[K12OSN] electricity use

Vince Callaway vince at totalsense.com
Wed Mar 14 02:33:11 UTC 2007

Funny you should bring this up.

First off, If you have a computer pulling more than 10 amps you have a

One of the advantages of using thin clients is lower power consumption.
A diskless client operates on less than 1/4 amp of power.  The power
supply in most desktop PC's are going to be way overkill and will waste

I know it means spending money, but if you replace those big power
supplies with low voltage ones you will greatly reduce the power
consumption.  The power supplies used for automotive applications are a
great way to go.

You can use something like this item:
and share one 12v power supply between multiple boxes.

Right now I'm putting together a proposal for a mobile system using just
these items.  The spec is they need 6 workstations with full internet
access.  They also need to run all of these off a standard automotive
electrical system.

I've chosen the Jetway 1.2Ghz Mini-ITX boards for the 6 stations.  With
a rated power consumption of 9 watts they came out on top.  My tests
show that with a keyboard, optical mouse and running they actually
consume about 15 watts.

I'm still waiting on the server parts, but it will consist of a 2 Ghz
Mini-ITX board with two 2.5" sata laptop drives.  I don't expect it to
have a really large draw. I hope that by using two drives I can get the
speed up a bit so things don't lag too much.  Since firefox is 99% of
the usage it is not that big of a deal.

I also have some testing to do on monitors yet.  CRT's are going to be a
power hog.  LCD's are a great way to go to reduce power.  Again they
cost money, but will save in the long run.

The big power hog in traditional computers is hard drives and fans.
Reduce those and reduce power consumption.

In case anyone is curious how it all comes together.  The server will be
connected to a Linksys router with a pcmcia card connecting it to sprint
broadband wireless.

This would be a great setup for the internet equivalent of a book

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