ccronje Posted June 23, 2021 Share Posted June 23, 2021 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 Quote Link to comment Share on other sites More sharing options...
Achmat Posted June 23, 2021 Share Posted June 23, 2021 (edited) 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, 2021 by Achmat Supergeek 1 Quote Link to comment Share on other sites More sharing options...
stoic Posted June 23, 2021 Share Posted June 23, 2021 (edited) 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, 2021 by stoic Quote Link to comment Share on other sites More sharing options...
Nexuss Posted June 23, 2021 Share Posted June 23, 2021 (edited) 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, 2021 by Nexuss Quote Link to comment Share on other sites More sharing options...
ccronje Posted June 23, 2021 Author Share Posted June 23, 2021 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 Quote Link to comment Share on other sites More sharing options...
Calvin Posted June 23, 2021 Share Posted June 23, 2021 See graph below for output of panels facing East at 30 degrees tilt in Cape Town. Peak is about 50% of nominal. Nexuss 1 Quote Link to comment Share on other sites More sharing options...
Tariq Posted June 23, 2021 Share Posted June 23, 2021 @Calvin, could I ask a big favor, can you do two graphs NE and NW for Cape Town, thanks Quote Link to comment Share on other sites More sharing options...
Calvin Posted June 23, 2021 Share Posted June 23, 2021 No problem at all - what is the tilt on the panels? Quote Link to comment Share on other sites More sharing options...
Tariq Posted June 23, 2021 Share Posted June 23, 2021 @Calvin, 30 degrees, thanks Quote Link to comment Share on other sites More sharing options...
Calvin Posted June 23, 2021 Share Posted June 23, 2021 Combination 50/50% Just NE: Just NW: For reference: Directly North WannabeSolarSparky and Scorp007 2 Quote Link to comment Share on other sites More sharing options...
Tariq Posted June 23, 2021 Share Posted June 23, 2021 Hi Calvin, I assuming the50/50 combination means two strings, one NW and one N E. ? Quote Link to comment Share on other sites More sharing options...
Calvin Posted June 23, 2021 Share Posted June 23, 2021 Correct. The box in the top left of each graph has the configuration. 1 @ 315/30 means 1 panel facing NW tilted 30 degrees. Quote Link to comment Share on other sites More sharing options...
Leonb Posted June 24, 2021 Share Posted June 24, 2021 (edited) Edited. Found answer... Edited June 24, 2021 by Leonb Quote Link to comment Share on other sites More sharing options...
ccronje Posted June 24, 2021 Author Share Posted June 24, 2021 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! Quote Link to comment Share on other sites More sharing options...
ccronje Posted June 24, 2021 Author Share Posted June 24, 2021 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. Quote Link to comment Share on other sites More sharing options...
Calvin Posted June 24, 2021 Share Posted June 24, 2021 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. Quote Link to comment Share on other sites More sharing options...
zathras Posted July 24, 2021 Share Posted July 24, 2021 (edited) @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, 2021 by zathras Region Quote Link to comment Share on other sites More sharing options...
Guest Sarel Posted July 24, 2021 Share Posted July 24, 2021 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 Quote Link to comment Share on other sites More sharing options...
zathras Posted July 25, 2021 Share Posted July 25, 2021 Perfect thank you Sarel Quote Link to comment Share on other sites More sharing options...
BGb Posted August 2, 2021 Share Posted August 2, 2021 (edited) 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, 2021 by BGb Quote Link to comment Share on other sites More sharing options...
rterblanche Posted May 19, 2023 Share Posted May 19, 2023 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 Quote Link to comment Share on other sites More sharing options...
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