Going to use personal weather station to track solar array degradation.

[CaySol]

With my weather station and inverters importing into Home Assistant. Going to use the integral of irradiance (w/m^2) from the weather station to get daily wh/m^2 and PV daily production to get a ratio that I can track as time goes on. Any big drops should alert me of issues with the array as well.

 

[mciholas]

What tracks degradation, dirt, etc, of the weather station?

In other words, who is measuring who?

Mike C.

 

[Tulex]

With my weather station and inverters importing into Home Assistant. Going to use the integral of irradiance (w/m^2) from the weather station to get daily wh/m^2 and PV daily production to get a ratio that I can track as time goes on. Any big drops should alert me of issues with the array as well.

What weather station, and what did you do to get it into HA?

 

[CaliSunHarvester]

tracks degradation, dirt, etc, of the weather station?

Probably easier to clean a weather station's sensor than dozens of panels in hard to reach places.

 

[Tulex]

Probably easier to clean a weather station's sensor than dozens of panels in hard to reach places.

We've had some decent panel cleaning lately. It is spring after all. In fact, Winter snow does the cleaning, spring rain does the rinsing.

 

[CaySol]

What tracks degradation, dirt, etc, of the weather station?

In other words, who is measuring who?

Mike C.

I did wonder about that but figured the sensor on the weather station would have less degradation than the panel.

 

[mciholas]

Probably easier to clean a weather station's sensor than dozens of panels in hard to reach places.

And what about sensor degradation over time?

The sensor is like a solar panel, semiconductor receiving solar energy, so it degrades as well.

Mike C.

 

[CaySol]

What weather station, and what did you do to get it into HA?

It’s an ambient weather model. And I followed these instructions.

Ambient Weather Station

How to integrate Ambient Weather station within Home Assistant.

www.home-assistant.io

Basically you go into your account for the station and create keys that you paste into the HA integration setup.

Ambient Weather WS-2902

 

[CaySol]

And what about sensor degradation over time?

The sensor is like a solar panel, semiconductor receiving solar energy, so it degrades as well.

Mike C.

as quickly as panels though? I thought it was a different process/materials.

 

[mciholas]

as quickly as panels though? I thought it was a different process/materials.

I don't know. The manual for an irradiance meter says to recalibrate it every year due to aging. Another one says aging could be up to 3% per year.

Maybe the sensor is way better than panels, but the reverse could be true.

Mike C.

 

[CaySol]

So this Wh/m^2 is the same as sun hours in the PVwatts website calculation. So daily PV production divided by this number should give you your effective array size(tilt angle, azimuth, sun tracking and shading etc being factors why you won’t hit the rated for the day).

The number should be constant from day to day if there is no degradation (and the sensor is accurate).

 

[Steve777]

I have an Ambient Weather station which measures irradiance too. What I have noticed over the years is that the station's sensor is aimed straight up, which is probably fine for getting a reading of average sun from the sky. However my panels are aimed S and tilted to better catch the sun. The results of this are that from late spring til Oct or so the weather station and PV output correlate fairly well (speaking of mid-day readings). But in winter, the panels produce far more than the irradiance values from the weather station would indicate they could/should. I suspect this is due to the PV panels being aimed more closely at the sun, while the weather station's sensor is aimed straight up.

And as far as cleaning goes, much easier to clean my ground mount PV panels than the weather station which is up a pole 11' off the ground.

BTW - I had suggested to Ambient Weather that they should integrate the irradiance numbers they graph to show WH's, as that would be quite useful for us solar folks. But after seeing how far off their sensor and numbers are from a properly aimed set of panels, not so sure that it would be all that useful after all.