I've had mixed results from different vendors - but a recent battery by Tripp Lite - the Smart 1500SLT - activated during a recent short brownout. It instantly start beeping and flashing the Power LED even after utility power returned in a few seconds:
“POWER” LED: The LED flashes and an alarm sounds (4 short beeps followed by
a pause) to indicate the UPS is operating from its internal batteries during
a blackout or severe brownout. If the blackout or severe brownout is
prolonged, you should save files and shut down your equipment since
internal battery power will eventually
Eventually, the beeping went to a solid tone and shortly after, cut power to the server shutting it off. My question is, we have other UPS units that are "SMART" units from Tripp Lite and APC - and I've spoken with numerous customer support reps without a clear answer - what "feature" has to be available so that when an internal battery completely drains itself - but the utility power is on - the connected PCs/Servers still remain on?
I have another APC Back-UPS that is beeping every so often to indicate the battery is dead - Back-Ups XS 1300 - and I'm trying to contact APC to see how it will react once the battery is completely drained.
Basically - aren't there batteries out there that don't rely on a battery's presence at all in order to operate on utility power? i.e. even if I unplugged the battery from the unit - the attached PCs/Servers would remain on.
Another larger unit I have is the APC Smart-UPS 1500.