Author Topic: Electricity Vampire  (Read 3427 times)

Mr Dumpster Stache

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Electricity Vampire
« on: June 09, 2015, 01:15:27 PM »
I bought a Kill-A-Watt and have discovered that my desktop computer (21.5 inch iMac, circa 2010) is one of the worst power suckers in the house when I leave it on. However, even when it is off, every few seconds it pulses a little 0.03 or 0.04 amp. Is there something inside that needs this power to work properly, or can I just keep it unplugged/powerstrip turned off?

jeromedawg

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Re: Electricity Vampire
« Reply #1 on: June 09, 2015, 01:24:29 PM »
I bought a Kill-A-Watt and have discovered that my desktop computer (21.5 inch iMac, circa 2010) is one of the worst power suckers in the house when I leave it on. However, even when it is off, every few seconds it pulses a little 0.03 or 0.04 amp. Is there something inside that needs this power to work properly, or can I just keep it unplugged/powerstrip turned off?

I think this is how a lot of electronics are. Unless you put it to sleep or hibernated it, there's no reason why you shouldn't be able to just plug it into a powerstrip and turn the powerstrip off when you're not using it. In fact, you should be using a powerstrip already if you haven't been vs plugging directly into the wall.

Blonde Lawyer

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Re: Electricity Vampire
« Reply #2 on: June 09, 2015, 01:56:46 PM »
The only thing I can think of is the internal clock.  When I let my laptop battery get very dead, the internal clock resets. I have to remind it where I live. 

shitzmagee

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Re: Electricity Vampire
« Reply #3 on: June 09, 2015, 03:54:44 PM »
I would guess you are putting your computer to sleep rather than hibernating it (Sleep is default for MAC desktops). Sleep mode puts the computer in a low power state rather than actually turning it off. Sleep mode is generally preferred for convenience because the computer comes back on quicker, but it also draws power while sleeping.

http://macs.about.com/od/usingyourmac/qt/Change-How-Your-Mac-Sleeps-Pick-The-Sleep-Setting-You-Want-Your-Mac-To-Use.htm

Sibley

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Re: Electricity Vampire
« Reply #4 on: June 09, 2015, 04:18:50 PM »
Turn it off completely (not sleep or hibernate mode). Then you can turn off the power strip. The computer's internal time may get messed up, but that's just an annoyance.

vagon

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Re: Electricity Vampire
« Reply #5 on: June 09, 2015, 06:00:47 PM »
I doubt very much the clock would reset. Motherboards have batteries that take care of that.
Any clock issues is probably a function of it reconnecting to NTP rather than relying on its own timesource.

seattlecyclone

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Re: Electricity Vampire
« Reply #6 on: June 09, 2015, 07:23:01 PM »
Keeping the power strip turned off when the computer isn't in use should be just fine.

Do consider whether this will be worthwhile though. You say the power spikes up to 0.03-0.04 amps from time to time. Here's how you calculate the power usage for a sustained 0.04 amp load:
0.04 Amps * 120 Volts = 4.8 Watts
4.8 Watts * 24 hours per day = 115.2 Watt-hours per day = 0.1152 kWh per day.

My local utility bills me about 5/kWh, which means using a constant 0.04 amps would cost me about half a penny per day. Your computer's power usage fluctuates between 0 and 0.04 amps though, so the actual savings would be even less than this.

If the power strip switch is easy enough to reach, you might as well do this. If it's buried under your desk, your expected medical expense from crawling around down there is probably at least as much as the cost of the power you're saving by doing it.