Disconnecting aux battery- which cable?

[Geoarch]

the batteries are in parallel - connected together - when driving or if it's sitting, turned off.
So a charger will charge both, but if there's a great difference in the health of either battery, one may not get what it fully needs.
So if I'm doing any more than a maintenance charge, I do each individually.

Thanks. That's what I thought.

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[Puch]

I watched a auxiliary battery disconnect video that showed you can just disconnect the negative cable and pull the fuse to disable the auxiliary battery. Their cable setup was slightly different (older model).
Mine is a 21, which cable do I disconnect for the auxiliary battery?

I’m not 100% sure, but I believe if you disconnect the wrong one it won’t start?
In other words:
If you disconnect the main negative cable you get no start. Put it back on and disconnect the other one. It should start.

 

[TestMule]

My JT was built in August of 2021.

I went out to start it today and it was dead, dead, dead. The first suspect in my mind is the aux battery. So, I want to delete it from the circuit. I believe I need to disconnect the cable that is connected to the right hand terminal (as you are facing the front of the vehicle) and pull a fuse.

Which fuse should I pull? I think it's the same one as noted above but I'm not sure what all that mid-year change entailed.

Thanks for any insight. I'm gonna go pull the cable and see If I still have power.

 

[NortonJTSS]

Mine was built May 2021. I had to disconnect the one on the right and then reattach the left one

 

[NortonJTSS]

My JT was built in August of 2021.

I went out to start it today and it was dead, dead, dead. The first suspect in my mind is the aux battery. So, I want to delete it from the circuit. I believe I need to disconnect the cable that is connected to the right hand terminal (as you are facing the front of the vehicle) and pull a fuse.

Which fuse should I pull? I think it's the same one as noted above but I'm not sure what all that mid-year change entailed.

Thanks for any insight. I'm gonna go pull the cable and see If I still have power.

F42

 

[TestMule]

Thanks, guys. The cable connections for battery negative power and aux positive are on a single plate. I guess I am gonna have to cut that plate in half, then pound out the post in the plate so I can slip it over the battery connection. Weird setup. My JL was not setup like that having one ring terminal per cable and no connecting plate.

 

[ShadowsPapa]

Thanks, guys. The cable connections for battery negative power and aux positive are on a single plate. I guess I am gonna have to cut that plate in half, then pound out the post in the plate so I can slip it over the battery connection. Weird setup. My JL was not setup like that having one ring terminal per cable and no connecting plate.

????
No, the two cables going to the top of the IBS on the main battery are:
AUX GROUND
and
BATTERY to chassis ground.

Aux positive doesn't come up to the main battery negative at all. Aux positive goes to N1, not to the main battery.

Not sure what you are talking about, but there's nothing to cut or pound out regardless of year.

If you had a 2020, you'd simply remove the cable i have marked 2020 to remove the aux ground from the main battery and chassis.
In 2020, the cable in the right on the pic marked 2021 is what goes to the chassis ground in 2020.

If you have a 2021 (depending on month of build) then you would remove the cable marked 2020, then the cable marked 2021, and put the cable marked 2020 back on the IBS on the main battery negative because in 2021 and later that cable goes to the chassis.

You don't cut anything or pound out anything.

The arrow in the picture points to the IBS - ALWAYS charge through the top of the IBS, or the stud on top, and always connect load grounds to the stud on top of the IBS.
Don'tcharge directly to the negative battery post

I went out to start it today and it was dead, dead, dead. The first suspect in my mind is the aux battery.

Why? Because that's what the internet says, even though the main battery can go just as easily? It could as easily be the main/crank battery that went south. A lot of forum members here have had that happen, and the aux was still good.
I still don't get why the aux is always the suspect - just because that post years ago kept getting repeated over and over and in forum after forum.

 

[TestMule]

????
No, the two cables going to the top of the IBS on the main battery are:
AUX GROUND
and
BATTERY to chassis ground.

Aux positive doesn't come up to the main battery negative at all. Aux positive goes to N1, not to the main battery.

Not sure what you are talking about, but there's nothing to cut or pound out regardless of year.

If you had a 2020, you'd simply remove the cable i have marked 2020 to remove the aux ground from the main battery and chassis.
In 2020, the cable in the right on the pic marked 2021 is what goes to the chassis ground in 2020.

If you have a 2021 (depending on month of build) then you would remove the cable marked 2020, then the cable marked 2021, and put the cable marked 2020 back on the IBS on the main battery negative because in 2021 and later that cable goes to the chassis.

You don't cut anything or pound out anything.

The arrow in the picture points to the IBS - ALWAYS charge through the top of the IBS, or the stud on top, and always connect load grounds to the stud on top of the IBS.
Don'tcharge directly to the negative battery post.

So I have a JT built in August of 2021. The cable marked 2020 above is the one I will swap over to the right side. That post on the 2020 cable is press fit to the bottom of that plate that both cables attach to. That's what I was referring to as needing to pound or press out. If I don't, there is no open ring terminal in that plate to go over the other connection to the right.

 

[TestMule]

Well, I am gonna get some bigger tools and try to loosen that bolt on the left hand post. I see where it has been removed and the bare post is still there. The cable on the left side is then swapped over to the right side.

Time for some big boy tools...

 

[ShadowsPapa]

This is the IBS - it has a stud on it. You move the 2020 cable, which in your case is actually chassis ground, over to this stud after removing the cable that has the plate and stud on it -

In other words, there's still a stud to attach the ground cable to.
It's going to be tight............

 

[TestMule]

I appreciate the info posted in response to my issue.

The aux battery has been disconnected from the system, the negative cable has been taped up and fuse 42 has been pulled.

The main battery was toast. It took almost 4 hours to put a minimal charge in it and after one start the battery voltage dropped to 9.1 - 9.3 volts. No more starts for that battery!

Luckily, an acquaintance saw my FB post and pulled an almost new OEM battery out of his shop. He had kept it after he had done a dual battery upgrade to his JL.

Once I had installed the battery, the JT started right up. Battery voltage at idle was 14.2 - 14.4 volts and after shutting it down it was 12.8 - 12.9 with no issues starting up again. No CEL or battery malfunction lights on the dash, either!

Thanks again for the help and assistance.

 

[ShadowsPapa]

I appreciate the info posted in response to my issue.

The aux battery has been disconnected from the system, the negative cable has been taped up and fuse 42 has been pulled.

The main battery was toast. It took almost 4 hours to put a minimal charge in it and after one start the battery voltage dropped to 9.1 - 9.3 volts. No more starts for that battery!

Luckily, an acquaintance saw my FB post and pulled an almost new OEM battery out of his shop. He had kept it after he had done a dual battery upgrade to his JL.

Once I had installed the battery, the JT started right up. Battery voltage at idle was 14.2 - 14.4 volts and after shutting it down it was 12.8 - 12.9 with no issues starting up again. No CEL or battery malfunction lights on the dash, either!

Thanks again for the help and assistance.

People need to realize - it's not always the aux battery that goes first.

I am going to have to isolate my batteries, charge each and reset the IBS on it after witnessing two battery chargers sort of going goofy while charging.
My BatteryMinder 1500 (1.5 amps) ran hotter than normal, and after a few hours, flashed error.
My larger NAPA charger (made by Carlisle) at 10 amps said the voltage was at 13.2 but it was only 75% after running almost 24 hours. When I shut it down and restarted it, it said the batteries were 100%.
And after all of that, voltage stayed above 14.x all the while making several fairly long drives this AM.

So, time to charge each independently and see what's going on.
I know it's cold out, but it still.................
ironically, everything works perfectly, including ESS and in fact, the voltage stays quite high during an ESS stop event! It will stay in the upper 12s for a minute, and hasn't dropped below 12.2 volts before the light changes.
WEIRD - but then doing the independent battery charging and IBS resetting on my 2020 pretty much resolved issues with that one. 2 1/2 years, who knows.

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