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Re: (ET) PV powered ET more questions

It doesn't take much leakage current to give
you a reading on the DVM.
The best way to check for real leakage problems is to
conect a 10k resistor between the battery and frame
and read the voltage acrost it.  If you get more than
10V across it there is a 1mA leakage path.
Use this equation, Voltage/10,000 to gives you the
leakage current.  More than a few milliamps is not
good.
Rod
--- daveb <daveb seanet com> wrote:
> really?  maybe that explains why the my digital
> meter seems schizophrenic at times.   It wasn't damp
> at all when I was doing the metering though, and I
> got a zero reading before hooking the pack up to the
> harness.  after hooking up to the harness I'd get
> just a little over 1v per batt and a total of about
> 4.8v from all four.  I don't think that could be
> dust.  could it?
> 
> thanks,
> 
> dave
> 
> -- 
> Open WebMail Project (http://openwebmail.org)
> 
> ---------- Original Message -----------
> From: "Bob Murcek" <rmurcek geisinger edu> 
> To: <daveb seanet com> 
> Cc: <Elec-trak cosmos phy tufts edu> 
> Sent: Mon, 03 May 2004 23:49:29 -0400 
> Subject: Re: (ET) PV powered ET more questions
> 
> > If you're using a meter with really high input
> resistance, like a digital meter, it would take
> nothing more than damp dust in the right place to
> get a voltage reading to the frame....
> > 
> > >>> "RJ Kanary" <rjkanary nauticom net> 5/3/2004
> 9:32:54 PM >>>
> >       Both the meters can go to ground, especially
> if they have ever gotten
> > wet. It would not pass much current, until another
> item goes to ground, with
> > the resultant arcing.
> >   Other prime suspects are the armature
> contactors,  {The bushings around
> > the large terminals.} , the traction motor
> armature terminals, and that
> > perennial favorite, the Delco® lift motor.
> > 
> > ----- Original Message ----- 
> > From: "daveb" <daveb seanet com>
> > To: "Chris Zach" <czach computer org>; "Markus
> Lorch" <mlorch vt edu>
> > Cc: <Elec-trak cosmos phy tufts edu>
> > Sent: Monday, May 03, 2004 9:33 PM
> > Subject: Re: (ET) PV powered ET more questions
> > 
> > > over the wkend I finally got the chance to start
> the conversion of my E12S
> > to
> > > the alltrax controller.  I'm not nearly finished
> yet as I am taking this
> > > opportunity to thoroughly check out the wiring
> for shorts, clean things up
> > > etc.
> > >
> > > so far I've removed and re-installed the rear
> batteries after painting the
> > > box and installing the plastic battery bags from
> Bill G.  Before I started
> > I
> > > was getting 5v between the pack and the frame. 
> with the batteries cleaned
> > up
> > > in the new bags and connected together but not
> to the wiring harness I
> > read
> > > 0volts.  when connecting the cable that runs to
> the shunt I read 4.8v
> > again.
> > > Ok I reason even though I inspected the wires in
> and out of the box
> > something
> > > is grounded but where.  So I get the bright of
> idea of using the ohm meter
> > > but find nothing!  No continuity anywhere
> between the cable and the frame
> > and
> > > yet I read 4.8v.  How can that be?  is it
> because my ohm meter's battery
> > is
> > > only 9v, old and probably needs replacing?
> > >
> > > The next time I'm at the farm I'll disconnect
> the cable from the shunt and
> > > measure voltage to the frame and proceed
> downstream
> > > disconnecting/checking/reconnecting as I go.
> > >
> > > oh and I measure 15.8ohms across the motor's
> field.  is that within range?
> > I
> > > seem to remember someone not long ago mentioned
> field resistance but I
> > don't
> > > remember what the correct amt was.
> > >
> > > any other ideas or comments would be greatly
> appreciated.
> > > thanks,
> > > dave
> > > seattle
> > >
> > > --
> > > Open WebMail Project (http://openwebmail.org)
> > >
> > >
> > > ---------- Original Message -----------
> > > From: Chris Zach <czach computer org>
> > > To: Markus Lorch <mlorch vt edu>
> > > Cc: Elec-trak cosmos phy tufts edu
> > > Sent: Thu, 29 Apr 2004 22:25:25 -0400
> > > Subject: Re: (ET) PV powered ET more questions
> > >
> > > > Um no.
> > > >
> > > > If the higher capacity batteries are in series
> with the low capacity
> > > > ones and you run the charger, what will
> happen? Either you will boil
> > > > and overcharge the lower ones to charge up the
> higher ones, or you will
> > > > never fully charge the higher capacity
> batteries.
> > > >
> > > > The "right" solution is a 36 volt inverter. If
> you're only going to use
> > > > a little bit of power, then a 24 volt (better)
> or a 12 volt could *do*.
> > > > However two of your batteries will be out of
> sync on charging, and
> > > > you'll still wind up overcharging some
> batteries on the pack to get
> > > > everything back in sync.
> > > >
> > > > Get a Trace DR3624. You'll have 3,600 watts of
> power, and it will
> > > > pull the pack down evenly. With that you
> should be able to run anything.
> > > > Chainsaw, etc.
> > > >
> > > > Chris
> > > >
> > > > Markus Lorch wrote:
> > > >
> > > > >>This is so I can use Solar PV to charge my
> batteries,
> > > > >>carry a small inverter on the ET to run a
> small
> > > > >>commercial inverter for string trimmers and
> electric
> > > > >>chain saws (Price Club/CostoCo had a nice
> deal on
> > > > >>1.75kw Xantrex inverters)
> > > > >>(and run the fridge, a radio and a couple of
> lights in
> > > > >>a pinch.) (There are a LOT of trees hanging
> over a LOT
> > > > >>of electric lines anywhere I drive, many
> more than
> > > > >>10-15 degrees past vertical)
> > > > >
> > > > >
> > > > > The previous owner of my E20 has put two
> larger (higher capacity)
> > > > > batteries in my elec-trak. These drive the
> 12V components. I also
> > > > > have a 300W inverter hooked up (cheap $20)
> to which I connect my
> > > > > small electric trimmer. It worked fine all
> afternoon yesterday.
> > > > >
> > > > > Maybe you can also have two batteries be
> larger?
> > > > >
> > > > > see my other post on chargers.
> > > > >
> > > > > Markus
> > > > >
> > > > >
> > > > >
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>
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> > > > >
> > > > >
> > > >
> > > >
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> > > ------- End of Original Message -------
> > >
> > >
> > > _______________________________________________
> 
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