Reminds me of the trouble we got into with our solar powered alarm systems out at the Hanford Nuclear Reservation a few years back. It seems that under the worst conditions (sub-freezing temps, overcast skies for days), the battery systems would deplete enough that the voltage on the control panel would crowbar the system into alarm mode. Imagine having to team up around the clock to run generators to batt chargers to bring the batteries in 35 remote systems back to life. Pretty bad when you have Rad alert sirens going off up and down the Columbia and all points in between. Can you say pucker factor?