[conspire] ... devices that deal with low-voltage [Re: A timely question.]

[Tony Godshall]

>> I don't know how authoritative this is, but it sounds reasonably good to me:
>> http://www.apc-forums.com/thread.jspa?messageID=9770

> That's helpful, thanks.  tl;dr version:  An internal relay-controlled
> array of transformers dials up the voltage, after an 8-33 ms lag, when
> input feed drops -- making it up by drawing higher current.  Protracted
> use in that mode generates a lot of excess heat, which will reduce
> service life of the battery and associated parts, or UPS failure.

And in that mode you get yellow blinky and beep beep so if you
are around you say, "hey, the power's bad" and do a clean quick
shutdown and then turn it off until the lights come back to full
brightness.

BTW, switched-mode power supplies can often take a certain
amount of low voltage just fine- I seem to reply reading 90W-240W
AC input range- many don't even have a 110/220 switch.  Of course
the closer you run them to their rated max, the less leeway you have.
My tri-core tri-drive AMD64 servers run at 100W even though the
power supplies are rated like 400W or 600W so there's a bit of leeway
there.  And even more on the 28W E350

Tony