[SATLUG] Home network

Jonathan Hull masterr at gmail.com
Mon Apr 14 08:44:45 CDT 2008


>  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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