"Frank" wrote in message
ps.com...
On May 7, 12:30 pm, " wrote:
On May 7, 12:29?pm, "Robert11" wrote:



Hello:

Have been buying a bunch of those standard 9V batteries (a few
different
brands) over the past few months, and have noticed that instead of 9V
they
have been measuring out, with a VOM, at around 10.0 to 10.25. ?This is
under
no load.

Anyone else notice this ?

Was wondering if this might be the cause of all the problems I've been
having with my fire alarms
giving 3 to 4 chirps, around once a day ?

It's probably the same type of chirp signal that the unit gives when
the
batteries are low.

Thanks,
Bob

I doubt thats it, under load the voltage drops fast,

Have you blown the fire alarms out with compressed air....

They might be overheating


Don't believe voltage changes with load. Amperage is number to
deteriorate.
Electromotive potential determines voltage. If you open up a standard
9 volt battery you will find 6 1.5 volt batteries in series.
Battery's voltage will depend on materials it is made from. Alkaline
batteries will vary from the standard 1.5 volts of old carbon/zinc
batteries.

Battery voltage is only "nominal" or approximate. An old type battery, a
carbon/zinc was nominally rated at 1.5 volts but actually under no load put
out 1.7 volts, other types will vary. A car lead/acid battery actually puts
out 2.2 volts per cell. When cars used 6 volt batteries they used 3 cells
which actually gave 6.6 volts or a nominal 6 volts. Today's car batteries
out a nominal 12 volts which is actually 14.2 volts.