- OT: psu watts & amps ....an volts !
- Posted by RJK on May 1st, 2008
Out of curiosity, I bridged the positive 230 volt mains supply, with my
ammeter, to my PC, at the mains power plug which supplies, amongst a few
other small wattage odds and ends :-
Back-UPS 650, Orange Livebox, Linksys WAG354G, PC system box with Seasonic
SII 430w and several case fans, - Conroe mb and D935 cpu - 3 x hds - dvd rw
and cd rw drives, 2 pci cards, 1 x AGP 6200 card, 19" LCD monitor and Labtec
powerfullish PC speakers.
....and I get a reading of .794 amperes, which calculates out at 182.62 watts
consumption, which in theory means that, (ignoring a few variables for
simplicity), the above should run for 5.47+ hours per kwh ! ...or in other
words here in Somerset, England & EDF Energy - TEN PENCE for almost five and
a half hours !!!
WHERE ...then, is our huge household electricity bill coming from ? (just
kidding - DON'T answer that one please !!! )
I though I had a good grasp on calculating out the required Watts rating for
a PC system box, but, more recently I've been falling back on sites like
Antec's http://www.extreme.outervision.com/powercalc.jsp which makes it a
bit quicker.
....How can I reduce consumption, other than by leaving it all switched off
? :-)
regards, Richard
- Posted by Colin Barnhorst on May 1st, 2008
You might also want to ask in the microsoft.public.windowsxp.hardware
newsgroup.
"RJK" <nospam@hotmail.com> wrote in message
news:OgQato6qIHA.3408@TK2MSFTNGP03.phx.gbl...
- Posted by Pegasus \(MVP\) on May 1st, 2008
See below.
"RJK" <nospam@hotmail.com> wrote in message
news:OgQato6qIHA.3408@TK2MSFTNGP03.phx.gbl...
*** You inserted your ammeter into the circuit between the power
*** outlet and the PSU.
*** The actual power consumption is less but we cannot tell by how much.
*** Ten pence for 5.5 hours would be much the same thing as the
*** famous unit of furlongs per fortnight. How about 2 pence per hour?
Use the various power saving modes available on your machine, and
turn it off when it's not in use. And while you're at it: Add up the cost
of the postage stamps you would use for every EMail you've sent, or
the cost of the phone calls if you had rung the receiver.
- Posted by M.I.5¾ on May 2nd, 2008
"RJK" <nospam@hotmail.com> wrote in message
news:OgQato6qIHA.3408@TK2MSFTNGP03.phx.gbl...
To start with, both your method and calculation are flawed. Power (in
watts) is the Voltage multiplied by the Current *multiplied by the Power
Factor*. You omitted this rather important last bit and probably have no
realistic way of measuring it. This means that the actual power is less
than just the volts times amps (known as VA). Computer power supplies are
switch mode units and take their input at often very low power factors. A
second problem is that your meter is mot likely of a type known as 'mean
sensing, RMS indicating' These indicate correctly *only* when measuring a
sine wave. The current waveform into a Switch Mode supply is never a sine
wave.
Everything else?
Maplin sell a plug in power meter that will indicate watts far better than
you are managing. If you are that worried, it would pay you to get one. As
a bonus, it measures kWh as well.
http://www.maplin.co.uk/Module.aspx?...rce=14&doy=2m5
It often appears on special offer, so if you are too mean to pay the
advertised price, wait and it may appear cheaper from time to time.
- Posted by RJK on May 2nd, 2008
LOL ..:-) well done, ...and thanks !
....especially for the Maplin link, I am strongly tempted to buy one.
regards, Richard.
"M.I.5¾" <no.one@no.where.NO_SPAM.co.uk> wrote in message
news:481ac34b$1_1@glkas0286.greenlnk.net...
