[PLUG] UPS is beeping sporadically

[Keith Lofstrom]

On Wed, Jan 26, 2011 at 10:25:28AM -0800, John Jason Jordan wrote:
> For the past several days my APC Smart UPS, model SUA1500, has suddenly
> started beeping at random times. If I ignore it the beeping stops after
> a minute or so. Once it stopped when I gave it a smart slap on the top
> of the case, although this remedy worked only once.

I agree with others, probably batteries.

However, I did see this symptom at our old house during cold weather.
The UPS would trip when the furnace blower started up, which sagged
the line voltage.  As the batteries got older, they were insufficient
to keep the computer alive, resulting in daily reboots when the 
thermostat timer changed programs at 5AM.  It took 3 days of getting
up early (or staying up late) and watching to figure that one out
( what?? there is /another/ 5 oclock? ).

> It appears to hold a charge fine, although I don't know how to test
> it to be sure. 

That is why you should still keep some incandescent light bulbs
around.  Test the UPS by powering an appropriate number of 100W
lamps, and see how long it stays running.  Probably not long.

Modern UPSes have a USB plug, which provides all sorts of nifty
info to the right Linux software, including battery condition
and power state.  When the power goes off for longer than a
minute or so, it is time for that software to initiate a shutdown.

Keith

-- 
Keith Lofstrom          keithl at keithl.com         Voice (503)-520-1993
KLIC --- Keith Lofstrom Integrated Circuits --- "Your Ideas in Silicon"
Design Contracting in Bipolar and CMOS - Analog, Digital, and Scan ICs