how much should my panel generate?

[porkpiepete]

Hi, I am new to all this solar stuff. I have just had 6 panels rated at 405 watts fitted to my roof which has a westerley direction. I am in England and at this time of year we have around 7 hours of daylight. How much power would it be reasonable to expect on a cloudy day?

[Mike 134]

I'm at 42 degrees latitude (Chicago) and my 18 405-watt panels have produced under 1000 watts total on a rainy cloudy day.

[J.P.M.]

If you check out something called PVWatts on the net and spend a bit of time (maybe 20 minutes or so) reading all the help screens, and take some care to get the inputs close, you'll get results.

Choose the hourly output option and look for the lowest daily output for December. That will be a decent 1st approximation for cloudy day outputs for the lowest output month of the year. Read the help screens again for how to interpret the results. Doing it this way is a bit of a bastardization of the model's intent but it'll give you better than a dart throw guess at an answer to your question.

[davidcheok]

Hi, I am new to all this solar stuff. I have just had 6 panels rated at 405 watts fitted to my roof which has a westerley direction. I am in England and at this time of year we have around 7 hours of daylight. How much power would it be reasonable to expect on a cloudy day?

https://globalsolaratlas.info

Selection your location, select residential, fill in the details.

Your panels should be facing south because the sun is all the way down there.

[AmyJones]

On a cloudy day, solar panels will produce between 10 and 25 percent of their usual electricity production, though estimates vary. Naturally, the equipment's quality and the amount of cloud cover will determine this. It's significant to note that locations for solar energy installations are frequently found in overcast and wet areas.

[porkpiepete]

https://globalsolaratlas.info

Selection your location, select residential, fill in the details.

Your panels should be facing south because the sun is all the way down there.

hi Thank you for the link. As far as I can tell from the information I have put in I should be getting around 4 times more power out of my panels that I am. I didn't think everything was working as it should be.
Unfortunately I have panels facing east and west because that is how my roof is so I changed the parameters to reflect this.

[J.P.M.]

hi Thank you for the link. As far as I can tell from the information I have put in I should be getting around 4 times more power out of my panels that I am. I didn't think everything was working as it should be.
Unfortunately I have panels facing east and west because that is how my roof is so I changed the parameters to reflect this.

Use PVWatts. It'll get you numbers that are easier to interpret.

[davidcheok]

hi Thank you for the link. As far as I can tell from the information I have put in I should be getting around 4 times more power out of my panels that I am. I didn't think everything was working as it should be.
Unfortunately I have panels facing east and west because that is how my roof is so I changed the parameters to reflect this.

If you have both east and west panels, u need to work on each side independently.

As for clouds, it all depends. You can have cloudy but bright days or cloudy but gloomy days. What type of clouds and how high they are also matters.
Share what your system is and what kind of production you are getting.

[venquessa]

2.4kW East West Roof. England, in January.

If you average more than 100W you will be lucky.

Part of the problem is the sun elevation and the short day length. The other part of the issue, in winter the sun never gets anywhere near East West in the UK. It remains very much SouthEast to SouthWest.

Wait until June/July before you make judgement.

[littleharbor2]

7 hours of daylight is not the same as 7 solar hours which is based on the full midday output. You may only be getting 2 1/2 equivalent sun hours.
Average Peak Sun Hours (United Kingdom) - Climatebiz