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What power should my panels generate???


Scorp007

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I found this is a very common question that comes up and thought it good to use the February figures which included a good dose of load shedding and also quite a few bad days. Normally not talked about :) Due to load shedding a numbers of my days are down badly at up to 60%.

As per my figures I included the type of system as well as location. I used the metric of kWh/kW capacity installed to give a measure even if the system was expanded.

Members like @system32 and @Antonio de Sa and others that already post at PVout could get the values real quick.

GRID TIED    GAUTENG    kWh/kW    1.62kW in series
FEB '23           (kWh)          Effic
01/02/23             2.4         1.48
02/02/23             5.3        3.27
03/02/23             3.5        2.16
04/02/23             8.6        5.31
05/02/23             7.7        4.75
06/02/23             8.2        5.06
07/02/23            6.9        4.26
08/02/23            2.5        1.54
09/02/23            1.5        0.93
10/02/23            2.0        1.23
11/02/23            2.9        1.79
12/02/23           6.3        3.89
13/02/23           3.3       2.04
14/02/23            5.1        3.15
15/02/23            7.3       4.51
16/02/23            5.3       3.27
17/02/23            2.7      1.67
18/02/23            3.5      2.16
19/02/23            0.5      0.31
20/02/23            1.6      0.99
21/02/23            5.1      3.15
22/02/23           6.7     4.14
23/02/23           7.0      4.32
24/02/23          4.7      2.90
25/02/23          4.3      2.65
26/02/23          5.9      3.64
27/02/23          6.8      4.20
28/02/23          8.2      5.06
 

 

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@Scorp007 @system32 herewith my figures for Feb 2023.

Location Vaalpark, Sasolburg. Free State.

2 X 5000 KVA growatt. 12 X 440 W solar Panels

PV 4.920 KW
Feb_23
Date Generated Iffec.
28/02/23 18.600kWh 3.780kWh/kW
27/02/23 15.100kWh 3.069kWh/kW
26/02/23 14.900kWh 3.028kWh/kW
25/02/23 13.800kWh 2.805kWh/kW
24/02/23 17.200kWh 3.496kWh/kW
23/02/23 16.700kWh 3.394kWh/kW
22/02/23 15.300kWh 3.110kWh/kW
21/02/23 18.400kWh 3.740kWh/kW
20/02/23 14.100kWh 2.866kWh/kW
19/02/23 14.100kWh 2.866kWh/kW
18/02/23 7.500kWh 1.524kWh/kW
17/02/23 9.200kWh 1.870kWh/kW
16/02/23 11.500kWh 2.337kWh/kW
15/02/23 12.300kWh 2.500kWh/kW
14/02/23 15.700kWh 3.191kWh/kW
13/02/23 11.700kWh 2.378kWh/kW
12/02/23 14.400kWh 2.927kWh/kW
11/02/23 6.400kWh 1.301kWh/kW
10/02/23 5.600kWh 1.138kWh/kW
09/02/23 10.600kWh 2.154kWh/kW
08/02/23 8.200kWh 1.667kWh/kW
07/02/23 15.800kWh 3.211kWh/kW
06/02/23 15.500kWh 3.150kWh/kW
05/02/23 18.200kWh 3.699kWh/kW
04/02/23 18.100kWh 3.679kWh/kW
03/02/23 17.000kWh 3.455kWh/kW
02/02/23 16.500kWh 3.354kWh/kW
01/02/23 10.800kWh 2.195kWh/kW
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Off Grid
Johannesburg. Last 28 Days. 
12 X 535W panels 2P 6S  Theoretical 6420W  



                                                                                        Load                                                                  PV Generation
 

Mar 12

12.9 kWh

15.3 kWh

Mar 11

12.9 kWh

15.7 kWh

Mar 10

11.4 kWh

13.7 kWh

Mar 09

12.4 kWh

14.5 kWh

Mar 08

12.2 kWh

14.7 kWh

Mar 07

10.8 kWh

14.7 kWh

Mar 06

11.8 kWh

12.9 kWh

Mar 05

9.9 kWh

13.8 kWh

Mar 04

9.5 kWh

10.4 kWh

Mar 03

9.5 kWh

12.2 kWh

Mar 02

11.8 kWh

14.1 kWh

Mar 01

8.8 kWh

12.6 kWh

Feb 28

11.0 kWh

13.4 kWh

Feb 27

12.5 kWh

15.3 kWh

Feb 26

10.9 kWh

13.2 kWh

Feb 25

13.3 kWh

15.3 kWh

Feb 24

11.0 kWh

13.7 kWh

Feb 23

12.6 kWh

15.9 kWh

Feb 22

13.9 kWh

16.8 kWh

Feb 21

13.1 kWh

14.9 kWh

Feb 20

11.7 kWh

14.2 kWh

Feb 19

10.8 kWh

13.1 kWh

Feb 18

7.1 kWh

9.4 kWh

Feb 17

9.1 kWh

13.3 kWh

Feb 16

14.4 kWh

17.4 kWh

Feb 15

13.6 kWh

16.4 kWh

Feb 14

12.5 kWh

14.9 kWh

Edited by zsde
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14 hours ago, Scorp007 said:

I found this is a very common question that comes up and thought it good to use the February figures which included a good dose of load shedding and also quite a few bad days. Normally not talked about :) Due to load shedding a numbers of my days are down badly at up to 60%.

As per my figures I included the type of system as well as location. I used the metric of kWh/kW capacity installed to give a measure even if the system was expanded.

Members like @system32 and @Antonio de Sa and others that already post at PVout could get the values real quick.

GRID TIED    GAUTENG    kWh/kW    1.62kW in series
FEB '23           (kWh)          Effic
01/02/23             2.4         1.48
02/02/23             5.3        3.27
03/02/23             3.5        2.16
04/02/23             8.6        5.31
05/02/23             7.7        4.75
06/02/23             8.2        5.06
07/02/23            6.9        4.26
08/02/23            2.5        1.54
09/02/23            1.5        0.93
10/02/23            2.0        1.23
11/02/23            2.9        1.79
12/02/23           6.3        3.89
13/02/23           3.3       2.04
14/02/23            5.1        3.15
15/02/23            7.3       4.51
16/02/23            5.3       3.27
17/02/23            2.7      1.67
18/02/23            3.5      2.16
19/02/23            0.5      0.31
20/02/23            1.6      0.99
21/02/23            5.1      3.15
22/02/23           6.7     4.14
23/02/23           7.0      4.32
24/02/23          4.7      2.90
25/02/23          4.3      2.65
26/02/23          5.9      3.64
27/02/23          6.8      4.20
28/02/23          8.2      5.06
 

 

Hi ... what inverter do you have.  At 1.6kwp installed capacity you may not be generating enough voltage for the panels to work hard enough throughout the day, or your demand must be low.

Please also post the panel size each and the number of panels.

 

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Not sure what the point of the above is....

In a grid-tied system, with zero feedback to the grid your system (Panels + Inverter) will only satisfy the load.

The answer is "panels should cover the load"

So what are you comparing? 

You should be asking yourself how much of my daily load is covered by the power generated.

Even then, if your load is constant over the entire day, you will have periods of drawing from the grid to supplement your loads in the early morning and late afternoon. 

 

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49 minutes ago, FixAMess said:

Not sure what the point of the above is....

In a grid-tied system, with zero feedback to the grid your system (Panels + Inverter) will only satisfy the load.

The answer is "panels should cover the load"

So what are you comparing? 

You should be asking yourself how much of my daily load is covered by the power generated.

Even then, if your load is constant over the entire day, you will have periods of drawing from the grid to supplement your loads in the early morning and late afternoon. 

 

@FixAMess I think the idea is to see how efficient your solar panels are based on the amount of solar energy generated on Sunny/Cloudy days. We all know that we do not harvest all that is available, in my case from about 12:00 till about 15:00 once battery is fully charged, 3KW geyser water is hot to set value, my system is just idling. I usually use that time to balance my battery cels.

See attached

image.thumb.png.474098c922ad765bc3dd4e8a5c25c843.png

Edited by Antonio de Sa
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23 minutes ago, THULANE said:
3 hours ago, Antonio de Sa said:

@Antonio

12 X 440 W solar Panels PV 4.920 KW

My question is, what ever we do, the PV cant reach the exact calculated KW?

I have PV =3200KW but it never passed 2400KW.

 
     

 

@THULANE it depends, I've had days at 5 Kw but my average is about 4 Kw from about 10:00 AM, my panels are facing due North and no shade.

see attached.

image.thumb.png.b2908fded3c426fbbece16644e79c3c7.png

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2 hours ago, FixAMess said:

Not sure what the point of the above is....

In a grid-tied system, with zero feedback to the grid your system (Panels + Inverter) will only satisfy the load.

The answer is "panels should cover the load"

So what are you comparing? 

You should be asking yourself how much of my daily load is covered by the power generated.

Even then, if your load is constant over the entire day, you will have periods of drawing from the grid to supplement your loads in the early morning and late afternoon.

Also not sure what the question means "What power should my panels generate???"
If your panels are true north and are at the optimal angle, not too hot, they should get close to the rated capacity.
My panels are 6.4kWp, are north facing, are at a decent angle and I do often get 6.4kWp.

11 Mar 2023: Clear hot day (I did also check Jan and clear days are below 6.4kWp)
image.thumb.png.001c11b4b79d9b97e2075c311dad1587.png

16 Feb 2023: Cloudy day, panels are cooler, exceeded 6.4kWp:
image.thumb.png.c5a99159020d2a6e6ba8f2ccbb5869bf.png

5 Jan 2023: Here is another cooler day showing 7.9kWp from the panels
image.thumb.png.85b28c3da07f4e7f5d4d6e964eabd436.png

 

 

Edited by system32
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3 hours ago, JayN said:

Hi ... what inverter do you have.  At 1.6kwp installed capacity you may not be generating enough voltage for the panels to work hard enough throughout the day, or your demand must be low.

Please also post the panel size each and the number of panels.

 

No not at all. Do not think around the lines of a battery inverter. During the night my inverter switches off and uses no power. 

My inverter generates the grid voltage even with only 2 panels. 6 x 270W panels in series. Just for info my panels run at just below Imp. 

Please explain what you mean by panels not working hard enough? 

Edited by Scorp007
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9 minutes ago, system32 said:

Also not sure what the question means "What power should my panels generate???"
If your panels are true north and are at the optimal angle, not too hot, they should get close to the rated capacity.
My panels are 6.4kWp, are north facing, are at a decent angle and I do often get 6.4kWp.

Clear hot day:
image.thumb.png.001c11b4b79d9b97e2075c311dad1587.png

Cloudy day, panels are cooler, exceeded 6.4kWp:
image.thumb.png.c5a99159020d2a6e6ba8f2ccbb5869bf.png

 

 

The question was aimed at what production one can get in a day. Good and bad days. Not just the peak value during cloud edge. That's why I used the kwh/kw of panels metric per day. 

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1 minute ago, Scorp007 said:

The question was aimed at what production one can get in a day. Good and bad days. Not just the peak value during cloud edge. That's why I used the kwh/kw of panels metric per day. 

The kWh total production only makes sense if you grid feeding, in my case I don't grid feed yet and so I waste about 50% of the potential production.

Edited by system32
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4 minutes ago, system32 said:

The kWh total production only makes sense if you grid feeding, in my case I don't grid feed yet and so I waste about 50% of the potential production.

Yes that's why I included the type of system. I thought it will be good to see one can have a lot of unused PV during a day as you indicated. Daily yields capture the area under the PV graph. 

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4 minutes ago, system32 said:

The kWh total production only makes sense if you grid feeding, in my case I don't grid feed yet and so I waste about 50% of the potential production.

@system32 Agree with you 100% from about 12:00H my system is just idling. On a nice sunny day like today I could possibly generate another 15 KW of power till about 16:00H  

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51 minutes ago, BluePeter said:

I have 14 x 600W Canadian =  8.4kWp

I'm regularly generating over 7kW at about 11h00.

Usually around 7.6 - 7.8 between 12h30 and 14h00.

Sometimes getting 8.2kW around 13h00, but difficult to measure as my batteries are charged by then, and the load is much less.
 

That's what people need to see. They can use a forecasting Web and then they don't get the saving expected due to low load. 

This people need to factor in. 

Not easy to sum up the yield over a whole day. So we rely on stats from the inverter. 

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3 hours ago, Scorp007 said:

They can use a forecasting Web and then they don't get the saving expected due to low load. 

 

Yes, agreed.

I expect to break even in 5 years, as we use a lot of power.  But if it's 7 years then it's also okay.  
Energy inflation will be higher than our cost of capital (18% Eskom increase in June!).

But there's a lot of other value.  

Some are monetary:  less restaurant bills when I can't cook, being able to work in the evenings when my business needs it, less appliances that blow.

Others are lifestyle:  watching a family move on a Sunday night, helping kids with homework, ungrumpy wife. 

Worth every cent of the investment.  

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