545      iPhone_iPad_Mac_apple

Wattage for 27

HI,

     I am trying to determine battery sizing for a backup battery

and I am having trouble determing the proper wattage used for my

27-inch mid-2011 IMAC  2.7 GHz Intel Core I5 that I bought on 11 / 7 / 2011.

I found at the following APPLE website   

     https://support.apple.com/kb/HT3559

BUT, the power figures on the bottom of the stand of my IMAC says:

     Model number: 11312  100-240V~  50-60Hz  4.0A

     Serial No: C0*******HJP  EMC No: 2429 

THUS, I thought the wattage was 120V x 4.0 amps = 480 watts???  (not 170W as listed above)

1) Can someone please clarify for me what the correct wattage is??

thanx much!!

Mark

<Edited by Host>

Step 12 of this iFixIt tear down also indicates 310w https://www.ifixit.com/Teardown/iMac+Intel+27-Inch+EMC+2309+and+2374+Teardown/123 6

Even though the tear down is a late 2009 27" model their parts list says it's the same power supply.

EveryMac indicates a 310w power supply https://www.everymac.com/systems/apple/imac/specs/imac-core-i5-2.7-27-inch-alumin um-mid-2011-thunderbolt-specs.html

Step 12 of this iFixIt tear down also indicates 310w https://www.ifixit.com/Teardown/iMac+Intel+27-Inch+EMC+2309+and+2374+Teardown/123 6

Even though the tear down is a late 2009 27" model their parts list says it's the same power supply.

Mike's right, and it's likely that Apple are too on the actual consumption, since the supply may not be rated at full power in that enclosure, and would have some overhead for unpowered accessories.

1. The 170 W is actually just the CPU chip¹!

2. The actual formula for determining AC wattage using rated volts and amps is PF x V x A (where PF is power factor). Not usually published I ignore PF and just multiply volts and amps as you have. However, because Apple doesn't know the details of each individual iMac configuration going out the door, they have to state the maximum rating which assumes that every port is in use, every accessory has been added, the graphics board is going full tilt, the RAM is fully populated, etc., etc., etc.. Ergo, 480 W. But the power supply used in Mike's specific configuration was based on the known loading in that configuration so they only installed a 310 W power supply. Eh. Their call. They've made billions at this game so who am I to argue with their ratings.

Now, back to sizing the UPS. Go ahead and use the 480 W -- a margin of safety won't hurt you at all -- and add in the wattage of all the other devices you want on battery backup. Take that total wattage and multiply by 1.25. That's my rule-of-thumb for UPS selection. Then select a UPS with equal or higher watts rating (ignore the VA rating). I also prefer UPS units with replaceable batteries but that is your choice (keeping in mind every couple years the battery will need to be replaced).

________________

¹ For example: https://www.bit-tech.net/reviews/tech/intel-core-i5-4670k-haswell-cpu-review/6/

最后更新：2017-08-20 16:18:09

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