2015 Ltz battery died… got new Hd battery at NAPA cranked right up Drove for 15 minutes gauge needle over to about 12 and voltage atBatt 12.3

[Joeltz]

Battery died new Napa hd and cranked right up The Volt gauge went to normal straight up @ 14 After 90 seconds gauge needl slowly dropped to about 11….
Tried a couple times and same problem
90 seconds needle drops Voltage at battery at idle is 12.3….. anybody had same problem

 

[Doubeleive]

Battery died new Napa hd and cranked right up The Volt gauge went to normal straight up @ 14 After 90 seconds gauge needl slowly dropped to about 11….
Tried a couple times and same problem
90 seconds needle drops Voltage at battery at idle is 12.3….. anybody had same problem

get a meter and test voltage at battery while running and while key off.
voltage should be min 13.4v running.
or have the alternator tested, most auto parts places do it for free.

 

[Fless]

Moved you here.

 

[gooffeyguy]

Does your model year have EPM?

 

[Doubeleive]

Does your model year have EPM?

View attachment 403069

it will have rvc for sure, my 18 has it and I do not get voltage fluctuations that low especially with a new battery it should hang around 14v 98% of the time, 15v+ at startup for the first minute or so is automatic every time the key is cycled, regardless of battery state of charge.

 

[gooffeyguy]

it will have rvc for sure, my 18 has it and I do not get voltage fluctuations that low especially with a new battery it should hang around 14v 98% of the time, 15v+ at startup for the first minute or so is automatic every time the key is cycled, regardless of battery state of charge.

Yeah, mine only goes down to about 12.6 at the lowest.

 

[gooffeyguy]

You can always try to turn tow/haul mode on, or manually turn the headlights on. That is supposed to make the RVC not kick in as much

 

[swathdiver]

Battery died new Napa hd and cranked right up The Volt gauge went to normal straight up @ 14 After 90 seconds gauge needl slowly dropped to about 11….
Tried a couple times and same problem
90 seconds needle drops Voltage at battery at idle is 12.3….. anybody had same problem

The alternator kicked the output up high because the new battery needed a chargin'. When your engine is running you are seeing alternator output on the dash gauge. When the engine is off and the key is on, you are seeing the battery's state of charge.

Look up EPM and RVC to learn how your charging system works.

 

[Joeltz]

get a meter and test voltage at battery while running and while key off.
voltage should be min 13.4v running.
or have the alternator tested, most auto parts places do it for free.

Thanks double…. A guy has a NEW 84143540 170 amp that got dropped and the brown socket and tab got broken…. Can I put my old back plate on the new alternator that he wants $125 for ?

 

[Doubeleive]

Thanks double…. A guy has a NEW 84143540 170 amp that got dropped and the brown socket and tab got broken…. Can I put my old back plate on the new alternator that he wants $125 for ?

not sure never really opened one up before, I think that socket is soldered in though