Hello. I have owned my Venstar T7850 for over a year now and am mostly very happy with it. There are certainly some issues to be resolved and maybe most can be handled with firmware updates. But one issue that is getting me again and again has to do with recovery from power failures - which are common around here.

When the Venstar gets power back after an outage, it seems to require not only a connection to the wifi router but also to the Skyport internet in order to do a date/time update. If no such connections exist, the thing defaults to what seems like date/time zero. It is never correct date/time but the tstat marches on as if it were correct. This means that the schedule that is programmed gets used and that often creates poor/unanticipated results.

When I switched to the Venstar from my old Honeywell, I did not know or consider the lack of backup batteries in the new unit and what might happen without them. Of course, the clock does not keep running. So I am wondering if any hardware folks have any way or idea how to add a battery backup to these units that might keep the clock running?