On Wednesday, October 1, 2014 9:33:57 AM UTC-4, dpb wrote:
On 10/01/2014 7:47 AM, trader_4 wrote:

...



... since these are both AC and battery powered, why does the battery

go out in a year, just as fast or faster than battery only powered ones?

...



'Cuz they're a poorly designed (read "cheap to build") and don't

actually cut the battery (completely) out when A/C is on nor use

rechargeable batteries would be the likely cause...



I've not looked, but I'd think such a unit would be readily available

altho undoubtedly at a somewhat higher price point. There are just the

minimal one each floor of the old battery-powered type here as nothing's

been modified since all the recent Code changes. So, that's just three

and the once't a year deal isn't so bad as there are no cathedral

ceilings, etc., ...



--

A diode that costs maybe 10 cents has a big impact on price?