Battery gauge
Thread Starter
Pro
Joined: Dec 2009
Posts: 638
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From: Flakewood Wrench, FL
Battery gauge
The battery gauge on this 66 looks unresponsive. It always stays just a tick to the right of center. What is the test for determining functionality? I've got a meter but not sure of settings. Thanks in advance.
Team Owner
Joined: Aug 2007
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Army
Turn the high beams on, play radio at high volume, step on the brakes and honk the horn simultaneously with the key ON but engine OFF and you should see some major deflection to the left side.
You may just have a healthy, perfectly functioning charging system....
You may just have a healthy, perfectly functioning charging system....
Team Owner
Joined: Jul 2006
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From: Kannapolis NC
With a good battery charge, that's what you should see with the engine running. Close to zero with everything off, deflection to the left if you turn on headlights. With the battery low on charge, the needle should deflect right to show charging. Sounds like yours is in good shape.
Le Mans Master
Joined: May 2009
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From: WV
I just went through this last weekend on my 60. Just to the right is correct. With engine off mine goes to about -13, about +7 when I first start it and within 30 sec. it goes to just the right of 0.
Thread Starter
Pro
Joined: Dec 2009
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From: Flakewood Wrench, FL
If I turn the headlamps on, rotate the buckets, turn the radio on and step on the brake pedal- all at the same time, the needle moves ever so slightly to the left. I mean ever so slightly. I don't ever see a discharge reading under normal operation. I guess that's a good sign but I would expect more deviation in such a gauge under discharge.
Team Owner
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Army
If I turn the headlamps on, rotate the buckets, turn the radio on and step on the brake pedal- all at the same time, the needle moves ever so slightly to the left. I mean ever so slightly. I don't ever see a discharge reading under normal operation. I guess that's a good sign but I would expect more deviation in such a gauge under discharge.
Team Owner
Joined: Jul 2006
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From: Kannapolis NC
If I turn the headlamps on, rotate the buckets, turn the radio on and step on the brake pedal- all at the same time, the needle moves ever so slightly to the left. I mean ever so slightly. I don't ever see a discharge reading under normal operation. I guess that's a good sign but I would expect more deviation in such a gauge under discharge.
Just for grins, turn on the headlights and have someone watch the gauge while you wiggle the bulkhead connector just below the master cylinder. If you see changes as you wiggle, I'd pull the connector off and clean the pins on both sides of the plug. Post back what you find if you do that. (Engine OFF)
Team Owner
Joined: Feb 2003
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From: Sitting in his Nowhere land Hanover Pa
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With the engine running and using a meter what is the alt putting out? If it's 14.1 or around every thing is normal and don't mess with anything. If not you have a problem. If you under stand how the gauge works your understand.
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Team Owner
Joined: Jul 2006
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From: Kannapolis NC
Sorry, I don't understand that sentence.
Last edited by 65GGvert; Aug 10, 2015 at 09:53 AM.
Team Owner
Joined: Feb 2003
Posts: 54,155
Likes: 9,464
From: Sitting in his Nowhere land Hanover Pa
2024 C2 of the Year Finalist - Unmodified
2015 C2 of Year Finalist
Team Owner
Joined: Feb 2003
Posts: 54,155
Likes: 9,464
From: Sitting in his Nowhere land Hanover Pa
2024 C2 of the Year Finalist - Unmodified
2015 C2 of Year Finalist
Thread Starter
Pro
Joined: Dec 2009
Posts: 638
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From: Flakewood Wrench, FL
It's not an amp gauge, it's a voltage gauge. The voltage drop across a piece of wire run from the starter to the horn relay is used to deflect the needle. So if it doesn't deflect left momentarily when you turn on the lights, either there is a very strong battery source, or the resistance of the wire is very low. Both those are good things. The only other possibility is that the gauge isn't deflecting properly. I think you can take a 1.5 volt battery and momentarily connect it across the gauge to check deflection, but it's been a long time since I tried anything like this and don't remember the details. If it were me, I wouldn't worry about it. If it deflects left and right slightly with changes, just be aware of the movement so you'll know if it's charging when it should. Unless I had to have the gauge out for something, I would just note the operation and use it as is.
Just for grins, turn on the headlights and have someone watch the gauge while you wiggle the bulkhead connector just below the master cylinder. If you see changes as you wiggle, I'd pull the connector off and clean the pins on both sides of the plug. Post back what you find if you do that. (Engine OFF)
Just for grins, turn on the headlights and have someone watch the gauge while you wiggle the bulkhead connector just below the master cylinder. If you see changes as you wiggle, I'd pull the connector off and clean the pins on both sides of the plug. Post back what you find if you do that. (Engine OFF)
Team Owner
Joined: Jul 2006
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From: Kannapolis NC
It is indeed reading volts. It is reading the voltage drop on a wire connected between the starter and the horn relay. That wire is in parallel with the gauge connections and reads the positive or negative based on the current flowing through the resistance of that wire. Since it is connected in parallel (a shunt) it reads the difference in the voltage between those two points that is dropped on that shunt wire. It is a voltage meter.
Pro
Joined: May 2012
Posts: 707
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From: Portland Oregon
If you want to be sure the gauge moves take a AA battery and MOMENTARILY touch the terminals across the back of the battery gauge. Battery Connector off. 1.5 volts will cause a full scale deflection of the gauge . just momentarily flash the terminals don't hold it there
Also you should have 12 v to ground on both the black wire and the black wire with white tracer at the battery gauge connector
I have never been able to get a major deflection on my gauge and assume I have a high resistance connection somewhere although I have cleaned the firewall connector and all other terminations
Randy
Team Owner
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Army
It's been like this seems forever. I've never had charging issues or a gauge that moved erratically. I always do repeated gauge checks while driving this car. I feel like a pilot running thru his instrument checklist. It never deviated enough to catch my eye which is why I wondered if it worked at all. I did the fuse block connectors and there is no change.
The gauge shouldn't be erratic; hence the 'regulator' part of "Voltage Regulator". Personally, I would live with what you have...you could spend money, time and get frustrated and perhaps not make it any better...
Melting Slicks
Joined: Feb 2011
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From: Syracuse, NY and Clearwater, FL
