Start test with dead AUX battery!

[SwissSteph]

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

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[Rubi D]

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

Thanks Steph, will check it out.

 

[EU_Wrangler]

So this means that models from 2019 can start without the AUX battery?

 

[SwissSteph]

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]

That's good to know... thanks for the info!
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]

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]

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]

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:

 

[SwissSteph]

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

 

[Dan789]

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.

 

[SwissSteph]

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.

 

[SwissSteph]

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.

 

[EU_Wrangler]

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...

 

[SwissSteph]

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

 

[Dan789]

So stuffed around with this yesterday. The solution in the end is quite simple and involved no wiring.

Firstly, the 2 batteries supplied by Jeep are disgustingly heavy. What are they thinking in this day and age. Car manufacturers should be installing Lithiums into these cars from day dot.

Steph, I noticed above that you said you have to remove the fender to get to the second battery. Not sure why this is the case on your Jeep, but if you remove the main battery, the second one comes out quite easily after that.

To the solution.

My main goal in this is to keep everything as standard as possible.

In total, Jeep have supplied 100 amp hours of AGM batteries, in which you can only use roughly 40% of before the voltage starts to drop off quite significantly. In my eyes, for the weight of this battery setup, this is a useless combination.

A battery that I have removed from my dual battery setup in my Patrol is a 100 amp hour Lithium that can be used as a cranking battery. This battery gives me roughly 90-95 amp hours of use before the computer on the top of it shuts down the battery to protect it. (I have done this a few times to it, just needs a little power to restart the battery once this occurs).

Now, the above is equivalent to 180-190 amp hours in AGM. This also occurs at half the weight of the current AGM batteries Jeep supplied.

Below is the link to the battery I mentioned.
https://www.deepcyclesystems.com.au/product/dcs-12v-100ah-lithium-ion/

This sits in the same position as the existing battery. Note, if going down a similar path, you will need to remove the plastic cover that sits beneath the battery the covers the second battery as it has clamps on it that wont allow the battery to sit in correctly. In addition to this, you will also need to make up something to hold the battery down. I will be using the existing 10mm bolt holes to complete this.

Now to look at the ESS battery. Quite a simple fix. If you remove the fuse cover in the engine bay adjacent to the battery, you will notice that there are wires running up onto the end of it. These are noted as being N1 through to N7. If you take note, N1 & N2 are both noted as BUS, where the rest are noted as fuses. These essentially are the inputs from batteries. N1 comes from the existing ESS battery, where as N2 comes from the AUX battery.

Now noting that I am trying to keep everything as standard as possible, I made up a little copper BUS bar that will link the 2 of these bolts together. This essentially now has the ESS system working of the 1 battery, of which is almost double in capacity to the original system supplied by Jeep. What it also does is tricks the system into thinking that it is still cranking off the smaller battery, essentially what everyone else is doing with the complex fuse and wiring setups. Best of all, it all looks standard as you can't even see the BUS bar sitting underneath the wires in the fuse box.

Now the wiring for the second battery sits inside of a plastic box underneath the main battery. As I want to keep everything standard, I have removed the negative lead and coiled it up in the plastic box. I have also taped up the positive lead, bent over the rubber cover, taped it up and then left it all sitting in it's standard location.

The also added benefit of the above, is that I have removed nearly 40kg's of weight that's not required from the engine bay, and we all know how good shedding weight is.

I have also Installed a Victron 100/20 solar charger in the rear of the car. This has been wired into the accessory plug outlet in the rear of the car. This is a gem of a charger. Not only does it have the capability of charging via solar, it also has the ability to allow a load side to come off it. It has Bluetooth capabilities that allow you to monitor solar input and configure a shut down on the load side that will prevent your battery from completely going flat.
What this means is that I have wired into it my fridge, a 12v oven and some lights. Now if the main battery ever gets down to a pre set voltage, the load will shut off keeping the battery at a level so that I can still start the car. Another benefit of this is that the Lithium battery can accept the full charge of the alternator. This helps for a quick charge in the Lithium.

So if you want a solution that allows you to have a battery that does all that you wnat in one apckage without bying expensive charging setups for dual batteries and stuffing around with your wiring, then look into this solution. Understand the capital outlay is quite high, but the long term running of it is quite low in the scheme of things.

Sorry for the long post, I was trying to explain my thoughts and actions as best as I could so if someone else wanted a different solution it is there for them to use. Once my battery turns up this week, I will update this post with some photos of the install if anyone is interested.

Cheers

Daniel

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