The Ford Barn

Ordsgt · 08-10-2023, 08:17 AM

I got my car back together (1930 Tudor) and it runs and looks good. I am running a Nu Rex 6v alternator. It was charging fine on the meter and everything appeared good. Driving down the road the other day the ammeter went to 0 and stayed there. I went home and put a voltmeter on the alternator and it showed 8.2 volts but nothing on the amp meter. I drove it later that day and it showed 12 amp charge but after a few miles it went back to 0 and stayed there. I replaced the meter but it still shows no charge but voltage indicates it is charging. I have checked the harness connections and all appear good. Wiring harness is a couple of years old but in excellent condition. Had no issue before the car was completely torn down and rebuilt from the frame up. Any ideas ?

Y-Blockhead · 08-10-2023, 09:12 AM

Sounds about normal to me. Once the battery is charged, the internal regulator doesn't charge any more than needed to keep all of your accessories happy.

My amp gauge always shows a charge at first startup, then settles down. This is probably due high draw from the starter.

rotorwrench · 08-10-2023, 10:25 AM

This is the characteristic of having an internal electronic control unit to the alternator. The only thing I get concerned about is that in the case of the 6-volt conversion alternators, the electronic voltage/current controllers usually allow for a higher than normal voltage output so they tend to overcharge the battery during long daylight drives. At night, it's no problem since the lights are helping to consume the excess to a certain degree. A person can run with the lights on if they choose to.

The old 3-brush units with the aftermarket voltage regulators, like the Fun Projects type installation, were about as good as it gets for a 6-volt battery but they give about the same indication on the ammeter as an alternator does.

Big hammer · 08-10-2023, 10:28 AM

Alternator sounds like it’s doing its job, second drive charging at 12 amp sounds like you have a draw. Did you leave the headlights on, honk the horn a lot, brake light switch sticking on ?

katy · 08-10-2023, 10:59 AM

What does the ammeter do with engine not running, turn headlights on?

Planojc · 08-10-2023, 11:02 AM

Sponsored Links (Register now to hide all advertisements)

Normal for an alternator.

P.S. · 08-10-2023, 11:04 AM

Normal operation- https://www.youtube.com/watch?v=Qk9cKhXipmg

Ordsgt · 08-10-2023, 11:40 AM

Well a second issue came out. Started the car up and there was no lighting no horn. After running RPM up got power to that circuit. Just surprised as none of this was happening before the tear down

Brentwood Bob · 08-10-2023, 11:52 AM

Is the ground cable connection good? Clean, and tight.
At the battery, and at the frame,
Secondary ground strap to the motor?

Y-Blockhead · 08-10-2023, 12:06 PM

Quote:

Originally Posted by Ordsgt

Well a second issue came out. Started the car up and there was no lighting no horn. After running RPM up got power to that circuit. Just surprised as none of this was happening before the tear down

Are you new to alternators? Was the alternator "excited" (show a charge on the ammeter?) at this point? Some alternators need to be at a higher RPM to start charging when first started up.

My PowerGen starts charging at startup.

nkaminar · 08-10-2023, 12:59 PM

Add a volt meter. You can buy an addition to your instrument panel that hangs below. The volt meter is a better tool for keeping track of your alternator and battery. Before you start the car, turn on the ignition and look at the volt meter. It should register about 6.3 volts for a healthy battery. After you start the car the battery voltage should start to come up (with a fast idle or driving down the road). It should eventually reach about 7 volts or a little more. 8 volts is too high and may be caused by a bad ground. As the battery voltage comes up the current shown on the ammeter will go to zero. Even with the lights on it will read zero because the alternator is supplying current to run the lights and not the battery.

Regarding no power to the lights and horn before the alternator starts to come on: That sounds like an electrical issue. It could be a bad ground or a bad connection somewhere. It is probably related to the high voltage (8.2 volts) you measured at the alternator.

P.S. · 08-10-2023, 02:17 PM

Quote:

Originally Posted by nkaminar

Regarding no power to the lights and horn before the alternator starts to come on: That sounds like an electrical issue. It could be a bad ground or a bad connection somewhere. It is probably related to the high voltage (8.2 volts) you measured at the alternator.

100% this. Something between the alternator and battery is not making good connection. That is the electrical loop that goes from the starter switch to the terminal box to the ammeter, through the ammeter, then from the other side of the ammeter back to the terminal box and to the alternator.

Ordsgt · 08-10-2023, 04:22 PM

Thanks for all you input, Problem solved! Traced out the wires and checked connections found battery to starter loose and output from starter fuse assy also loose. Now had power to the fuse but nothing coming out. Pulled fuse and it looked good but put a meter on it anyway and it was no good. Replaced the fuse and now had current to horn lights etc. So I went to start it up and it would not fire. It has always fired right up. looking under the hood for a problem and noticed coil wire was not in. Had disconnected it to check in the junction box. Connected wire and engine fired right up and ammeter went to 12 amp.
Happy Model A man

Y-Blockhead · 08-10-2023, 04:30 PM

Quote:

Originally Posted by Ordsgt

Thanks for all you input, Problem solved! Traced out the wires and checked connections found battery to starter loose and output from starter fuse assy also loose. Now had power to the fuse but nothing coming out. Pulled fuse and it looked good but put a meter on it anyway and it was no good. Replaced the fuse and now had current to horn lights etc. So I went to start it up and it would not fire. It has always fired right up. looking under the hood for a problem and noticed coil wire was not in. Had disconnected it to check in the junction box. Connected wire and engine fired right up and ammeter went to 12 amp.
Happy Model A man

Strange, how did the engine run with the fuse blown. With fuse blown you would have no battery power to the junction box?? Unless it is not wired correctly.

Ordsgt · 08-10-2023, 05:20 PM

I have electronic FSI ignition which is directly off the battery terminal. That is what FSI states to do in the instructions

Y-Blockhead · 08-10-2023, 06:48 PM

Quote:

Originally Posted by Ordsgt

I have electronic FSI ignition which is directly off the battery terminal. That is what FSI states to do in the instructions

Gotcha...

08-10-2023, 08:17 AM	#1
Ordsgt Senior Member Join Date: Sep 2020 Location: Yorktown Virginia Posts: 182	Ammeter issue I got my car back together (1930 Tudor) and it runs and looks good. I am running a Nu Rex 6v alternator. It was charging fine on the meter and everything appeared good. Driving down the road the other day the ammeter went to 0 and stayed there. I went home and put a voltmeter on the alternator and it showed 8.2 volts but nothing on the amp meter. I drove it later that day and it showed 12 amp charge but after a few miles it went back to 0 and stayed there. I replaced the meter but it still shows no charge but voltage indicates it is charging. I have checked the harness connections and all appear good. Wiring harness is a couple of years old but in excellent condition. Had no issue before the car was completely torn down and rebuilt from the frame up. Any ideas ?

08-10-2023, 09:12 AM	#2
Y-Blockhead Senior Member Join Date: Jul 2011 Location: Redondo Beach, CA Posts: 5,849	Re: Ammeter issue Sounds about normal to me. Once the battery is charged, the internal regulator doesn't charge any more than needed to keep all of your accessories happy. My amp gauge always shows a charge at first startup, then settles down. This is probably due high draw from the starter. Last edited by Y-Blockhead; 08-10-2023 at 10:57 AM.

08-10-2023, 10:25 AM	#3
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 16,440	Re: Ammeter issue This is the characteristic of having an internal electronic control unit to the alternator. The only thing I get concerned about is that in the case of the 6-volt conversion alternators, the electronic voltage/current controllers usually allow for a higher than normal voltage output so they tend to overcharge the battery during long daylight drives. At night, it's no problem since the lights are helping to consume the excess to a certain degree. A person can run with the lights on if they choose to. The old 3-brush units with the aftermarket voltage regulators, like the Fun Projects type installation, were about as good as it gets for a 6-volt battery but they give about the same indication on the ammeter as an alternator does.

08-10-2023, 10:28 AM	#4
Big hammer Senior Member Join Date: Jun 2014 Location: Land of Lincoln Posts: 3,131	Re: Ammeter issue Alternator sounds like it’s doing its job, second drive charging at 12 amp sounds like you have a draw. Did you leave the headlights on, honk the horn a lot, brake light switch sticking on ? __________________ Don't force it with a little hammer tap, tap, tap get a bigger hammer tap done

08-10-2023, 10:59 AM	#5
katy Senior Member Join Date: Jun 2015 Location: Red Deer, Alberta Posts: 5,046	Re: Ammeter issue What does the ammeter do with engine not running, turn headlights on? __________________ If you don't hear a rumor by 10 AM, start one!. Got my education out behind the barn!

08-10-2023, 11:02 AM	#6
Planojc Senior Member Join Date: May 2010 Location: Plano, Texas Posts: 850	Re: Ammeter issue Sponsored Links (Register now to hide all advertisements) Normal for an alternator.

08-10-2023, 11:04 AM	#7
P.S. Senior Member Join Date: Jul 2012 Location: California Posts: 1,700	Re: Ammeter issue Normal operation- https://www.youtube.com/watch?v=Qk9cKhXipmg

08-10-2023, 11:40 AM	#8
Ordsgt Senior Member Join Date: Sep 2020 Location: Yorktown Virginia Posts: 182	Re: Ammeter issue Well a second issue came out. Started the car up and there was no lighting no horn. After running RPM up got power to that circuit. Just surprised as none of this was happening before the tear down

08-10-2023, 11:52 AM	#9
Brentwood Bob Senior Member Join Date: May 2010 Location: brentwood, ca Posts: 4,249	Re: Ammeter issue Is the ground cable connection good? Clean, and tight. At the battery, and at the frame, Secondary ground strap to the motor?

08-10-2023, 12:59 PM	#11
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 3,907	Re: Ammeter issue Add a volt meter. You can buy an addition to your instrument panel that hangs below. The volt meter is a better tool for keeping track of your alternator and battery. Before you start the car, turn on the ignition and look at the volt meter. It should register about 6.3 volts for a healthy battery. After you start the car the battery voltage should start to come up (with a fast idle or driving down the road). It should eventually reach about 7 volts or a little more. 8 volts is too high and may be caused by a bad ground. As the battery voltage comes up the current shown on the ammeter will go to zero. Even with the lights on it will read zero because the alternator is supplying current to run the lights and not the battery. Regarding no power to the lights and horn before the alternator starts to come on: That sounds like an electrical issue. It could be a bad ground or a bad connection somewhere. It is probably related to the high voltage (8.2 volts) you measured at the alternator. __________________ A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past. Last edited by nkaminar; 08-10-2023 at 01:04 PM.

08-10-2023, 04:22 PM	#13
Ordsgt Senior Member Join Date: Sep 2020 Location: Yorktown Virginia Posts: 182	Re: Ammeter issue Thanks for all you input, Problem solved! Traced out the wires and checked connections found battery to starter loose and output from starter fuse assy also loose. Now had power to the fuse but nothing coming out. Pulled fuse and it looked good but put a meter on it anyway and it was no good. Replaced the fuse and now had current to horn lights etc. So I went to start it up and it would not fire. It has always fired right up. looking under the hood for a problem and noticed coil wire was not in. Had disconnected it to check in the junction box. Connected wire and engine fired right up and ammeter went to 12 amp. Happy Model A man

08-10-2023, 05:20 PM	#15
Ordsgt Senior Member Join Date: Sep 2020 Location: Yorktown Virginia Posts: 182	Re: Ammeter issue I have electronic FSI ignition which is directly off the battery terminal. That is what FSI states to do in the instructions