Solar Wattage Production 2021 AI GL

[psmd]

Good evening all
Have a 2021 GL and was recently monitoring the wattage production from the roof.
I was in full sun on a blue sky day-(clean panels) and was seeing about 125 w on the Victron panel.
Felt like that a is a little low but don't have a reference. (3) 100 W panels should produce 300?
Wondering if there is a way to tell if my panels are workiing?
Thanks,
Paul

[foobar]

Originally Posted by psmd

Good evening all

Have a 2021 GL and was recently monitoring the wattage production from the roof.

I was in full sun on a blue sky day-(clean panels) and was seeing about 125 w on the Victron panel.

Felt like that a is a little low but don't have a reference. (3) 100 W panels should produce 300?

Wondering if there is a way to tell if my panels are workiing?

Thanks,

Paul

Panels produce 100% of the rated output at the earth's equator at noon, when the sun's rats are perpendicular to the the panel.

Seriously, the rating standard is designed to reproduce that level of solar input as the standard by which all panels are measured.

Obviously, we don't live at the equator, so the additional atmosphere the sun's radiation has to travel through in Northern latitudes will scatter more of the rays and reduce the intensity of the solar radiation by the time it hits your panels.

That is degradation factor #1.

Number 2 is that the panels on your roof will never be oriented perpendicular to the sun's rays.

So the steeper angle of incidence is degradation factor #2.

Solar panels are rated at 77F and their output reduces as the sun heats them up beyond 77F.

So high temperature is degradation factor #3

Dirt and other debris can shade the cells in the panel. Shading is degradation factor #4.

These are the main factors.

The key takeaway here is that your peak output in ideal conditions in North America is going to be on the order of 60-70% or so of the total panel wattage ratings. Clouds, shade, dirt, hot panels will all reduce the output.

I have 700 watt high efficiency panels on my Airstream. I get around 400watts in ideal conditions (no clouds, no haze, no shade, clean solar panels, and bright sun on a cool day, with most of my panels somewhat oriented towards the sun). That's around 60% of my total wattage rating. I might get a bit more in Arizona :-)

[field & stream]

X2 the above. An excellent description of reality.

I think about this in terms of Amp hours instead of Watts, because the purpose of the panels is to restore Ah to the batteries. (To get amps divide the watts by the voltage, in this case 12.). Each “100 watt” panel will produce about 5 amps per hour under excellent solar conditions. Under good conditions you can expect 20-30 Ah per day per 100w panel. Clouds and trees can reduce that to almost nothing.

[Wazbro]

To sum up from the other 2 posts here, your 3 100 watt panels should be producing about 180-210 watts or 2 of them should be producing around the 125 watts your Victron panel reported to get 60-70%.

[TeddyK]

Originally Posted by foobar

Panels produce 100% of the rated output at the earth's equator at noon, when the sun's rats are perpendicular to the the panel.

Seriously, the rating standard is designed to reproduce that level of solar input as the standard by which all panels are measured.

Obviously, we don't live at the equator, so the additional atmosphere the sun's radiation has to travel through in Northern latitudes will scatter more of the rays and reduce the intensity of the solar radiation by the time it hits your panels.

That is degradation factor #1.

Number 2 is that the panels on your roof will never be oriented perpendicular to the sun's rays.

So the steeper angle of incidence is degradation factor #2.

Solar panels are rated at 77F and their output reduces as the sun heats them up beyond 77F.

So high temperature is degradation factor #3

Dirt and other debris can shade the cells in the panel. Shading is degradation factor #4.

These are the main factors.

The key takeaway here is that your peak output in ideal conditions in North America is going to be on the order of 60-70% or so of the total panel wattage ratings. Clouds, shade, dirt, hot panels will all reduce the output.

I have 700 watt high efficiency panels on my Airstream. I get around 400watts in ideal conditions (no clouds, no haze, no shade, clean solar panels, and bright sun on a cool day, with most of my panels somewhat oriented towards the sun). That's around 60% of my total wattage rating. I might get a bit more in Arizona :-)

I’m in Arizona you’re about right. Consistently getting about 750w of 1kw array 3 hrs a day high sun which is 31 degrees off axis this time of year. (Newpowa 100w 9BB)

Also have 2 ground deployable that can chase sun all day moving to right angle. There are days I’m harvesting 50% of 1kw roof array from 2 ground deployables if needed.


Point is Foobar is right, angle to sun is everything w solar. Your numbers are low. I wash wax mine early am cloudy morning every month or so. Try to park perpendicular to the sun see if that improves

[field & stream]

Originally Posted by TeddyK

I’m in Arizona you’re about right. Consistently getting about 750w of 1kw array 3 hrs a day high sun which is 31 degrees off axis this time of year…………Point is Foobar is right, angle to sun is everything w solar. Your numbers are low. I wash wax mine early am cloudy morning every month or so. Try to park perpendicular to the sun see if that improves

While your numbers are not strong, I would say they do not indicate that there is anything wrong with the system. I would call it lower end of normal for this time of year in New Jersey.

Others are right, angle of the sun is key. You didn’t say what time of day you reported but in March the sun angle is not great even at noon. The suggestion to park giving the best angle is a good one. I suggest you duplicate the test conditions and record results every month through your camping season.

[psmd]

Good morning all- thank you for the insight given.
I should have clarified that I was in Atlanta at about 1 pm - blues skies etc etc.
but I will definitely keep a log and see what the variations are.
Is there a way to unplug individual stock panels to determine if any on of them is malfunctioning? Or will that shut down all 3?
Thanks
Paul

[Vantair]

Another consideration is what is the combined trailer loads the solar is to power during this analysis ?

Are the batteries topped off not requiring much load ?

If you turn off all DC loads in the trailer, your panels wil instantly reflect this and production will drop to almost zero.
Inversely, power on lots of loads and watch the solar production jump up higher to the point that can max generate given the sun angle or shade.

[psmd]

I hadn’t considered that at all.
I didn’t realize that production watts shown on the Victron would be influenced by need.
So you’re saying that maybe I only needed 125 at that moment?

[Vantair]

Exactly.
The simple heavier loads Off then back On again will demonstrate this in spades.

[Vantair]

Here is some historical examples of actual prior sunny days showing Solar generation is minimal. Again, because of very low demand. (All days, Trailer parked locked at home with nothing going on load wise).

Yesterday afternoon, intentionally turned on the AS inverter, router, network switch, 4 HD cameras, video recorder combined was pulling @ 35 watts in our case.

You can see present day solar generation due to extra load vs that of last few low load days.

Overall, More solar generation produced today to charge back 220AH AGM batteries up from 50% drain overnight while also powering the left on electronics.