AMP Gauge

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Nov 4, 2012 | 08:48 AM

OregonJen

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Joined: Feb 2011

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AMP Gauge

This may have been addressed before, but I am getting conflicting information about my amp gauge. We converted to 12V on our 47 1Ton, reproduction wiring harness, rebuilt instrument cluster. I was told to put in a "shunt" to the gauge so that all the amperage output from the alternator was not going through the gauge, reducing the chance of a fire - - or don't use it at all and put in a voltmeter. I feel that with the 12V we're running half the amperage and my alternator is 60amp so it should be fine. Does anyone know how to wire a shunt? Should I just wire it like it was, or not use it? Thank you for the input...
Cary

Nov 4, 2012 | 11:15 AM

newold46

Fleet Mechanic

Joined: Sep 2010

Posts: 1,585

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From: South Carolina

I knew I'd seen this question before, I think I asked it! You don't need to wire anything to the ammeter, it's not measuring volts. It measures amps instead.
Here is a better explanation.

Nov 4, 2012 | 02:12 PM

COMPLIT1107

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Joined: Jan 2008

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From: Gibsonia, PA

On my '50 (all 12v), I just wired it like it was originally, passing everything from the alternator (1-wire setup) to a terminal block, then from the block through the gauge (with a little extra tape where it goes through the holes) and back to the term. strip, then on to the fuse box, battery and ignition. Mine works, but not as expected. I used solid core wire (#8) and the original was braided core with the braided cloth insulation. I think the solid wire and the heavier insulation "kills" some of the magnetic field the gauge picks up. I only get about 1/8 gauge Postive deflection. But I've driven it every day for 1.5 years. (the voltmeter shows a good 14v when running).

Just my $0.02...

Nov 4, 2012 | 03:03 PM

OregonJen

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AMP Gauge

Great info from 5th Avenue Tech Tips. I really trust this guy so will wire it up like it was before. Thanks! CJC

Jan 14, 2016 | 10:20 AM

winggs

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Joined: Dec 2015

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I am in the process of converting my 46 Ford ½ ton from 6v to12v. I need some clarification on how to complete this conversion. I am planning on changing the generator to 12v alternator, pertronic ignition1285SL, with 12v coil, 12v seal beam headlights, 12v bulbs in tail lights and park lights, 12v wiper motor, 12v bulbs in instrument cluster, 12v signal light switch and flasher unit. I am not sure what to do regarding the 6v instrument cluster gages. How many step down transformers will I need to convert the gages? What is required to convert the original horn? Looking at previous posts it would appear that I could use the original starter. I already have new original 6v wiring harness, for the taillights, headlights, coil and a new dash wiring harness. Will these changes be sufficient?
Am I missing something? Thank you for your help.

Jan 14, 2016 | 04:25 PM

newold46

Fleet Mechanic

Joined: Sep 2010

Posts: 1,585

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From: South Carolina

One per gauge, except for the ammeter. It measures current, not voltage.

Parts: Electrical | Fifth Avenue Internet Garage

Jan 15, 2016 | 10:03 PM

38 coupe

Cargo Master

Joined: Aug 2010

Posts: 2,916

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From: Houston

With a brand new wiring harness and clean ground connections 6V is all you need. You can swap in 6V halogen headlight bulbs if you want. 12V and alternator is a lot of unnecessary work unless you are installing air conditioning.