Can 14-volt alternator be bad?

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Richard Galli - 12 Sep 2008 22:10 GMT

My 1998 Maxima has been draining the battery lately. While I drive the
car, mostly on the highway, a good battery showing 12 volts will be
drained until the car shuts off.

Not a parasitic current problem. Checked and the system draws only 3ma
(milliamps) when shut off.

Not a battery problem: Happened with my "old battery" as well as with a
brand new Optima that started at 12.6 volts and was drained down to less
than 9 volts while I was driving.

Checking voltage across the battery terminals, the alternator seems to
be pumping 14 volts into the batter with the engine running.

Is it possible that the alternator is bad -- despite the initial voltage
reporting 14 volts? Is it possible that the alternator is pruducing
insufficient current at 14 volts?

Advice would be appreciated.

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AS - 13 Sep 2008 20:02 GMT

What is the voltage across the battery terminals with the engine running
while the headlights, a/c full blast? You may need to have the engine
at 1500 or so RPMs.

I have found that sometimes, removing and reinserting the main fuses
and the alt-s fuse in their respective sockets as to clean the contacts
works wonders.

Do make sure that the alternator belt has the proper tension too.

Let us know what fixed the problem.

Good luck!

AS

> My 1998 Maxima has been draining the battery lately. While I drive the
> car, mostly on the highway, a good battery showing 12 volts will be
[quoted text clipped - 15 lines]
>
> Advice would be appreciated.

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Devils Advocate - 15 Sep 2008 04:16 GMT

I had the same generation maxima testing good, but had it rebuilt has a last
alternative and it resolved my problem.

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Al Moodie - 15 Sep 2008 14:37 GMT

>My 1998 Maxima has been draining the battery lately. While I drive the
>car, mostly on the highway, a good battery showing 12 volts will be
[quoted text clipped - 15 lines]
>
>Advice would be appreciated.

At 10 years it's probably an alternator problem. The diodes in the
alternator begin to leak. Diodes are only meant to pass current in one
direction, but over time they begin to leak, when you turn off the
motor (and hence the alternator) current drains from the battery back
through the alternator.

To check: With motor off, put an ammeter in the circuit between the
battery and alternator.

You can replace the alternaor or replace the diode pack in the
alternator. Try a Google search for replace alternator diodes.

Al Moodie.

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e.meyer - 15 Sep 2008 16:14 GMT

> On Fri, 12 Sep 2008 17:10:35 -0400, Richard Galli
>
[quoted text clipped - 32 lines]
>
> Al Moodie.

There was a recall on 98 Maxima alternators. If yours was never
replaced, check with the Nissan dealer, you might still get a freebee.

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codifus - 16 Sep 2008 15:44 GMT

> > On Fri, 12 Sep 2008 17:10:35 -0400, Richard Galli
>
[quoted text clipped - 35 lines]
> There was a recall on 98 Maxima alternators. If yours was never
> replaced, check with the Nissan dealer, you might still get a freebee.

Yup, check with Nissan corporate. E-mail them here;

http://www.nissanusa.com/apps/contactus

The 98 Maxima definitely had an ALT recall.

About 2 months ago I e-mailed NissCorp about my 98 Sentra losing it
wipers. The motor disconnected from the wiper arms. 10 year old car
and Nissan fixed it for free.

Oh, and be very wary of the dealer. My dealer was quite ready to
charge me for the job but once I mentioned my VIN # and an e-mail I
got from Nissan corporate, the dealer was like" Ah yes, there IS a
recall on the wipers for your car.

Yeah, like I didn't ask them about that several times.

CD

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