What is the expected peek output of solar power system?

[rama_1951]

Hello
Recently I installed a 4KW (16 panels at 250W each) and a 5KW invertor. I have been monitoring the system daily. The system generates about 3.1KW power at peek - between 11am to 1:00pm. The panels are installed at east-west configurations with 8 panels on each side. Is this is what is expected? I am expecting at least 4KW or close to it at peek period. I suspect installation fault. Any comment welcome. Regards.

[Ian S]

Hello
Recently I installed a 4KW (16 panels at 250W each) and a 5KW invertor. I have been monitoring the system daily. The system generates about 3.1KW power at peek - between 11am to 1:00pm. The panels are installed at east-west configurations with 8 panels on each side. Is this is what is expected? I am expecting at least 4KW or close to it at peek period. I suspect installation fault. Any comment welcome. Regards.

So you have half your system angled facing east and half facing west? If so, you are never going to have all your panels optimally oriented towards the sun which is how the nameplate wattage is determined. Also, not sure where you are but if the panels get above about 72 degF, their power output will be further degraded. IMHO, you system would appear to be operating properly.

[rama_1951]

What is the expected peek output of solar power system?

Thanks for the response. I live in Cairns, Northern Queensland, Australia. The temperature is about 30 Deg C (86 Deg F) during daytime. When the sun is directly overhead both the east-west panels will receive the same amount of sunlight. So I will expect optimum power output, minus the heat factor.
Yesterday I visited another user who has 2.5KW system. I noticed the system was producing about 2.4KW at peek. The only difference is that all the panels are facing North.
I do produce about 21.50KW per day. I do expect more for a 4KW system.
Regards.

[Ian S]

Yesterday I visited another user who has 2.5KW system. I noticed the system was producing about 2.4KW at peek. The only difference is that all the panels are facing North.

That's a big difference. In other words, your friend has a more optimal orientation. Unfortunately, your east-west won't achieve the high peak output that requires all panels simultaneously to be perpendicular to the incoming sun rays at some point during the day. Your inverter would also have to have the ability to deal most effectively with two different panel orientations. What is you friend's daily production?

[rama_1951]

What is the expected peek output of solar power system?

That's a big difference. In other words, your friend has a more optimal orientation. Unfortunately, your east-west won't achieve the high peak output that requires all panels simultaneously to be perpendicular to the incoming sun rays at some point during the day. Your inverter would also have to have the ability to deal most effectively with two different panel orientations. What is you friend's daily production?

Thank Ian. Now I understand the difference. My friend's daily output is about 15kW from his 2.5KW system. My East is clear. I do have some trees on the West from neighbour's property. I will negotiate to trim them down to prevent or reduce shadow. Thanks again for the advice.
Regards. Rama

[Naptown]

Thanks for the response. I live in Cairns, Northern Queensland, Australia. The temperature is about 30 Deg C (86 Deg F) during daytime. When the sun is directly overhead both the east-west panels will receive the same amount of sunlight. So I will expect optimum power output, minus the heat factor.
Yesterday I visited another user who has 2.5KW system. I noticed the system was producing about 2.4KW at peek. The only difference is that all the panels are facing North.
I do produce about 21.50KW per day. I do expect more for a 4KW system.
Regards.

Actually at noon they will never receive peak as angle if incidence comes into play.
Depending on roof pitch this can be significant. Steeper the roof the worse the production

[bonaire]

Actually at noon they will never receive peak as angle if incidence comes into play.
Depending on roof pitch this can be significant. Steeper the roof the worse the production

I wonder what the OPs inverter is. First, it is oversized and wont operate entirely optimally. If it is a single string inverter and it is using to strings bound together, that is bad for a dual orientation. This solution might work well with a dual MPPT inverter like a Power One Aurora or use of Microinverters.

[Naptown]

Maybe a 5% loss
Read the white paper SMA did on this.
Sunpower also has verified this.
As long as a single string is coplaner the losses are minimal.
Don't however split one string over two surfaces

[inetdog]

Maybe a 5% loss
Read the white paper SMA did on this.

If the shade the OP reported on the West panels will be partial during the time that both sets are producing well, then he would benefit more than that from having dual MPPT.

[silversaver]

26 panels of 255W with Voc 37V, if using SMA 6000TL, how many strings will you run? 2 strings of 13 panels?

[Naptown]

26 panels of 255W with Voc 37V, if using SMA 6000TL, how many strings will you run? 2 strings of 13 panels?

That could be pushing it based on the voltage. Depending where you are
Thr 5000 TL-US can take up to 1000 volts but may not be legal yet
I have only seen the biggest TL at 5000 watt

[silversaver]

That could be pushing it based on the voltage. Depending where you are
Thr 5000 TL-US can take up to 1000 volts but may not be legal yet
I have only seen the biggest TL at 5000 watt

I felt I might have ask the wrong person. Thank you

http://www.sma-america.com/en_US/products/grid-tied-inverters/sunny-boy/sunny-boy-6000tl-us-7000tl-us-8000tl-us-9000tl-us-10000tl-us-11000tl-us.html

I have found a good tool from SMA site to design the array:

http://www.sunnydesignweb.com/sdweb/SunnyDesign/PvPlant/PvPlant?ProjectId=37526222-045c-4143-9dcb-9a78696b7e24