Auxiliary battery bypass.

[andrei]

Obviously, however, a man should always purchase the best that he can afford. I’ve had no issues with mine and it looks stock among the other wires and modules under the steering column

Don't even know where to begin dissecting that pile of shit you spewed there, or if it even worth the effort.

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[X35]

Don't even know where to begin dissecting that pile of shit you spewed there, or if it even worth the effort.

Have a good night there big shooter

 

[Terrymo]

What are all the misleading videos on YouTube then saying it works? Very confusing to a common man such as myself.

It’s not just you, it’s a very common mistake. As you now know the function is not dependent on the small auxillary 12 volt battery. I try not to call it the stop start battery for this very reason, because it is the cause of confusion, but I’m not one of the battery experts here.

 

[Doctor Wu]

So then there are only 2 ways to disable stop/start. Hit the button on the dash each time or install a disabler. I have learned something here but still am confused on the necessity of the aux battery. I guess it works in tandem with the main if you are using stop/start to enable better electronics etc. I think I will leave the aux disconnected and begin a habit of hitting the disable button every time.

 

[Doctor Wu]

And also removing the plunger under the hood apparently but that will trigger a warning light.

 

[X35]

Yes doc, the AUX battery is dead weight and bypassing it is the right move.

I’m not an engineer but those sumbitches at FCA or whomever owns them now put it there to run the radio and A/C while you’re sitting at a light with the engine off, otherwise it severs no other purpose.

Sure, pull the plunger closest to the left fender and the Jeep will not start stop, however you will have a start stop warning lamp always displayed that can mask some potential battery issues

 

[Doctor Wu]

Dash button it is. Appreciate all the comments.

 

[THAW]

I have learned something here but still am confused on the necessity of the aux battery. I guess it works in tandem with the main if you are using stop/start to enable better electronics etc.

The intended function of the AUX (ESS) battery is preventing voltage sag for the vehicle electronics while the starter is briefly engaged for an ESS restart.

 

[alphawolff]

So then there are only 2 ways to disable stop/start. Hit the button on the dash each time or install a disabler. I have learned something here but still am confused on the necessity of the aux battery. I guess it works in tandem with the main if you are using stop/start to enable better electronics etc. I think I will leave the aux disconnected and begin a habit of hitting the disable button every time.

Alright, here's the run down.


When you are engaged in a stop start event, both batteries are isolated from one another. The aux runs the interior electronics, and the primary is reserved for engine re-start.

The issue is the aux battery is extremely weak, and has a tendency to die, especially with excessive stop start use.

By isolating the aux battery, you completely remove its failure point from the equation. By disabling stop start, either by pushing the button or installing a defeat device (all it does is turn the button off automatically on start), you effectively never drain the aux battery outside of normal battery drain, and it's constantly in parallel with your primary to help ease load.

I personally suggest the defeat device (im lazy), as both batteries should last 4-5 years if not longer if you do not use stop start. If you use stop start with both batteries in circuit, the aux battery WILL fail within a year or two, and subsequently kill your primary battery. It is strongly recommended to never use stop/start, and if the aux battery does eventually die, delete it.

Yes doc, the AUX battery is dead weight and bypassing it is the right move.

I’m not an engineer but those sumbitches at FCA or whomever owns them now put it there to run the radio and A/C while you’re sitting at a light with the engine off, otherwise it severs no other purpose.

Sure, pull the plunger closest to the left fender and the Jeep will not start stop, however you will have a start stop warning lamp always displayed that can mask some potential battery issues

The actual reason that I heard from our TA instructors was our radios during engine start had a tendency to cutoff and sometimes even reboot due to the voltage spike. The solution was the aux battery. A few of our models use a single battery (3.2L cherokee I believe) with stop start, and it uses some capacitors or some such to get around this issue. I don't remember the exact details, but the radio cutting out was the #1 reason for the dual battery system.

 

[Doctor Wu]

Excellent answer. Thank you.

 

[andy29847]

My recommendation :

https://www.smartstopstart.com/jeep-dodge-chrysler-products.html

Highly recommend the Smart Stop/Start device that x35 recommends. I use the devices on both of my Jeeps. The reviews on the cheaper Amazon products that are similar indicate that there are some problems with function.

 

[andy29847]

The battery system design in our Jeeps suxs. One indicator for that is that only the Jeep forums seem to have separate sections devoted to battery problems. Deleting the aux battery eliminates the parts of the design that generate mystery and cause problems. The aux is there because some of the computer control modules on Jeeps have a reset threshold of 7volts. If voltage drops below that threshold during a start, the Jeep, she no run. Deleting the aux, adding a stop/start device, and installing a bigger-better main battery made my Jeeps operate like all the cars and trucks I have owned for the last 50 years.

https://www.jlwranglerforums.com/forum/threads/how-the-ess-battery-system-works-3-6-engine.159038/

 

[scootertoo]

Yes doc, the AUX battery is dead weight and bypassing it is the right move.

I’m not an engineer but those sumbitches at FCA or whomever owns them now put it there to run the radio and A/C while you’re sitting at a light with the engine off, otherwise it severs no other purpose.

Sure, pull the plunger closest to the left fender and the Jeep will not start stop, however you will have a start stop warning lamp always displayed that can mask some potential battery issues

" to run the radio and A/C while you’re sitting at a light with the engine off, otherwise it severs no other purpose. "

If you happen to be sitting at that stop light for an extended time, you might notice that while that aux battery may be running the A/C (blower), it is not gonna keep blowing cold air cause the compressor is not running then

 

[andy29847]

" to run the radio and A/C while you’re sitting at a light with the engine off, otherwise it severs no other purpose. "

If you happen to be sitting at that stop light for an extended time, you might notice that while that aux battery may be running the A/C (blower), it is not gonna keep blowing cold air cause the compressor is not running then

ESS start - This is where you are driving, you stop for a light, sign, or traffic, and the Jeep turns off (when you reach a full stop with the brake depressed). When you are ready to resume your drive, you let off the brake and the Jeep automatically restarts. When you make a stop with the ESS system turned on, and the engine shuts down, the 2 batteries remain connected together until you release the brake. Both batteries are keeping the vehicle electronics powered. When the brake is released, the Power Control Relay separates the batteries. When the batteries are separated, the auxiliary battery powers the vehicle electronics, keeping things like the radio and AC on while you wait. Next the starter is energized solely on the power of the main battery. The batteries remain separated until the engine is started, and the starter turns off. Once the starter turns off, the Power Control Relay rejoins the batteries.

 

[scootertoo]

ESS start - This is where you are driving, you stop for a light, sign, or traffic, and the Jeep turns off (when you reach a full stop with the brake depressed). When you are ready to resume your drive, you let off the brake and the Jeep automatically restarts. When you make a stop with the ESS system turned on, and the engine shuts down, the 2 batteries remain connected together until you release the brake. Both batteries are keeping the vehicle electronics powered. When the brake is released, the Power Control Relay separates the batteries. When the batteries are separated, the auxiliary battery powers the vehicle electronics, keeping things like the radio and AC on while you wait. Next the starter is energized solely on the power of the main battery. The batteries remain separated until the engine is started, and the starter turns off. Once the starter turns off, the Power Control Relay rejoins the batteries.

Thanks for the complete explanation of the ESS (stop/start) and how it works. Above and beyond your description, when ESS is working and stops the engine while at a light, the fact remains that at that point, the A/C compressor is not working to generate "cold" air into the A/C system.

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