[ausev] Ive discovered my scooter is over unity!!!

[Erik]

Some voltmeters also read funny in the presence of high frequency noise.  An
analog meter usually won't lie, but my harbor freight meter can give some
creative responses.

On Fri, May 15, 2009 at 7:36 PM, Matt <mba at hazmat.com> wrote:

> Most likely, the battery pack voltage is drooping under high current (high
> load), and the reference voltage for the battery meter is drooping as
> well.  The measurement is only as accurate as its reference. I would
> investigate how you are powering your voltage meter and where it gets its
> reference from.
>
> Matt
>
> On Fri, May 15, 2009 6:20 pm, Chris Robison wrote:
> > Some questions:
> >
> > What is the make and model of your scooter? At what points in the system
> > are you placing your probes or clips? Can you reproduce the behavior on
> > a stand (with the rear wheel raised)?
> >
> > I could imagine motor regeneration causing temporarily higher voltages,
> > but if your 64V pack is "sitting" at 110V after shutting down, I'd guess
> > you either have a measurement error or a battery pack that won't last
> > long.
> >
> >   --chris
> >
> >
> >
> >
> >
> > Aaron Richardson wrote:
> >> I put a volt meter on my pack to see how much its sagging under load.  I
> >> see the resting pack voltage is about 64V (5x12v SLA).  When I
> >> accelerate the pack sags down to about 55 or so and then climbs as the
> >> scooter increases speed.  On a freshly charged pack it got to 110V!!
> >>
> >> I dont think Im inducing current into my sense wires because the voltage
> >> goes to 64V when I let off the accelerator and coast at high speed.  It
> >> seems this voltage it right.  If I shut the scooter off then this is
> >> where the pack sits.
> >>
> >> So, whats causing this voltage and can I trust the sag voltage when the
> >> scooter is moving very slowly?
> >>
> >> thanks,
> >> Aaron
> >>
> >>
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> >
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>
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