June 23, 20215 yr Good day, I have a fairly basic question regarding my solar panel efficiency and was hoping someone could shed some light on it for me (pun not intended). I have 6 x 330watt solar panels that as far as I understand are connected in a 3s2p configuration (Make/model : Waaree Energies WS-330). In my understanding this should have a maximum possible output of 1980watt. The panels are facing East on roughly a 30 degree angle. On a clear sunny day in Cape Town winter I get a maximum output of around 800watt from the panels at the best time of the day, which is significantly less than I expected. Is this just what I should expect from solar panels that are facing East, or could it be that there is some kind of physical problem with the panels and/or the way they are connected? Would appreciate any input you may have. Thank you Chris
June 23, 20215 yr 16 minutes ago, ccronje said: Good day, I have a fairly basic question regarding my solar panel efficiency and was hoping someone could shed some light on it for me (pun not intended). I have 6 x 330watt solar panels that as far as I understand are connected in a 3s2p configuration (Make/model : Waaree Energies WS-330). In my understanding this should have a maximum possible output of 1980watt. The panels are facing East on roughly a 30 degree angle. On a clear sunny day in Cape Town winter I get a maximum output of around 800watt from the panels at the best time of the day, which is significantly less than I expected. Is this just what I should expect from solar panels that are facing East, or could it be that there is some kind of physical problem with the panels and/or the way they are connected? Would appreciate any input you may have. Thank you Chris Could be that one of your strings is not connected correctly. Those MC4 connections can be faulty or not correctly fitted if you made up some of your own cables. Try connecting each string on its own to the inverter and see what the output is. Edited June 23, 20215 yr by Achmat
June 23, 20215 yr If you are not able to face your panels north, then lowering the angle will give you better output mid day when the rays have to travel through less atmosphere, which will make it a lot more efficient. Edited June 23, 20215 yr by stoic
June 23, 20215 yr Sounds about right to me , I have 5 x 455w panels facing east , and they max out around 1kw+- at the moment on a clear day. Same size North west array is producing about 1350watts max. Edited June 23, 20215 yr by Nexuss
June 23, 20215 yr Author 26 minutes ago, Nexuss said: Sounds about right to me , I have 5 x 455w panels facing east , and they max out around 1kw+- at the moment on a clear day. Same size North west array is producing about 1350watts max. Interesting, thank you for the info
June 23, 20215 yr See graph below for output of panels facing East at 30 degrees tilt in Cape Town. Peak is about 50% of nominal.
June 23, 20215 yr @Calvin, could I ask a big favor, can you do two graphs NE and NW for Cape Town, thanks
June 23, 20215 yr Hi Calvin, I assuming the50/50 combination means two strings, one NW and one N E. ?
June 23, 20215 yr Correct. The box in the top left of each graph has the configuration. 1 @ 315/30 means 1 panel facing NW tilted 30 degrees.
June 24, 20215 yr Author 18 hours ago, Calvin said: See graph below for output of panels facing East at 30 degrees tilt in Cape Town. Peak is about 50% of nominal. Thank you very much Calvin, these graphs really help!
June 24, 20215 yr Author 16 hours ago, Calvin said: Combination 50/50% Just NE: Just NW: For reference: Directly North Interesting, it seems like time of the year makes a much bigger difference on EAST, compared to North.
June 24, 20215 yr 5 hours ago, ccronje said: Interesting, it seems like time of the year makes a much bigger difference on EAST, compared to North. Yes, remember that in mid winter the sun rises NE (60°) and sets NW(300°) (at CPT latitude anyway), so East or West facing panels are never pointing straight at the sun. In summer the sun rises SE and sets SW, so at mid-morning the East panels at least face directly towards the sun. For most people the size of the PV array is determined by the requirements in winter, and in winter it is really important that they should face as close to North as possible.
July 24, 20215 yr @Calvin very curious as to the impact of tilt on the north facing configuration? Say 0 or 2 degrees tilt. I have a single panel installed on an almost flat kliplok roof facing north in Johannesburg. But happy to use cpt for ballpark impact Edited July 24, 20215 yr by zathras Region
July 24, 20215 yr There are may sites where you can punch in your numbers and address to model this accurately: https://pvwatts.nrel.gov/pvwatts.php http://www.solarelectricityhandbook.com/solar-irradiance.html Groetnis
August 2, 20215 yr I am also curious to find out if my system is working correctly, used the following site https://re.jrc.ec.europa.eu/pvg_tools/en/tools.html. There is a certain inherent inefficiency associated with PV systems, for the 9 panel set it was estimated to be about 14% linked to temp and angle being suboptimal, (should be closer to 35 degrees) There is weather station nearby from where I extracted solar radiation, the above software uses historical climatic data and could vary significantly from what was experienced on the ground eg Feb 2020. Low solar radiation linked to rain and cloudy conditions. I have 2 sets of panels 8 and 9, there is large variation month on month but the grand total appeared to be ok. Info on my panels NE NW combined no panels 8 9 17 watt per panel 365 365 365 installed peak power kW 2.92 3.285 6.205 degrees 9 289 Azimuth -9 71 Angle 12 17 Edited August 2, 20215 yr by BGb
May 19, 20233 yr On 2021/06/23 at 7:09 PM, Calvin said: Combination 50/50% Just NE: Just NW: For reference: Directly North Sorry I know it's an old post but which software was used to make these graphs
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