power from panels not as expected

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Crazy_Ivan
Posts: 5
Joined: Wed Dec 14, 2022 9:47 pm

Hello,

I'm pretty sure I know the answer to this already just wondered if anyone else has had the same issue and how they rectified it.

I have a 3.7Kw inverter, 10Kw of Mira batteries and 3.7Kw of solar panels installed, 5 on the front, and 4 on the hip.
Normally on very sunny days like today at their peak my panels would generate 3.6Kw at their max when the sun was in the right position.

Last saturday the peak was 3.3kw - pretty good, now over the course of the week with the dry spell we are having the output power has slowly started to drop peaking at 2.6kw today - I am assuming there is a layer of dust of the panels which is hampering their performance, as this is all over my car as well.

Has anyone else noticed this and is there anything I can do besides the obvious of aiming a hose at my roof and cleaning them off?

Cheers
Scott
9 x longi panels
1 x Fox 3.7 hybrid inverter
4 x Fox Mira Batteries
Ched
Posts: 64
Joined: Fri Feb 03, 2023 11:02 pm

Don't use your hose as the calcium and/or magnesium dissolved in water will dry on your panel and cause 'water marks'. Much better to wait for the rain to wash off the dust.
It's good practice to have them cleaned once or twice a year. A decent water fed pole window cleaner should be able to clean them from the ground as they use pure water.
calum
Posts: 398
Joined: Fri Feb 24, 2023 11:00 am
Location: Stockport

Looks like we're due some sharp showers next week which should sort things out.

Where I am (SE Manchester) the water is from the Peaks and pretty soft, so if we had a long period of dry weather I wouldn't feel too worried about rinsing them down if needed, but if you get limescale in your kettle etc then definitely don't do that!
H1-3.7 / 6xHV2600 / 14x400W / RS485 Modbus->HA
FoxESS Modbus HA Integration
Contact Fox here
reef
Posts: 107
Joined: Sat Sep 09, 2023 10:06 am
Location: East Yorkshire

The last few days reduction has been due to saharan dust in the atmosphere rather than anything on the panels. I have a weather station and it has recorded solar insolation maxing at about 600w/m2 vs around 800w/m2 that would be expected at this time of the year. This is with a clean sensor too as it's at a level I can reach.

I've seen a similar approximately 20% fall in the peak on tge solar PV, reaching at most about 3.6-3.8kW from our 4.8kW system.
Wolfenden12
Posts: 3
Joined: Sat Aug 19, 2023 6:35 pm

Aw thanks! Since that dust shower (Chorley) my panel production has dropped dramatically! Despite rain last night and today the yield is showing as a measly 90w!! Presuming the rain will just do its thing over the next few days?
calum
Posts: 398
Joined: Fri Feb 24, 2023 11:00 am
Location: Stockport

From what I can see of my panels, here in Stockport we've had plenty of rain to wash off the dust, but of course now we're under a good bit of cloud.
H1-3.7 / 6xHV2600 / 14x400W / RS485 Modbus->HA
FoxESS Modbus HA Integration
Contact Fox here
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