Software to show electricity consumption

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peterlavington

Anybody know of free software that will show me how much electricity
(presumably in watts) I am using whilst my PC is on?

Weird question I know but I'm interested since there are times I leave
my machine running overnight and wondering if it's costing me a lot in
power.

I've asked Jeeves and Google but with no joy.

Thanks
 
Anybody know of free software that will show me how much electricity
(presumably in watts) I am using whilst my PC is on?

Weird question I know but I'm interested since there are times I leave
my machine running overnight and wondering if it's costing me a lot in
power.

I've asked Jeeves and Google but with no joy.

Thanks
Click to expand...
I'm not an electrical engineer, but I would think that the amount of
mains current consumed by your pc while it is on is governed by the
wattage of your power supply.

This takes the mains current and supplies it to the components. If the
PC is running then the amount of current used is steady as the
components don't change and therefore draw a consistent level of
current. So a 500w power supply left on for an hour is going to draw
500w per hour or .5 kwhour per hour (in the UK electricity tends to be
measured in kilowatt hours). Also in UK terms we tend to think in terms
of electric fires, a one bar electric fire uses 1 kilowatt per hour so
your computer with a 500w power supply would use half as much.

I'd be grateful if somebody who knows more about these things than I can
explain where I'm wrong, as I'm sure I am!

Oh yes, and don't forget your monitor/printer/etc....
 
From: <[email protected]>

| Anybody know of free software that will show me how much electricity
| (presumably in watts) I am using whilst my PC is on?
|
| Weird question I know but I'm interested since there are times I leave
| my machine running overnight and wondering if it's costing me a lot in
| power.
|
| I've asked Jeeves and Google but with no joy.
|
| Thanks

You won't find it. Computers don't monitor the current and voltage on the AC side of the
power supply.
Get a Digital Multimeter, take the current and voltage readings with the PC quiescent and
calculate it for yourself.
 
What you want to do can not be done with software alone. You also need a
hardware interface card. They do make them for industrial use.
..

--
Regards,

Richard Urban

aka Crusty (-: Old B@stard :-)

If you knew as much as you think you know,
You would realize that you don't know what you thought you knew!
 
Hello, andy!
You wrote on Fri, 13 May 2005 20:36:57 +0100:



as> I'm not an electrical engineer, but I would think that the amount of
as> mains current consumed by your pc while it is on is governed by the
as> wattage of your power supply.

Not true!

as> This takes the mains current and supplies it to the components. If
as> the
as> PC is running then the amount of current used is steady as the
as> components don't change and therefore draw a consistent level of
as> current. So a 500w power supply left on for an hour is going to draw
as> 500w per hour or .5 kwhour per hour (in the UK electricity tends to
as> be
as> measured in kilowatt hours). Also in UK terms we tend to think in
as> terms
as> of electric fires, a one bar electric fire uses 1 kilowatt per hour
as> so
as> your computer with a 500w power supply would use half as much.

The power consumption is not constant at all. The power supply rating simply indicates how much it can supply rather than what is being used. The CPU load, disk activity, and whether the machine is in standby all affect the instantaneous power consumption. To answer the original question, I know of no system that can actually measure the power consumption. External devices are needed.

David


as> I'd be grateful if somebody who knows more about these things than I
as> can
as> explain where I'm wrong, as I'm sure I am!

See above. I am an electrical engineer.

as> Oh yes, and don't forget your monitor/printer/etc....

True
 
Hello, andy!
You wrote on Fri, 13 May 2005 20:36:57 +0100:




as> I'm not an electrical engineer, but I would think that the amount of
as> mains current consumed by your pc while it is on is governed by the=20
as> wattage of your power supply.

Not true!

as> This takes the mains current and supplies it to the components. If
as> the=20
as> PC is running then the amount of current used is steady as the=20
as> components don't change and therefore draw a consistent level of=20
as> current. So a 500w power supply left on for an hour is going to draw
as> 500w per hour or .5 kwhour per hour (in the UK electricity tends to
as> be=20
as> measured in kilowatt hours). Also in UK terms we tend to think in
as> terms=20
as> of electric fires, a one bar electric fire uses 1 kilowatt per hour
as> so=20
as> your computer with a 500w power supply would use half as much.

The power consumption is not constant at all. The power supply rating =
simply indicates how much it can supply rather than what is being used. =
The CPU load, disk activity, and whether the machine is in standby all =
affect the instantaneous power consumption. To answer the original =
question, I know of no system that can actually measure the power =
consumption. External devices are needed.

David
Click to expand...


You need something like this:


http://www.p3international.com/products/special/P4400/P4400-CE.html

About $30US
 
David said:
Hello, andy!
You wrote on Fri, 13 May 2005 20:36:57 +0100:





as> I'm not an electrical engineer, but I would think that the amount of
as> mains current consumed by your pc while it is on is governed by the
as> wattage of your power supply.

Not true!

as> This takes the mains current and supplies it to the components. If
as> the
as> PC is running then the amount of current used is steady as the
as> components don't change and therefore draw a consistent level of
as> current. So a 500w power supply left on for an hour is going to draw
as> 500w per hour or .5 kwhour per hour (in the UK electricity tends to
as> be
as> measured in kilowatt hours). Also in UK terms we tend to think in
as> terms
as> of electric fires, a one bar electric fire uses 1 kilowatt per hour
as> so
as> your computer with a 500w power supply would use half as much.

The power consumption is not constant at all. The power supply rating simply indicates how much it can supply rather than what is being used. The CPU load, disk activity, and whether the machine is in standby all affect the instantaneous power consumption. To answer the original question, I know of no system that can actually measure the power consumption. External devices are needed.

David


as> I'd be grateful if somebody who knows more about these things than I
as> can
as> explain where I'm wrong, as I'm sure I am!

See above. I am an electrical engineer.

as> Oh yes, and don't forget your monitor/printer/etc....

True
Click to expand...
Thanks for putting me right there David (knew somebody would if I
asked). Mind if I ask a suplimentary question or two?

How much variation is there in the level of mains power taken by things
like disk activity? I can see that having it on standby would make a big
difference though.

I would have thought that the big power drain is the cooling fans which
run constantly, with the other mechanical 'bits' like spinning hard
disks next and electronic components coming last of all?
 
From: "Richard Urban" <[email protected]>

| What you want to do can not be done with software alone. You also need a
| hardware interface card. They do make them for industrial use.
| .
|
| --
| Regards,
|
| Richard Urban
|
| aka Crusty (-: Old B@stard :-)
|
| If you knew as much as you think you know,
| You would realize that you don't know what you thought you knew!

Richard:

That won't work either because you are measuring information on the DC side of the supply
and not the AC side.

Power consumption is equal to the sum of the power losses.
The two losses are..
1) sum of the DC power consumed
2) power loses in the AC power supply

So if the DC consumed is 75watts and the power supply consumes 30watts then the total power
consumption will be 105watts on the AC side.
 
andy said:
Thanks for putting me right there David (knew somebody would if I
asked). Mind if I ask a suplimentary question or two?

How much variation is there in the level of mains power taken by
things like disk activity? I can see that having it on standby would
make a big difference though.

I would have thought that the big power drain is the cooling fans
which run constantly, with the other mechanical 'bits' like spinning
hard disks next and electronic components coming last of all?
Click to expand...

Hi, Andy. Little fans use just a few watts each. The HDD, based on the
amount of heat it produces, is probably next, and the CPU, when active is up
there too. Frankly, you might worry more about people standing in front of
an open refrigerator! Besides, you can have your computer go into standby
overnight (better yet: Hibernate) and at that point, it is about as
energy-demanding as a nitelite.
One thing you can take away from this discussion is that any appliance you
have lists its Maximum wattage, not the actual watts consumed in normal use.
 
The cards I used in the past monitored AC current and generated a
proportional and linear 4-20ma output for control purposes. The card also
had a computer interface to connect to a computer with monitoring software.

Now, could a computer monitor itself? I have never tried it.

--
Regards,

Richard Urban

aka Crusty (-: Old B@stard :-)

If you knew as much as you think you know,
You would realize that you don't know what you thought you knew!
 
How much variation is there in the level of mains power taken by things
like disk activity? I can see that having it on standby would make a big
difference though.
Click to expand...

Disk activity, not so much.

Your big "Eaters" are your heat producers like your CPU (~90W on newer ones)
I would have thought that the big power drain is the cooling fans which
run constantly, with the other mechanical 'bits' like spinning hard disks
next and electronic components coming last of all?
Click to expand...

Fans are actually quite low, usually around 1-5W.

Matt Gibson - GSEC
 
From: "andy smart" <[email protected]>

| I'm not an electrical engineer, but I would think that the amount of
| mains current consumed by your pc while it is on is governed by the
| wattage of your power supply.
|
| This takes the mains current and supplies it to the components. If the
| PC is running then the amount of current used is steady as the
| components don't change and therefore draw a consistent level of
| current. So a 500w power supply left on for an hour is going to draw
| 500w per hour or .5 kwhour per hour (in the UK electricity tends to be
| measured in kilowatt hours). Also in UK terms we tend to think in terms
| of electric fires, a one bar electric fire uses 1 kilowatt per hour so
| your computer with a 500w power supply would use half as much.
|
| I'd be grateful if somebody who knows more about these things than I can
| explain where I'm wrong, as I'm sure I am!
|
| Oh yes, and don't forget your monitor/printer/etc....

500 watts power supply for the avg. home computer is an overestimate to say the least ;-)
Most range between 125watt and 300watt power supplies. However, that's the max. rating the
supply can handle, not what is consumed.

The way to measure is with a Analogue/Digital MultiMeter. Then measure the quiescent
current and voltage on the AC side. The appraent ower consumed will be the volate
multiplied by the current.

I sacraficed an AC power chord with the following test platform...

ASUS P2B-B motherboard
200W power supply
PIII 550MHz slot 1 CPU
128MB
10GB HD
3.5" floppy drive
CDROM drive
AGP video card
3COM PCI NIC
ISA sound card

After 10 minutes of opertion, and the PC was quiescent, I measured..

121.4 VAC
..49 amps

Which yields an apparent power consumption of 59.486 watts.
 
Matt said:
Disk activity, not so much.

Your big "Eaters" are your heat producers like your CPU (~90W on newer ones)




Fans are actually quite low, usually around 1-5W.

Matt Gibson - GSEC
Click to expand...
Thanks everybody! I feel much better informed on this topic now.
 
From: "andy smart" <[email protected]>

| I'm not an electrical engineer, but I would think that the amount of
| mains current consumed by your pc while it is on is governed by the
| wattage of your power supply.
|
| This takes the mains current and supplies it to the components. If the
| PC is running then the amount of current used is steady as the
| components don't change and therefore draw a consistent level of
| current. So a 500w power supply left on for an hour is going to draw
| 500w per hour or .5 kwhour per hour (in the UK electricity tends to be
| measured in kilowatt hours). Also in UK terms we tend to think in terms
| of electric fires, a one bar electric fire uses 1 kilowatt per hour so
| your computer with a 500w power supply would use half as much.
|
| I'd be grateful if somebody who knows more about these things than I can
| explain where I'm wrong, as I'm sure I am!
|
| Oh yes, and don't forget your monitor/printer/etc....

500 watts power supply for the avg. home computer is an overestimate to say the least ;-)
Most range between 125watt and 300watt power supplies. However, that's the max. rating the
supply can handle, not what is consumed.

The way to measure is with a Analogue/Digital MultiMeter. Then measure the quiescent
current and voltage on the AC side. The appraent ower consumed will be the volate
multiplied by the current.

I sacraficed an AC power chord with the following test platform...

ASUS P2B-B motherboard
200W power supply
PIII 550MHz slot 1 CPU
128MB
10GB HD
3.5" floppy drive
CDROM drive
AGP video card
3COM PCI NIC
ISA sound card

After 10 minutes of opertion, and the PC was quiescent, I measured..

121.4 VAC
.49 amps

Which yields an apparent power consumption of 59.486 watts.
Click to expand...


Nope. That's 59.486 Volt-Amps unless you're measuring the current
drawn by a resistive device like a light bulb.

A computer, a motor, or just about any useful device has a capacitive
or inductive component and the current and voltage waves are out of
phase resulting in a VA fiure that's higher than the wattage used.

The Power company bills based on Watts but has to incur the costs of
generating the Volt-Amps. The obvious cost is the i-squared-r loss of
the higher current.

http://www.onewilshire.com/resource_center/colo_toolkit/ExplainingWattsandVoltAmps.htm
 
as> Thanks for putting me right there David (knew somebody would if I
as> asked). Mind if I ask a supplementary question or two?

as> How much variation is there in the level of mains power taken by
as> things
as> like disk activity? I can see that having it on standby would make a
as> big
as> difference though.

as> I would have thought that the big power drain is the cooling fans
as> which
as> run constantly, with the other mechanical 'bits' like spinning hard
as> disks next and electronic components coming last of all?

Hello Andy,

Fans are very low power, less that 4-5W each. Disk drives can consume between 5 and 30W depending upon activity and the speed they are running. The CPU is actually a big variable and can vary considerably upon activity. 5W if inactive up to over 70 or 80W for a very fast CPU if 'pegged' doing a high computational task like MPEG2 encoding. Another big power hog is high end video cards. If it has a fan on it, it can probably consume 50W or so when rendering complex moving images. Most other things consume low power, but as they say, you do get nickel and dimed on them. I have rarely seen a computer (not counting the monitor) consume more than 250W at peak load.

David
 
From: "Al Dykes" <[email protected]>


|
| Nope. That's 59.486 Volt-Amps unless you're measuring the current
| drawn by a resistive device like a light bulb.
|
| A computer, a motor, or just about any useful device has a capacitive
| or inductive component and the current and voltage waves are out of
| phase resulting in a VA fiure that's higher than the wattage used.
|
| The Power company bills based on Watts but has to incur the costs of
| generating the Volt-Amps. The obvious cost is the i-squared-r loss of
| the higher current.
|
| http://www.onewilshire.com/resource_center/colo_toolkit/ExplainingWattsandVoltAmps.htm
|
| --
| a d y k e s @ p a n i x . c o m
|
| Don't blame me. I voted for Gore.

Thanx Al you are correct.
I didn't want to muddy the waters by getting into phasors mathematics.
 
From: "Al Dykes" <[email protected]>

|
| Nope. That's 59.486 Volt-Amps unless you're measuring the current
| drawn by a resistive device like a light bulb.
|
| A computer, a motor, or just about any useful device has a capacitive
| or inductive component and the current and voltage waves are out of
| phase resulting in a VA fiure that's higher than the wattage used.
|
| The Power company bills based on Watts but has to incur the costs of
| generating the Volt-Amps. The obvious cost is the i-squared-r loss of
| the higher current.
|
| http://www.onewilshire.com/resource_center/colo_toolkit/ExplainingWattsandVoltAmps.htm
|
| --
| a d y k e s @ p a n i x . c o m
|
| Don't blame me. I voted for Gore.

I just re-read my post and I did use the terminolgy "apparent power" so all-in-all, my post
was good enough for this level of discussion. ;-)

http://www.allaboutcircuits.com/vol_2/chpt_11/2.html
 
The obvious conclusion to this discussion is that the electricity cost
of operating most personal computers is, in most cases, insignificant
when compared to most devices [Clothes dryers, freezers, refrigerators,
air conditioners, etc]. You can ramp that figure up with usage of high
end video adapters and Raid enabled hard drive configurations, etc;
however, this does not
cover very many users past extreme game players and those who must have
the latest, newest, best of everything without regard to the need for
or cost thereof. If power cost is a consideration of running the
Computer all night just turn off the monitor plus other peripheral
devices such as the printer and exterior USB or Firewire devices.
Gene K
 
You need an ammeter that loops over the 120VAC power cable, and senses the
current throught the line. You will need to separate the two conductors,
but not open the insulation. There are ammeters that require opening the
power cord and separating one of the power lines including cutting the wire,
don't use this. Then multiply the shown current usage times the voltage,
then multiply that times .606 to get true power usage in watts. This is a
rough measurement as the ammeter needs calibration to get an accurate
reading.
Although PCs are low power usage items, the overall power usage has
increased due to the increase of the system bus clock frequency, and the
cpu's multiplier in the past few years. Based on the same voltage input,
which has remained the same over the years, as the frequency goes up, the
power usage goes up. This makes more heat, and is why we have such
substantial coolers on our cpus (P4/Athlon) compared to their physical size.
This is the primary culprit, followed by the system bus clock for RAM, and
other system bus items.
HDs, etc. have maintained or lowered their power usage over the years with
exception of high rpm HDs and high rpm cdreaders. This is due to the higher
motor speeds for the platters. Which, again, is a function of frequency of
power usage.
 

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