing Peter
The thing most people including those electrically trained fail to keep in mind is solar panels do not have to put out any current, so it is not really voltage drop that is the problem, it is how high the voltage is held at the solar panel. The Vmp at the solar panel for the average 12v nom. cell is between 16v and 18v @ 25*C, solar panels in the Aust sun are unlikely to remain at 25*C so the Vmp must be derated to match the internal temp of the solar panel.
This graph from Kyocera shows the effect temp has on output
From the chart you can see that at 25*C the current output starts to drop off at roughly 17v, but at 50*C the current starts to drop off at just below 15v. If the target voltage is 14.8v before the end of bulk charging is achieved there is only a margin of 0.2v between the point were the panel simply reduces its output. At the 17v mark with the panel's internal temp at 50*C the output has dropped by 25%, so as you can see it doesn't take much resistance in the solar wiring to seriously effect the total harvest available. It is not unusual where poor cable sizing has been use to see 16v plus at the panels, the output of the panel has already started to drop off at this point, does this make the panel get even hotter? Perhaps Peter can enlighten us, he has expressed an opinion on this subject on another forum so his response will be interesting
T1 Terry
Quote T1"'I'll let you do your own testing Peter
The thing most people including those electrically trained fail to keep in mind is solar panels do not have to put out any current, so it is not really voltage drop that is the problem, ""
So he is saying that voltage drop in the cables is not the problem, yet he says bigger cables overcome the problem
Electrical principles are the same , it does not matter if it is AC ,DC 2V or 1000V!! or what the source is!!
Electrical source can have many different characteristics but the basic electrical principle still apply ,even within those sources themselves
Clearly you should steer well away from anything to do with the technical side side of electricity.& not give advice on such matters
As usual, all you could come up with is a smoke screen
I'll leave to those who have even some basic understanding of electrical principle, who can see you have totally failed to comprehend my post & the blatant failure to directly reply to those points,,to be the judges.
So, instead of a big copy & post of something that" looks" good but is virtually irrelevant ,directly answer my points
I would remind all readers ,this man is not even an ordinary electrician & has little respect for any electrical theory, for one simple reason,he does not understand it.!!
Never a truer word [quote T1]"One day I'll know it all, but till then, I'll keep learning."
perhaps should follow that????
-- Edited by oldtrack123 on Sunday 14th of May 2017 09:34:36 PM
Good question Iza.!
Of course the BAD effects of a regular cut & polish may not show up for years , and the degrading then would no doubt be claimed to be due to aging
-- Edited by oldtrack123 on Sunday 14th of May 2017 09:31:39 PM
Voltage drop is not the actual problem, the fact the solar panel can not get its output current through the wire without the output voltage increasing to a point where the output starts the steep downhill run to zero output is the problem. Yes, the same principle that causes voltage drop is causing this problem, but looking at it as voltage drop alone causing the problem masks the real cause, the panel voltage climbing higher than the temperature adjusted Vmp resulting in less output, not the output being lost in the cable, it just doesn't get out of the panel in the first place.
T1 Terry