Siemens SM55 12V Solar Panels

Re: Siemens SM55 12V Solar Panels

Working on 56 modules 4 string of 14 ea on a grid tie system in Sacramento, CA. Have some low output issues but not really determined tobe module problem or Fronius inverter problem. Panels are @ 18 years old and inverter @10? Years.
Have one broken panel (replacement provide free from SMUD local utility. Planning on reconfiguring system to 3 strings of 19 panels, to get the voltage up into the center of the range of the inverter. Currently it's close to min for inverter, especially on hot summer days we are currently having.
They seem to be well constructed and by Voc and Isc test still putting out close to ratings. Isc is a little low but when you factor in the age and take 20% off the are about what to be expected.
SMUD had a test project that they did to about 100 homes and ex-wife still has a refurbished system going. But is having low output. Waiting for cooler weather to reconfigure on the roof to determine if panels or inverter issue. Inverter working hard with only @10 vdc above min mppt tracking range.

If you have a specific question, I will try and answer it, or by then someone with more experience might have chimed in and provide your answer.