[Nut-upsuser] Ablerex MARS

[Carlos Rodrigues]

Right now megatec just calculates a linear approximation. It doesn't
give accurate values, but it is enough to have a fuzzy idea of the
charge left (like saying "it's almost noon" instead of "it's 12:45"),
and I'm not seeing how to plot a more accurate charge that fits all
the models that megatec is supposed to support (especially given I'm
no electrical engineer).

Now, I've introduced these values to megatec, and I've commited it to
SVN. Can you (not Charles) check if they are acceptable now?

On 4/22/06, Charles Lepple <clepple at gmail.com> wrote:
> On 4/22/06, lonely wolf <wolfy at nobugconsulting.ro> wrote:
> > The voltage doesn't look to have a linear dependency with the charge ...
>
> Here's the charge curve used by the Tripp-Lite driver:
>
>    http://boxster.ghz.cc/projects/nut/browser/trunk/drivers/tripplite.c#L456
>
> Generally speaking, measuring the voltage to find charge is a bit
> problematic unless you take into account the amount of current flowing
> in or out of the battery as well (a real-world battery has non-zero
> Thevenin resistance, so it is not a pure voltage source). The best you
> can do is plot voltages over time (as reported by the UPS), and try to
> fit the curve.
>
> --
> - Charles Lepple
>
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--
Carlos Rodrigues