Thermostat Battery Replacement

[kcappa]

I had reported problems with my Nest Thermostat humidity readings that were 7-10 percentage points higher than the readings from 3 different humidistats that I had purchased.  Google sent me a replacement (refurbished).  Got that installed.  From the start, the humidity reading was about 6-8 percentage points higher than the humidistats.   I reported it back to google chat support.  Now, they are telling me I need to replace the batteries because the AAA battery needs to be 3.8v or higher.  First off, the battery google supplied and was installed 1 week ago shows 3.129v.  So, I replaced with a new Duracell and it reads 3.239v.  Google chat support said I still needed a new battery.  Now I have a brand new Energizer AAA alkaline battery and it reads 3.150v.  Support tells me the thermostat won't function properly without a AAA battery with 3.8v.  So, how does one find a 3.8v AAA battery?  The packages don't say anything about the voltage.  Is this some type of special AAA battery?  (not to mention the question of why Google provides a battery that doesn't meet the 3.8v requirement.)  Has anyone had experience with humidity readings not being accurate and getting solved when a battery was replaced?  Everything else on the thermostat seems to function properly.  I'm skeptical that a battery is really going to fix the problem.

[Markjosephp]

Hello kcappa,

Thanks for sharing with us your detailed experience using your Nest Thermostat's humidity readings. I'd be happy to shed some light on the situation here!

It's understandable that you're puzzled about finding a AAA battery with a 3.8V rating. Typically, standard alkaline AAA batteries have a voltage of around 1.5 volts. We only suggest using high-quality 1.5 V AAA alkaline batteries from a known manufacturer.

As for the humidity reading discrepancies, it's not unheard of for batteries to impact sensor accuracy, but it seems like you've already tried new batteries without resolving the issue. If the problem persists, it could be worth exploring other potential causes, such as the placement of the thermostat or a possible configuration issue. Try performing a factory data reset and removing the thermostat in the app before proceeding with adding it back.

Let us know how it goes.

Best regards,
Mark

[kcappa]

Thanks for your response Mark.  What is perplexing is that the person that was helping me on the chat insisted that my battery was not adequate because it didn't read 3.8v. (In fact, the agent would help be any further until I had a battery that had a reading of at least 3.8v.   I was going to try a Lithium Ion battery, but based on your response the alkaline AAA 1.5 v batteries are adequate.   And, maybe a Lithium Ion battery might not even be recommended??  Just as an FYI - I think I also saw something on the website about using a 3.8v battery,  I think Google needs to get everyone on the same page to avoid confusion like this!

Also, regarding the humidity reading issues.  I think I have ruled out the placement of the thermostat as a possible issue as the other devices I have 3 other humidistats in the exact same area as the thermostat.   The 3 devices all consistently show readings of 7+ percentage points lower than the google nest.  I will try the factory reset.   I will try the factory data reset.  Could you share a link on how to do the factory data reset?  I don't think relocation of the thermostat is a viable option.

Again, thanks for helping out.

[Markjosephp]

Hey there,

I understand the confusion you've experienced with the battery voltage requirements for your device. I can confirm that alkaline AAA 1.5V batteries are indeed suitable for your thermostat, and there should not be a requirement for a 3.8V battery, and that is only applicable for the Nest Learning Thermostat or the Nest Thermostat E. As for the humidity reading issues, it's good to hear that you've ruled out placement as a possible cause. I suggest performing a factory data reset to recalibrate it. Here's how to Reset or restart your thermostat.

In addition to your thermostat's battery health, check the batteries' impedance to know if the battery should be replaced or not. To do this, on the thermostat display, go to Settings, then Battery and then Battery Status.

• If impedance is lower than 1500 mΩ (milliohms)
  • This impedance is an indicator that the batteries are in good condition and don’t need to be replaced yet.

• If impedance is higher than 1500 mΩ
  • This impedance is an indicator that the batteries need replacement. 
    1. Remove the batteries.
    2. On the thermostat, clean the contacts. These are the metal parts that the batteries press against when inserted into the slots.
    3. Reinsert the batteries.
    4. Check the impedance again. On the thermostat display, go to Settings, then Battery and then Battery Status.

If impedance is still higher than 1500 mΩ, replace the batteries with a pair of recommended replacement batteries.

If you have any further questions or encounter difficulties during the process, let me know. 

Best regards,
Mark