Over charging

[djwhog]

Ok I am afraid my Cuda (70) is charging a tab to high. I have one of the repo Mopar yellow cap batteries and even before it did the same thingg. I did change the electronic regulator with a year matching new Mopar unit. Same story.

14.5 at idle 14.8 while driving.

So I suspect the alternator muct have a feild and rectifier bridge that is at fault.

So should I just buck up and get a new Alternator 2 wire? Or is there something simple I am missing here guys?
thanks!

[72cudamaan]

Sounds like the alternator is working just fine. Maybe you have a defective regulator if you think the voltage is too high. After all, that is all that controls the voltage. By the way, do you have the ability to check the amperage output. I think that is more important anyway.

   Of course this is just my opinion, as I'm sure you will get different responses either way.  Good luck

[quagmire]

The voltage and amperage that an alternator puts out are directly related to each other.  If the amperage being put out is too high, the system voltage will increase as a result.  The voltage you are seeing isn't really bad or damaging at all.  It's only slightly high, but not enough to cause problems.  You could have a shorting alternator field winding, but that wil usually result in maximum output and severe overcharging.  That being said, I'd load test the case ground and voltage sense wire first.  If the wiring is ok there may be an issue with the voltage regulator, but it really isn't overcharging.

[djwhog]

Nope I have no amp tester, but the voltage is the same with new and old regulator and all the grounds are good and I even have all new cables... Maybe I will leave it alone, I just do not want to boil the battery.

I will see if I can take it to a buddies shop 1st and do a amp output test.

The old battery had signs of acid o nthe tray from over charging. I thought the new reg would fix it,

It does have a parts house alt that the last owner put on, naybe that is it?

I have also read some folks have this issue from a bad ammeter gauge too?

thanks guys...

[quagmire]

14.8v will not cause a battery to boil over.  Like I said, if the alternator were internally shorted it would be full fielded and you'd have way more voltage (16+).  The VR grounds through it's case, and the voltage sense wire going to it tells it how much to duty cycle the field windings.  Any resistance in this circuit will drop the voltage that it sees and make the VR over duty cycle to compensate.  Unless you have checked this circuit it could very well be your problem.  An amp output test will not tell you anything that you don't already know.  That test is used when you have low voltage, it wont tell you anything if you have the opposite problem.

[djwhog]

Thanks quagmire, maybe it is a poor regulator gound, it does have a lot of good fresh paint under her, so I will run an extra ground to est and also do a voltage drop test too.

[quagmire]

Definitely a good idea.  You should also measure voltage on the sense wire and compare it with the voltage at the battery when it is running.  If the sense wire voltage is lower then that is a problem and it will need to be corrected also.

[djwhog]

good point will do thanks for the tips!