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Unread 01-31-2010, 05:43 PM   #1
sparctacus
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Too much power

Recently, for reasons unknown to me my voltmeter started reading over 16v while driving. For the last week it ran fine with no ill effects. As of yesterday the battery started dying. I checked the water level and it was empty. The battery is new and so I thought that was weird but I topped it off anyway. I started it up and it ran just fine. For kicks I put a multimeter across the battery and was a little shocked to find 17.80 Volts!!!

After about a minute of idling the water started boiling out the top of the battery. Anyone else seen this? I'm a little surprised and wonder where all this extra power is coming from and how I make it stop.

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Unread 01-31-2010, 05:46 PM   #2
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Your voltage regulator is history. On MOST older Jeeps, including CJ's, it's a small electrical compent mounted on the firewall or the fenderwell. Later, they were incorporated into the alternator, but I don't know about 1986. Either way, I'd bet that's your problem...
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Unread 01-31-2010, 07:39 PM   #3
wrongway92407
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Check the Batt, also some times a dead cell can cause the alt to overcharge!
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Unread 02-01-2010, 12:40 PM   #4
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The voltage regulator is in the alternator on mine (Delco-style). Also the batt shows 13V with the engine off. So no dead cells there right?
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Unread 02-01-2010, 12:42 PM   #5
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It's also worth mentioning that when I turn everything on heater lights etc.. the voltage drops to 14V while idling in gear but while I accelerate the needle goes way up to 16.5. With everything on!!!

This has got to be a blown voltage regulator in the alternator correct?

(my wife's going to kill me if I guess wrong ... again )
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Unread 02-01-2010, 12:46 PM   #6
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You know that you can have these parts checked instead of guessing, right?

Most parts stores do it for free.
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Unread 02-01-2010, 12:51 PM   #7
halpeters
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Bad voltage regulator... As long as the alternator is the original style to your '86, it is an AC Delco, with an "internal regulator".

The alternator is working, so it is possible to get a regulator kit, and just change out that part of the alternator. It is located on the back side, where the plugs and wires attach.

The best thing is to take the alternator to an alternator / starter shop to have it rebuilt, this will include new bearings and brushes, or just buy a rebuilt alternator.

You may need at new battery at this point, if you ran it out of water....

This needs to be fixed, or it will damage other electrical stuff... radios, bulbs, etc...

Hal
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Unread 02-09-2010, 10:19 PM   #8
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yup, swapped out alternator (it was under warranty) and all is right with the world. Nothing else seems to be damaged at this point.
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Unread 02-10-2010, 08:19 AM   #9
wm69
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I was pleasantly surprised at how easy it was to swap out the regulator. Had one go bad not too long ago, part was about 10 bucks at Napa, and it was easy to take the alt in half, pop the new regulator in, and put it back together.....
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Unread 02-10-2010, 11:55 AM   #10
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Quote:
Originally Posted by sparctacus View Post
Recently, for reasons unknown to me my voltmeter started reading over 16v while driving. For the last week it ran fine with no ill effects. As of yesterday the battery started dying. I checked the water level and it was empty. The battery is new and so I thought that was weird but I topped it off anyway. I started it up and it ran just fine. For kicks I put a multimeter across the battery and was a little shocked to find 17.80 Volts!!!

After about a minute of idling the water started boiling out the top of the battery. Anyone else seen this? I'm a little surprised and wonder where all this extra power is coming from and how I make it stop.
Overcharge (anything above about 14.6 volts) and the battery will BOIL...

You have a Delco Remy 10 SI alternator with internal regulator.

You can take your Jeep to the discount places and they will run a test on your alternator, battery, ect,
But I would be afraid to drive it very far with 18 volts in the system!
When the battery boils enough, it will warp plates and ruin the battery, and the battery can explode!

I would be more comfortable with taking the alternator off and having it tested OFF the vehicle.

Discount stores do it for free, and you can get a replacement on the spot if you need one.
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Unread 02-19-2010, 01:08 PM   #11
sparctacus
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I ended up driving it very slowly and with all electrical components turned on, this kept my voltage down to just at 15v. Electrical test and warranty swap on the alt and everything is fine.
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