Beloit has changed, I think dramatically, since your days. All for the good. Having ABC Supply based in the city and one of the richest women in the US, Diane Hendricks, has brought new lodging and dining. It is our go to place for good eating.
I would guess that the GoPower is displaying the power currently being applied to the batteries, assuming the solar panels are in the sun and operable. Once the sun goes down the display voltage should drop, the time to get the proper measurement would be in the morning before the sun comes out. Full batteries would display 12.73. For a table of lesser voltages Google "Interstate State of Charge".
Paul and Janet Braun
2003 Toyota 4Runner V8 now 2012 Toyota Sequoia V8
Escape 19' 2010 now 2014 Escape 21'