[SATLUG] Home network

Jonathan Hull masterr at gmail.com
Mon Apr 14 08:51:32 CDT 2008


Whoopse, I just realise I said the wrong thing about calculating
wattage. Do Amps * Volts. Not Volts / Amps. Heh.

So if amp-meter says .5, it is 110v * .5a = 55w.

-Jon

On Mon, Apr 14, 2008 at 8:44 AM, Jonathan Hull <masterr at gmail.com> wrote:
> >  I have setup a SOHO because I like the control and I have commercial
>  > electric rates.  Remember the P3 probably at least a 300 Watt power supply.
>  >  300W X 24Hrs X 30Days / 1000 = the number of KiloWatts used for the month.
>  > Multiply that by the $/KW and you get an idea of how much it will cost you
>  > to run that server for one month.
>
>
>  A 300W PSU doesn't run at 300W at all times, so in all likelyhood it
>  will be much less than that. A more accurate calculation would include
>  using an amp-meter. I got one of those cheap multi-meters with a clamp
>  AMP-meter for under $20 on Amazon and use it to gauge how much power
>  various computers use. Most of my older PC's (P2/P3) never show more
>  than 60W of power when I test them on normal load, even if the PSU is
>  listed as 300 or 400W.
>
>  A little tip about how most amp-meters work. For a normal amp-meter it
>  has to be wired in-line, which is a pain. I really prefer the clamp
>  kind. To use a clamp meter you need to find a extension cord that you
>  don't mind cutting the outer rubber insulation off of (don't strip the
>  inner wires). Wire whatever you want to test with the hacked up
>  extension cord in line and put the clamp around either the hot or
>  nuteral (not ground), usually black or white, with the meter set to
>  amperage. You can then caluclate the wattage from amerage by deviding
>  the voltage (110) by the amperage shown on the meter. Wattage =
>  Voltage * Amperage
>
>  Hope that helps. It helped me pick out the best PC from my garage to
>  use as a print server.
>
>  -Jon
>


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