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I have 2 300 watt panels hooked in series to my victron solar controller. I would expect to never see more than 600 watts. Occasionally I will see a day where it reports pMax of 635 or some other value greater than 600. How is this possible to see a greater wattage than the theoretical max of the panels?
Solar panel specifications usually have a error margin. To prevent complaints panels are usually rated on the conservative side as people don't tend to mind getting extra.
The other source of difference can be caused by temperature variations and other environmental variation from standard testing. STC (Standard Test Conditions): 1000 W/m2, 25ºC, AM (Air Mass) 1.5
If the temperature is lower than 25ºC the panels will output slightly higher voltage, which is why when specifying panels the temperature range that they will be used in needs to be known.
If you look at the Victron panels datasheet you will see the Temperature coefficient which indicates how much variation to expect as temperatures vary from 25ºC.
I have more information now. In my array I have 5 panels. There are 3 groups. 2 in series, 2 in series, and one alone. 3 controllers total. On both series arrays on the same day I see the power exceeding 'max' by 13% or so. On the single panel I'm more like 5% below max. I'm in the tropics so the temp is closer to 30C at mid day. It's basically a controlled environment due to them being effectively in the same place at same time. I beleive the single panel. I don't beleive the series output. Also I'm not an expert so I'm generally just curious and slightly confused by this....
Also I have surveyed some other folks around me with similar setups and so far only the series wired folks are seeing this (all using victron). Parallel and single are not seeing power exceeding. We are all in the same geographic location so that variable is ruled out for the folks I asked.
