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Discussion Starter #1
I know, I have already search for the subject at the forums, but no answer to my question.
Volt gauge says 12.8v and it stayed there for the whole night, message at the cluster says Battery not Charging, what is it? Alternator?
Just replaced the Batteries not that long ago and put 2 Optima Yellow Tops, so, I don't think is the batts. Voltage started at 14.5V when I left work and by the time I got home ( 1.5hrs. later ) it was 12.8 V and stayed there.
Could it be the alternator?

Just want to know before I spend the 200.00 bucks!:spider
 

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Discussion Starter #2
Engine Control Module

Someone told me, that it could be the Engine Control Module, what is it?
 

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Gunney, you MAY have toasted your alternator with those Optima’s.

You are going to hear a lot of battery marketing BS and that Optima’s walk on water and talk directly to god. It ain’t so. I have been there and have the tee-shit and, for what it’s worth I’m an electrical engineer.

An Optima (or any Acid Glass Mat) battery is not a good choice for a daily driver and a yellow top is the wrong Optima – they are made to be a deep cycle battery that is for trailers and trolling motors. They are not designed to be a starting battery, DESPITE what their advertising says.

Unlike a conventional chemistry battery, any AGM batteries will draw every bit of amperage your alternator will put out and either shorten its life or burn it out. People will argue about this until they are blue in the face but that is how AGM chemistry and physics work. Ask yourself why an external battery charger has a different charge voltage and current regulation profile for AGM vs. Conventional battery charging. Your truck’s electrical system is designed work with conventional batteries.

If you are lucky you only have a cell that is open. When an AGM cell shorts internally, they burn or explode because in a dual battery rig the other battery can discharge through the bad battery and they will go from ambient to arc welder in just a few seconds.

First, have your alternator tested by an auto electric shop or a good mechanic, not Autozone, and then loose the Optima’s ASAP. One of the best batteries available for these trucks, and also with the best warranty is the AC Delco rated at 760cca. Heavy-Duty Battery | Off-Road Vehicles, Trucks, Industrial | ACDelco

You Optima guys can save a postage stamp on the hate mail. I have heard it all. :rolleyes:
 

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Just make sure you have lots of draw!!! And you will be fine.
 

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Discussion Starter #5
The reason I got this batts is cause I am running 4 Alpine amps and they strongly suggested the Optimas...
Lets see what the mechanic suggests, going there in the morning...
Thanks for the advice.
 

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mine did that and it was the alt!!! it jst went out just like your i took it off and got a local guy to rebuild it for 85 bucks!!! he said it hadn't ever been touched before and had 203000 miles
 

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Discussion Starter #7
mine did that and it was the alt!!! it jst went out just like your i took it off and got a local guy to rebuild it for 85 bucks!!! he said it hadn't ever been touched before and had 203000 miles
For sure... you got your moneys worth out of that one.... I am aproaching 160k.... I think it could be it ...!
 

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check and see if there are any codes in it. if it says battery not charging, more than likely there is a dtc stored somewhere. like stated before, have the alternator checked and see if it is charging. check voltages at the batteries with the truck running. checked the alternator wiring too. maybe a wire got pinched or is loose somewhere.
 

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mine didn't throw a code... thats what i thought to. but most places will rebuild it in about a day for about 100 bucks and i got ine off in like 8 minutes!!!
 

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Mines doing the same thing but after a lil while if driving it will charge up to 14 volts and the light would go off. I'm thinking a bad battery ?
 

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Thanks. Going to the mechanic and getting it checked out.
 

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Got two new batteries and she starts now but still says battery not charging. Got the alternator checked and it passed all tests. Any ideas guys ? It will sometimes charge and sometimes it won't. I don't wanna spend money on a new alternator if that's not the case.
 

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can you test the alt, when it says not charging?

Carry a volt meter, when you get the condition, check the voltage at alt. If its below 13-14 volts, your alt is not working correctly.
 

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from what i am seeing here it sounds like the regulator in the alternator. when the voltage shows low, it means the regulator is not working to keep the voltage up. when they fail, the voltage will drop. and can not charge properly. take the alternator into a place like auto zone or advanced auto and let them put it on their tester to bench test the alternator.
 

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I've had it out and bench tested yesterday. It passed twice at two different shops. Someone was telling me I could have a grounding issue on my main battery ?
 

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the other thing to check is for corrosion in the terminals also. the slightest corrosion can cause a problem. also check where both batteries connect under the red box on the engine.
 

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Since it's intermittant, I would check all of your main grounds.

Have you made any modifications to the vehicle lately?

Have you checked for codes stored in the ECM?
 

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I have some corrosion in the redbox where my alternator ties into the batteries. I'm going to clean that and check all my grounds. And no I'll hook up my scanner Now
 
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