Auto Start-Stop Question

[rk911]

I find the auto start-stop very annoying. Just wondering if there is any harm in manually turning it off each time I start the engine and running without it on?

Nope. I found it VERY annoying and can't understand why such a thing was ever devised. I found THIS and had my shop install it. Works flawlessly as advertised.

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[AndySpill]

Jeep also puts this same stupid 2-battery solution into non-Wrangler products though too, such as the Cherokee. It makes no sense whatsoever to put it in that vehicle if the entire purpose is solely to support vehicles with tons of aftermarket electrical gee-gaws on it.

My co-worker has a bunch of add-on gizmos on his Bronco, has never had a problem with the battery or ESS on it even with just a single battery. I think it's just piss-poor engineering on Jeep's part to build the system this way. The number of complaints alone that Jeep must get about this crappy system has to far outweigh any benefit, along with all the warranty visits to fix something that cannot be fixed.

In fact, my co-worker who now has a Bronco got rid of his Cherokee specifically because the ESS never worked right in that vehicle either. It pissed him off enough to go to the dark side rather than buy a Wrangler.

I agree John that the system in retrospect, even if designed with good or profitable intentions is bad. One should not have to trickle charge with the same frequency of my locale's fire apparatus, while sitting in bay waiting for the next call, just to get ESS to work.

Nor do I accept the notion that "if we build it sucky, the aftermarket or our roll up your sleeves owners will rectify it," as an excuse Stellantis gets to make simply because they can.

 

[AndySpill]

As someone who got stranded at a traffic light on 2 different occasions, I was told that Jeep's software at the time did not take into account if the main battery had enough amps to restart the engine or not.

This was eventually addressed in a software update that my local dealer wanted to charge me a diagnostic fee and additional labor to install. I declined and opted to just press the button every time until I sold the Jeep

As I think about this, sadly, your anecdote makes sense. Both batteries crank the engine and prior to cold crank the ESS battery is tested. Perhaps the ESS battery had enough current to allow ESS to engage, and helped the failing main battery to cold crank, but then during that ESS event the ESS battery was depleted to the threshold where its remaining power, plus that of the main battery was insufficient to effect the crank such that whatever additional power the main battery got from the alternator since cold crank did not offset the power lost by the ESS battery during the ESS event.

One of the failings of a main battery on its way out would be inability to accept (much) charge.

Don't you love being charged (money, not electrical current) by a dealer for, rather than providing you additional features, rectifying design mistakes with software upgrades.

Got to "love" that.

 

[AndySpill]

Nope. I found it VERY annoying and can't understand why such a thing was ever devised. I found THIS and had my shop install it. Works flawlessly as advertised.

"Works" is a funny word here. Yes, it claims to prevent ESS from engaging and indeed does that, but without you also disconnecting the ESS battery and bypassing it with a pull of Fuse 42, and/or a fused jumper between terminals N1 and N2 in the PDC, you still risk the dissimilar size batteries in parallel negatively effecting one another.

 

[AndySpill]

Every once in a while thread contributors and readers can benefit from a review summary of basic concepts. Here goes for those interested.

A critical vehicle system is the battery/charging setup for reliable starting and operation. That system should work in virtually all climates even for vehicles sitting for long periods with modest "parasitic" loads--three months for healthy a AGM battery should be expected.

Buffering of electrical loads while the engine/alternator is running is a secondary function easily satisfied by virtually any battery of minimal size and performance, and so is not further discussed here. Also, the diagnostic/predictive benefit that ESS provides for the electrical system in general, a side effect of allowing ESS to "work" before engine/charge shut off, is not further discussed.

There are burdens a battery/charging system must overcome to be successful. Vehicle use without charging is typically the heaviest. Using the "accessory" ignition setting while operating loads is an obvious example. ESS operation is another.

To be clear, ESS operation which shuts down the engine--meaning charging--while electrical loads continue is a burden on the battery/charging system.

Jeep attempted to satisfy this burden, in way too many JL Wranglers, by adding a second, "aux" battery, along with additional hardware and software. However, the attempted fix generally doesn't work, and sometimes results in electrical issues, primarily because the additional stuff is bad science. The dual battery system tries to charge dissimilar batteries as if they are one, and thus fails the particular charging needs of AGM type batteries. The final result is premature battery failure.

Dual battery JL owners will have their own views and opinions, and respond as they think right. Environmental, political, and social considerations aside, there are different ways to go. There's external charging, the aux battery/F42 disconnect (not really a "bypass" or a "delete"), and other options. But some things are always true. Whether or not an owner allows ESS to shut off charging, the stock dual battery/single charge system will almost certainly result in premature battery failure. And ESS charging shut off will almost certainly accelerate that failure. Let each owner make their decisions, fully informed.

This makes me think about why the batteries weren't separated when dual AGM battery JLs were parked, so as to isolate the ESS battery from parasitic draw that would, on top of loss of power over time, reduce its strength, that the main battery had the larger size to better accept.

It probably had to do with making jump starts/trickle charging more difficult had it been designed this way.

 

[Heimkehr]

I was shocked to find that ESS is also present with a manual transmission.

My first test drive was in a 3-pedal JLU.

I keep my vehicles for a long time, and therefore wasn't fully versed on the many e-nannies, etc. that late model autos are now encumbered with. So, when the Jeep's engine shut off at the first stop light during the test drive, I was genuinely surprised (and a bit annoyed that the salesman might think that I flubbed a shift, which I didn't.)

When I asked what happened, the salesman quickly said something about ESS functioning, after which he turned it off at my request. The engine restarted when I went to pull away and that was that.

I couldn't purchase and install the ESS defeat harness fast enough after my new Jeep came home. Thank God for the aftermarket.

 

[SargeDiesel]

But it's "Automatic." My son thinks the abbreviation should be different. I'm sure others agree...

Could be worse... some refer to it as the ASS... ?

 

[rk911]

"Works" is a funny word here. Yes, it claims to prevent ESS from engaging and indeed does that, but without you also disconnecting the ESS battery and bypassing it with a pull of Fuse 42, and/or a fused jumper between terminals N1 and N2 in the PDC, you still risk the dissimilar size batteries in parallel negatively effecting one another.

Agree and that's on my list of things to do but rather than pulling fuses I'd just as soon remove the aux battery altogether. What issues will that trigger?

The only accessories I wil, or possibly will be adding, are my mobile (not hand-held) dual-band amateur radio transceiver and, possibky, a 12-volt dash cam. The transceiver will be powered directly from the main battery just like the radios in every other vehicle I've owned since the 1970's. The dash cam is something I have very little experience with but it, too, will be powered from the main battery.

Given that is there ANY reason to keep the aux battery?

K.I.S.S.

 

[SargeDiesel]

I agree regarding the start stop. Especially with a Diesel. Very annoying. I keep mine manually turned off almost every trip now.
Many folks on here have posted their experiences regarding ESS. Battery issues. Etc
I'm going with the belief that by manually turning it off constantly, this will help ensure a little more battery life in Aux Battery, less wear & tear on Engine & Starter (although Owners manual states Engine has an upgraded starter specifically for start/stop)
However, i recommend keeping it active occasionally.
This should also keep the Aux battery healthy.
By keeping the system active occasionally, I discovered a defective Main Battery, ESS system kept saying charging. Dealer replaced under warranty.
Lastly, there are ways to bypass, but I prefer to press a button and not risk losing warranty etc

I use the original eliminator sold here on the forum... I use its memory function rather than pushing the button each time.
*
I agree with you on the rest... I keep mine disabled, but I do (maybe once a week)
When I know I'm going for a long ride, I will enable it. I usually get a message that its not ready.. "charging". Then I will let it charge, cycle through a stop, recharge and then I will turn it back off.

 

[rk911]

...I couldn't purchase and install the ESS defeat harness fast enough after my new Jeep came home. Thank God for the aftermarket.

Same here. Dumbest idea since, well since a lonnnng time.

 

[Bandit59]

I find the auto start-stop very annoying. Just wondering if there is any harm in manually turning it off each time I start the engine and running without it on?

No harm. I either push the bottom or stay ez on the brake and it will not turn off. But sometimes I forget untill I get to my first stop.

 

[Mack.]

ESS does more harm than good, so you're on the right track turning it off on every start up

Just imagine 4:00 pm NY City 3 miles east of the GW bridge. What is worse gas mpg or new starting system components per mile? A started relay takes a hell of a beating in such an instance. On GW Bridge rush hour traffic and starter failure. They will strip out your vehicle in 20 minutes flat and have all the parts hoisted up the big wall and over the fence on the access road and sold by 5:30PM

 

[Mguy]

This makes me think about why the batteries weren't separated when dual AGM battery JLs were parked, so as to isolate the ESS battery from parasitic draw that would, on top of loss of power over time, reduce its strength, that the main battery had the larger size to better accept.

It probably had to do with making jump starts/trickle charging more difficult had it been designed this way.

I'm less interested in the "why" behind the stock JL electrical system. Here are some of my observations on "what" can be done, with "parasitic" loads being part of the overall problem.

My new AGM Mopar aux battery, provided under warranty, has a fully charged resting voltage of 12.8 plus. After 3 months, in a relatively cold environment, it self-discharges (no parasitic loads) to 12.6 volts. My 3.6L engine turns over with that 12.6V aux battery alone, with no problems, in 20F to 40F temperature. The aux battery remains in my Jeep as a backup.

My 30 month old Mopar main battery (another warranty replacement), not bothered by the aux battery after the negative/F42 disconnect and prevention of ESS charging shut-off, recently passed a load test. Fully charged and then siting in sub-zero temperatures and feeling typical parasitic loads for a week, the engine started with no issues. It was -14F. This same main battery, when about 15 months old and fully charged in a relatively warm environment, sat for 2 months suffering parasitic loads, and then started the engine with no problem. It should go another 30 months.

There are a few obvious conclusions. The aux negative/F42 disconnect creates a more reliable single battery system adequate for typically driven JLs. A healthy aux battery provides a good backup for starting (at least for gas engines). Preventing ESS charging shut-off is good for single main battery performance. Also, regardless of whether Mopar batteries are of "lower" quality than those touted elsewhere in this forum, they are not "low" quality.

 

[Joe98]

I find the auto start-stop very annoying. Just wondering if there is any harm in manually turning it off each time I start the engine and running without it on?

No harm. That is what the button is for.

To start my Jeep:

Press the start button
Press the auto stop start button
Press the radio power button
Press the fan button
Press the "accept terms" in the info screen.

It makes me feel like I am in a sci fi movie!

 

[Riverjeep]

I find the auto start-stop very annoying. Just wondering if there is any harm in manually turning it off each time I start the engine and running without it on?

Nope, won't hurt a thing, I turn it off with every start up.

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