Explaning ESS to a middle schooler

[Fudster]

Mm. How well did your 6th grader absorb the explanation? And is it going to be on the test?

You tell me James:

Son: “If inertia exists then why doesn't dinner (ESS battery charging) come out better rather than burnt when mommy's also on the phone (the engine's also moving the vehicle) with work?”

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[AlgUSF]

If you were a computer scientist, you'd call the ESS system a "Greedy Algorithm". You're finding the "local minima" in a function, but ignoring the "global minima" which may be to delete the whole system and go back to old school.

 

[agpthng]

You are forgetting a major component and that is the AUX battery which has a very short lifespan. They can start failing as early as 2 years and if you've got the original one still at 4 you are an enigma.
So you need to factor in how much gas you are really saving for the year. It's pretty pathetic I'm guessing and then factor that against the cost of the AUX battery which resides in your Jeep to power that $hitty ESS system. This is real life, something the dip$hit ECO morons don't consider.
Everything looks wonderful and all warm fuzzies on paper but in real life there is always a trade off.

Yes - failing aux battery - mine supposedly failed this summer - 3 years old - didn't even know I had an aux. battery till everything went haywire!

 

[Rodeoflyer]

I typically don't replace anything until it fails.. just me. However I'm 3 years in on the stock main/aux but have used a tazer to disable the ESS so yeah..

ESS with a manual transmission was pure H-E-L-L .. it had to go

 

[Pmccammon00]

ESS is also about emissions.

And people on this forum could argue forever about if the emissions from gasoline are better/worse than battery production.

I figured out how to avoid those nasty gasoline emissions altogether. Just go diesel

 

[Heimkehr]

ESS with a manual transmission was pure H-E-L-L .. it had to go

I remember my first test drive in a new JLU with the third pedal.

We had just come up to a red light, our first, at a large and busy intersection. Upon coming to a complete stop, the engine shut off. I remember feeling surprised and annoyed at the same time, figuring the salesman will think I bodged a shift.

"What the hell was that??" I said, before thinking to moderate my language. He replied that it was the Engine Stop feature fitted to many new vehicles. He said it that way because my newest vehicle was a 2006 Honda, and I had previously mentioned to him that I was interested in learning what new automotive tech had appeared in the intervening 14 years.

The salesman then stated that the engine would automatically restart after I lifted my foot off of the brake pedal (I had kept the clutch pedal depressed). It did just that. Phew.

We weren't even at the other side of the intersection when I asked if the feature could be turned off; he replied in the affirmative. "Well, do it then, please", I said, after which he pressed the relevant button on the dashboard. And that was that.

I eventually configured my JLU order with the ZF 8-speed transmission. I also purchased and installed the eliminator harness without delay after I got the vehicle home.

"ESS" can take a long walk off of a short pier.

 

[Rodeoflyer]

Auto trans is just mindless to me..hit the gas, hit the brake. hit the gas, hit the brake, work the radio, check your cellphone lol

 

[Heimkehr]

Auto trans is just mindless to me..hit the gas, hit the brake. hit the gas, hit the brake, work the radio, check your cellphone lol

...which is why the three-pedal Jeep was first on my Test Drive list, Bertie.

And the universal praise directed toward the superlative 850RE isn't accidental. It has the AutoStick feature when we want to row our own, or fully automatic shifting when one decides that one's nose isn't going to pick itself.

Horses for courses.

 

[Rodeoflyer]

my wife calls me Bertie.. I hope you're female or at last pee sitting down haha

 

[jeepoch]

Auto trans is just mindless to me..hit the gas, hit the brake. hit the gas, hit the brake, work the radio, check your cellphone lol

If you want to be that lazy then yes, of course, it's that simple. With the ZF8 AutoStick feature (I believed this is a misnomer and should be named 'ManuStick'), you can row through all 8 gears if you so desire. There is nothing preventing you from keeping it in full automatic. But I predict that you'll find how smooth and seamless it's shift points are, you'll soon appreciate that it's much (much) better and tireless at it than you are.

I like to think of it as a Jeeper's auto-pilot. Use it when you want the Jeep to auto trim its ailerons (gearing). Otherwise you can always continue to have full control.

This ManuStick is also a supreme advantage in off-road situations. No riding the clutch and loosing momentum. For me the overall goal is in not only selecting the proper gear, but having it get there with as little delay as possible. Having the engine and trans controllers execute a gear change in hundreds of milliseconds or less, is much (much) quicker than performing any left leg and corresponding right foot throttle calisthenics.

But, that's just me. I like having all options available.

Jay

 

[Rodeoflyer]

I understand and most days wish I had an auto trans. I will do this yearning for a manual after 5-6 years with an auto trans, then hate the manual again. I'm sure that won't be an option soon. Will I miss it? Probably.

 

[Old Jeeper]

Love it/hate it, either's fine by me.

Love it/hate it in the JL, either's fine by me.

Research shows it saves gasoline. Small amounts yes.

So...the engine stops at traffic lights and vehicle appliances run off battery power, saving gasoline, hopefully more so than any additional fuel to get the engine going again--the so called 7 second rule of ESS savings. That's the easy part.

But---that depleted battery from the ESS event has to get its energy back from somewhere, in this case an alternator, dependent on a gasoline powered engine, which presumably has to work that much harder to torque an alternator under greater load, to turn the mechanical energy of the engine into electrical energy and then into the chemical energy of the battery in need of post ESS event recharging.

I remember science lessons on how conversion of energy from one form to another loses energy from a closed system, and here where going from the chemical energy of gasoline to the mechanical energy of an engine, to the electrical engine of an alternator, to chemical energy of a battery.

So--as I see it, the way this system saves gasoline must be that given all the gasoline to get an engine up to speed, the additional or marginal extra gasoline for the running engine to torque that smart alternator beyond what it would require when the batteries are charged, is less than the gasoline savings of turning the engine off at stop lights. In fact it is so much less that we're even saving (small amounts of) gasoline despite the conversion of chemical to mechanical to electrical to chemical energy of the post ESS event battery recharging process.

How do I explain this to a middle schooler? Do I say that there are enormous economies of scale to get a car engine going such that torqueing an alternator for an already running engine is a "child's play" additional energy load in terms of the additional gasoline consumed? It's not as if other sources of energy like regenerative braking are being used in the JL (yet) to recharge an ESS battery.

Thanks.

It only saves gasoline if you are in a place (like FL) where the lights are the longest I have ever seen in any state where I have driven...ALL 50 of them. That said you have idle time to capture. the savings, right off the bat that means only the front few catches the savings the rest of them are pulling up to the light and the front few are leaving on the green.

Savings maybe some but hard to measure and IF you live in Texas, AZ Nev, and other states with LONG HOT summers you want to keep the AC on!

 

[TimmH]

The small battery costs about $120~$150 depending what you end up buying aftermarket. This system also taxes the big battery because they are connected in parallel and the small battery has a huge resistance, like 10 ohm. The big battery costs anywhere between $200~$400 depending what brand you get.

If you use your Jeep for off-roading as it is intended to be used and tax the electrical system with a high volume compressor + winching things your batteries wont last. Ask me how I know. And you'll have to deal with reliability issues constantly "ESS not ready battery charging", "Battery protection mode" etc...

You will never recover the pennies saved from ESS or your mental health lost to the issues the system causes. My 2020 Camry does not have ESS. Toyota knows it is just something else that can go wrong.

ESS is not about saving the consumer money. It is about emissions at a large scale. About the thousands of wranglers stopped in traffic in Los Angeles.

After 3 years of dealing with it. I bypassed my aux and disabled ESS. I have 0 issues since then and my Aux battery can be used to start the jeep in case of an emergency

This is where I think the savings is mostly lost for the consumer. I highly doubt I saved $120 in fuel using ESS, than I did replacing my ESS battery after 2 years, which is again apparently in need of replacement but not causing issues. At best, in my unscientific testing, I gain less than .5mpg when using ESS.

My AUX battery is in perfect mode of operation right now. Good enough to maintain proper operation of electronics and starting, but weak enough to always be in "charging" mode and never activate ESS.

 

[entropy]

This is where I think the savings is mostly lost for the consumer. I highly doubt I saved $120 in fuel using ESS, than I did replacing my ESS battery after 2 years, which is again apparently in need of replacement but not causing issues. At best, in my unscientific testing, I gain less than .5mpg when using ESS.

My AUX battery is in perfect mode of operation right now. Good enough to maintain proper operation of electronics and starting, but weak enough to always be in "charging" mode and never activate ESS.

The main issue with that is that it is also killing your more expensive larger battery.

 

[jeepoch]

I understand and most days wish I had an auto trans. I will do this yearning for a manual after 5-6 years with an auto trans, then hate the manual again. I'm sure that won't be an option soon. Will I miss it? Probably.

Bert,
Not to derail this thread too much, I promise to reconverge on this topic shortly but I too used to believe that rowing a manual was the only way to achieve true driving nirvana.

However, after somewhat settling on purchasing my new 2019 JL Sport S 3.6L Auto (due to an insanely great deal), it only had taken me a few miles to realize the ZF8 transmission in this thing is way more than I expected and is unquestionably way better than any auto (or manual) I had ever driven in any other vehicle. Remarkably, I find myself routinely 'shifting' it way more than what one would ever consider as a typical automatic.

I've found that I tend to let it upshift through the gears during acceleration (it's much better at it than I am) but I enjoy manually downshifting almost everywhere. Certainly not in every situation, like in stop ang go crap but enough to where it is entirely still fun to do so.

Off-road and certainly almost always in 4Lo, the 'D' lever position is as rare as missing the depressing of the clutch pedal. Selecting the exact gear manually using AutoStick for the given situation is both easy, smooth and impressively quick. Riding the clutch and accidental stalls in the toughest of terrain are but long forgotten memories.

I am in no way whatsoever now craving for the left foot calisthenics again. This 8 speed tranny is the absolute best of both worlds. It is one of the major reasons that this JL has earned the title of the best damn daily driver I have ever owned. It's a blast to drive anywhere, on but especially off-road.

Bringing this thread back on topic, so many people have such a love/hate relationship with ESS. It is unquestionably the worst implementation of any feature on the JL (period). The engineers and managers involved in the development and integration of using two dissimilar sized batteries should be unceremoniously stripped of their automotive expertise credentials. They deserve every critique and should wear that egg-on-their face humiliation rightfully in utter shame.

With that said, I'm actually the oddball who doesn't mind listening to the silence of a non-idling engine while stopped at traffic lights. Sort of a strange bliss, whether being frugal, environmentally friendly, technically saavy, or just mentally ill, it gives me some weird little amount of even more driving enjoyment. I'll admit that I like playing the silly little game of toying with the seven second rule.

Do I keep the motor running or are the conditions at this intersection going to let me be idling long enough as to be beneficial in any conceivable way? Even with this subtle little distraction I find that it hones my situational awareness of not just suffering through the potential delay of the traffic light itself but now also by the many factors of the intersection dynamics in total.

What are the number of cars queued in each lane? Is this wait going to be longer than a single cycle? Are the left turn signal timings in my favor (generally not). Are there any pedestrians, panhandlers, people on their phones not paying attention?

I really find that ESS really allows for way more enjoyment with an overall real-world purpose. This adds to my driving 'fun' factor. For me solving puzzles at red lights is much more entertaining than just sitting there picking my nose as others seem to do with amazing regularity. Become more aware of your immediate surroundings and you'll likely see this too. It's remarkably fun when they realize you've caught them at it. People really do think they are invisible in their cars.

Anyway, one of the best ways I prevent the engine off is not just with the brake pedal pressure, but with the 'M' AutoStick lever. By simply moving the shifter over one tap, no ESS results (by design). Again more interaction with this way cool transmission.

Lastly, I used to curse when I came into a parking spot and the ESS engages. This then unintentionally causes an unwanted starter motor engagement when putting the trans in park to then once again intentionally turn the engine back off (via the ignition switch). Thankfully AutoStick to the rescue one more! I'm now in the habit of placing the gear shift lever into 'M' when approaching a parking spot. No more accidental ESS events when parking.

So I have found the bright side of ESS with the help of this wonderful Auto/Manual transmission. I may likely never miss owning a manual tranny again.

Jay

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