iMac Pro iMac Pro running on UPC warning (Battery Backup)

rjtiedeman

macrumors 6502
Original poster
Nov 29, 2010
278
45
Stamford, CT
Every now and then I get a warning that my iMac Pro is running on battery backup. The screen dims for a moment then it goes back to normal. The house lights never flicker and nothing else appears to be affected. I was wondering if this is normal for all UPCs or is my unit is faulty and oversensitive? Is it harming or slowing down my iMac Pro?
 

mam8dg

macrumors newbie
Mar 20, 2019
16
15
I run my iMac Pro using a UPS (CyberPower CP1000PFCLCD) and don't have that issue.
 

mikehalloran

macrumors 68000
Oct 14, 2018
1,600
389
The Sillie Con Valley
Time to check the battery health of that UPS? Better still, why is it being triggered?

Lights don't have to flicker for there to be a brown-out condition.

BTW, low voltage is far more likely to take out something with a motor like, say, a refrigerator than a Mac. Data loss is the biggest concern otherwise.
 

rjtiedeman

macrumors 6502
Original poster
Nov 29, 2010
278
45
Stamford, CT
I run my iMac Pro using a UPS (CyberPower CP1000PFCLCD) and don't have that issue.
My UPS is a Cyberpower 1350AVR purchased from COSTCO 2 or 3 years ago. Not sure how good the batteries are but the Energy Saver app is showing 100% charge. I am not sure if it pays to replace batteries in a consumer grade UPS from Costco. Also not sure if it's the batteries. The bars on the display are showing 1 bar for load capacity and 5 bars for the battery charge. A new CyberPower 1500VA is $130 and has new simulated sine wave tech..
 

hfg

macrumors 68040
Dec 1, 2006
3,566
276
Cedar Rapids, IA. USA
My UPS units all undergo a "self test" maybe once every day or so during which they switch to battery power to test the health of the battery. This lasts less than 10 seconds during which my iMacs will display a message that it is running on battery power. Of course you have to have the UPS connected via USB to your computer, which I assume you do for shut-down options.

I haven't noticed that the display dims during this self-test, but this could be a "UPS Setting" option if you are running a monitoring program. Normally, OS X provides the option to shut off the display after a user-selected time to save power. Or it could simply be a result of using a smaller VA UPS, or one with square-wave rather than sine-wave output which is running at the load capacity with your computer system.
 
Last edited: