Article Summary:
The USB port on the back on the Nest Learning Thermostat can be used to quickly charge the battery. In rare cases it is used for troubleshooting by Nest Support.

The Nest Learning Thermostat keeps its internal battery charged using your heating and cooling system wires, but if there’s a problem the battery may drain. To preserve battery life the thermostat display may turn off and it might disconnect from Wi-Fi. If it gets too low you won’t be able to control your system.

If needed, you can use the USB port on the back to charge it up. Simply pull off the thermostat display from the base and plug it into a USB port on your computer or a wall charger like the one you use to charge your phone. You’ll see a blinking red light at the top of the thermostat display to confirm that it’s charging. Usually your thermostat will take about half an hour to recharge. But if the battery is fully drained it can take as long as two hours to recharge.

If you have a 2nd or 3rd generation Nest Learning Thermostat, you’ll need a micro-USB to USB cable.

The 1st gen Nest Learning Thermostat has a different connector and uses a mini-USB to USB cable.