Re: Thinking of installing myself...

[Nomen Nescio <nobody@xxxxxxxxx>]

Bass said:

>In the 24 years I installed professionally, I did hundreds of my own
>installations and countless
>more takeovers.  With the exception of a few extremely large systems that
>I did,
>every professional installation in a residence that I ever saw had either a
>single 12 Volt x 4 Amp Hour or 12 Volt x 7 Amp Hour battery.  Not one
>professional installer does battery load calcs on residential systems.

I'm a professional installer, and I do battery calculations on residential
systems.  The fact that you use a single 4 amp-hour battery only goes to
show why you should not be allowed to touch fire alarm systems.  Oh wait,
you don't have a license.  You're NOT allowed to touch fire alarm systems.

NFPA 72, 11.6.2, "Household Fire Alarm Systems," states that "the secondary
source shall be capable of operating the system for at least 24 hours in
the normal condition followed by 4 minutes of alarm.  Now, please explain
to us how to determine whether a given system complies with this
requirement without doing battery calculations.

Then you can explain to us how even a 7 amp-hour battery provides 24 hours
of standby on a system with three alphanumeric keypads, a zone expander or
two, plus several motions and glass breaks.  I'm being deliberately vague
on the equipment list to make a point:  you just don't know the answer
until you do the math for the exact system in question.

Of course, you'd probably solve this problem with one of those special
Napco diode battery harnesses.

- badenov