iMac 27" Battery / On Location Power?

MandiMac

macrumors 65816
Feb 25, 2012
1,256
653
Well, if the product indeed does output up to 200 W you should be safe. My iMac needs around 60 W in idle state.

https://support.apple.com/en-us/HT201918

But then again, how long do these 42000 mAh last? These translate to 210 Wh which means you could power your iMac theoretically between one hour and three hours. Is that enough?
 

jerwin

Suspended
Jun 13, 2015
2,895
4,646
Well, if the product indeed does output up to 200 W you should be safe. My iMac needs around 60 W in idle state.

https://support.apple.com/en-us/HT201918

But then again, how long do these 42000 mAh last? These translate to 210 Wh which means you could power your iMac theoretically between one hour and three hours. Is that enough?
Power consumption depends on the GPU, CPU and memory; that's why apple specifies them. In my experience the GPU is much more likely to spin up the fans to audible levels than the CPU. I'm running m290x and i5. More heat output means more power consumed, so if you have an i7 or m395x, you may need more than 200 watts.

so, use an accurate kill-a-watt meter (or the like), and run a realistic workload using the specific applications you need to run in the field. I mean, if you plan on using Logic Pro in the field, then someone else's Safari benchmarks aren't going to be of much use to you.
 
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joema2

macrumors 68000
Sep 3, 2013
1,605
816
I've got a 2015 5k 27" iMac that I need to use on location without access to wall power.

Surprisingly there is almost no info on the web for how to do this (mainly, how much power is needed).

Would something like this work?
https://www.amazon.com/Powkey-Porta...0713XJBG2/ref=cm_cr_arp_d_product_top?ie=UTF8
That's probably not enough. My 2017 i7 iMac 27 is hooked to a UPS that measures power draw, whether the UPS is on line or not. It showed the following numbers:

Idle with screen off: 40 watts
Idle with screen on: 60 watts
Play Youtube video in Safari: 80-100 watts
Play local video in VLC: 100 watts
Play video at normal speed in FCPX: 100 watts
Fast forward through video in FCPX: 110 watts
Render 1080p video in FCPX: 180-200 watts with 220 watts peak
Play video at normal speed in Premiere Pro 2018: 180 watts
Unigen Heaven benchmark: 180 watts

The power bank you listed has 210 watt hours capacity. Whether that is theoretical battery capacity or measured after the AC inverter is unstated. Maybe 80% inverter efficiency is a good guess, so you probably have 168 watt hr usable capacity at the AC plug, and that assumes 100% battery efficiency.

Depending on the load, that might run a iMac 27 less than 1 hr, maybe less than 45 minutes.

Also if the peak AC output is only 200 watts, a surge above that would trip it off line and kill power to the iMac.

You need a much higher capacity battery and inverter. The Ecoflow RIVER is one of the highest quality units, but it's only about 450 watt hrs: https://www.amazon.com/ECOFLOW-RIVER-Portable-Power-Station/dp/B071S8LW83

Probably something like the Goal Zero Yeti 1000 is what you'd want to run an iMac 27 for a few hours, it's $1300: https://www.amazon.com/Goal-Zero-Portable-Generator-Alternative/dp/B074T392CQ

If you have a 2016 or later MacBook Pro, you can run those via external USB-C DC power using something like this Anker PowerCore+ 26800. Since it's DC-to-DC with no conversion it's more efficient: https://www.amazon.com/Anker-PowerCore-Portable-Capacity-PowerPort/dp/B01K6TA748
 
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