Sunday we wandered over to the house and found a controller for the hot water panel pump. As proper geeks we then had to stand around and watch what it did as the sun warmed up the panels.
After lots of other errands, we got back to the house late enough that the sun was not heating the panels too much any more. So we did not get to see peak output. But we did get to enjoy the nice warm house for the rest of the evening while we stained trim.