How much power am I really using? - Page 2

kladner · 2013-12-12, 22:17

Kill a Watt EZ goes for US $ 30-40.

EDIT: I have one. It collects all sorts of cumulative data. If you give it your (true) cost per KWh, it will tell you the cost of your activities over various time periods once you use it for a while with a representative load.

sdbardwick · 2013-12-12, 22:18

One caveat regarding low-end Kill-a-watt type meters: a few APFC power supplies have been known to fool them into giving abnormally low readings.

So if one's dual GTX590 GPU rig indicates a power draw of 200W at full load, you'll need a different meter.

petrw1 · 2013-12-12, 22:20

Quote:

Originally Posted by chalsall

Please correct me if I'm wrong, but this is "in the CPUs".

Measuring the total power draw on the DC rails is a little tougher....

I don't know if one exists but I imagine a device that I plug between the power bar and wall plug with a simple display of watts or amps.

chalsall · 2013-12-12, 22:34

Quote:

Originally Posted by sdbardwick

Fluke and other makers have a bunch of clip-on probes/meters. If they measure DC current via clip-on probe, then they are using Hall effect sensors.

Interesting.

Are you familiar with the concept of "signal to noise"?

Measuring the current in a DC circuit is rather difficult to do without being within the circuit.

chalsall · 2013-12-12, 22:36

Quote:

Originally Posted by petrw1

I don't know if one exists but I imagine a device that I plug between the power bar and wall plug with a simple display of watts or amps.

That's trivial. AC is trivial.

And, yes, such devices exist COTS.

MattcAnderson · 2013-12-13, 07:18

Here is a link to buy a kill-a-watt meter.

http://www.p3international.com/products/p4400.html

Regards,
Matt

Mark Rose · 2013-12-13, 07:43

Quote:

Originally Posted by MattcAnderson

Here is a link to buy a kill-a-watt meter.

http://www.p3international.com/products/p4400.html

Regards,
Matt

It's a few bucks cheaper on Amazon.com, if you're price conscious.

kladner · 2013-12-13, 08:00

I got mine at Home Depot. Of course, I did pay a pile of sales taxes since I bought at a brick-and-mortar store.

fivemack · 2013-12-13, 13:00

Quote:

Originally Posted by chalsall

Please correct me if I'm wrong, but this is "in the CPUs".

Measuring the total power draw on the DC rails is a little tougher....

No, that's the current drawn at the wall

2013-12-12, 22:17	#12
kladner "Kieren" Jul 2011 In My Own Galaxy! 2×3×1,693 Posts	Kill a Watt EZ goes for US $ 30-40. EDIT: I have one. It collects all sorts of cumulative data. If you give it your (true) cost per KWh, it will tell you the cost of your activities over various time periods once you use it for a while with a representative load. Last fiddled with by kladner on 2013-12-12 at 22:20

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2013-12-12, 22:18	#13
sdbardwick Aug 2002 North San Diego County 5·137 Posts	One caveat regarding low-end Kill-a-watt type meters: a few APFC power supplies have been known to fool them into giving abnormally low readings. So if one's dual GTX590 GPU rig indicates a power draw of 200W at full load, you'll need a different meter.

2013-12-13, 07:18	#17
MattcAnderson "Matthew Anderson" Dec 2010 Oregon, USA 2⁵·5² Posts	Here is a link to buy a kill-a-watt meter. http://www.p3international.com/products/p4400.html Regards, Matt

2013-12-13, 08:00	#19
kladner "Kieren" Jul 2011 In My Own Galaxy! 2×3×1,693 Posts	I got mine at Home Depot. Of course, I did pay a pile of sales taxes since I bought at a brick-and-mortar store.