[MLB-WIRELESS] Power over Ethernet

[Ian Donaldson]

On Tue, 12 Nov 2002 20:57, Tom Parker wrote:

> You need to get an accurate picture of the current consumption using a
> meter with the Eden working quite hard (if you're running linux perhaps
> repeated filesystem operations of some kind would be good).  Once we know
> this figure we can work from here.  I think there are a few people
> interested in this board so this would be good to work out.

I did some experiments last night with a current clamp meter and the Eden. 
Hopefully they are accurate.

The Eden is: Via C3 CPU 533 MHz, fanless, diskless, headless. Measurements 
were taken on the 12V DC line into the PSU.

Base power consumption: 700 mA, rising to about 1 A if the CPU is worked 
hard. Energising the WLAN card adds about 50 mA, and actually transmititng 
packets via WLAN adds 50 mA on top of that.

Putting packets on the wire over ethernet doesn't appear to increase 
consumption over simply having the interface active. Plugging in a 5.25 IDE 
hard drive adds about 300 mA, although I don't intend to use a drive as 
I've got the Eden PXE booting over the network.

Via's claims about power consumption appear to be accurate, at most the 
system pulls about 15W which is pretty low for an x86 PC.

So if I could get 2A @ 12V down ethernet, that would be more than enough.

Regards,

Ian
-- 
Ian Donaldson, SA @ MI                       -- ian at myinternet.com.au


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