Start test with dead AUX battery!

SwissSteph

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Hello everyone,

Have you already read the following topic https://www.jlwranglerforums.com/forum/threads/auto-start-stop.77215/page-3 and the message. Thanks to its author!!!

Message #31 which explains simply and very clearly what to do to test the possible problem?

While reading this topic I was really anxious about having to go through a dealer again to request a repair. For the record, my last experience with FCA took 8 months to arrive (with a lawyer) at a conclusive repair under warranty!

Since the service bulletin doesn't mention our 2.2 Diesels, I went to do this test a few minutes ago and after a moment of great angst, the test passed. This means that if my AUX battery is dead, I can still start my Jeep.

I can only advise you to do this quick test and see if it's OK or not for you and take advantage of the warranty to have FCA make the necessary modifications.

Feel free to post your test results here! Thanks for your participation :like:
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Rubi D

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Hello everyone,

Have you already read the following topic https://www.jlwranglerforums.com/forum/threads/auto-start-stop.77215/page-3 and the message. Thanks to its author!!!

Message #31 which explains simply and very clearly what to do to test the possible problem?

While reading this topic I was really anxious about having to go through a dealer again to request a repair. For the record, my last experience with FCA took 8 months to arrive (with a lawyer) at a conclusive repair under warranty!

Since the service bulletin doesn't mention our 2.2 Diesels, I went to do this test a few minutes ago and after a moment of great angst, the test passed. This means that if my AUX battery is dead, I can still start my Jeep.

I can only advise you to do this quick test and see if it's OK or not for you and take advantage of the warranty to have FCA make the necessary modifications.

Feel free to post your test results here! Thanks for your participation :like:
Thanks Steph, will check it out.
 
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SwissSteph

SwissSteph

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yes, but mine from (late) 2018 can too, so either it was made right on the edge, or FCA applied a fix and either our Jeeps with the 2.2 Diesel engine never had this problem.

If we have several answers here we will be able to know the answer
 

EU_Wrangler

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That's good to know... thanks for the info! :like:
I have seen in the forum that the Aux battery has caused many electrical issues. Hopefully the 2.2D configuration is not that problematic....
 

Htfan

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So this means that models from 2019 can start without the AUX battery?
yes, but mine from (late) 2018 can too, so either it was made right on the edge, or FCA applied a fix and either our Jeeps with the 2.2 Diesel engine never had this problem.

If we have several answers here we will be able to know the answer
The 2018s can have a TSB applied to update the Aux battery logic so it can start without the Aux battery. However, the TSB 18-092-19 description says nothing about this updated functionality.

There are many existing threads on this subject with excellent information.

One for reference:

https://www.jlwranglerforums.com/fo...g-tsb-18-092-19-for-failed-ess-battery.60581/
 

Dan789

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So, have been trying to research how these batteries are configured. Lots of information that is very confusing.

Are the 2 batteries paralleled together?

Main reason for my interest in this is I am looking to take out the main battery to put in a 100ah Lithium. I would use this to power fridge and accessories with a load disconnect at 20ah, of which would still allow me to start the car.

Want I want to do is remove the second battery.

What will this affect?

Will I need to run a power cable down to where the second battery was to power up whatever items are being powered off this battery, or is this battery just for the ESS?

Setting up this way saves me a world of hurt trying to put a second battery in the rear. Also saves me trying to fill my battery through a 30 amp max charger. Can fill max from alternator.
 

Htfan

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So, have been trying to research how these batteries are configured. Lots of information that is very confusing.

Are the 2 batteries paralleled together?

Main reason for my interest in this is I am looking to take out the main battery to put in a 100ah Lithium. I would use this to power fridge and accessories with a load disconnect at 20ah, of which would still allow me to start the car.

Want I want to do is remove the second battery.

What will this affect?

Will I need to run a power cable down to where the second battery was to power up whatever items are being powered off this battery, or is this battery just for the ESS?

Setting up this way saves me a world of hurt trying to put a second battery in the rear. Also saves me trying to fill my battery through a 30 amp max charger. Can fill max from alternator.
Many of us have asked similar questions. Your question "are the 2 batteries in parallel?" Answer is yes with an exception. When ESS is engaged (engine off) the 2 batteries are separated.

Here's a great thread with good information (lots of reading):
NOTE: there are some additional links to other threads and information on a N1-N2 jumper that is utilized by some people.

https://www.jlwranglerforums.com/forum/threads/3-6l-ess-dual-battery-consolidated-information.25377/

This diagram is from this same thread:

underhood jumper 3a.PNG
 
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SwissSteph

SwissSteph

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I am preparing the "N1-N2" modification and I will put pictures here once finished :like:
 

Dan789

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Thanks Steph. I did read some articles that were posted on this.

Just trying to wholly wrap my head around this.

From what I have read, the second battery is there only for the ESS system. If this is the case, then linking it with the Lithium would not be an issue, considering that the Lithium can start the car with around 2% (2 amps) left in the battery, it would take the car sitting there for quite some time on ESS before it cannot be started.

In my case, sounds like an easier solution to just remove the main & second battery and just replace with the 1 battery and link together.

I don't have to worry then about tring to fit a battery in the rear of the car to run Aux items.
 
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SwissSteph

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According to my understanding (?) the AUX battery is for the "start/stop" but also to keep the radio or other accessories running when the engine is stopped (at a red traffic light for example).

Indeed, removing the AUX battery for good is, for me, the best solution, but for the moment I don't really want to have to completely disassemble the left fender to be able to remove the AUX battery, especially since I added fender flares so that my wheels don't stick out too much (it's the law here).

I think that my "DIY" way "N1-N2" will be clean and especially very easy to put in "action" or "back to original".

For the moment I have received all the material to do it, I have to make the connectors and then the assembly. As promised I will put the pictures here to help.
 
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SwissSteph

SwissSteph

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Here is the ordered material, I just have to crimp the connectors having found the right length of the two wires.

As I have to disconnect the negative cable of the AUX battery at the negative terminal of the main battery, I found on a broken ratchet wrench the sleeve that I will try to use to isolate very cleanly the connector of the disconnected negative cable. For the moment I don't know if it will work yet, I'll see later.

In my opinion, the advantage of using this type of fuse is to be able, without disassembling everything, to put back in a few seconds in an "original" state.

You just have to trigger the fuse (small red button) and reconnect the negative cable to the negative terminal of the main battery.

SBA_6532.jpg


SBA_6537.jpg
 

EU_Wrangler

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Very interesting thread.
Is there any reason to choose a 40A fuse specifically?

As I understand, the procedure to bypass the Aux battery without the jumper fuse should be to move the negative lead off the Aux battery up to the ground stud on the fender, and then the Aux battery positive lead up to positive post of main battery. Please correct me if I am wrong...
 
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SwissSteph

SwissSteph

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The goal is to bridge with a 40A "N1-N2" fuse and leave the AUX battery cable (negative) disconnected from the main battery negative.

The 40A is recommended because it seems, from several testers, that a 30A is too limited.

Once done, the battery will still be in the Jeep, but completely useless
 
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