Hi,

I am running a Sunsynk Inverter on 10x 300W panels, facing East, approx. 25 degrees tilt and wondering what Energy I should get compared to what I am getting. I only get about 10 kW per day and this seems quite low to me? Am I wrong or what can I check to see if everything is alright?

Thanks!

You can open a free account at Solcast and monitor their forecasted yields compared to your actuals.
They are pretty accurate. Remember you should add your site data in terms of Azimuth and tilt as accurately as possible. Also their forecast models are based on best available solar radiation forecast models and actuals do vary at times especially with broken clouds around.
Here is their write up about the forecasting models. https://articles.solcast.com.au/en/articles/2963469-solcast-probabilistic-forecasting-fields-what-are-they-how-do-we-create-them

 

Go to the "Add Site" link and create your free account.  https://toolkit.solcast.com.au/

Here is an example of what my site data forecast is right now, including the actuals for the past 3 days and the forecast ahead for the next 3 days.

Edited March 26, 20224 yr by zsde

https://re.jrc.ec.europa.eu/pvg_tools/en/tools.html#SA

Around 13kWh/day in March, assuming no shadows and you utilize 100% of it. (I guessed you are somewhere in Gauteng)

 

I have 8 x 460W panels, facing N at approx 30 deg tilt. I am in Pretoria-East area. My generation graph below:

 

@Joerg and @Werner Pieterse I have 12 X 410 W panels two 5000 W growatt inverters here is my solar production since installation. very similar to the one above

Just note OP's panels are facing east 

10 hours ago, P1000 said:

https://re.jrc.ec.europa.eu/pvg_tools/en/tools.html#SA

Around 13kWh/day in March, assuming no shadows and you utilize 100% of it. (I guessed you are somewhere in Gauteng)

Thank you. That's what I'd expect, also. I am in Knysna but the values shouldn't differ too much...Wondering why they are so low...

On 2022/03/26 at 7:02 PM, Joerg said:

I only get about 10 kW per day and this seems quite low to me?

You have 3kW's worth of panels facing east, I would guess 4 hours at 80% + a wee bit thereafter, but it depends, do they see sunlight from sunup or are they in shadow (trees/larger houses etc. blocking the sun) for a while after sunrise?

So, I'd guess 9.6kW + maybe another 2-odd kWh for the rest of the day, assumption is sunshine all day and no shadow during sunlight hours from any structures/plants. So around 12kWh, would be my guess. @P1000's response is probably the most accurate and scientific. I could also paste my graphs, but just like the others' above, probably of little value.

I have 8 panels either facing east or flat on their backs or finally looking west (rotated manually  during the day, really 3 positions, not tracking the sun...) and another 9 panels facing north, fixed at, I'm guessing 40° off the horizontal. (The 8 panels are probably at 40° off the vertical/60° off the horizontal when looking east or west.) The 8 panels produced power probably nearly 2 hours before the 9 fixed panels and produce power much later as well. The kWp is 17 * 280W aka 4760W and production today (with the odd cloud here and there) was 26.5kWh, yesterday with no clouds that I can recall, they produced 31kWh. I am guessing, I must see if I can calculate somehow, how much power to ascribe to which panel string, that the rotatable panels produce 55 to 60% of the total, even though they are only 47% of the power production potential.

32 minutes ago, Joerg said:

Thank you. That's what I'd expect, also. I am in Knysna but the values shouldn't differ too much...Wondering why they are so low...

Because they're facing east. You should be getting about 12kWh per day in March as per the photovoltaic GIS.

 

 

 

Edited March 27, 20224 yr by Froggie

Is this a grid-tied system with export? Are any batteries being used, and if so, what capacity? Is there any time during the day that the battery is full and the system is mostly producing below capacity because of low loads?

On 2022/03/26 at 7:02 PM, Joerg said:

Hi,

I am running a Sunsynk Inverter on 10x 300W panels, facing East, approx. 25 degrees tilt and wondering what Energy I should get compared to what I am getting. I only get about 10 kW per day and this seems quite low to me? Am I wrong or what can I check to see if everything is alright?

Thanks!

I have half my panels facing East. The East-facing panels produce useful (but not full) power until about 14:30. And if the weather is cloudy in the mornings, my system doesn't do so well. 

No set of panels is going to work optimally all the time. As I said, if it's a cloudy morning (like today) I suffer, but if it's a bright morning and then overcast in the middle of the day at least I had good PV in the morning and may not do too badly.

How much power does your property consume? My system, on a sunny day, will work flat out until batteries are charged, then it derates the solar and draws only what it needs. So I probably never get full solar production.

I can force the issue by heating up a geyser that nobody uses in the afternoons, but then if the weather isn't so good and that excess PV isn't there, then the system will use the batteries.

So perfection is elusive.
 

Hm hard to say. but also have interest in it