Can Rechargeable Batteries be used in Smoke Alarms

Smoke Alarm Batteries

Yes, but perhaps the question should be:

“Should I use rechargeable batteries in a Smoke Alarm”

One of the problems with conventional rechargeable batteries is the self discharge – at between 1% and 2% per day this is higher than the drain from the smoke alarm itself.

So a conventional rechargeable will be pretty much flat after just a couple of months or so. This in itself is not such a problem as you can just take it out, recharge it and put it back in.

The real problem is how quickly the voltage drops off as the rechargeable battery approaches exhaustion. In most single use batteries the voltage drops off at a fairly consistent rate, so the low battery warning beep you get in a Smoke alarm can go on for weeks. Rechargeable batteries hold their voltage really well right to the end, but then drop off very quickly, this means you get the low battery warning for a much shorter time – This can be just a day or so, perhaps even just a few hours.

So unless you check your smoke alarm battery ever day, there is a real possibility of the rechargeable battery going flat without you ever knowing! – not a great thought.

So I think the answer is “Yes you can, but you probably shouldn’t“.

Instead I would suggest you use conventional Alkaline type batteries or, for extra piece of mind, why not look at using the ULTRALIFE Lithium PP3 type battery, this can last up to 10 years in a Smoke Alarm.

More details HERE