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From: The Natural Philosopher <tnp@invalid.invalid>
Newsgroups: comp.sys.raspberry-pi
Subject: Re: Pi 4 power consumption, my measurements are much less than
 usually quoted
Date: Sat, 25 Jan 2025 12:16:59 +0000
Organization: A little, after lunch
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On 25/01/2025 11:19, Chris Green wrote:
> I have a 2Gb Pi 4B which I run headless and it has a collection of
> little Python scripts and such which gather data.  It also runs
> syncthing so the data gets copied to my desktop machine (and others).
> 
> When idle (or doing not much) it consumes just 316mA which, according
> to my sums is just over 1.5 watts.  That's a whole lot less than the
> seemingly always quote value of 2.7 watts.
> 
> This does have some significance for me as I'm considering upgrading
> the Pi B+ that runs all the time on my little boat in France using
> the batteries on the boat.  The batteries are kept charged by solar
> panels, during the winter there's not much power to spare.
> 
> One of the many sites that shows 2.7 watts for an idle 4B is this one:-
> 
>      https://www.pidramble.com/wiki/benchmarks/power-consumption
> 
> But the figure seems to be that same just about everywhere.  I suspect
> this may be the 'idle' figure when running a GUI, mouse, keyboard,
> etc.
> 
Indeed you are most likely right., The power consumption of such a 
machine is utterly dependent on what exactly it is doing. Throw some USB 
disk drives on and you may see up to 25W...

I am not speaking from facts, but only from general experience, that 
video processing takes power and no GUI will be a huge drop in power. I 
doubt that a keyboard or mouse takes much. But WiFi certainly does and 
so does, to a lesser extent, Ethernet.

Also it is surprising how many 'authoritative sources' merely cut and 
paste each others data. Without checking.

E.g once many years ago I was interested in the power to weight ratio of 
WWII fighter aircraft. One German fighter had its power quoted in kW and 
bhp. But they did not match. Clearly someone had transposed two digits . 
Because they then *did* match.

I attempted to rectify this, but the original text was reinstated. As 
the figures had been copied from yet another 'authoritative source' and 
in academia, 'authoritative sources' are more true than the real world.

As with most things in the real world, if you want real facts, measure 
the thing yourself. Don't necessarily rely on 'experts' and 'authorities'



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