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ger19

macrumors regular
Original poster
Sep 30, 2022
154
204
I'm looking at battery backup units and I'm trying to figure out how much power the iMac draws so that I can better evaluate what unit to buy. I'm looking at a CyberPower unit labeled 550VA/330W. I'm not sure how to read that but I'm thinking it means it would run a 330W draw for almost two hours (550/330=1.67). I'm probably totally off there but still, finding out how much the iMac draws seems like the first step in understanding what I'll get out of an uninterruptible power supply. I would expect the best number to have is what it draws in sleep mode. If I'm using it and power goes off, I'm sure there'd be enough power to shut down normally with just about any power supply. But, if I'm away from the computer and the power goes out, it would most likely be in sleep mode (it certainly will be after 20 minutes) so that seems like the useful number. Any help understanding this would be appreciated.
 

arw

macrumors 65816
Aug 31, 2010
1,236
978
What CyberPower model do you have in mind? The 550 VA / 330 W is the maximum power it can provide.
But the time it can provide those 330 W on battery is probably way below 10 minutes.
CyberPower has a runtime graph for each model depending on the actual load.
You should mention your exact iMac model and if other peripherals like external HDDs are connected.
I suspect their total will be less than 100 W.
Then you can check the graph to see the runtime for that specific load.

Example: The SX550G can run a 300 W load for 3 minutes on battery. Or a 100 W load for 18 minutes.
(see 'Runtime' tab at the bottom of the page)
 
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ger19

macrumors regular
Original poster
Sep 30, 2022
154
204
Thanks to you both. From the link (Significant1) posted, my Mac uses 43w on standby. From the link above (arw), the 550VA will last about 44 minutes at a 50w draw. So, less than an hour. Interesting, I would have thought a unit like that with the low draw of an iMac would allow it to hold over for a long time - like several hours. I’ll probably just get the smaller one and save some money since I’m pretty much going to have to shut it down right away power goes out.
 
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