MaikaiLife
Solar Enthusiast
Trying to understand where does this other 4500W go if the maximum is 15K?
Sol-Ark 15K Specifications Clarification
- Thread starter MaikaiLife
- Start date
sunshine_eggo
Happy Breffast!
Nowhere.
I expect they're addressing "over-paneling," i.e., putting more PV power on the PV input than the output can deliver. Very common practice. They're basically saying that the attached array may not be more than 19,500W, but you'll only get 15,000W out of it... which is as much as you would expect to consistently get from a 19,500W array (80%).
I expect they're addressing "over-paneling," i.e., putting more PV power on the PV input than the output can deliver. Very common practice. They're basically saying that the attached array may not be more than 19,500W, but you'll only get 15,000W out of it... which is as much as you would expect to consistently get from a 19,500W array (80%).
MaikaiLife
Solar Enthusiast
Hi @sunshine_eggo so then would you recommend that if I'm trying to get 15,000W during peak hours I should over-add enough panels (within the solar limits) to the 19,500W maximum?
timselectric
If I can do it, you can do it.
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- Feb 5, 2022
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I definitely would. But, I'm an overpaneling nut. lol
sunshine_eggo
Happy Breffast!
Yes. Solar newbs don't realize that getting rated power out of panels is exceedingly rare. Panels are rated for perfect sun, clear skies (1000W/m^2) and panel CELL temperatures of 25°C. The reality is that 80% of the solar energy hitting the panel is heating it, so even with perfect sun, the cells are going to be 40-50°C even when it's only 25°C outside. They perform worse at higher temperatures. You'll typically lose about 10% there, and then you almost never have perfect solar conditions and are getting LESS than 1000W/m^w on your panels.
Solar power looks like this:
That peak in the middle on the left is the only place you'll have a CHANCE of getting 15kW.
Over-paneling has the potential to get you something that looks like this:
That flat spot is the max output of the MPPT, or 15kW in this case.
If you can use it (load) or sell back to grid, one option is to AC couple some of the panels (micro-inverters) to produce more than 15k. Or get another inverter.
MaikaiLife
Solar Enthusiast
Awesome response @sunshine_eggo, I'm totally off-grid with no option of a grid so getting every last drop of power for cooling and battery charging will be desired. Thanks so much this totally answers my question!
sunshine_eggo
Happy Breffast!
Something worth considering is splitting your array, e.g., let's say you have 4 strings:
1 string facing SE, 2 strings facing S and 1 string facing SW. While you'll get less total kWh total for the day, you'll get more peak power during mornings and afternoons at the expense of mid-day power.
This is also a technique where you could go even higher than the recommended 19kW. If it's impossible for your array to ever put out more than 19kW due to different panel orientation, you could go even higher.
Once I get my main array fully deployed, I'll likely install two W facing strings to supplement my afternoon power. My array is pointed at 165 vs. 180 since we tend to get better sun in the morning, but I get very little production after 4pm. Sun just isn't hitting the panels. With a couple West facing strings, I'll be able to gather more kWh in the afternoon.
Not much after 4pm:
Here is an example of a Sol-Ark 15K with east-south-west facing 19.4kW paneling on a sunny day in October.
The left chart is total production at any given time, the middle is production per MPPT and the third one is production percentage distribution.
You can see that even with 19.4kW panels I only get about 11kW peak in the middle of the day.
This is a roof mount system with 48 degrees on the east and west side and 30 degrees on the south side in Texas. East and South are 16x440W while west is 12x440W and has pretty significant shading from a dormer and has two panels on a slightly less steep roof slope. I have Tigo Optimizers on every panel.
I would get more out of the system if all 44 panels were facing south but the production is a bit more spread out through the day with this setup and this is all the roof space I had to work with.
This was my worst day production ever, I only got 2.4 kWh all day long with nothing but rain and overcast:
The left chart is total production at any given time, the middle is production per MPPT and the third one is production percentage distribution.
You can see that even with 19.4kW panels I only get about 11kW peak in the middle of the day.
This is a roof mount system with 48 degrees on the east and west side and 30 degrees on the south side in Texas. East and South are 16x440W while west is 12x440W and has pretty significant shading from a dormer and has two panels on a slightly less steep roof slope. I have Tigo Optimizers on every panel.
I would get more out of the system if all 44 panels were facing south but the production is a bit more spread out through the day with this setup and this is all the roof space I had to work with.
This was my worst day production ever, I only got 2.4 kWh all day long with nothing but rain and overcast:
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