Update: 12 days later the new CR123 lithium battery died as well. No data is logged during the night period, and even if it is really cloudy in the day either. We’ve contacted Davis and are awaiting a reply.

Weather station

We set up the Davis Vantage Vue wireless weather station in 2013 January. For the most part it has been running fine and better than the two previous stations we have had: Oregon WMR968 (2007 Jan – 2012 Dec) – Radioshack WX200 (2002 July – 2006 Dec).
However, back in the fall it started to act up. The symptoms were that it (the ISS/transmitter station package) stopped working at night. It has a CR123A lithium battery as backup to the solar panel which powers it during the day, so we thought it had just died. We purchased a new battery for about $5Can, tested it and installed it. The station startedworking again immediately… and after only a few weeks, it broke again. The new battery was dead.
OK. So maybe it was a bad battery. Install another new, tested battery. Worked fine for a few weeks then stopped again.
Some research said that the onboard “supercapacitor” had probably failed. Something that stores up extra solar panel power during the day to run the instrument package at night.
Last night I took down the ISS and took it apart. Inside was far less then I thought there would be and nowhere to be found was a supercapacitor.
Pictures will come later, but in essence the solar panel connects to the battery and to the instrument package, which is well sealed with goop against moisture. If there is a capacitor inside that package, I don’t want to open it up in fear that it will not be able to be sealed again.
So for the interim, purchase of some new CR123 batteries will happen today and the station will go back outside, to a new location… something more easily accessible (6′ instead of 8′ above ground, and not behind one more garden gate that freezes up in the winter).
After that we will look into larger external power sources and perhaps a newer bigger solar panel to help out.

Another interesting side effect of the outside ISS unit not working correctly… the indoor unit temperature acts very strange. On the image below the left side of the graph with noisy data is with the outdoor ISS unit out of service, the right side smooth data after the ISS is operational again.