Start stop battery dead again??

[Reinen]

It has a lot to do with your driving habits. Leaving your Jeep parked for a week is very stressful on the batteries. The batteries want to be driven daily for 30+ minutes.

I don't drive that often. I mounted a NOCO 2D charger in the engine compartment with an external plug on the windshield cowl. l just grab the retractable cord on my garage ceiling and plug it in. Easy peasy.

And the retractable power cord on the garage ceiling is very convenient for many other things. IMO every garage should have one.

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[kapk22]

It has a lot to do with your driving habits. Leaving your Jeep parked for a week is very stressful on the batteries. The batteries want to be driven daily for 30+ minutes.

I don't drive that often. I mounted a NOCO 2D charger in the engine compartment with an external plug on the windshield cowl. l just grab the retractable cord on my garage ceiling and plug it in. Easy peasy.

And the retractable power cord on the garage ceiling is very convenient for many other things. IMO every garage should have one.

That’s a cool idea

 

[Reinen]

That’s a cool idea

If you're thinking of doing it, the NOCO external plug just fits here and it's a very easy run into the engine compartment. I did make one modification to the plug. It has a drain hole but its clearly designed for a vertical mount, not horizontal. I drilled a 2nd drain hole at the bottom corner of the well between the pos & neg plugs outward at a 45 degree angle. There is nothing there but plastic and it will fully drain any water that may get in there.

 

[kapk22]

@kapk22

Testing the batteries should be done with a load tester, not a multimeter. To test the main battery pull all the cables off its negative terminal and place your load tester on the battery.

To test the Aux battery move the load tester's negative lead to the cables you just disconnected from the main battery's negative terminal, leaving the load tester's positive lead on the main battery. This will test (only) the Aux battery; yes, even as the load tester's positive lead remains on the positive terminal of the main battery, because the only circuit formed is with the Aux battery.

Reconnect those cables after you are done.

To take the Aux battery out of the vehicle's electrical circuitry disconnect the cable on the main battery's negative post that is connected to the Aux battery and tape it up. Which cable that is can be found here: https://www.jlwranglerforums.com/forum/threads/ess-battery-cable-change.86624/

Then open the fuse box cover and pull fuse 42. Turn ESS off on the dash or with aftermarket tech to do that for you (e.g. JL Tazer, Auto Stop Eliminator.)

The kid at batteries plus tested the batteries. He said my main is only putting out around 600 cranking amps and “should be replaced”. He said the auxiliary battery is completely dead. He also said the main battery starts the engine.

If this is the case, what am I risking leaving the setup the way it is until I can isolate them this weekend?

I was just worried about the jeep not starting.

 

[Reinen]

The kid at batteries plus tested the batteries. He said my main is only putting out around 600 cranking amps and “should be replaced”. He said the auxiliary battery is completely dead. He also said the main battery starts the engine.

If this is the case, what am I risking leaving the setup the way it is until I can isolate them this weekend?

I was just worried about the jeep not starting.

The Main and Aux batteries are connected in parallel 99.99% of the time. Consider them two parts of the same battery. Always replace both at the same time or battery life will severely suffer. There is no point in isolating them. If one is dead it has already killed the other.

What are you risking? Dead Jeep, dashboard freakouts, the low voltage will make the Jeep think everything is broken and it will throw all sorts of random codes. The JL does not like insufficient battery power at all. I would not trust that Jeep to make it to any destination.

On a cold start both Main and Aux start the engine.
On ESS warm starts the Main starts the engine while the Aux powers electronics. This is the only time the batteries don't work in parallel.

 

[kapk22]

The Main and Aux batteries are connected in parallel 99.99% of the time. Consider them two parts of the same battery. Always replace both at the same time or battery life will severely suffer. There is no point in isolating them. If one is dead it has already killed the other.

What are you risking? Dead Jeep, dashboard freakouts, the low voltage will make the Jeep think everything is broken and it will throw all sorts of random codes. The JL does not like insufficient battery power at all. I would not trust that Jeep to make it to any destination.

On a cold start both Main and Aux start the engine.
On ESS warm starts the Main starts the engine while the Aux powers electronics. This is the only time the batteries don't work in parallel.

Ok. I will plan on figuring out which negative goes down to the auxiliary tonight and pull off (tape it up. Then have them swap the main battery out tomorrow after work. Cross fingers it starts two more times.

They only sell diehard. But he said it’s American made.

 

[kapk22]

This is really confusing. Is he saying the negative terminal going to the auxiliary is “cable B”?

If this is correct, pulling that off the main and wrapping electrical tape around it should do the trick, correct?

Then I will just replace the main battery and eventually pull that old auxiliary battery out of there. I assume leaving the positive terminal on that auxiliary battery won’t hurt anything, since it doesn’t have a ground to close the circuit. I will snap a picture of my terminals!for reference as well.

 

[WillysMeow]

Bmpcamry09, Thaw and another user have excellent threads on this, sorry can’t find now as phone sucks lol.

Basically remove smaller battery, very thoroughly wrap the positive and negative cable ends up And put them back in the under fender box, reinstall three bolts and replace couple inner fender plastic Christmas tree pins. Some have been successful just bending the plastic inner fender back, I was already working around my tires, too lazy to pile the wheel abs tire off, working on the ground and Jeep at stock height it’s little more work to get in there.

Pull fuse F42 and youre done.

That’s the best easy way IMO and what I did. After warranty I’ll pull the two extra cables out and rewrap the battery cables harness.

 

[kapk22]

Bmpcamry09, Thaw and another user have excellent threads on this, sorry can’t find now as phone sucks lol.

Basically remove smaller battery, very thoroughly wrap the positive and negative cable ends up And put them back in the under fender box, reinstall three bolts and replace couple inner fender plastic Christmas tree pins. Some have been successful just bending the plastic inner fender back, I was already working around my tires, too lazy to pile the wheel abs tire off, working on the ground and Jeep at stock height it’s little more work to get in there.

Pull fuse F42 and youre done.

That’s the best easy way IMO and what I did. After warranty I’ll pull the two extra cables out and rewrap the battery cables harness.

Dang... I didn't want to tackle removing that stupid battery until the weekend. I remember pulling the fender off and breaking the little plastic tabs. I mixed up batteries plus when I mentioned the diehard battery. They sell Duracell. I am trying to decide what battery to replace the main now.

If I have the Tazer mini, do I still need to pull the fuse?

 

[Megawatt]

I have a 2022. Both batteries have been changed twice. But I also live in the desert and it’s common for the +110f heat to kill batteries.

Important reminder, if jeep replaces your batteries they have a separate 3 year warranty that does not have anything to do with your original warranty 3/36k or the 5/50k warranty. I just had my second set of batteries replaced past 61k miles. Dealership saw they were replaced two years ago and replaced them for free.

 

[THAW]

If I have the Tazer mini, do I still need to pull the fuse?

Yes. Tazer provides ESS button memory, fuse F42 removal prevents a dash light caused by PCM reset at cold start due to the PCR opening without the AUX (ESS) battery providing power to the PDC (fuse box).

 

[kapk22]

Yes. Tazer provides ESS button memory, fuse F42 removal prevents a dash light caused by PCM reset at cold start due to the PCR opening without the AUX (ESS) battery providing power to the PDC (fuse box).

thank you sir

 

[WillysMeow]

As Thaw said and don’t pile the fender!


Peel back the inner fender liner to access the small battery.

 

[Bryce919er]

I remember pulling the fender off and breaking the little plastic tabs.

NO...
https://www.jlwranglerforums.com/forum/threads/deleting-removing-the-aux-battery.166850/

 

[kapk22]

NO...
https://www.jlwranglerforums.com/forum/threads/deleting-removing-the-aux-battery.166850/

much better. thank you

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