AVR Trim.

[#1]

I have had an APC 3Kva Smart UPS for a couple of weeks now. Second hand from eBay with new batteries. It is fantastic with over 2 hours of backup for my servers. Powerchute is also fantastic with all the information it gives.
I have noticed (after it emailed me) that the UPS spends most of Sunday in AVR Trim as the input voltage is at about 252Volts. (It is a nice day and everyone must must be out of their houses not using electricity!)
Should I be concerned about this? Does AVR Trim use the batteries at all?

[#2]

Mine has lots of interesting lights on the front to show you what its doing at any particular time.
I've snipped an bit from the user manual for mine (attached)
Basically though, if its reducing the power its delivering, it won't use the batteries.
If its having to increase the power, it will use the batteries to make up the difference.
When there is no input power, obviously the difference the batteries are making up is 100%.
Its probably worth having a search at the APC website for your model, the manuals/documentation are normally very clear and helpful.
Again, depending upon the model you have, you may find that you also have the option for various external peripherals.
Relays and temperature sensors can be used to trigger events and alert you to stuff (or perform an action)
Many models also allow you to output electrical signals as a response to certain events (louder sounder - strobes etc can be used; depending upon power requirements for these, you may need to use relays to trigger them)
Also worth taking a look at the emergency shutdown wiring which allows you to add a button to completely power down and isolate the unit in seconds if needed - always comforting when you are dealing with batteried capable of delivering such current.

Whether you would need any of these options is questionable, but I know you like to embark upon stuff from a personal interest/project POV too - so it could be fun

[#3]

Searching further, it appears that your model *may* use battery power if the voltage is too high.

Quote

To avoid unnecessary use of the battery where utility voltage is chronically high, set the high transfer point higher if the connected equipment can tolerate this condition

Options available are:

Quote

• 253 VAC • 257 VAC • 261 VAC • 265 VAC

This taken from: Smart-UPS XL 2200/3000 VA 120/230 VAC 3U Rack Mount User Manual [Part no SUA3000RMXLI3U]
Is this the one you have? http://www.apc.com/resource/include/techspec_index.cfm?base_sku=SUA3000RMXLI3U&tab=models

[#4]

Quote

To avoid unnecessary use of the battery where utility voltage is chronically high, set the high transfer point higher if the connected equipment can tolerate this condition

I seen this bit in the manual but the voltage is not that high. This refers to the point where the unit completely switches to battery power. Mine is just below this. I checked after I had first posted and I can see from my power meter pictured at http://www.seanbranagh.ie/computing/networking.html that the unit is still drawing all the power from the mains when in AVR trim mode. This answered my question.
I have just arrived home from work now and there is no email from the UPS complaining about extended overvoltage as there was yesterday so it would probably only be a Sunday afternoon.

[#5]

mod:note
Errant duplicate post removed.
Jonathan

[#6]

Thanks. Not sure how I managed to do that!

[#7]

On the plus side, the APC kit is pretty intelligent - it frequently discharges and recharges the batteries to attempt to ensure optimum capacity.
Clearly if it is running on battery power, it could shorten the life of the batteries, but they will try to keep going as long as they can, and it will give you plenty of warning if there is a problem.
Also, if it was needing to run on batteries, you can at least draw comfort that its only shortening the life of the batteries, rather than your harder to replace servers.