Check your smoke alarm batteries now
A batch of aftermarket lithium 9V batteries sold across online marketplaces has been flagged for potential early failure — in some cases without triggering the low-battery warning chirp. Here is what to check and what to do.
Action: test your alarms today
- Press and hold the test button on every smoke alarm in your home. The alarm should sound within 10 seconds.
- If it does not sound — or chirps and stops — replace the battery immediately with a fresh alkaline 9V of the type specified in the alarm manual.
- If the alarm still fails after a battery change, replace the entire unit. Any alarm over 10 years old should be replaced regardless.
- Check the CPSC Recalls database (US) or UK product recalls page for specific affected product models.
Background: why this matters
Smoke alarms are the single most effective life-safety device in a home. According to USFA research, working smoke alarms cut the risk of dying in a home fire by roughly half. Yet a smoke alarm with a dead battery — particularly one that failed silently — provides no protection at all.
The concern with this batch of batteries is not that they are dangerous in themselves, but that some units appear to reach a low-charge state before triggering the alarm's low-battery warning chirp, meaning the battery appears fine until it is not. This is more likely to happen in alarms that use the battery to power both the sensor circuit and the audible alarm.
Who is affected
The issue appears limited to third-party 9V lithium cells purchased from online marketplaces in the past 18 months, particularly those without recognisable brand markings. Standard alkaline 9V cells from established manufacturers (Duracell, Energizer, Panasonic and similar) are not known to be affected. Sealed 10-year lithium alarms — where the battery is built into the unit and not user-replaceable — are also unaffected by this issue.
What to check
Beyond this specific alert, this is a good opportunity to carry out a full smoke alarm check. NFPA guidance recommends testing every alarm monthly and replacing batteries annually. The American Red Cross and the UK GOV fire safety guidance both recommend replacing any unit more than 10 years old, as the sensor itself degrades over time.
For placement guidance — how many alarms you need and where to put them — see our smoke alarm placement guide. For an interactive check of what your home or workplace needs, use the use cases checklist.
Sources checked: CPSC Recalls · UK product recalls · NFPA smoke alarm guidance · Published 10 October 2026, updated 14 October 2026
Battery recall FAQ
Questions about smoke alarm batteries
Open the battery compartment and look for the model number printed on the battery itself, or check the alarm's user manual. Lithium 9V cells are typically used in 10-year sealed or long-life alarms. If you are unsure, compare with the recall notice on the US CPSC Recalls database or the UK product recalls and alerts page. Always use batteries specifically recommended by the alarm manufacturer.
Test the alarm immediately by pressing and holding the test button. If it does not sound within 10 seconds, replace the battery with a fresh alkaline 9V cell of the correct type. If the alarm still does not sound after a battery change, the unit may need to be replaced — smoke alarm sensors degrade over time and all units should be replaced after 10 years. Check NFPA smoke alarm guidance for full maintenance advice.
No. Rechargeable batteries are not suitable for smoke alarms — their voltage drops gradually as they discharge, which can prevent the low-battery warning from triggering correctly and leave you with a silent, dead alarm. Always use a fresh primary (non-rechargeable) alkaline or lithium battery of the exact type specified in the alarm's manual. This guidance is consistent across both NFPA 72 and UK manufacturer guidance.