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Jumperless aux battery/PCR bypass

IanNubbit

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There seems to be a lot of concern about the batteries and very little concern about exposing the "computer" to electrical fluctuations that might occur during a stop start using just one battery. Common sense would seem to indicate that if the manufactures thought running stop start on just one battery was OK, they would only provide one battery. While I mostly understand how starting solenoids on older cars and truck isolated some electrical equipment during starts, I am not sure how the system in JL Jeeps operates.
I may be speaking for myself, but I waited till I had a Tazer to make sure Start/Stop never comes on before I removed the second battery. I purposely didn't do this until then. But to that point, the KL (Cherokee runs a single battery system with Start/Stop, the difference is the type of battery. The JL/JT uses a AGM battery designed for running electronics, and a Lead Acid for starting almost eclusivly. Cars have normally used Starting style batteries for almost forever as they are great for holding voltage during a quick heavy load, they are not good at holding a small load though. Alot of my terminology is not perfect there, but I think the point gets across.
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sharpsicle

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What is your source that the 2 battery system was developed to protect against possible voltage fluctuations as opposed to just conserving main battery power for the restart?
I said it was for both. Beyond that we're talking about the fundamental rules of electricity.
 
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JTR178

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Finally did this today when I replaced my main battery. Took her for a test spin around the neighborhood and no issues/lights/warnings. Now the Aux battery can sit down there alone like the red headed stepchild it is.
 
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jebiruph

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I said it was for both. Beyond that we're talking about the fundamental rules of electricity.
What are the symptons of the voltage fluctuation that affects the computers that isn't just the battery failure that I am talking about? Like I said, I've never seen a report of a voltage fluctuation causing a restart issue, other than the battery not being able to provide enough power for the restart.
 

sharpsicle

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What are the symptons of the voltage fluctuation that affects the computers that isn't just the battery failure that I am talking about? Like I said, I've never seen a report of a voltage fluctuation causing a restart issue, other than the battery not being able to provide enough power for the restart.
Are you curious about what tends to kill the AUX battery? Or what an over- or under-volt condition could potentially do to a computer? Because those are two very different conversations.

We're mixing application with anecdotal evidence at this point, so I'm hesitant to answer.
 

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brianinca

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I just replaced a 2nd AUX14 battery after nine months. The electronics wigged out on me refueling in Santa Clarita on my way back from San Diego. ASS dead on the dash, dinged every startup.

Took me a week to order from O'Reilly's, swapped it out through the top in half the time it took me in April. Exchanged and got a refund from O'Reilly's, they didn't blink.

ASS problem disappeared. It is NOT a main battery problem, though this issue is what I presume killed my factory battery in October-22. Hopefully having changed it out faster will keep me from cashing in on the 36 month replacement warranty.

Looking at the Speedflate bypass, seems a tidy solution.

Declaring this not a problem, and a problem only if the main battery is the underlying issue, flies in the face of my personal experience.
 

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ecidiego

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You prefer going through the top? The bottom is so much easier. 3 bolts, 4 christmas trees, 3 rivets.
 

ShadowsPapa

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The JL/JT uses a AGM battery designed for running electronics, and a Lead Acid for starting almost eclusivly.
They are both AGM batteries. The smaller battery is no different in any way other than in size/capacity. It's not designed for anything, really. It's chemistry is identical internally.
The main battery is AGM and runs the fans, EHPS and other functions.
Tied together, they run both as a team.
During an ESS event, both actually drop in voltage. FCA has split the load so the voltage drops about the same on both - the larger battery is taking higher draw loads while the smaller one operates things like HVAC, heated wheel and seats, cluster, radio.
I have not yet determined which operates lights at an ESS stop.

Other than size, the batteries are identical.

ASS problem disappeared. It is NOT a main battery problem, though this issue is what I presume killed my factory battery in October-22. Hopefully having changed it out faster will keep me from cashing in on the 36 month replacement warranty.

Looking at the Speedflate bypass, seems a tidy solution.

Declaring this not a problem, and a problem only if the main battery is the underlying issue, flies in the face of my personal experience.
And yet others here have seen it as a MAIN batter issue and have proven it with their experience. It's split with the majority now appearing to be main battery issues.
And since they are in parallel - if both are toast - you have a chicken/egg thing and can't prove it either way.

Did you have to jumper N1 to N2 or N3 when you did this, or was removing the fuse enough?
If all is good, just pull the bloody fuse. So simple. It's easier than making and putting in a jumper.
You only need the jumper IF you pull the aux battery and remove the PCR, etc.
Otherwise N1 is powered by the main battery just like always, no different.
The PCR is a normally close device meaning the main battery supplies power to the N1 at all times except if there is an ESS stop event.
If you disable ESS via Tazer, then the main battery already powers the N1 post. You don't need any jumpers at all anywhere.

Jumper ONLY needed if you pull the aux battery AND pull the PCR and related wiring.
 

Lunentucker

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They are both AGM batteries. The smaller battery is no different in any way other than in size/capacity. It's not designed for anything, really. It's chemistry is identical internally.
The main battery is AGM and runs the fans, EHPS and other functions.
Tied together, they run both as a team.
During an ESS event, both actually drop in voltage. FCA has split the load so the voltage drops about the same on both - the larger battery is taking higher draw loads while the smaller one operates things like HVAC, heated wheel and seats, cluster, radio.
I have not yet determined which operates lights at an ESS stop.

Other than size, the batteries are identical.



And yet others here have seen it as a MAIN batter issue and have proven it with their experience. It's split with the majority now appearing to be main battery issues.
And since they are in parallel - if both are toast - you have a chicken/egg thing and can't prove it either way.



If all is good, just pull the bloody fuse. So simple. It's easier than making and putting in a jumper.
You only need the jumper IF you pull the aux battery and remove the PCR, etc.
Otherwise N1 is powered by the main battery just like always, no different.
The PCR is a normally close device meaning the main battery supplies power to the N1 at all times except if there is an ESS stop event.
If you disable ESS via Tazer, then the main battery already powers the N1 post. You don't need any jumpers at all anywhere.

Jumper ONLY needed if you pull the aux battery AND pull the PCR and related wiring.
I don't want to be hauling a dead useless freeloading AUX battery around. 😂

Jeep Gladiator Jumperless aux battery/PCR bypass spbattery
 

ShadowsPapa

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I do find it interesting that there's bypassing being done - but leaving the thing in there.
On the other hand, killing ESS and removing that fuse you then have the batteries sitting there and if you don't remove the aux ground, they remain connected together in parallel so you have extra capacity that way, but why?
 

Lunentucker

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I do find it interesting that there's bypassing being done - but leaving the thing in there.
On the other hand, killing ESS and removing that fuse you then have the batteries sitting there and if you don't remove the aux ground, they remain connected together in parallel so you have extra capacity that way, but why?
Yeah, when I do it it's all coming out.
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