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voltage drops

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=135166
Printed Date: May 15, 2025 at 8:50 AM


Topic: voltage drops

Posted By: widerides
Subject: voltage drops
Date Posted: October 28, 2013 at 8:56 PM

Hello,

I have a Jeep Wagoneer with a stock 63 amp alternator.
I have a 4 gauge wire going from my battery to my amps.
I use to run a smaller system with the same wiring.

Now I run a larger system with the same wiring as before.
The "new to me system" is one that came out of my friend's car.
He used the same amp wiring kit I have in my Jeep without issue for years.

Now the for the problem.
With the stereo on or off, my voltage will be at 14v for 5 seconds and then drop down to 12v for 2 seconds. Then back up to 14v and repeat.

When I disconnect the amps from my battery the problem goes away.

Do I need an alternator that puts out more amps?
Maybe a short?
What do you all think?

Thanks,
Forrest



Replies:

Posted By: KPierson
Date Posted: October 28, 2013 at 9:26 PM
63A? How much current does your "new to you" amp draw?

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Kevin Pierson




Posted By: i am an idiot
Date Posted: October 28, 2013 at 9:34 PM
Does the amp play?




Posted By: powerslave
Date Posted: October 29, 2013 at 10:12 PM
A 63 amp alternator won't cut it with any amp that has a 30AMP or more fuse in it. 20Amps is even pushing it for that low output alternator. I would upgrade that alternator if you plan on anything at 1000 watts.

Also? I see a lot of people wanting help, but never post the type of equipment they're using; no brands or model numbers. It's almost impossible to make any kind of assessment without that information. Everyone has to guess, and that's no help.




Posted By: oldspark
Date Posted: October 29, 2013 at 11:07 PM
That the "voltage will be at 14v for 5 seconds and then drop down to 12v for 2 seconds. Then back up to 14v and repeat" suggests bad charging, though I'd expect only old external electro-mag regulators to bounce like that.
But internal electronic regulated alternators can still have intermittents or worn brushes.

Just in case it is faulty or you are thinking of a larger alternator anyway...





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