Have no solution for you except to replace battery. My 3rd gen Nest thermostat was working perfectly for about 2 years. Then, wifi started to drop. Now the thermostat can’t connect to wifi at all. Later on, it shut off by itself. Then, a prompt that battery charge is low & the unit needed to be shut down. Recharging the battery via USB revived it for a few days but the frustrating cycle started again. I’m focusing on the possibility of needing a battery replacement. There are a few batteries out there for my 3rd gen thermostat. Most (if not all) of them provide 3.7V 380mAh). But they don’t seem to meet the quoted spec from one of Google Gold product expert (for my 3rd gen thermostat: 3.7V 2.1 Wh=567.6 mAh). He didn’t state it specifically, but it’s implied that we all should go out & buy a new one to replace ours with bum batteries. It seems that Google should start thinking about making batteries for customers who need to replace their thermostat’s batteries. Hate to say it, but if I am steered toward buying a new Nest thermostat to replace my current one that is only 2-3 years old, I will definitely look for a different brand of thermostat, rather than staying with the Nest that doesn’t seem to last very long, and with Google doing a very poor job providing a logical (i.e. less expensive) fix. At least provide a trade-in program of some kind to keep us in your ecosystem, instead of letting customers’ frustration brew to the point that Google Nest products becomes synonymous with a Lemon. In the mean time, I will try replacing the thermostat battery with a 3.7V 380mAh battery that Is offered by many online merchants and see if it’ll solve the wifi & shut-down problems.
