[Shop-talk] Boosting a UPS?

[Randall]

> I plugged it into one of the non-backup outlets on the UPS 
> that powers the Team.Net
> server. Now when I turn the little fan off or on, the UPS 
> beeps a few times. Interesting.

If it is a non-backed outlet as you say, then I think this might be more a symptom of problems on the supply side.  It shouldn't be
an indication that the UPS itself, or it's batteries, are worn out or nearing overload, since the non-backed outlet is connected on
the input side internally.  Most likely though, it is just the power fail detection in the UPS picking up the sudden drop when the
fan motor is first turned on.

> I have also heard that one can increase the capacity by 
> wiring normal 12 volt car, motorcycle,
> lawn tractor, etc. batteries into the circuit. Anyone have 
> any experience doing so?

That would only get you increased run-time (meaning longer operation without AC power).  Almost always, the load that the UPS can
carry is limited by the inverter element (that turns battery power back into AC power).  Adding a bigger battery isn't going to help
that.

I have added run-time in that fashion, but only with a UPS designed to do so and only with batteries that were similar in
construction and capacity to the originals.  Wiring up a car battery would probably work (or two of them in series if your UPS runs
on 24 volts as the larger ones do), but you might need to provide for separate charging.

As a side comment, I've had several APC "consumer" UPS units now that appear to work normally right up until they are needed.
Passes internal self test and everything, but won't carry a load without AC input.  Not a battery issue, same symptoms even with a
brand new battery.  Didn't seem to be a bad power transistor either.

So, IMO, it is worth occasionally doing a full load test where, after making sure things are backed up and saved, you yank the plug
out of the wall and see what happens.

Randall