For 10 years my panels “wake up” in the morning with 12w then 24w then 36w etc as the sun rises.
For the last few months the panels generate nothing until they show 48w on many days (sometimes they act normally). There has been no change to the environment (trees etc) and I can’t see it being sudden sun appearing from behind a cloud otherwise I would have noticed it over the years, so could there be something wrong with the panels or inverter to cause this “sticky” wakeup? Does anyone have any suggestions?
have you tried cleaning the panels, it may be just a fine layer of dirt causing this problem, jim
Could be the inverter. My inverter starts with 77W (for 10-15 mins) and stays on the same value before it goes any higher than this, and does the opposite in the evening. Can you tell us about any similar patterns in the evening? If there are any, then it is the inverter.
Thanks for suggestions - no the shut down is always smooth so maybe not the inverter.
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I haven’t cleaned lately but it is not a consistent problem - only about half the startups are affected, so if it was dirt I would have thought it would have been a consistent problem. Thinking as I write I suppose it could depend on the surface moisture on the panels - maybe if they are dry and dirty it might cause problems but if there is dew on them the dirt may be more transparent and cause less problems. I will have a good look at them when I get home in a couple of months time and report if I find a good clean is the solution.
When this problem exists, is it foggy or very damp? I have a problem with my system that started 1/2021 (system installed 2018). It would not start generating until 12 or later in the afternoon on foggy days (only in the winter). When the Isolation Resistance (solar cells to frame) is <1.5 Meg ohms, the system throws an Isolation Error and will not start. Once the IsoR is >1.5 Meg ohm, the system starts right away. On sunny days, the IsoR is >8 Meg ohms and the system starts at 0730 in the winter. My Fronius Primo makes this measurement. Maybe yours does this also?
Thanks for suggestion - I have checked the status of the inverter and there are no errors - mine is a sunnyboy tl4000 and seems to log any problems but I will check to see if the documentation says it would report any high resistance issues.
Updating on this old post I started - I am sure the problem with high startup values is as folllows… there is some leakage to earth and the inverter will not start in these conditions. It reports the problem on the screen but continues to try and does not log an error code. As the sun strengthens the voltages rise and at some point, either the inverter decides the leakage is small compared with the higher voltages as the panels produce more, or the insulation leak dries out in the sun and the leak dissapears, so the inverter eventually starts up but at quite a high power level as the sun has had time to rise further. My inverter (SMA 4000TL) will do this “try to start” procedure for maybe 15 minutes - only after then does it give up and report a panel insulation fault. That’s why I was not getting any error codes as it was starting within 15 minutes. I will need to look for cable damage when the weather improves.