Callum Lerwick wrote:
On Wed, 2009-02-04 at 02:59 +0100, Ralf Corsepius wrote:
> Also: 1-2W of ca. 100W is 1-2% of the absolute value.
> If the measurement device should be this
>
http://www.powermeterstore.com/p1206/watts_up_pro.php?p_tab=specs
> which is specified to have an accuracy of
> "+/- 3% (loads above 10 watts)",
> then this measurement is below the accuracy of the device and not much
> more but a "tendency".
And just what do you think the nature of this inaccuracy is? Even if the
meter is 3% off in absolute terms, unless the inaccuracy is somehow
non-monotonic, it is still perfectly valid as a relative measure.
If you have any
clues about measuring, you know the answers.
Which
is what is at question here. It doesn't matter what units you use, watts
$$$ or trees, it's still saving something.
The unit to use here is Wh.
Ralf