Is this ok to bypass Aux?

[Jammer]

But last year my motor would not shut off I even disconnected the cables on the big battery and it still kept running. They said the auxiliary battery was going bad and that's why it would not cut off. finally I got to cut off took it to the dealership the next day It was covered on a warranty and they replaced the auxiliar battery and the big battery but I could not get i the motor shut off for hours and he said it was due to the auxiliary battery being bad. How is that possible

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[Fudster]

@WranglerDad

"While the car is running there’s current coming through the red positive wire. I have the Aux battery removed…"

I'm assuming that you're referring the the cable that normally connects to the Aux battery's positive cable....

FWIW, I think if you put a multimeter up to an exposed loose end of that cable, having removed the Aux battery, and the other end up to a ground, that you'd find current going through it at all times, vehicle engine on or not, but an 1) instant at cold crank and 2) during ESS events. This is because from the factory, both batteries are hooked up in parallel at all times but the two times just listed. I think CJ @Stuckinthesand alluded to this.

That you can detect current in this cable when YOU complete a circuit with it is not relevant. What's relevant is whether the cable on its own completes a circuit. And provided you've tapped up this positive cable's loose end, up, it doesn't.


@WranglerDad by pulling Fuse 42 you have prevented a relay (an electric switch whose on/off status is controlled by electrical current, not, like a wall switch, a human hand) to never engage in a manner that separates the two batteries. Your JL thinks that ESS/Aux battery is still in there, when in reality, all calls against that ESS/Aux battery's cables for current, as a result of this fuse pull, are just rerouted to the main battery. As far as your JL is concerned, there's no reason to not engage the ESS system at a stop light provided all the other conditions for doing so (e.g. not a turned steering wheel, engine warm, etc.) are met given that it seems good current on what it thinks is ESS battery--really your main battery only.

But you don't want ESS to engage on a dual AGM battery JL like yours with just one battery, as the ESS event can rob that one battery of cranking power at the conclusion of the ESS event.

So turn ESS off through one of the following mechanisms:

1) Press the ESS off button at crank
2) Buy tech to do it
3) Pull the hood pin, which will prevent remote start I read, and maybe do some other bad things that I'm still waiting to hear the specifics on.

or,

4) provided you are not running an early 2018, reinstall that fuse 42. Try to crank. Expect it to fail as there is no ESS battery power. Now try to crank again. The second crank should go against the main battery. If successful the vehicle will put an "ESS off" light in the dash and crank (on the 1st try thereafter) and run from this point on from only the main battery.

Some people hate seeing dash (EVIC) notices. If that's you don't do step 4). But it's "feature" or curse (it's all a matter of perspective) is it will turn ESS off for you but warn you of that in the dash (a.k.a. EVIC)

Things will remain that way until, if at all, an energized ESS battery is reattached to the ESS cables.

Step 4 should not be tried on early 2018's that haven't been flashed by the dealer with TSB 18-092-19. On these vehicles a dead ESS battery will prevent any attempt by the vehicle to crank, even if the main battery has all the power in the world.

@Jammer

The two AGM battery JLs have those batteries hook up in parallel at all times but an instant at cold crank and ESS events. By nature of this connection, current will flow from the battery with greater voltage to the one with less until they even out. That said, it seems that the ESS/Aux battery is subject to greater failure rates, and when either battery starts experiencing problems, it could negatively affect the other battery.

Antigravity Batteries:

This manufacturer, who I am new to, seems to sell Lithium based batteries of substantially lighter weight for similar power, than the AGM (i.e. Lead Acid) ones in our JLs.

Lithium currently comes in two chemistries: Lithium Iron Phosphate (LiFePO4) the Lithium Ion, the latter seen in cell phones, and scooters, and sadly, house fires.

LiFePO4 batteries are recognized as a much more stable chemistry because these batteries invariably are equipped with BMS (battery monitoring devices). They are great for inside the cabin of climate controlled RVs where Lead Acid batteries are not advised due to off gassing.

Both Lithium chemistries die below freezing. While there is chemical research that is addressing this, and making Lithium Ion batteries safer, it's not at market yet. Some LIFePO4 batteries have heaters, which sadly, like the very cold they seek to protect the battery from, also rob it of power.

The problem isn't with AGM (absorbent glass mat) batteries so much as the lack of quality control in their manufacturer and the poorly designed dissimilar size batteries of the JLs ESS system.

" But last year my motor would not shut off I even disconnected the cables on the big battery and it still kept running. "

Your aux battery was still connected, energizing things. When you say motor, do you mean some appliance or the vehicle's engine. I hope the former.

"They said the auxiliary battery was going bad and that's why it would not cut off."

I say that if anyone hooks up two batteries up in parallel, either or combined capable of running an appliance, and yanks the connections to one, the appliance still runs.

"How is that possible? "

You got incorrect advise?

 

[Jammer]

I have an early 2018 JL Rubicon because I bought it in July 2018. What if I do the dual battery setup then I don't have to worry about anything right ? I've seen people do the dual battery setup and delete the AUX battery

 

[Jammer]

I have the taser in my auto start stop is turned off. So that problem is solved but I do pull it out when I take to dealer to get worked on so what would happen then

 

[Jammer]

Fudster I sent you a PM

 

[Fudster]

I have an early 2018 JL Rubicon because I bought it in July 2018. I've seen people do the dual battery setup and delete the AUX battery

There's a good chance that you have the TSB 18-092-19 functionality in your 2018. If not, you can have the dealer download it for you. Reading ahead, unmarry your JL Tazer before bringing your JL to the dealer for any service, especially the "flash" to download this TSB.

You can test if you have the TSB as follows:

With Fuse 42 inserted... (this is critical for the test)

Two factory cables will connect to the negative post of the main battery. One has its other end the body ground on the passenger's front fender. Leave this cable alone and attached. The other cable should be temporarily removed from the negative post of the main battery. This action disconnects the ESS/Aux battery from the vehicle's electrical system. This cable you just detached has as its other end the ESS/Aux battery's negative terminal. Keep the cable's lose end away from metal for the test.

Now attempt to crank the JL. Expect it to fail. This is because the default JL behavior is to not attempt a crank if the ESS/Aux battery is not detected/has no current.

Older 2018's without the aforementioned TSB will need a working ESS/Aux battery or its cable's rewired into the main battery (see Fuse 42 pull, or N1/N2 jumper, which prevents the batteries from every being isolated.)

Try the crank again. It's this second try I am interested in. If you have the TSB's functionality, and your main battery has ample current, your JL should crank against that main battery only. Expect, if successful, for the vehicle to put an "ESS off" light in the dash--BTW exactly what you want, ESS off, if running with one battery. Tape up that loose cable and your done.

From this point on you should crank on your first try, only against the main battery, and the vehicle will only operate from this battery. Not until such point that you reconnect an ESS/Aux battery, if any, with current, and recrank, will the default factory cranking behavior return.

You need not turn ESS off with your JL Tazer. Your vehicle has done this for you using the "cable disconnected but Fuse 42 inserted" approach.

If this second crank fails, provided your main battery has power, then it probably failed because you don't have the TSB. Reconnect that detached cable and consider getting your vehicle flashed at the dealer, again with the JL Tazer unmarried during the dealer flashing process.

~~~~~~~~~~~~~~

If you hate the prospect of this ESS off light in the dash then don't bother with my test, and instead, in addition to pulling the cable mentioned, also pull Fuse 42. Doing so will prevent the vehicle from every isolating the two battery's connections (regardless of whether one or two batteries are connected.) What this means is that any calls for electric current to the ESS/Aux battery will also go, at all times, to the main battery, allowing you to delete the Aux battery--which you can physically remove from the vehicle or not at your choice.

This pulling of Fuse 42 won't turn the ESS off light in the dash. In this case I suggest you turn ESS off using your Tazer. This technique should work for any 3.6L Jl, with or without the TSB. It won't turn it off because you've tricked your vehicle into thinking that the main battery is the ESS/Aux battery with this fuse pull.

Regardless of how we configure for one battery use, we don't want to run ESS events. Doing so can rob the main battery of cranking power at the end of the ESS event as appliances will get their power during ESS events from only this battery, not the ESS battery as factory designed.

"What if I do the dual battery setup then I don't have to worry about anything right ?"

When I hear this I think of the Genesis Offroad system. Is this what you are referring to? If so, this is a wonderful piece of JL equipment that only those seeking to run appliances off road should, consider, IMHO, spend their money to acquire. While it while address stock dual battery issues, to acquire it for this reason only is "killing a fly with a baseball bat." The kit is pricey, the batteries are pricey, and it's a IMHO non-trivial install.

Unless you are committed to running ESS, one battery is fine. And even if you are, the solution isn't the Genesis Offroad kit. It's trickle charging your batteries (shore or solar power) while the vehicle is parked.

By no means do I wish to disparage Shane or his kit. It is a remarkable piece of hardware for energy management and conservation.

"I've seen people do the dual battery setup and delete the AUX battery"

The Genesis Offroad kit has the JL source the power it normally got from the ESS/Aux battery to, instead, one of the two identical batteries you purchase for the kit, taking the factory ESS/Aux battery out of the electrical schematic of the vehicle. You can also physically remove this factory ESS/Aux battery if you wish.

Please do not confuse turning ESS off with disconnecting the ESS battery. They are two separate and independent things. You can in theory have the ESS system turned on or off with either one or two batteries. You should have the ESS system turned on only if you are running Shane's kit, or the factory dual battery system with factory wiring.

 

[Jammer]

I am at a meet with our Jeep club at a off-road shop tonight and one of the guys mechanics here said what you were saying just take the positive cable connect it to the main battery and tape off the black negative cable leaving alone just tape it off and it'll be no problems every now and then it might in the message thing say something about the start stop but I won't see it and because I have the tazer I'll be okay That's all I need to do. Like you were saying red cable to the main battery black cable leave it alone leave it hanging tape it off and I'll be fine cuz I have the tazer

 

[Jammer]

Fudster someone said on here make sure you put the aux battery in if you to a dealer warnety work. can they say removing the aux battry made something break or go bad because of the aux being removed ?

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