Volt gauge reading issues?

[Mike2500]

Has anyone ever had a volt gauge reading goofy? This how mine works, when you start the car it reads in the center and the battery light will light up and after reving the engine it goes out and reads almost fully to the right. What is the proper reading for the volt gauge to read while at idle and normal driving speeds? I feel like the needle is out of adjustment or may be a bad wire, any help or advice wuold be greatly appreciated.

 

[bill81vette]

Have you checked the alternator to see what it is putting out and if it remains stable while revving the engine????

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[SVO]

A volt meter reads the charge condition of your battery. Unless you have a heavy power drain or charging situation, the needle on you volt meter will probable run in the middle of the dial with a fully charged battery. With the charge light coming on, it sounds like the alternator isn't charging at low rpm. Raising the rpm by blipping the throttle raises the rpm enough for the alternator to cut in and start charging. Deflection of the needle to the high voltage side of the meter indicates the alternator is sending a charge to the battery. You can use a hand held voltmeter to check the dash voltmeter. Attach the voltmeter to the battery and check the battery charge, then crank the car and observe what the hand held meter is reading. You dash voltmeter should track closely to what the hand held meter is showing.

 

[Hib Halverson]

A volt meter is not always a good read of the condition of the battery. While a volt meter can be indicative of a bad battery, you, also, can have a volt meter reading 12.6v on a battery that's no good. All the voltmeter does is tell you at what voltage is between ground and the positive post of the battery. Sometimes that's telling of the battery condition and sometimes not. Whlle voltage is a clue, to tell the condition of the battery, you need more than just the voltage. You need a load test.

First thing I would do, considering the age of the car's electrics, is do what "SVO" suggests and validate the car's volt meter using a DMM. Next, I'd have the battery tested with a "battery tester". Most DIYs do not own that piece of equipment, so you may need to go to a service shop to have it done.

If the battery tests ok, next thing I'd do, is run the engine and double check the charge light with the DMM. If the DMM confirms system voltage is dropping below battery voltage at idle, I'd first check alternator wires and connections. If you find no problems there, you can either have the alternator bench tested or just assume it's got a failing regulator or rectifier bridge and replace it.

 

[Mike2500]

Thanks guys for all the help and I will get to checking when I get a free chance, I have Navy Res. drill this weekend so I can't play in the garage!

 

[Hib Halverson]

Thanks for serving, "Mike2500".

 

[Mike2500]

Your welcome and thank you for all the support.