Nest thermostat battery not charging: how to fix this problem?

Imagine a situation where you have a Nest Learning Thermostat or Nest Thermostat E installed, and at some point, the battery on this device simply stops working due to which you cannot regulate the temperature in your room.  

What’s more, you don’t have access to the HVAC System owner’s manual, and you don’t understand how to make the battery work again.

If the sudden appearance of a problem with the Nest Thermostat is relevant to you, then this article will help you. In this article, we will discuss different ways to resume charging the device, such as replacing the battery or C-wire. We’ll also discuss low battery warnings, the lifespan of the battery, and how to figure out how long your device’s battery will last.

What is a Nest Thermostat?

A Nest Thermostat E or Nest Learning Thermostat is a device that regulates the temperature in your house, room, or apartment. That is, this device helps you to fully control the HVAC system using only an application on your phone. There are different types of thermostats, which are divided according to different points: temperature control and operating procedure.

According to temperature control, thermostats are divided into categories such as simple, which maintain one temperature, and complex, that is, programmable, in which you can set the mode. Also, according to the technique of operation, thermostats are mechanical, electromechanical, and electronic. 

A Nest Thermostat is a kind of electrical temperature controller.

In particular, from other companies, this thermostat is distinguished by a special design, which most often shows either only a temperature figure or newer models can even show the day of the week, time, and percentage of humidity in the air. 

You can notice these characteristics not only on the device itself, but also in the application of your phone, and, being far from home, you can control the atmosphere and temperature of your house. 

What is the battery life of a Nest thermostat?

The Nest battery life of your Nest Thermostat E or Nest Learning Thermostat depends only on the type of HVAC system power supply. If the thermostat battery has access to constant charging, then its battery life can last up to 10 years. 

However, if you constantly discharge and charge the battery of the device, then it can rearrange to work after a year and a half or two.

How to check the Nest Thermostat battery lifespan?

Below, you can find instructions on how exactly you can check the battery power of your Nest thermostat.

First step

You need to open the Quick View menu, just click on the button in the form of a ring.

Second step

Now you need to go to the settings menu, select the Technical Information option and press the Power button.

Third step

The normal charge for a thermostat battery is 3.7, check if your battery is charged to this number or higher.

Fourth step

If you see that the number is below 3.7, then you urgently need to recharge your thermostat.

Low battery warning

Also, on some thermostat models, you may get the Nest Thermostat low battery warning

When a blinking red light appears, your thermostat screen will freeze or not respond at all to your touch.

You will also feel that there is no temperature regulation in your house, and you will become unusually cold or hot.

If you haven’t noticed the previous two things and the blinking red light isn’t there either, you might be able to tell that your thermostat is running low on battery if it’s not connected to the internet.

Instructions on how to fix Nest thermostat battery 

Finally, we got to the main point of this article, and below you can find the methods for fixing the battery of your Nest Thermostat E or Nest Learning Thermostat. These methods use different materials, such as USB cables, and are suitable for different situations.

C-wire adapter

C-wire is a must for normal charging of your Nest thermostat and any failures with c-wire will not allow you to charge the device normally, it’s like a wire to charge a phone.

Remove the Nest thermostat cover and check if the c-wire is connected correctly and securely, if not, then try reconnecting the c-wire to one of the three departments.

Restart thermostat

It is also possible that the Nest thermostat device itself needs to be rebooted, for example, due to recycling.

Press the button on the thermostat, do not release it for 15 seconds, but maybe less, the main thing is that the screen turns off. After that, press the button in the form of a ring again, waiting for the thermostat to turn on.

Charge the Nest thermostat e and nest learning thermostat manually

In the same place, manual recharging of the device can help you, for which you need a USB cable. Since the problem is probably in charging from the HVAC system.

You need to remove the screen and the device from the wall and connect the USB cable to it. Also, find a source of electricity to which you will connect the Nest thermostat with a USB cable. If you have the Nest Thermostat E and Nest Learning Thermostat models, use the Micro-USB port to charge the Nest thermostat manually. 

All wires connected 

It is also possible that the HVAC system is not properly transmitting electricity to your Nest thermostat’s internal battery through the use of special batteries. And if the wires are not connected correctly, your internal battery will not get the right charge.

To fix this problem, remove the thermostat from the wall charger. After that, you will see an overview of the wires, you need to check their integrity and correct connection. If there is any wire faulty, replace it.

Factory reset the Nest thermostat

If you understand that the problem is in the best thermostat system itself, then a factory reset can help you. However, it is worth noting that after this method, you will have to adjust the thermostat again to your preferences.

To reset the settings, you need to open the menu on the thermostat, you need to press the button in the form of a ring on the device. After that, in the settings menu, you need to turn the button to the “Reset” option and then click on “All settings”.

Utilize a c-wire

Also, if you understand that the problem is in the system, but c-wire works well, you can use c-wire to ensure a constant flow of power.

You can use either c-wire directly or a c-wire transformer. A c-wire transformer is a good and quite budget option. You connect the transformer to the outlet and then connect the cable to the thermostat. The main thing is to choose an outlet that is close to the device.

Replacing thermostat unit

Alternatively, you can simply replace the unit, but before doing so, check with the HVAC system owner’s manual or the manufacturer of your thermostat owner’s manual.

You can either change the device or buy a new one, but there is also an option to simply change the internal battery. It is best to change the battery, as it will be inexpensive, and you will also save your thermostat settings.

Can I replace the Nest thermostat battery?

If you find that you cannot go to a technical center or read the HVAC system owner’s manual, but the battery on your best thermostat fails on its own and causes the entire system to freeze, then you may well try to replace the batteries yourself; however, it is important that you all did it carefully and followed the instructions. 

How to replace the Nest thermostat battery?

Below are the steps to help you successfully and safely change your Nest thermostat batteries.

Step 1

First, you need to remove the thermostat from the wall or display. Do this very carefully, as with sudden movements, you can damage the wiring or the Nest thermostat itself.

Step 2

Now you need to turn the device over, open it, and find the battery compartment. After that, take out the old batteries.

Step 3

Once you have verified that the battery compartment is empty, you can insert new AAA batteries.

Step 4

After that, close the cover, make sure that the mount is completely secure and return the thermostat to its original place. You can turn it on and check if the Nest Thermostat E or Nest Learning Thermostat has improved its quality of work.


What do I do if my Nest thermostat is not charging?

If the Nest thermostat battery won’t charge, and you don’t want to use the device’s maintenance services, you can try to solve the problem yourself, using for example a USB cable or C wire. However, you can also simply change the device, or battery, or buy a new thermostat from your thermostat maker’s shop. 

How do I know if my Nest thermostat is charging?

l have a blinking light, and most often you will even be shown a color of how much your battery is charged. For example, red is a critically low charge, yellow is an average charge, and green is a full charge of the Nest thermostat battery. It takes about 2 hours to fully charge your device.

Why does my Nest thermostat battery keep dying?

If your situation is not related to the “Nest thermostat battery won’t charge” problem, but rather the fact that the battery constantly stops working, then this is most likely due to age or simply a battery failure.  


The Nest Thermostat is one of the devices that makes people’s lives several times easier, especially for those for whom the temperature and atmosphere in the room should be favorable, for example, due to health problems.

However, if there is a problem with the battery power, the Nest thermostat will not be able to function as it used to, and consulting the HVAC system owner’s manual can be costly and time-consuming.

We hope that after reading this article, you have been able to find a suitable solution for your problem with the best thermostat not charging the battery, and now you have a deeper understanding of the device’s battery health and the consequences of a low battery.

Read also: Honeywell WiFi thermostat connection problems, how to troubleshoot and fix them?

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