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Battery Voltage Low

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Old 03-21-2018, 07:36 PM
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Battery Voltage Low

Hey guys, so my battery light has recently been on so I pulled out the trusty SCT X4 and I've been consistently reading between 11.0-11.5 V battery voltage on the scanner. I'm assuming the battery light comes on if voltages are less than 12 V for a prolonged period. My alternator is only a couple years old, at best.. and my batteries are a few months old at best... What do you guys think? The battery voltage doesn't drop the longer I drive, which makes me think it's not the alternator, unless the alternator just isn't putting out enough juice to push it over 12 V?
It should be noted that, these are the Walmart everstart maxx batteries, or whatever they are called, and when new, I never saw more than 13 V on the scanner. It would hover in the 12-13 V range, which i thought was pretty low for new batteries. My old ones would read over 14 V pretty consistent.
The batteries are still under warranty, but I have a feeling when Walmart tests them, they are going to test 'OK' .......
Thoughts?
 
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Old 03-21-2018, 07:44 PM
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Battery light on = bad alternator. They did a dis-service by using a battery indicator for the warning, it comes on because the alternator voltage output is below spec.

its also possible you have a bad wire on the control connector, or the connector is not fully installed.
 
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Old 03-21-2018, 07:46 PM
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Old 03-21-2018, 08:51 PM
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Time for the alternator pinpoint test
 
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Old 03-24-2018, 10:53 AM
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Originally Posted by TooManyToys.
Battery light on = bad alternator. They did a dis-service by using a battery indicator for the warning, it comes on because the alternator voltage output is below spec.

its also possible you have a bad wire on the control connector, or the connector is not fully installed.
Good to know! Put a new alternator on and back up in the 13 V range.
 
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Old 03-24-2018, 11:46 AM
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Glad to hear it’s resolved and thanks for putting the solution in a thread.
 
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Old 03-24-2018, 02:25 PM
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Just to clarify, it's not a "battery" light as you state. Your alternator has 3 terminals and one is wired to your dash when the alternator isn't meeting minimum voltage requirements. This light won't come on if the batteries are weak but the alternator is charging properly.
 
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Old 03-24-2018, 02:30 PM
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OP: Now you need to turn the "sights" of that good ol' SCT to your FICM voltages, I'm sure that guy was not happy during this alternator experience. If you are seeing Main voltage 45 or below, get it fixed soon or you will be replacing both that and injectors that will go out next. This is one of those cascading type problems that helped give the 6.0 a bad rep.

Scott
 
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