Battery/alternator issue?

[stenerson]

Getting the red battery/alternator low voltage light. It's nighttime. Checked battery while engine running and it's holding at about 14.46ish.. Dark out, I'll mess with testing the alternator in the morning. The harness not easily accessible on this 3.6 engine. Any likely suspect? Here's a video as I drive. I notice that bar meter thingy is jumpy. But drove for a while it stayed at 14v. The battery is a year old Everstart H8 AGM. I upgraded to the large size.
video of light while driving

 

[stenerson]

Good afternoon gents. Update if anyone has any hints where to look next? Alternator testing with my meter at 14.92v....Battery while running under load (high beams on, blower full blast, radio) 14.74ish. ..Turned off vehicle. 20 mins later battery is holding at 12.79v.....I'll probably have to take it in, not very good at electrical. But if I'm missing something dumb I appreciate the tips. As I said above, the dash meter stays on 14v when driving. All terminals clean and treated with the anti-corrosion lube, thin layer.

 

[Slinge]

My battery light would come on at 1st start of the day.
When I checked alternator it was charging.
Then I checked Alt at the 1st start of the day
It didnt start charging right away
it took a couple seconds ; I figured the Alt was working intermittently .
Changed Alt .... hasn't turned on again .

 

[crash68]

I'd look for bad grounds and typically you test the battery static voltage after sitting overnight. Ideally have the battery load tested. Another test is to use a volt meter on the battery terminals while starting the vehicle and check the voltage drop, if it drops into the 10V range it's probably bad.

 

[stenerson]

I'd look for bad grounds and typically you test the battery static voltage after sitting overnight. Ideally have the battery load tested. Another test is to use a volt meter on the battery terminals while starting the vehicle and check the voltage drop, if it drops into the 10V range it's probably bad.

Thanks. Will do.

 

[stenerson]

My battery light would come on at 1st start of the day.
When I checked alternator it was charging.
Then I checked Alt at the 1st start of the day
It didnt start charging right away
it took a couple seconds ; I figured the Alt was working intermittently .
Changed Alt .... hasn't turned on again .

The light's been on since yesterday, but now it's gone. Oh well, hopefully it was a fluke. I'll try the static voltage test after sitting overnight as crash68 suggested. Thanks.

 

[Slinge]

Mine would come on , I could drive around the block , turn off truck.
Start truck ....no Batt light.

 

[stenerson]

It was on all day yesterday during several short trips, about 90 mins driving total. But went off yesterday evening and during today's driving. Might be a sign that the alternator is on it's way out. But hopefully a fluke.

 

[04fxdwgi]

Check for loose ground cables, clean your battery terminals (including the bolts on the terminal fuses and such. ANY connection). If those are good, get a $20 toaster style battery tester.

From what you are describing there is a bad connection somewhere or the battery is about to go out to lunch.

Stuff like that are usually warning signs, not a fluke. It won't fix itself, especially these rolling computers.

 

[62Blazer]

If you show 14.92V from the alternator that means it is charging. The battery should basically show the same voltage when the engine is running....the 14.7 at the battery is basically the same reading. The 0.2 volts difference does not indicate any issue...just that you read it a slightly different location at a different time.
For checking the charge of the battery, doing is 20 minutes after turning off the engine doesn't really show you anything. I would check the voltage after sitting overnight, and also do an actual load test on the battery.
In regards to the warning light, there should be a specific code stored in the ECM. There are multiple different reasons/codes that can trigger that light.

 

[stenerson]

Check for loose ground cables, clean your battery terminals (including the bolts on the terminal fuses and such. ANY connection). If those are good, get a $20 toaster style battery tester.

From what you are describing there is a bad connection somewhere or the battery is about to go out to lunch.

Stuff like that are usually warning signs, not a fluke. It won't fix itself, especially these rolling computers.

Good tips, will check for ECM codes.