Nest Thermostat Battery Won’t Charge: How to Fix

Though your Nest thermostat doesn’t only run on battery power, you still need battery power as a backup/support when your system doesn’t deliver enough power to keep your thermostat up and running. So there’s a cause for concern if your Nest thermostat battery won’t charge.

If that sounds like what you’re currently experiencing with your thermostat, then keep reading as I’ll attempt to walk you through troubleshooting tips to fix the problem. Let’s dive in!

Nest Thermostat Battery Won’t Charge

Here’s what to do if your Nest thermostat battery won’t charge:

  • Restart the thermostat.
  • Manually charge the thermostat with a USB.
  • Check your thermostat base to see if all wires are properly connected, not loose/burned.
  • If it still won’t charge, reset the thermostat to fix internal glitches.

So that’s a quick way to troubleshoot your Nest thermostat that has refused to charge. If that worked for you, congratulations. But if not, keep reading as I’ll go into more details about the above troubleshooting steps.

How to Fix ‘Nest Thermostat Battery Not Charging’ Issue

1. Restart Your Thermostat

So the first troubleshooting step to try if your Nest thermostat battery won’t charge is to restart the device. As with most smart devices, restarting can help resolve some issues you’re having with your thermostat, including the battery issue. So go ahead and restart the thermostat to see if that will resolve the problem.

If you’re not sure how to restart your Nest thermostat, here’s how:

  • Press and hold down the thermostat ring (for about 10 seconds) until the screen turns off. Next, release the ring.
  • Turn it back on by pressing and releasing the ring—to finish the restart process.

If this doesn’t solve the process problem, see the next troubleshooting step.

2. Manually Charge the Thermostat

If your Nest thermostat still won’t charge after restarting it, the next troubleshooting step is to try charging it manually with a USB cable. Perhaps the battery is completely drained and needs to be boosted before it can charge automatically via power from your HVAC system.

To charge your Nest thermostat manually, remove the display and then plug it into a USB—either on your computer or a wall charger. If it’s charging, you’ll see a blinking red light on your thermostat’s front.

Ensure you use the right USB cable to charge your thermostat. Nest Thermostat E and Nest Learning Thermostat (2nd and 3rd gen) have Micro-USB port, while 1st gen Nest Learning Thermostat has Mini-USB port.

After the battery is recharged, put the display back onto the base and then watch to see if the charging problem is resolved. If not, then chances are the problem is from your HVAC system and not the thermostat. Perhaps the system is not supplying enough power to charge the battery due to wire issues or so. See the next troubleshooting step.

3. Check That the Wires Are Properly Connected

Your Nest thermostat’s battery charges via power received from your HVAC system. And this power is transmitted via wires connected to your thermostat’s base. So if the wires are loose, burned, or have any issues, chances are your thermostat won’t receive sufficient power to charge the internal battery.

How to Fix Nest Thermostat Battery Won’t Charge

So remove your thermostat from the wall and then check the base to see if any wires are loose or burned. Also, see if any of the wire is exposed and tape it properly.

4. Reset the Thermostat

Assuming your thermostat has no wiring issues, and you tried other troubleshooting steps above but still won’t charge, then performing a factory reset is the last troubleshooting step that may help.

For the most part, resetting your thermostat will help fix several issues you’re having with it, including battery issues.

Here’s how to reset your Nest thermostat:

  • Press the thermostat ring to open the Quick View menu.
  • Select Settings. Next, turn the ring to Reset and then press to select All Settings.

This will restore default factory settings in your thermostat and it should fix the battery problem.

Note: Performing a factory reset will erase all your custom settings. So you’ll have to start all over again to set up your thermostat (just like you did when you first installed it).

If the problem persists, you may have to contact an HVAC expert to check your thermostat or contact the Google Nest help desk.

Related Questions

How do I know if my Nest thermostat is charging?

When the device is charging, you’ll see a blinking red light on the display. This shows the thermostat is charging, and it may continue like that for about two hours if the battery was completely drained.

How long can Nest the thermostat battery last without power?

On average, a Nest thermostat battery lasts anywhere between 2 to 3 hours without power. That means even if your HVAC system is turned off and there is no continuous flow of power to the thermostat, it can still last for 2-3 hours.

How do I know when my Nest thermostat battery is low?

If your Nest thermostat battery is low, you’ll see the low battery warning on the display. Also, persistent red flashes could indicate low battery. You may check your battery level to confirm and then charge it with a USB cable if it’s not charging automatically.

Can you replace batteries in a Nest thermostat?

Yes. But you can only replace batteries in 1st gen Nest Learning Thermostat. 2nd and 3rd gen Nest Learning Thermostat comes with a built-in battery, so you can’t replace the battery. You can only charge the battery with a USB cable when it can’t be charged automatically via your HVAC system.

That said, if you have a 1st gen Nest Learning Thermostat and not sure how to change the batteries, here’s how:

  1. Remove the thermostat display from its base.
  2. On the back of the display, remove the old batteries.
  3. Insert 2 new 1.5V AAA alkaline batteries (lithium batteries are not recommended).
  4. Now put the thermostat display back on its base.

That’s all about changing the batteries on your Nest thermostat.

You may also like to read our article about troubleshooting connection and display issues in White Rodgers Thermostat, Braeburn Thermostat, and Pro1 T701 Thermostat.

Wrapping Up

As mentioned, your Nest thermostat doesn’t only get power from the battery, but the internal battery is still useful as it helps keep the thermostat on during a power outage or when your HVAC system isn’t supplying enough power to keep the thermostat on. So you want to ensure your thermostat battery works properly—charging automatically as it is programmed.

If the battery isn’t charging, follow the troubleshooting tips above to fix the issue. And if the problem persists, get an HVAC system to help you fix the issue or contact the Google Nest Support Desk.