Sold my home with a 5.72K grid-tie system and the buyer had an electrician come out to inspect the solar. They did a VOC measurement on the strings and had some concerns.
The system is 22 260W Suniva panels about 5 years old. There are 11 panels on each string feeding into a ABB/Aurora PVI-5000 inverter, dual MPPT. The spec VOC is 38.3V per panel. With 11 panels in series, that would be 421.3V. The electrician measured the same 378V on each string. The panels are pointed due south at an angle of 28deg at 40 latitude and had already been producing for a couple hours that morning when the electrician made his measurement at 8AM. Ambient temperature was around 75 to 80 degrees, high for the day was going to be 107. I also noticed light powerline shadows on the panels in the electricians photos. My production for the last 5 years has been inline with the GoSolar projections as the system produces about 35kW to 38kW per day in the summer and usually exceeds the yearly projections.
The electrician wants $2500 to pull apart the whole system and verify each panel. It has also freaked out the buyer who also now wants verification. It seems to me the conditions were not ideal for this measurement and my question is, is this an accurate way to measure performance or is there possibly something wrong with this system?
The system is 22 260W Suniva panels about 5 years old. There are 11 panels on each string feeding into a ABB/Aurora PVI-5000 inverter, dual MPPT. The spec VOC is 38.3V per panel. With 11 panels in series, that would be 421.3V. The electrician measured the same 378V on each string. The panels are pointed due south at an angle of 28deg at 40 latitude and had already been producing for a couple hours that morning when the electrician made his measurement at 8AM. Ambient temperature was around 75 to 80 degrees, high for the day was going to be 107. I also noticed light powerline shadows on the panels in the electricians photos. My production for the last 5 years has been inline with the GoSolar projections as the system produces about 35kW to 38kW per day in the summer and usually exceeds the yearly projections.
The electrician wants $2500 to pull apart the whole system and verify each panel. It has also freaked out the buyer who also now wants verification. It seems to me the conditions were not ideal for this measurement and my question is, is this an accurate way to measure performance or is there possibly something wrong with this system?
Comment