doorbell (battery) with existing mechanical chime....trickle charge??

[spencerh]

I have an existing mechanical chime doorbell--80 y/o--and I would like to add a Nest doorbell while allowing the old mechanical chime to ring. It seems the battery Nest doorbell has the option to allow this by connecting to the existing doorbell wires. My existing doorbell appears to use an 8VAC transformer (measures 11V across the terminal when open, and 8V across when the doorbell is pressed).

My question: will the connection to the existing 8VAC transformer trickle charge the battery in the Nest doorbell? Or will I still need to remove the Nest battery periodically to charge them?

TIA for you help.

[MplsCustomer]

@spencerh 

It looks like your existing doorbell transformer does not meet Google Nest's minimum requirements (see below), and some customers posting here have found that the bare minimum is sometimes not enough. When we got our second Nest Hello a couple of years ago, we upgraded to a 16V 30VA transformer.

https://support.google.com/googlenest/answer/9247132?hl=en

[spencerh]

Thanks for this comment, but my question is a little bit different. I realize my existing transformer is not sufficient for the wired Nest, so I must use the battery Nest.

My question: If I use the battery Nest, will the battery be recharged by the 8V transformer that is connected (ie trickle charge)? I believe the Ring doorbell has such a function.

[MplsCustomer]

@spencerh 

The ONLY way the battery is charged on the battery doorbell is trickle-charged:

"If you’ve connected your Nest Doorbell (battery) to your existing doorbell wiring, the wires don’t directly power the doorbell. Instead, the battery is trickle charged by the power that comes through the wires, and the doorbell runs off the battery charge." (https://support.google.com/googlenest/answer/11830989?hl=en)

So, according to Google Nest's requirements, for the battery doorbell to be trickle-charged you need a voltage of 8 to 24 V AC and power of 10 to 40 VA. As I said, I have seen other posts where customers whose transformers meet only the minimum requirements have problems. So maybe your very old 8VAC transformer will be sufficient, or maybe it won't. Why not just upgrade your transformer?

[spencerh]

Thanks for sticking with this.

I am reluctant to 'upgrade' my transformer as I do not know if the higher voltage will damage my existing mechanical chime, plus it requires work!

From the link you cited, it appears that the battery version of Nest doorbell will charge from 8VAC, but maybe not below freezing. I live in California so that may not be a problem here.

Have you installed the battery version to your existing doorbell transformer? What has been your experience with charging? Do you never have to remove the battery from the Nest doorbell to charge it?

[MplsCustomer]

@spencerh 

Per Google Nest's cold weather page, the battery definitely cannot charge at temperatures below freezing:

"At temperatures between -4°F (-20°C) and 32°F (0°C), the doorbell can continue to work, but the battery will drain because it can’t be charged. If the battery drains completely, the doorbell will shut down, and you’ll need to bring it inside to be charged."

We have 3 of the older Nest Hellos. But judging from the many posts in this forum, it seems to be a challenge to keep the battery doorbells charged, whether wired or not. You can search through the forum and judge for yourself.

[spencerh]

so I take it that you have (or have upgraded) your transformer to 16VAC.

Do you NOT have any problems keeping the battery charged?

Or do you have a wired version/no battery?

[MplsCustomer]

@spencerh 

Yes, we upgraded our transformer.

We have 3 of the older Google Nest Hello Doorbells, which are wired and not battery powered.

[aatienza · Accepted solution]

Hey folks,

spencerh, checking in — we hope you've got the answer you're looking for. Let us know if you have more questions in mind.
 

I appreciate the help, MplsCustomer.

Thanks,

Archie

[aatienza]

Hey there,

I just wanted to follow up to see if you still need our help. Please let us know as we would be happy to answer any questions you may have. 
 

Thanks,

Archie

[aatienza]

Hello there,

Just checking in to make sure that you've seen our responses. Please let me know if you have other questions or concerns as I will be locking this in 24 hours if I won't hear back from you again. Feel free to start a new thread and we'll be happy to help.
 

Thanks,

Archie