Start test with dead AUX battery!

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SwissSteph

SwissSteph

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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.
The official Jeep (FCA) method for changing the AUX battery is to remove the right fender completely (!) and then access the battery tray from below.
Another method is to completely remove the fuse box (including the 3 or 4 very large connectors underneath), then push those large cables and finally access the AUX battery from the top. Several members explain these two methods here and on youtube.

All this is of course for a left hand drive (steering wheel)
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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
The idea is interesting, if you have pictures it will be for me (bad English) and maybe other members easier to understand everything, thanks :like:
 
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SwissSteph

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The assembly is almost finished. I wanted to fix this "fuse-box" on the cover of the fuse box, but the height of this fuse is too high, I'm afraid that the insulation of the engine cover could touch the "red button" and thus "trigger" the fuse (which would "cut" the bridging done).
So I put two longer wires to be able to place this fuse-box just next to my battery (Optima Yellow) on the right side, there is the place and it's impossible to press by mistake on the "red button" at the risk of tripping the fuse.

SBA_6561.jpg


img1.jpg
 

Dan789

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SwissSteph

We are still waiting on the Lithium battery to turn up. When it does, I will post up some photos of the install.

For the easy modification I mentioned above, find the fuse panel that is highlighted below.

20211022_070440.jpg


Once opened, look at the cover to see the section that is highlighted in the image below. You will want to find N1 & N2.

20211022_070502.jpg


In the fuse panel itself, these are located in the circled position highlighted below. As you can see, all we have done is to install a BUS bar (Copper bar) under the two wires where they screw down.

20211022_070517.jpg


Once you have completed this, the car will start as normal with the second battery removed. We removed it as it is dead weight not required.

We have been running around like this now for just over a week with the ESS on with no issues. If the ESS system notices that there is not enough voltage in the battery, it will just simply not work. This is not a problem to us as we don't like the car turning of at the lights and will be installing a Tazer mini shortly to turn this feature of permanently. (At the moment we just use the button on the dash everytime we get in the car).

Hope this helps someone with an easy fix for this.
 
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SwissSteph

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Because I drive on the left side of the road (all of Europe and the USA, and other countries), we don't have the same layout for the battery at all, mine is on the right side of the vehicle
 
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SwissSteph

SwissSteph

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On the picture I put just above, so with left hand drive, it is under the fuse box and the main battery.
 
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