Mainly for safety reasons you should be using the proper battery. The UPS
checks the battery by analysing the current load by pulsing it, and reading
back the decay factor.

If you start messing around by trying batteries that are not properly rated
for it, there will be very little dependability. Also, if you put a battery
with too high an amp hour rating, it will not get charged properly, and the
result may be in damaging the UPS.

As for protecting your investment, it is a bit skimpy for my taste that
someone would not at least put in the proper battery in to their UPS.

--

Jerry G.
=====

"aurgathor" wrote in message
news:1101811497.9+GL3fFjQIKbD+bAQSNOqw@teranews...
I have a 650VA APC UPS (Back-UPS Pro 650)
that has worn batteries (occasionally, it starts to
beep and the red battery light comes ON) .
The UPS is there to ride through brownouts and
outages lasting usually less than 10 seconds (have
quite a few of those) so if the batteries are less
than perfect, I don't care as long as it can last for
10 - 20 seconds.

So, how does the UPS's circuitry determines if
the battery is going bad? Is it simply a voltage
measurement, or something more sophisticated?
How difficult would be to modify the UPS to
lower the treshold for a bad battery?

Alternatively, how would the unit work if I were
to connect a marine or car battery instead of
the manufacturer supplied battery?

TIA