Intermittent BATTERY light

[juan214]

Ok so a couple days ago my battery light started flickering then goes out.

Battery:
Battery was change this month well past due.
Battery well over 12V at stop

Alternator:
Alternator change a few months back, charging issues.
Charging at 14.22 at start drop then drops to just over 14.02

Starter (if it makes a difference)
All connections secure.

All points show charging at same levels.

Just ran an erand and the light stayed on. Now I could test the charging at the battery. looks like once it drops under 13.85 the light comes on. Ran it for ten minutes is 13.9v average lights is still lit.

Any ideas for more tests?

 

[juan214]

Ground Circuit Voltage Drop Test​

Start by checking the ground path for the charging circuit first.

1. Setup the multimeter on the DC Volts.
2. Connect your voltmeter black lead to the alternator housing.
3. Connect the red meter lead to the battery negative (-) post. READING 00.15
4. Every point shows 00.15v at ground cable end, ground on both side of solenoid, radiator support, hood, different point on intake.

Going to reinstall the old alternator.

 

[juan214]

Reinstalled the old alternator its charging at 14.42 steady and 00.05 at all ground points.

Any ideas on this.

I'm guessing the one I just pulled needs a Voltage Regulator.

 

[juan214]

Let the truck relearn Idle, and shift points. Took it out for a long test drive, opened it up on the highway. No battery light flickering or otherwise. Coincidence, after reinstalling the old Motorcraft alternator plus all the work done in the last five months truck got its fuel economy back plus 2.7 mpg on the highway.

Let's see what the next couple of days bring.

 

[juan214]

Decided to take the Bosch alternator to O'riely's . It passed there test they came out to test the battery on the truck and said it was battery "BAD BATTERY". Battery was just purchases and the date sticker says 9/21. He said Oh its a Walmart battery that's why. Shot down the street to Advance and they said there tester was broken.

Its a Wallymart battery 65-850CCA, I got out my tester and it says 100% charge, 13+/- volts, and 820CCA back it goes.

 

[Trainmaster]

New stuff is always suspect. Unfortunately so are the parts-store "free tests". Sounds like your problem's solved.

 

[juan214]

New stuff is always suspect. Unfortunately so are the parts-store "free tests". Sounds like your problem's solved.

I told the guy before the test I always go to AutoZone and Advance after to get second and third opinions against each of their readings. He did show me that their tester stated "BAD BATTERY". It's always fifty fifty that's why I kept my old Motorcraft Alternator. Check the battery with my tester, it read 100% charged 12.53 Volts and 1123 CCA. My POS (CEN-TECH) tester says the battery is fine. Going back there today and see if I get a different reading.

 

[juan214]

New stuff is always suspect. Unfortunately so are the parts-store "free tests". Sounds like your problem's solved.

Did my morning drive today the battery came on again. Got home light was out. Battery tested 100% charged, 12.41 volts, and 1200+ CCA.

Note: Come to find out when the battery was being tested on the terminals the paint used on them gives false readings showing the CCA are a lot lower, and BAD BATTERY.

Any thoughts, any tests I can do?

 

[juan214]

Motorcraft alternator is charging at 14.35 at Idle and 13.93 at 2500 RPMs.

Voltage Drop Test done again and they are at most 00.050 at ground points, some go as low as 0.0001 and 0.000.

Motorcraft Alternator AC voltage Test
2500 RPMs 0.203 - 0.220 volts

Motorcraft Alternator Diode Pack Test
Positive Post to case reaches 0.844
Case to Positive Post reaches 0.375

Not installed:
Bosch Alternator Diode Pack Test
Positive Post to case reaches 0.806
Case to Positive Post reads OL

 

[heston gee]

Decided to take the Bosch alternator to O'riely's . It passed there test they came out to test the battery on the truck and said it was battery "BAD BATTERY". Battery was just purchases and the date sticker says 9/21. He said Oh its a Walmart battery that's why. Shot down the street to Advance and they said there tester was broken.

Its a Wallymart battery 65-850CCA, I got out my tester and it says 100% charge, 13+/- volts, and 820CCA back it goes.

There are only a handful of battery manufacturers for the big box stores.

Decided to take the Bosch alternator to O'riely's . It passed there test they came out to test the battery on the truck and said it was battery "BAD BATTERY". Battery was just purchases and the date sticker says 9/21. He said Oh its a Walmart battery that's why. Shot down the street to Advance and they said there tester was broken.

Its a Wallymart battery 65-850CCA, I got out my tester and it says 100% charge, 13+/- volts, and 820CCA back it goes.

There are onlyba handful of battery manufacturers for the big box stores. Exide it the largest. The battery at Walmart, Sam's, O'Reilly's, Napa, etc are manufactured by exide. If I'm not mistaken, so are Motorcraft. So whoever said that about batteries doesn't know their squat.