Solar power: return to Glenridding Hydro

We went past the intake for Glenridding Hydro. It doesn't look to have been damaged by the recent deluge. There is a small solar panel, presumably to power the controls. It looks like it can be contacted remotely, judging by the aerial. Vertically polarised, I note. The panel is roughly 0.4mby 0.2m. That's 0.08m. Using an online calculator, I got a figure of 0.61 kWh/square metre/day for these latitudes. That's an average power of 0.61 x 1000 x  0.08/24 = 2 watts. But it won't work at night. Another way is to say that if peak solar intensity is 1400 watts per square metre when the sunlight hits the Earth square on, then at 54 degrees north on top of as tilt of 23 degrees, 1 square metre will be stretched to 1/cos77 = 4.4 square metres. That reduces the intensity to 320 watts per square metre. For this panel, that is 320 x 0.08 = 25 watts at midday. We'd need about 50 watthours for the whole day to make the figures marry. Two hours of peak sunshine. Maybe not quite but not too bad. 25 watts for 12V power means 2 amps.