Nest Protect 2nd gen Battery (US): what it works with

Google · model Nest Protect 2nd gen (battery) · For the US and Canada

• Matter Unconfirmed
• Apple Home Unconfirmed
• Google Home Yes
• Amazon Alexa Unconfirmed
• SmartThings Unconfirmed
• Home Assistant No

Six AA lithium batteries power this version of Nest Protect (2nd gen), a smoke and CO alarm. It reports to the Nest and Google Home apps over Wi-Fi and links to other Protects wirelessly. Google no longer sells it but still supports it.

Checked against 6 sources on Oct 23, 2026

Ecosystem compatibility

“Via Matter” means you add it with that platform's Matter controller instead of a brand skill or app. “Unconfirmed” means we couldn't find an official source either way. How we verify.

Specs that matter for setup

Radio

Wi-Fi, Bluetooth^[1],[2]

Hub required

No^[2]

Local control

Unconfirmed

Detects

Smoke, Carbon monoxide (CO)^[2]

Power

6 × AA lithium^[1],[2]

Alarms link wirelessly

Yes^[1]

• Radio: Wi-Fi (2.4 GHz) and Bluetooth LE for setup; it also has an 802.15.4 radio for linking Protects, which isn't in our radio list.
• Hub: Connects over Wi-Fi to a Nest or Google account; no hub.
• Local control: Google doesn't say whether Protect works without the cloud.
• Detects: Split-spectrum smoke sensor and electrochemical CO sensor; the CO sensor lasts up to 10 years from manufacture. Tested to UL 217, UL 2034 and NFPA 72 per Google's store page.
• Power: The battery model runs on six AA lithium batteries (Energizer L91 named by Google). A wired 120 V model also exists with its own record.
• Alarms link wirelessly: Google's spec page lists an 802.15.4 radio for wireless interconnect between Protects; it doesn't describe how the alarms sound together.

Before you buy

• Google lists Nest Protect as no longer available for sale, but still supports it.
• Protect has to be replaced 10 years after its manufacture date because the CO sensor wears out.
• Some features stay in the Nest app only, and setup needs it.

Quick answers

Does the Nest Protect 2nd gen Battery (US) work with Apple Home?

Not confirmed. We couldn't find an official source either way. Google's Protect pages don't mention Apple Home.

Does the Nest Protect 2nd gen Battery (US) work with Google Home?

Yes. The Nest Protect 2nd gen Battery (US) works with Google Home directly. Protect (2nd gen) shows in the Google Home app as a Smoke & CO tile, with alarms, notifications, Sound Check, Pathlight and Nightly Promise. Setup, factory reset, Protect Video Capture, Emergency Shutoff and emergency contacts stay in the Nest app. More smoke and CO alarms for Google Home

Does the Nest Protect 2nd gen Battery (US) work with Amazon Alexa?

Not confirmed. We couldn't find an official source either way. Google's Protect pages don't mention Alexa.

Does the Nest Protect 2nd gen Battery (US) work with SmartThings?

Not confirmed. We couldn't find an official source either way. No SmartThings support found.

Does the Nest Protect 2nd gen Battery (US) work with Home Assistant?

No. Home Assistant's Nest page says smoke and CO alarms aren't supported by the Smart Device Management API its Nest integration uses. Community custom integrations exist but aren't counted.

Sources

1. Nest Protect technical specifications — Google Nest Help manufacturer · accessed Oct 23, 2026
2. Nest Protect 2nd Gen - Installation and Tech Specs — Google Store manufacturer · accessed Oct 23, 2026
3. Nest Protect now available in the Google Home app — Google Nest Help manufacturer · accessed Oct 23, 2026
4. Control your Nest Protect with the Nest app and Google Home App — Google Nest Help manufacturer · accessed Oct 23, 2026
5. Nest Protect expiration dates — Google Nest Help manufacturer · accessed Oct 23, 2026
6. Google Nest - Home Assistant — Home Assistant ecosystem · accessed Oct 23, 2026

Official product page: store.google.com