Battery Voltage Low

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craigweiler

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So a few months ago the battery in my 2016 Ram 1500 5.7 finally died and I replaced it with a new Napa Premium. Everything has been fine until a few weeks ago. In the mornings on start up I was getting Low Battery Voltage and the battery symbol would lite up. If I turned the truck off and restarted, it would go away and I'd be on my way. The other day it happened and it stayed on. I used AlfaOBD to clear the code & started reading threads on here about similar issues. I have tested the battery with the HFT load tester and all is good (1000cca). With a multi meter the battery is 12.6 not running & 11.8 - 12.3 for a few minutes and then it jumps to 14.8 and stays there. Start up the next day and it's the same thing over again. I'm at my witts end trying to figure this out. HELP
 

BossHogg

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The 11.8 to 12.3 and then jumps back up. Is that running? If so sounds like a bad alternator. But also check all main power and ground wires plus be sure connections are tight and corrosion free.
Yes that's running. All grounds are good and connections cleaned & tightened. The same goes for the main power leads and fuses on the positive terminal.
Are there any high-current electrical loads running, like heated seats, lighting, etc., when you see the voltage drop? Try the same test but with the engine at 1,200 (alternator at full output) or slightly higher RPM.

Try running several electrical loads with the engine at 1,200 RPMs and measure the battery posts and the battery terminal connectors. The negative battery post should have a module on it, measure voltage on both sides. You should see a steady voltage in the upper 13-volt range. This will test if any connections/grounds are weak.

The last thing I can think of is isolating the battery from the vehicle and running a "toaster" load test on the battery, look for consistent voltage output. Unexplained voltage drops can signal a bad-acting cell in the battery.
 

Dean2

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First, Gently seat all fuses and relays in the TIPM. Often some will be loose. Then, if the alternator is good it is possible your IBS sensor has issues. There are a ton of threads on here about the IBS, how to test it and how it works.
 

turkeybird56

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Check that Star case report. Doesn’t it say how to check IBS? Not by pc so not available on phone.

TBH sounds like alternator/IBS issues or combo there of.
 
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craigweiler

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Thanks @Dean2 for that information. I know now that my issue does not lie with the IBS. The presence of the "Red Battery" symbol accompanied by "Battery Voltage Low" message rules out a "Bad" IBS. There was alot of good info provided in there & I definitely need to perform the IBS SOC Adaptation procedure. I will post results.
 
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craigweiler

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Update: So I had time yesterday to pull the battery & make sure it was fully charged up. While the battery was charging I changed out the old alternator for a new one & then performed the procedure in the Mopar Bulletin @Dean2 posted after putting everything back together. I left the negative leads coming off the IBS disconnected for 4 hrs. Everything seemed to work properly afterward & was also good to go this morning when I went out and started it. Thers no more 11.8 to 12.3 volts for a few minutes after startup before it goes up. It's right at 14.67 & no "Red Battery" symbol or low battery voltage message. I'll update again in a few days on it's status. Thanks everyone for your knowledge and input here on Ramforum, couldn't have done it without you all.
 

turkeybird56

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Update: So I had time yesterday to pull the battery & make sure it was fully charged up. While the battery was charging I changed out the old alternator for a new one & then performed the procedure in the Mopar Bulletin @Dean2 posted after putting everything back together. I left the negative leads coming off the IBS disconnected for 4 hrs. Everything seemed to work properly afterward & was also good to go this morning when I went out and started it. Thers no more 11.8 to 12.3 volts for a few minutes after startup before it goes up. It's right at 14.67 & no "Red Battery" symbol or low battery voltage message. I'll update again in a few days on it's status. Thanks everyone for your knowledge and input here on Ramforum, couldn't have done it without you all.
YUP, on the Hemi's, around 14.5,6,7,8 at startup, especially if truck has sat for a few days normal. Takes a bit of time and not stop and go driving to get it to where the demand is like 14.2V. I am always around 14.5/6 after driving due to the fact no long runs.

Sounds like you were successful in yer issues troubleshooting and results, good continued success.
 

Tominator223

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So I have 04 5.7. I had the discharge light come on at random times. From the time it was new. Never had any battery go bad , still has og alt. At 400+ thousand miles . It was usually after left/right turns was strange. So jump forward 10+yrs. My throttle body had some issues had like 280thousand miles. So I change the TB . And haven’t had that discharge light come on since. Had a 03 2500 5.7 that did this to me once @ 40k miles & I traded it in as the stealer ship couldn’t get it to do it or find any codes. Just putting this out there . You know if one is looking for Gremlins
 

Dean2

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Glad you got it fixed but also, thank you for being different than so many who come and post a problem. Coming back and posting the solution along with a thank you is great and unfortunately, pretty rare. All the best.
 

turkeybird56

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Glad you got it fixed but also, thank you for being different than so many who come and post a problem. Coming back and posting the solution along with a thank you is great and unfortunately, pretty rare. All the best.
Dean2 you said a mouthful.
 

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