The Ford Barn

Dennis D 1929 · 06-19-2018, 08:28 AM

My barn find 1929 Coupe has a strange issue. The amp meter seems to run "backward". With engine off, and key off, if you pull the lights on, it reads +10 amps. Engine running reads -5 to -10 amps. The gauge looks like a new replacement, so my guess is someone put it in backwards or set it up that way to accommodate a neg. grounded battery. Could I just fix the issue by taking the gauge out and switching the wires or just switch the battery back to neg. ground ? Are there any known issues to running the car with a neg. grounded battery ? My guess is they built the car as positive ground (from what I've been told) for a reason. Thanks for any comments.

midgetracer · 06-19-2018, 08:45 AM

Just switch the wires on the Amp meter and all will be well. Switching to neg ground is more difficult.

Purdy Swoft · 06-19-2018, 10:56 AM

A lot of the ammeters that have been offered are actually 26-27 model T . The 26-27 model T was negative ground .These ammeters look and fit pretty much the same as the model A ammeter . If this is the case , I would do what midget racer says above .

Mike V. Florida · 06-19-2018, 07:11 PM

Where is the positive terminal of the battery connected? It was connected to the frame originally. This could explain the ammeter if the neg is now attached to the frame.

Dennis D 1929 · 06-19-2018, 08:15 PM

I have the positive cable to the frame as originally made.

Patrick L. · 06-20-2018, 05:29 AM

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I think what Midgetracer and Purdy said will fix it.

BILL WILLIAMSON · 06-20-2018, 09:22 AM

Chief hooked his Ammeter BACKWARDS for LAFFS & an excuse for NOT takin' "someone" to TOWN!!!---He taught me to be KRAZY, also!
Bill Fun

FRANK PKNY · 06-20-2018, 09:32 AM

Also it should go to zero when the key is off. This is important, because if it still reads plus or minus you have a stuck cut-out relay.

WHN · 06-20-2018, 11:04 AM

Had the same problem last year. Put in a new amp meter, had to reverse wires for it to read correctly. Enjoy.

Purdy Swoft · 06-20-2018, 08:12 PM

I think that most if not all of the model A parts vendors have been offering the 26-27 model T ammeters as replacements for the model A ammeter for 20 years or more .

DHZIEMAN · 06-21-2018, 12:44 PM

Quote:

Originally Posted by Dennis D 1929

My barn find 1929 Coupe has a strange issue. The amp meter seems to run "backward". With engine off, and key off, if you pull the lights on, it reads +10 amps. Engine running reads -5 to -10 amps. The gauge looks like a new replacement, so my guess is someone put it in backwards or set it up that way to accommodate a neg. grounded battery. Could I just fix the issue by taking the gauge out and switching the wires or just switch the battery back to neg. ground ? Are there any known issues to running the car with a neg. grounded battery ? My guess is they built the car as positive ground (from what I've been told) for a reason. Thanks for any comments.

Had the same situation on my 1930 Model A! Same thing, ammeter reading opposite, the difference for me is my battery went dead! Tried hooking up a 6 volt battery charger and bingo, lots of sparks, someone, had not understood the battery being positive ground. Got that fixed the battery charged and off the old girl went with ammeter reading right.

The original model A Ford generator did not care how the battery was installed, as it is self polarizing, which means no matter how the battery is installed the generator will polarize and work to charge the battery.

Purdy Swoft · 06-21-2018, 01:28 PM

The thing is , the generator will need to be repolarized . To repolarize the generator is to touch a wire from one terminal to the other terminal of the cut out for a second or two . Never try to repolarize the generator if a can style voltage regulator is in use . Repolarization should only be performed with a cut out in place .

Purdy Swoft · 06-21-2018, 01:32 PM

The model A generator can't repolarize itself .

BILL WILLIAMSON · 06-23-2018, 11:56 AM

Model As are like us, WE need a little HELP, at times.
Bill Oldasdirt

DHZIEMAN · 06-30-2018, 07:12 PM

Quote:

Originally Posted by Purdy Swoft

The model A generator can't repolarize itself .

Trust me, I thought it strange also! But, for my old car, reversing the bat leads, did the trick and the gen hesitated a bit on charging but did pick up and start charging positive ground.

I too, do not understand, probably should not have posted that I did it!

Dennis D 1929 · 07-01-2018, 05:27 PM

Switched the wires on Amp meter, problem solved . Battery remains positive ground. Thanks too all !

06-19-2018, 08:28 AM	#1
Dennis D 1929 Member Join Date: Mar 2018 Posts: 55	Charging Question My barn find 1929 Coupe has a strange issue. The amp meter seems to run "backward". With engine off, and key off, if you pull the lights on, it reads +10 amps. Engine running reads -5 to -10 amps. The gauge looks like a new replacement, so my guess is someone put it in backwards or set it up that way to accommodate a neg. grounded battery. Could I just fix the issue by taking the gauge out and switching the wires or just switch the battery back to neg. ground ? Are there any known issues to running the car with a neg. grounded battery ? My guess is they built the car as positive ground (from what I've been told) for a reason. Thanks for any comments.

06-19-2018, 08:45 AM	#2
midgetracer Senior Member Join Date: May 2010 Location: Bismarck ND Posts: 1,189	Re: Charging Question Just switch the wires on the Amp meter and all will be well. Switching to neg ground is more difficult.

06-19-2018, 10:56 AM	#3
Purdy Swoft Senior Member Join Date: May 2010 Location: Alabama Posts: 8,099	Re: Charging Question A lot of the ammeters that have been offered are actually 26-27 model T . The 26-27 model T was negative ground .These ammeters look and fit pretty much the same as the model A ammeter . If this is the case , I would do what midget racer says above .

06-19-2018, 07:11 PM	#4
Mike V. Florida Senior Member Join Date: May 2010 Location: South Florida Posts: 14,054	Re: Charging Question Where is the positive terminal of the battery connected? It was connected to the frame originally. This could explain the ammeter if the neg is now attached to the frame. __________________ What's right about America is that although we have a mess of problems, we have great capacity - intellect and resources - to do some thing about them. - Henry Ford II

06-19-2018, 08:15 PM	#5
Dennis D 1929 Member Join Date: Mar 2018 Posts: 55	Re: Charging Question I have the positive cable to the frame as originally made.

06-20-2018, 05:29 AM	#6
Patrick L. Senior Member Join Date: May 2010 Location: Largo Florida Posts: 7,225	Re: Charging Question Sponsored Links (Register now to hide all advertisements) I think what Midgetracer and Purdy said will fix it.

06-20-2018, 09:22 AM	#7
BILL WILLIAMSON Senior Member Join Date: Dec 2010 Location: FRESNO, CA Posts: 12,560	Re: Charging Question Chief hooked his Ammeter BACKWARDS for LAFFS & an excuse for NOT takin' "someone" to TOWN!!!---He taught me to be KRAZY, also! Bill Fun __________________ "THE ASSISTANT GURU OF STUFF"

06-20-2018, 09:32 AM	#8
FRANK PKNY Senior Member Join Date: May 2010 Location: POUGHKEEPSIE NY 12601 Posts: 1,016	Re: Charging Question Also it should go to zero when the key is off. This is important, because if it still reads plus or minus you have a stuck cut-out relay. __________________ [email protected]

06-20-2018, 11:04 AM	#9
WHN Senior Member Join Date: Mar 2017 Location: Connecticut Shoreline Posts: 1,823	Re: Charging Question Had the same problem last year. Put in a new amp meter, had to reverse wires for it to read correctly. Enjoy.

06-20-2018, 08:12 PM	#10
Purdy Swoft Senior Member Join Date: May 2010 Location: Alabama Posts: 8,099	Re: Charging Question I think that most if not all of the model A parts vendors have been offering the 26-27 model T ammeters as replacements for the model A ammeter for 20 years or more .

06-21-2018, 01:28 PM	#12
Purdy Swoft Senior Member Join Date: May 2010 Location: Alabama Posts: 8,099	Re: Charging Question The thing is , the generator will need to be repolarized . To repolarize the generator is to touch a wire from one terminal to the other terminal of the cut out for a second or two . Never try to repolarize the generator if a can style voltage regulator is in use . Repolarization should only be performed with a cut out in place .

06-21-2018, 01:32 PM	#13
Purdy Swoft Senior Member Join Date: May 2010 Location: Alabama Posts: 8,099	Re: Charging Question The model A generator can't repolarize itself .

06-23-2018, 11:56 AM	#14
BILL WILLIAMSON Senior Member Join Date: Dec 2010 Location: FRESNO, CA Posts: 12,560	Re: Charging Question Model As are like us, WE need a little HELP, at times. Bill Oldasdirt __________________ "THE ASSISTANT GURU OF STUFF"

07-01-2018, 05:27 PM	#16
Dennis D 1929 Member Join Date: Mar 2018 Posts: 55	Re: Charging Question Switched the wires on Amp meter, problem solved . Battery remains positive ground. Thanks too all !