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Re: cigarette lighter in positive ground

To: "Philip E.E Bacon" <pboldtrix@juno.com>, mmorris@nemr.net
Subject: Re: cigarette lighter in positive ground
From: David Councill <dcouncil@imt.net>
Date: Sat, 31 May 2003 09:01:35 -0600
With the positive ground, you just have to keep in mind that everything is 
reversed. So if you have converted to negative ground, proceed as normal. 
With positive ground, to most modern appliances, the ground is actually the 
hot lead so to speak. What I did was get one of those cigarette lighter 
adapters that plugs in the lighter and then took the two wires coming out 
and checked each lead with a voltmeter, verifying which was the 
conventional hot lead (measuring positive 12 volts on the volt meter). I 
marked that wire as the "hot". I then use the wires with fittings to plug 
in standard stuff - in particular I have a cassette player rigged to run 
off the adaptor, with the cassette player resting on the passenger seat. A 
temporary setup but it keeps the car all original with the AM radio still 
in place and operational..

Any standard appliance running on a positive ground car cannot touch any of 
the metal surfaces. In fact, that was the fate of my last 8-track player 
that I used to run in my first MGB. It was insulated against the dash but 
eventually it made contact - a puff of smoke and the 8 track no longer 
worked. And thus the end of a musical era.

Converting to negative ground is not a real problem because most of the 
devices in the car will work fine once the polarity is reversed. The Moss 
catalog has details but the generator needs to be polarized and the tach 
needs to be rewired in particular. And a switch of the battery leads. I did 
it on my son's 65B but I've kept my 67BGT as original as possible.

David Councill
67 BGT
72 B

At 10:15 AM 5/31/2003 -0400, Philip E.E Bacon wrote:
>I'm in the midst of doing the same thing to my 67 BGT, only difference is
>that my car has been converted to negative ground.   Suspect the
>appliance (the charger) was designed to operate on negative ground
>systems?  If the lighter works (it's only a resistive wiring system
>designed to heat up--not complicated) then probably the problem is
>incompatibilitiy with the unit plugged in.  This will be a problem with
>any device plugged in....tire inflator, etc.  I'm not too electrically
>savvy, but this is how my thinking goes..  Phil Bacon, GCBSCC, South Fla.
>
>
>On Fri, 30 May 2003 21:09:24 -0500 "MonteMorris" <mmorris@nemr.net>
>writes:
> > Tonight I installed a cig lighter receptacle in the 67 so I can
> > charge up
> > the cell phone on trips. Afer it was all wired in to the purple
> > circuit and
> > fused, I plugged the charger into it and it blew the 2A fuse that is
> > inside
> > the charger body. The ground wire on the receptacle's body was
> > grounded to
> > the car body and the hot wire was spliced into a purple one. What am
> > I
> > missing here? I'd imagine it would have to do with the positive
> > ground
> > system?
> > Thanks,
> > Monte

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