Why do my panels work better when it's cloudy?
james2170 Posts: 1Registered Users, Users Awaiting Email Confirmation ✭
Hi I have a strange problem so I wonder if anyone has any ideas, under complete cloud cover my panels are pulling 130W but when the sun comes out and with a completely clear blue sky and strong sunlight they drop to around 40-50W! This is consistent daily. I am baffled. Readings are from the LCD on my MPPT charger.
Have tried all sorts of angles on the panels but they seem to be in the correct position and the sun is hitting them. Not only this but also puzzled as to why my input is so low given I have 4 huge panels. This will be my next problem to solve. I've triple checked all my wiring but I'm open to any ideas I'm guessing I must have something wrong somehow.
My setup is 4x265W panels in series connected to an MPPT charge controller and 4x12V batteries in series (48V). I have nothing causing a shadow over any panel. I can add photos if it helps. I have tried a couple of different charge controllers and both produce the same result.
I am getting around 140V from all 4 panels at both times (under sun and then under cloud). Actually under sun the voltage goes up to around 150V sometimes but not over. The charge controller operates from 70V to 170V according to the manual so I am within the range and no alarms are on the controller so it seems happy.