Alternator Output
Thread Starter
Just Gettin By
Joined: Sep 2011
Posts: 90
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From: Mechanicsburg PA
Alternator Output
Truck runs fine. No charging issues. Belts tight. Guages and lights all work fine. But directional lights start to slow and guage lights start to dim when MANY accessories are used. I never had this before. Alternator looks originial.
1. Is Auto Zone/Advanced reliable in their charging system test?
2. To test charging systems, we used to start the vehicle and then disconnect the positive battery cable. Turn accessories on to see if the alternator can handle each accessory. Can I do this on my 1993? Someone told me don't do that.
1. Is Auto Zone/Advanced reliable in their charging system test?
2. To test charging systems, we used to start the vehicle and then disconnect the positive battery cable. Turn accessories on to see if the alternator can handle each accessory. Can I do this on my 1993? Someone told me don't do that.
Senior Member
Joined: Jul 2008
Posts: 58,557
Likes: 1,165
From: Long Beach Calimexifornia
Truck runs fine. No charging issues. Belts tight. Guages and lights all work fine. But directional lights start to slow and guage lights start to dim when MANY accessories are used. I never had this before. Alternator looks originial.
1. Is Auto Zone/Advanced reliable in their charging system test?
2. To test charging systems, we used to start the vehicle and then disconnect the positive battery cable. Turn accessories on to see if the alternator can handle each accessory. Can I do this on my 1993? Someone told me don't do that.
1. Is Auto Zone/Advanced reliable in their charging system test?
2. To test charging systems, we used to start the vehicle and then disconnect the positive battery cable. Turn accessories on to see if the alternator can handle each accessory. Can I do this on my 1993? Someone told me don't do that.
Last edited by ymeski56; Mar 21, 2012 at 03:20 PM.
It's a Canadian thing eh!
Joined: Nov 2010
Posts: 6,539
Likes: 196
From: Ontario, living across a hay field
But just because your alternator can put out 12v - 14v does not mean that the amperage is flowing 100%. Best way to test that is with a carbon pile tester, most shops do that for free and it will tell you if the alternator can run at its maximum capacity or you might have bad diodes.
For example my alternator is putting out 14.6V, but it just hit about 40-50 amps for a 130 amp alternator, so I'm only putting out about 1/3 of my total capacity. Not enough to be a problem but the the more accessories you turn on the more it will drain the battery.
For example my alternator is putting out 14.6V, but it just hit about 40-50 amps for a 130 amp alternator, so I'm only putting out about 1/3 of my total capacity. Not enough to be a problem but the the more accessories you turn on the more it will drain the battery.
Last edited by sylver91; Mar 21, 2012 at 02:56 PM.
Senior Member
Joined: Feb 2011
Posts: 1,437
Likes: 18
From: Nesbit, MS
Originally Posted by ramblinwilly
Truck runs fine. No charging issues. Belts tight. Guages and lights all work fine. But directional lights start to slow and guage lights start to dim when MANY accessories are used. I never had this before. Alternator looks originial.
1. Is Auto Zone/Advanced reliable in their charging system test?
2. To test charging systems, we used to start the vehicle and then disconnect the positive battery cable. Turn accessories on to see if the alternator can handle each accessory. Can I do this on my 1993? Someone told me don't do that.
1. Is Auto Zone/Advanced reliable in their charging system test?
2. To test charging systems, we used to start the vehicle and then disconnect the positive battery cable. Turn accessories on to see if the alternator can handle each accessory. Can I do this on my 1993? Someone told me don't do that.
5 Year Member
Joined: Oct 2010
Posts: 2,646
Likes: 258
From: Charlotte, NC
My thoughts.................
1. The factory alternators are inadequate at best, hence the reason why some of us do the 3G upgrade.
2. The factory battery cables aren't all that great either and could always use an upgrade/replacement if you haven't already done so. Upgrading the ground cables could also be something worth exploring as well.
3. Your battery may be slowly beginning to be on the way out.
4. Your battery terminal connection may not be what it should be.
1. The factory alternators are inadequate at best, hence the reason why some of us do the 3G upgrade.
2. The factory battery cables aren't all that great either and could always use an upgrade/replacement if you haven't already done so. Upgrading the ground cables could also be something worth exploring as well.
3. Your battery may be slowly beginning to be on the way out.
4. Your battery terminal connection may not be what it should be.