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Truck is struggling after new battery replacement…

preston42

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Anyone experience this? So frustrated…
Story starts with my 2019 Ram Rebel not starting in the cold about 2 weeks ago. Took battery in it was low and got a new Duralast H7 battery. It started up, after a few hours all systems reset (yes I’ve read other battery threads here), and I thought I was good. 3 days later on a cold 30 degree morning (in TX that’s cold) the truck started but was throwing a CEL light and then started randomly flashing different things on the dash “trailer brake unavailable”, and others. I got it back home and the next day the red battery emblem was flashing on the dash along with the CEL light (P0456-evap system sensor stating slow leak) and while truck was running under load this time voltage was creeping up to 15-15.1V. This morning, another cool morning at 40 degrees and it won’t start up. I tested the battery with my multimeter and it’s at 12.5V but won’t start this AM. I tested the batter yesterday evening with multimeter under no load when it was 65-70 degrees and it tested at 14.3, and under load it was 14.6V. Something seems wrong with the charging system.

I’m no mechanic and at a loss…is there a parasitic draw draining the battery? Problems with starting seem exclusive to cold weather, why? Could it be a bad IBS sensor that’s on the battery connection, bad voltage regulator in alternator, bad alternator in general, etc.? Will a PCM / BCM flash help?

I have an appt with dealership next Wednesday but just seeing if anyone has ideas or experienced something similar. Thanks
 

LaxDfns15

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Bizarre, seemingly unrelated issues make me suspicious of a bad ground connection.
Agreed. I'd check your cables to your battery (tightness, nothing broken) as well as ground connections. Common problem is a ground connection being placed on a painted surface.
 

ekaz

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Could be the alternator going out and not providing enough juice to run everything
 

djevox

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If your multimeter measurements are correct with the static charge and charging voltage, I don’t see a problem with the battery or charging system. Even if there’s a parasitic drain that’s not normal, your battery has enough static voltage to power all required modules and start. I have to look at the Theory & Operation of the starting system, but if it were me, I’d start with looking at what the PCM and BCM think the voltage is and compare it to battery voltage.
 

c3k

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I'm no expert...but: these batteries are NOT directly connected to ground. They've got a battery sensor. It's actually got an internal disconnect, a chip, and two wires feeding into it. It's pretty much a simple computer-controlled relay. Input voltage via the small wires, and the working current is from the negative terminal of the battery, through the relay, to the grounding strap.

I'd suspect that component.

Do at your own risk: disconnect the ground strap from the sensor and just hook the grounding strap directly to the negative terminal and see if the truck will start.
 

preston42

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Thanks everyone for the input as again I'm no mechanic this was helpful info. Update: as it warmed up this morning into the 60's around 11am I got into the vehicle to try starting again and it fired up. Drove it 3 loops around the neighborhood and started receiving the random lights on the dash including the battery light again (while running it was at 14.6V per the dash), this time the backup camera wasn't working and missing features of the passenger heated seating. So many wonky issues. I have a Dealer appt next Wednesday but will check the ground connections in the meantime and if I can get my hands on a new IBS sensor might try swapping it beforehand to see if that helps.
 

kapinallinen2

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Thanks everyone for the input as again I'm no mechanic this was helpful info. Update: as it warmed up this morning into the 60's around 11am I got into the vehicle to try starting again and it fired up. Drove it 3 loops around the neighborhood and started receiving the random lights on the dash including the battery light again (while running it was at 14.6V per the dash), this time the backup camera wasn't working and missing features of the passenger heated seating. So many wonky issues. I have a Dealer appt next Wednesday but will check the ground connections in the meantime and if I can get my hands on a new IBS sensor might try swapping it beforehand to see if that helps.
IBS is a current sensor, current doughnut, that bolt going thru it is a direct connection from the battery negative post to the vehicle grounds.
Your voltage reading of 15+ volts while charging looks little high, 12.5v is plenty enough to turn the engine over unless it sags due to high internal resistance of the battery or a poor connection.
I agree with checking the battery connections for tightness.

edit: all the other random stuff should return to normal after the truck gets done re-booting, give it a half a day or so.
 
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Darksteel165

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I know this doesn't help much but I have heard of people of people replacing OEM with after market and having problems. Once they switched back to an OEM brand battery things worked fine.
I wonder if there's something special in an OEM battery that isn't on regular batteries?
 

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