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Re: Ammeter

To: "Bowen, Patrick A" <jak0pab@jak10.med.navy.mil>
Subject: Re: Ammeter
From: Edward Hamilton <hamilton@ptd.net>
Date: Fri, 12 Jun 1998 01:44:40 -0400
Dave,
I too, elected to install a voltmeter in the passenger side cutout.  There is a
similar hole in the dash support on the driver side -- where I installed a oil
pressure gauge.  Both are Smiths and installed in the same recessed fashion as
the existing gauges.  They look original and make for a nice, clean, balanced
look.

Best regards,
Ed Hamilton

Bowen, Patrick A wrote:

> Dave,
>
> I must ditto what Pat said about the difference of currents, however are
> you talking about an ampmeter or a voltmeter?  Unless my mind is having a
> really bad day (which it just might) Most cars measure the voltage output
> not the amp output.  With the voltmeter while the engine is running it
> should read just to the positive side of 12 volts (about 13 or 14).  I have
> an interesting arrangement on my '79 Spit where a PO took a Smith's
> Voltmeter (possibly from a TR6) and placed in on the passenger side dash.
> There is a hole in the dash supports for a gauge there, I don't know if one
> has ever been factory standard in that position.  However it looks very
> nice there and very original (its an original Smith gauge).  Hope I helped.
>
> Patrick Bowen
> '79 Spitfire
>
> At 02:24 PM 6/11/98 +0100, Pat Catchpole wrote:
> >
> >Dave
> >
> >I'm sure some better informed sparky will correct me if the following is
> >incorrect, but an ammeter will indicate the net difference of currents in
> the
> >car electrics.  Therefore your calculation below will be true only if you
> are
> >parked up with the motor off.  When driving the alternator will be providing
> >juice back into the wires so the overall difference should never be 17A.
> This
> >is where an ammeter will be useful - if you see this sort of current then
> you
> >should be preparing to push :(
> >
> >The largest current draw that I can think of will be the starter motor.  I'm
> >sure that these meters will have some kind of overload protection in for
> when
> >the motor is being cranked over, so I would be inclined to get the 30-0-30
> type
> >as it will give a more visual indication for small variations in current.
> >
> >
> >Cheers
> >
> >Pat
> >
> >Subject: Ammeter
> >Author:  "Childs; David" <dchilds@epri.com> at Internet-po
> >Date:    11/06/98 07:52
> >
> >
> >Hello all,
> >
> >I was thinking of putting an ammeter in the Spit.  What range should I
> >get? 30-0-30 or 60-0-60.  What in that little car would pull more than
> >30 amps? One of the biggest loads I can think of would be the lights.
> > I would guess that the lights are 55 to 60 watts so lets assume 100
> >watts to be safe.  100/12*2=17 amps.  What is the general experience
> >here?
> >
> >TIA
> >
> >Dave C
> >
> >
> >




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