PV Test Jig
Every so often a roof needs work. At 34 years since it was new, it was time. When a roof has PV (photo voltaic) solar panels on it, that is a good time to clean and test them for rated output.
One method for testing the panels is to have a rotating jig and load bank. A very basic load bank should duel matched inputs and have switching for open circuit, short circuit and various loads to present to the PV panel along with current shunts for current sample outputs. To take this further, I used a reference panel to compare to others on hand.
Using the rotating jig with a shadow post I was able to compare a reference panel with the remaining panels that were removed from the roof.
Since these panels were over 10 years old, the output had diminished by approximately 10%. However, despite their age, they delivered fairly consistent power output relative to the reference panel. Washed and cleaned, the panels were reinstalled and are now in operation.
The net output to date from this array originally installed in March of 2008 is 71.733 MWh's with a total reduction of 55.9 tons of CO2 emissions that otherwise would have come from fossil fuels.
This array allows the workshop to run carbon neutral (net zero power consumption) including 2 tons of air conditioning with the excess power being used by the home in the background.
The three additional panels in the foreground were installed later on the roof to allow for a separate off-grid power storage bank for use on critical equipment and systems.
McGuire Broadcast, Inc. 2019