How clean are your solar panels?

[Muhendis]

On 2/27/2023 at 7:58 PM, BritManToo said:

That's BS, my panels are very dirty now and I doubt I'm losing 5%.

Batteries are still full by 2pm, I'll clean them when they don't fill my batteries up in the day.

A reasonable enough approach.

Bear in mind that, over time, the batteries will "fade". As this happens they will charge quicker and quicker.

A sure indication of loosing capacity.

[Crossy]

I'm conducting a "somewhat controlled" cleaning experiment with another member. Results here when we have something useful.

 

[Crossy]

The results of our semi-scientific study.

 

Background

Myself and @JAS21 live about 20km apart as the crow flies, at this time of year there's no localised storm activity so we get broadly similar weather. Although our systems are of different capacities the panels are oriented in roughly the same direction and angle. We also tend to clean our panels on a sort of regular basis.

 

The factor we used to determine if cleaning made a measurable difference was Total Daily Solar Generation which would be in kWh.

 

What we did

Testing took place over two 2-day periods.

 

Period 1 - 27th and 28th February 2023

JAS cleaned his panels on the morning of the 28th, I did nothing (my system is the control or weather-reference).

27th JAS = 21.92kWh  Crossy = 40.60kWh

28th JAS = 23.31kWh Crossy = 38.30kWh

 

The reference output went down by about 4.25%

If we apply that factor to JAS output on the 28th we get a corrected output of 24.71kWh.

So, the effective change from cleaning is about +12.7%

 

Period 2 - 4th and 5th March 2023

This time I cleaned my panels on the morning of the 5th and JAS did nothing (so his system is the reference)

4th JAS = 23.22kWh Crossy = 35.9kWh

5th JAS = 22.39kWh Crossy = 37.9kWh

 

The reference output went down by 3.6%

Applying that factor to my system output on the 5th gives a corrected output of 39.30kWh

So, the effective change from cleaning is about +9.5%

 

Conclusion

It's not a particularly good test methodology and neither set of panels was particularly dirty (JAS panels were probably a bit dirtier than mine), but there does seem to be a correlation between cleaning them and a not insignificant increase in output.

 

Of course, this does assume that I've done my sums correctly, which is why I've included our measurements if anyone wants to pull my maths apart ????

 

We will do the same test again when we clean again, actual schedule hasn't been decided as yet, probably about a month unless things look particularly grubby.

 

 

 

[007 RED]

4 hours ago, Crossy said:

The results of our semi-scientific study.

 

Background

Myself and @JAS21 live about 20km apart as the crow flies, at this time of year there's no localised storm activity so we get broadly similar weather. Although our systems are of different capacities the panels are oriented in roughly the same direction and angle. We also tend to clean our panels on a sort of regular basis.

 

The factor we used to determine if cleaning made a measurable difference was Total Daily Solar Generation which would be in kWh.

 

What we did

Testing took place over two 2-day periods.

 

Period 1 - 27th and 28th February 2023

JAS cleaned his panels on the morning of the 28th, I did nothing (my system is the control or weather-reference).

27th JAS = 21.92kWh  Crossy = 40.60kWh

28th JAS = 23.31kWh Crossy = 38.30kWh

 

The reference output went down by about 4.25%

If we apply that factor to JAS output on the 28th we get a corrected output of 24.71kWh.

So, the effective change from cleaning is about +12.7%

 

Period 2 - 4th and 5th March 2023

This time I cleaned my panels on the morning of the 5th and JAS did nothing (so his system is the reference)

4th JAS = 23.22kWh Crossy = 35.9kWh

5th JAS = 22.39kWh Crossy = 37.9kWh

 

The reference output went down by 3.6%

Applying that factor to my system output on the 5th gives a corrected output of 39.30kWh

So, the effective change from cleaning is about +9.5%

 

Conclusion

It's not a particularly good test methodology and neither set of panels was particularly dirty (JAS panels were probably a bit dirtier than mine), but there does seem to be a correlation between cleaning them and a not insignificant increase in output.

 

Of course, this does assume that I've done my sums correctly, which is why I've included our measurements if anyone wants to pull my maths apart ????

 

We will do the same test again when we clean again, actual schedule hasn't been decided as yet, probably about a month unless things look particularly grubby.

 

 

 

Good test that shows there is a difference.... Obviously my system is much smaller than both of yours, but I'm happy to do the test with you if you let me know in advance of the date(s).  As you are aware I'm approximately 24km West of you and suffer from a fair bit lot of industrial pollution. 

[KhunLA]

Good info ... thanks

 

If the ESSs don't top up by the end of the day, during dusty, dry, smog season, then I may have to break out the hose.  

 

Yet another reason to love rainy season ????

[Crossy]

24 minutes ago, 007 RED said:

Good test that shows there is a difference.... Obviously my system is much smaller than both of yours, but I'm happy to do the test with you if you let me know in advance of the date(s).  As you are aware I'm approximately 24km West of you and suffer from a fair bit lot of industrial pollution. 

 

If you clean your panels today (or first thing in the morning) and check energy generated tomorrow, we can use our system as the reference source (5th and 7th March). It would be interesting to see if the numbers correlate.

 

EDIT Actually, if you can let me have the daily total for the day before and the day after your last clean (and the dates) we can compare now using our system as reference.

[Crossy]

On 2/28/2023 at 11:26 AM, 007 RED said:

No problem... The supplier I used was Foshan Neexgent Energy Co. Ltd.  Their Home page is-

https://fsgxn.en.alibaba.com/minisiteentrance.html?spm=a2700.details.0.0.74b02051OpCg14&from=detail&productId=1600647586473

 

From the menu bar pull down the PRODUCTS list and then hover over "Solar Panel" to display another pull down list.  At the bottom of that list you will see "Solar Panel Cleaning" if you click on that you will see their various brush products they have.  You will see from their home page that they produce a fairly extensive range of solar equipment, including batteries etc.

 

I'm talking to Foshan Neexgent but looking at the horizontal brush version, I hope it will be more controllable and I'll be able to use it to clean our upstairs windows without breaking out the ladder (so I can justify with Madam). A bit expensive at the moment but Yannis is "checking for a better price". We shall see.

 

[007 RED]

1 hour ago, Crossy said:

 

If you clean your panels today (or first thing in the morning) and check energy generated tomorrow, we can use our system as the reference source (5th and 7th March). It would be interesting to see if the numbers correlate.

 

EDIT Actually, if you can let me have the daily total for the day before and the day after your last clean (and the dates) we can compare now using our system as reference.

Many thanks.  Last time I cleaned the panels was on the 26/02/23, at around 07:00 am, when I used my new ‘toy’ for the first time.  They were quite dirty as you will see from the photo which I included in my post above dated 27/02/23.  Since that clean, my better half tends to give them an occasional hose down from our balcony when she is watering the plants first thing in the morning. Bless her.

 

I just checked the panels a few minutes ago and they’re not looking too bad, so I’ll leave for now until they look really dirty.  I’ll also ask my better half not to hose them down in the morning.

 

OK, looking back at the system’s monitoring facility, I can provide you with the following data:

 

Date     Total kWh    Peak kW at 12:00

24/02    8.06             1.17

25/02    8.27             1.19

26/02    8.42             1.24       (Panels cleaned at around 07:00)

27.02     8.56             1.25

28/02    8.56             1.24

 

FYI…. I’ve just started measuring the sunshine at given times of the day using a very simple LUX meter to see if there is any correlation between sunshine and output power from the panels, particularly before and after cleaning.  No results as yet as its early days and I will have to wait until the panels need cleaning to get a better indication.

[Crossy]

5 minutes ago, 007 RED said:

Date     Total kWh    Peak kW at 12:00

24/02    8.06             1.17

25/02    8.27             1.19

26/02    8.42             1.24       (Panels cleaned at around 07:00)

27.02     8.56             1.25

28/02    8.56             1.24

 

Well, as luck would have it the 25th and 27th produced exactly the same amount of energy, 40.9kWh, so we can do a direct comparison with no correction for the control needed ???? 

 

8.56/8.27 = 1.035 so a 3.5% increase, not as big as we saw, but definitely a movement in the right direction ???? 

 

Let's continue this experiment.

[007 RED]

Not wishing to sound paranoid, but not only will dust, dirt and bird <deleted> affect the output of your solar panels, atmospheric pollution will play havoc with your output.

 

This morning started off with a good sunrise and blue sky.  My system ‘kicked into life’ around 06:30 am as normal (as shown in the graph below). As the sun climbed above the horizon there was steady build-up of output power which is what I would normally expect.  Then at about 10:30 am there was a dramatic fall-off in output from 0.97kW down to 0.25kW over the next hour.

 

On going outside, it was evident that there was a high altitude haze which was obviously effecting the sunlight’s ability to get through to the panels.  A quick check on my simple light meter gave a reading of 34,000 LUX.  The previous day, at about the same time, with a clear sky, it was reading 60,000 LUX.  Quite a dramatic drop.

 

A further check on my PM2.5 meter showed a reading of 92 ug/m3 (as shown below), which indicates extremely poor air quality.

 

As will be seen from the above graph there seems to be an initial improvement in sunlight getting onto the panels, followed by further sudden decreases.  I assume this is because the density of high altitude pollution is moving about and decent sunshine is occasionally able to get through.

 

I can’t say that I’m complaining.  Since the meter reader came 20 days ago, my small scale system has produced 176 units and we’ve only needed to purchase the grand total of 19 units for our local PEA.  At this rate our next bill is likely to be even smaller than the previous one (70.82 THB).

[Crossy]

1 hour ago, 007 RED said:

Not wishing to sound paranoid, but not only will dust, dirt and bird <deleted> affect the output of your solar panels, atmospheric pollution will play havoc with your output.

 

Yup, we've had a rather miserable on-off day too, still charged the batteries and export but just not so much as previously.

 

Don't have our own AQI but the local online ones are bouncing off 60.7ug/m³???? 

 

[PR3]

I cleaned my panels the other day, no water involved just a soft floor duster type thingy. They were a little dusty but once they were done saw an approx 150w gain. Not an enormous amount but worth the 5 minutes effort.

[Crossy]

Myself and @JAS21 repeated our earlier "controlled" experiment with cleaning, similar results to last time.

 

 

 

A 10% increase in the corrected output (equivalent to 4kWh per day for us) is definitely worth the effort of cleaning the panels.

[BritManToo]

Cleaned my panels at Mid-day (mad dog etc.)

Instantly up from just under 1.6kW to 1.8kW.

 

Edited April 26, 2023 by BritManToo

[Crossy]

2 hours ago, BritManToo said:

Cleaned my panels at Mid-day (mad dog etc.)

Instantly up from just under 1.6kW to 1.8kW.

 

About a 12.5% increase.

 

I wish cleaning ours would help today, not even covering local load let alone getting anything into the batteries ???? 

[Encid]

Here is a pretty cool solution for cleaning your dirty panels... and only 3,800 baht including delivery:

 

 

 

 

 

[Muhendis]

On 4/26/2023 at 1:58 PM, Crossy said:

 

About a 12.5% increase.

 

I wish cleaning ours would help today, not even covering local load let alone getting anything into the batteries ???? 

I figured that to be 11% ish. That must have been a whole load of carp to clean off for that level of improvement.

Is the local drainage system now a bit bunged up?

[MJCM]

We have to clean our Panels daily nowadays, reason being. Burning of the grass on the Rice Fields around us.

 

Yes they are still doing it, one day even the local Fire Department had to come with 2 trucks because some stupid <insert swear word> started to burn his fields while there was a lot of wind, and you guessed it it went out of control and endangering at least 3 houses (including ours)

 

[Crossy]

6 minutes ago, Muhendis said:

That must have been a whole load of carp to clean off for that level of improvement.

 

I admit to being more than a little surprised how much difference cleaning makes, even when the panels don't look particularly dirty.

 

What I do notice is that the difference is only really apparent on good generating days. On a miserable day the difference between the control and cleaned systems is much less apparent.

 

[Crossy]

1 minute ago, MJCM said:

Yes they are still doing it, one day even the local Fire Department had to come with 2 trucks because some stupid <insert swear word> started to burn his fields while there was a lot of wind, and you guessed it it went out of control and endangering at least 3 houses (including ours)

 

We don't get direct rice burning (just the second-hand crud) but we did have a similar idiot last year. 

 

Just outside the village was a rather overgrown plot, the owner wanted to sell it but needed to clear it first. A few litres of unleaded (ok it could have been diesel) and a match were procured and used. The resulting conflagration took out the 25kV feeding the village and (more annoying) the fibre trunk.

 

Amazingly the internet was back on in a couple of hours with ToT running a temporary link along the ground whilst PEA sorted out the damaged poles and cables. Power was restored after about 6 hours.

 

[MJCM]

1 hour ago, Crossy said:

 

We don't get direct rice burning (just the second-hand crud) but we did have a similar idiot last year. 

 

Just outside the village was a rather overgrown plot, the owner wanted to sell it but needed to clear it first. A few litres of unleaded (ok it could have been diesel) and a match were procured and used. The resulting conflagration took out the 25kV feeding the village and (more annoying) the fibre trunk.

 

Amazingly the internet was back on in a couple of hours with ToT running a temporary link along the ground whilst PEA sorted out the damaged poles and cables. Power was restored after about 6 hours.

 

Yes those ….. you have everywhere.
 

My wife told me that they know who done it and the owner of one the properties that was affected is claiming damages from that …..  Apparently the blaze set fire to a field and it destroyed a pump for irrigation and all the pvc pipes. We were lucky that the fire department came because the fire almost reached our field were the Solar Panels and Solar pumps are, that would have caused significant damage.