How often must I recharge battery if I do not have a C wire

[Cakinak25]

I just installed a Learning Nest Thermometer to run my heat only base-board system. I do not have a c-wire for power so must rely on the built in battery. After initiating the device, I saw that it was “low battery”. I charged the unit for a couple of hours and “low battery” went away. How many volts should a fully charged battery read? How long will this charge last? I live in AK and travel up to 3 months at a time. I don’t want this thing dying while I’m gone. 

[EdwardT]

Hi Cakinak25,

Thanks for reaching out. The level of charge of the thermostat’s internal battery should be 3.7 V or higher. If the battery drops below 3.6 V, it will be disconnected from your Wifi. If you don't have a C wire, I would suggest looking into the Nest Power Connector for your Nest Thermostat to get constant power.

Thanks,

Edward

[EdwardT]

Hi Cakinak25,

It's me again. I wanted to check back in to see if you have other questions and concerns. Feel free to let me know if you do. 

Thanks,

Edward

[EdwardT]

Hi Cakinak25,

I'm just checking in to make sure that you've seen our response. Please let us know if you have any other questions or concerns as I will be locking this in 24 hours.

Thanks,

Edward