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Basic Question about Expected Daily Production Rate

greg4950

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Joined
Jan 5, 2022
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Hi There,

I'm just starting the process of designing a solar system for the first time and am starting to put it all into one document. I had a quick question about generating power.

According to the attached image in Ontario, Canada, I should 1166 kWh/kW yearly. This value seems to line up with other sources and sun maps. My question is this:

Does that mean that if buy 1000w (1kW) of solar panels then I should expect them to produce approximately 3.19 kW of power per day? (1166 / 365 days) This seemed high to me off a gut feeling from just watching other videoes but I don't really know.

I know that there would be significant fluctuations based on the month and location within the province (I'm located in one of the better sun areas though) but I primarily need this to work April - Nov because the cabin is closed up for the winter.

I just want to make sure that I understand this relationship before starting to size a system based on my power needs.

Much thanks in advance for any help!

Greg
 

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Hi There,

I'm just starting the process of designing a solar system for the first time and am starting to put it all into one document. I had a quick question about generating power.

According to the attached image in Ontario, Canada, I should 1166 kWh/kW yearly. This value seems to line up with other sources and sun maps. My question is this:

Does that mean that if buy 1000w (1kW) of solar panels then I should expect them to produce approximately 3.19 kW of power per day? (1166 / 365 days) This seemed high to me off a gut feeling from just watching other videoes but I don't really know.

I know that there would be significant fluctuations based on the month and location within the province (I'm located in one of the better sun areas though) but I primarily need this to work April - Nov because the cabin is closed up for the winter.

I just want to make sure that I understand this relationship before starting to size a system based on my power needs.

Much thanks in advance for any help!

Greg
Nice map! And welcome to the forum!
I seem to recall a general rule-of-thumb to expect about 3-5 usable hours of sun per day.
But keep in mind that stated panel rating is only achieved under lab conditions. In the real world you can realistically expect much less.
Good luck with your project!
 
Solar Irradiance Calculator

Here you go. Go to the site, put iin your location, and it will show. you expected capture by month, considering local weather history.

Down to 1.3 kw per day per kw of panels in winter, up to 5-6 in the summer.

It varies so much month to month you really need to look at it that way, not by the year.
 
Nice map! And welcome to the forum!
I seem to recall a general rule-of-thumb to expect about 3-5 usable hours of sun per day.
But keep in mind that stated panel rating is only achieved under lab conditions. In the real world you can realistically expect much less.
Good luck with your project!
When you say to expect much less, is there a general rule or thumb? Like are we talking 25%, 50% less?
 
If you use the calculator at Bob's link it'll give you a figure for power per area of panels. I guess they've already taken panel efficiency into account.

Edit: Plus it will obviously depend on other factors like:
  • snow cover
  • direction facing (due south is best)
  • inclination angle (match latitude for annual compromise - so, for me, 45 degrees)
  • shading
 
Last edited:
The components of a solar system depend on how many appliances you need to use in your power system. Then use a battery with a large capacity.
I assume that the OP has already done all that. He's specifically asking how much power he can expect to get from his panels.
This is what he'll need to recharge the batteries to enable them to keep powering the loads, whatever they were calculated to be.
 
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