My $0.02 is that UPS's should definately be a category of hardware supported by SuperUser, until you start talking about something more relevant on [EE.SE][1], but at that point it's obviously not a good fit for Superuser.

Should be on topic:

 - Swapping a battery.
 - Discussing specs including run time, chemistry, performance, compatible batteries, etc.
 - Programming/interfacing to it (like your question).


Should be off topic:

 - Building one from parts.
 - Anything that involves soldering parts within a UPS.
 - Generally hacking a UPS from a hardware perspective, for example to use a bigger battery than what was originally intended/designed.


  [1]: https://electronics.stackexchange.com/