Re: Rechargeable Smoke Alarm Batteries?

[w_tom <w_tom1@xxxxxxxxxxx>]

  A recharged battery voltage will look to a charger circuit
as perfectly good even if the battery is actually defective;
does not hold charge.  To test for a failed rechargeable
battery, the smoke detector would discharge the battery - see
how long the battery maintains voltage.  But that is not
desirable since the battery could be discharged just as a fire
starts.  Furthermore it may take hours to fully recharge a
tested (discharged) battery.

  Makes more sense (from human safety requirements) to have
you replace the smoke detector battery annually and use that
removed battery in some other device or toy.

  This could change if new rechargeable battery technology
that don't wear out are proven successful and cost
significantly less.

DavidB wrote:
> My Smoke & CO2 Detectors are not connected to an alarm system and I am
> tired of changing batteries. Since the alarms have A/C, couldn't the
> A/C be continually charging a backup battery in the detector? I have
> looked without success - where do I find Smoke/CO2 Detectors with
> rechargable battery backups; do they make such a thing?