Posted March 12, 20232 yr 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
March 13, 20232 yr @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
March 13, 20232 yr 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 March 13, 20232 yr by zsde
March 13, 20232 yr 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.
March 13, 20232 yr 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.
March 13, 20232 yr 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 Edited March 13, 20232 yr by Antonio de Sa
March 13, 20232 yr 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.
March 13, 20232 yr 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.
March 13, 20232 yr @Antonio de Sa I have 7 X 450W facing North and no shade but never reached 3150W 🤦🏽♂️. Maybe it the brand, 🤷🏿♂️ I don’t know
March 13, 20232 yr 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.
March 13, 20232 yr 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) 16 Feb 2023: Cloudy day, panels are cooler, exceeded 6.4kWp: 5 Jan 2023: Here is another cooler day showing 7.9kWp from the panels Edited March 13, 20232 yr by system32
March 13, 20232 yr Author 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 March 13, 20232 yr by Scorp007
March 13, 20232 yr 🤦🏽♂️ I guess that’s where good PV brands kick in and get all of its Watts intended to.
March 13, 20232 yr Author 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: Cloudy day, panels are cooler, exceeded 6.4kWp: 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.
March 13, 20232 yr 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 March 13, 20232 yr by system32
March 13, 20232 yr Author 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.
March 13, 20232 yr 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
March 13, 20232 yr Author 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.
March 13, 20232 yr 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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