Per Nelson:
You must have really ****ty power if you worried about draining the
battery. My outages are generally not long enough to cause the
computer to shut down much less discharge the battery completely. I
doubt if completely discharging the battery once or twice over it's
lifetime will have much of an impact.

Our outages are rare (as in 1-2x per year max) but when they
happen they can be a day or two. The one we just had was a
couple hours short of two days for us, about 4 days for the guys
across the street.

Within those outages, of course, are many mini or micro outages
where some high-startup-current device kicks in and the lights
dim for long enough to trip a UPS. But in those cases my concerns
are moot.

I don't know enough about batteries to have an authoritative
opinion, but what I've always heard is that total discharge
damages lead-acid batteries from the get-go. I'm pretty sure
I've cooked a couple of batteries on my automobiles by totally
discharging them two or three times. I think that is what's
behind the special "Deep Cycle" marine batteries: they're
specially made so that deep or total discharge will not harm them
as much.

But, to address what I perceive is the real issue: yes, I might
be over-thinking this and yes, it's much more theoretical than
practical.... but that's just my inner obsessive.... -)

--
PeteCresswell