we had 4 inches of snow yesterday, covering up the solar panel to the FARS. So when I went out to the station to brush the snow off the UV/Solar sensors, I noticed that the solar panel had snow on it, which I cleared and then noticed that the fan wasn't working.
I am guessing that the batteries exhausted themselves as the panel was covered yesterday, not much direct sunlight, well none to be exact. Today it will be cold, sunny and no snow, so we should get some charge as well as running the fan and it will take a lot of days to recharge the batteries.
Something to consider when placing a VP2 station , access to solar panels that do get covered in snow.