Strange

[Deleted member 1888]

I am having a strange problem my 24v system is not pulling in the same solar it did last year. My solar is down my 2.7k array is only pulling in 2.3. 1.8k is pulling 1.2 and my 1.2k is pulling 900w. Could all my new panels be degraded that fast? or maybe my controllers are not working right? Maybe I just need to go 48v to pull full capacity from the panels?
Panels
array 1 - 9x 305w SERAPHIM (pulling 2.3)
array 2 - 6x 305w SERAPHIM (pulling 1.2)
array 3 - 8x 100w rich solar and 4x 100w windy nation (pulling 900w)
controller's 3 100a EPEVER
Anyone have any ideas as to why I and no longer pulling full?

 

[Don B. Cilly]

Have you considered temperature? Last year when?
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[Deleted member 1888]

Have you considered temperature? Last year when?
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Well this year has been extremely hot in the high 90 to 105, and last year I think we hit 90 a few times. So heat can kill my solar that bad?

 

[Rennit]

IDK where you are at but here it's hot AF and production will suffer because of that.

 

[Lt.Dan]

Heat won't degrade a panel like that. But the numbers you are posting are exactly where they should be in my mind?

 

[Deleted member 1888]

Heat won't degrade a panel like that. But the numbers you are posting are exactly where they should be in my mind?

So my plan to go 48v so I can add more Soler is most likely the best option. Because if we keep getting super hot days my solar will surfer, and I can't keep using my generator to keep my bank up.

 

[Lt.Dan]

As long as the 24v SCC isn't maxed out from amperage, then going to 48v will have minimal gains.

 

[sunshine_eggo]

Have you actually tracked your performance over time, or is this just going off memory? By "tracked" I mean a written or automated log of data that can be used to compare performance over various periods of time.

Around 0.3% performance loss per ° over 25°C, so that accounts for at least 10% loss as your cells are probably north of 55°C. You may find they are substantially hotter.

MPPT also throttle themselves when they get too hot.

If you're getting 75%+ rated power from an array in clear sky and hot conditions, you're winning.

My best performance is in Winter when panels are at Spring/Autumn tilt, but skies are clear and cool. I regularly hit and exceed rated in those conditions (6500' elevation helps).

 

[Lt.Dan]

2300w from a 2700w array is 85% which is exactly what you should be expecting. Thats even better than a lot of people, especially if its 95*+ where you are at.

I would not be concerned.

 

[Don B. Cilly]

Heat won't degrade a panel like that.

Not the same time of year last year, but compared to the cold season (with more southerly sun angles) it's well within expected yield.
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[sunshine_eggo]

Also, check the NOCT rating of your panels. That's more typical for what you'll get in hot conditions.

 

[Lt.Dan]

Not the same time of year last year, but compared to the cold season (with more southerly sun angles) it's well within expected yield.
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I meant heat won't cause permanent degradation like he's thinking. There are solar farms with 130*+ ambient and they see no extreme degradation.

 

[Deleted member 1888]

2300w from a 2700w array is 85% which is exactly what you should be expecting. Thats even better than a lot of people, especially if its 95*+ where you are at.

I would not be concerned.

OK thx guys that puts my mind a ease, its just do dang hot here right now.

 

[fratermus]

So heat can kill my solar that bad?

Voc and Vmp both trend downward as heat increases. To make matters worse cell temps > ambient temps. Here is a simple calculator to see the trends.

Plugging in 105deg F (converted to C) and 2.7kW it says:

Cell Temp	71.8°C
Derating factor	22.464%
Lost capacity due to temp	606.528W

at 80deg F

Cell Temp	57.91°C
Derating factor	15.7968%
Lost capacity due to temp	426.5136W