Jumpers (Not Jumper Cables) & Jump Starting

[Rahneld]

Actually people have been stupid and probably shouldn't be allowed to drive.
It's not rocket science. If you don't know how to jump start your car don't try. Recommendations to modify your vehicle to people who are incapable 8s just asking for problems.
These forums breed myths and the gullible or incapable only dig their troubles deeper

I agree. Jump starting a vehicle is generally a straight forward procedure that all motorists (at least non-electric ones) should know, despite many people neither knowing (let alone owning) the order to connect the cables or where.

That said, there appears to be much more going on with the JL's jump start process, despite the cable hookup being standard, that this thread sought to discuss. Those not in the know may try cranking the JL once the cables are connected, like in other vehicles, without waiting--and fail.

Even though that's well documented in the owner's manual, this thread sought to explain why: at least theorize why that wait is necessary, (time for the ESS battery to charge: as it's normally isolated at, and critical for crank) and how a jumper on N1 and N2 may alleviate the need for that wait, let alone the Aux/ESS battery in the first place, as @allieboy first discussed here.

That was, at least as I, and I know @allieboy saw it, the critical aspects here; not a primer on jumping 101. We sought to get our arms around the implications of this jumper, both from an engine crank and jump starting angle.

Again..I agree with you, along with knowing how to change a tire. Peace.

: - )

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[Hgrace]

This is one of 3 ESS or BSG vehicles I currently own. They all have been jumped. The JL is bar far the easiest and most straightforward.

 

[allieboy]

This is one of 3 ESS or BSG vehicles I currently own. They all have been jumped. The JL is bar far the easiest and most straightforward.

What powerpack did you jump it with?

 

[allieboy]

What powerpack did you jump it with?

Was the ESS battery dead or defective when you did?

 

[Rahneld]

So being parallel, one shouldn't go bad on it's own theoretically? They would both go dead then??

As you seem to allude to, the nature of a parallel connection is that the batteries in the connection will seek to equalize one another.

So if, say, the ESS battery is working (can accept and delivery charge) but has a tad bit less juice when the engine shuts off--the alternator somehow failing to "top it off"-- than the main battery, yes, the main battery will seek to energize it, or vice versa, as the batteries appear to be always connected in parallel but for the crank event, and with the jumper of this thread, always in parallel "period."

Nobody I know has yet to site some protective mechanism in the JL that cuts the batteries off, outside of the crank event, if one is dead. Of course I may have missed that, or it may exist and have yet to be cited.

To @allieboy's point, with that jumper the aux/ESS battery can be taken out of the picture, but if you don't turn the ESS system off, I suspect it will drain the main battery when engaged. I'm not certain. In theory, the ESS battery is checked for good current before an ESS event, which with this jumper one might conclude is now the current in both batteries, or just the main one if the ESS battery is disconnected, after the N1-N2 jumpering.

And if one battery goes bad, as you say, defining that as a defective battery with parasitic drain of the other but not accepting that charging, yeah, I'd agree with you about them possibly both having no charge afterwards.

I guess parallel connections bring out the best and worst in batteries: coming to another one's aid, or the defective one sucking the other dry.

: - )

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[Rahneld]

This is the correct procedure for any jump. You must let the voltage equalize and 'warm' the cells of the dead battery.

This may be, while true, oversimplification: I'm not certain. Again, this goes back to the ideas of this thread that the ESS battery in the 3.6L must acquire basic charge above and beyond the things you describe above, barring the jumpering of N1 and N2 discussed in this thread.

 

[Rahneld]

What powerpack did you jump it with?

Many of threads here suggest portable powerpacks to be incapable of jump starting the 3.6. (Maybe "powerpack" here means to you: "source of energy" ...like another cranked vehicle--or maybe you know more about this specific jump start story than me.)

I am theorizing that this may be the case with portable powerpacks because some of their "umph" may need to go to establishing a base charge in the ESS battery before a crank can be attempted.

With the N1-N2 jumpers in place, this charging of the ESS battery may not be required because the ESS battery isn't isolated from the main one during the crank with N1 and N2 connected.

More to point, it would be interesting to see if a powerpack might work, and how fast, if once N1-N2 are jumpered, the ESS battery was all together disconnected.

For me: much uncharted water here. And I'd really rather not test on a $50K vehicle.


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[Blu bi Kong]

As you seem to allude to, the nature of a parallel connection is that the batteries in the connection will seek to equalize one another.

So if, say, the ESS battery is working (can accept and delivery charge) but has a tad bit less juice when the engine shuts off--the alternator somehow failing to "top it off"-- than the main battery, yes, the main battery will seek to energize it, or vice versa, as the batteries appear to be always connected in parallel but for the crank event, and with the jumper of this thread, always in parallel "period."

Nobody I know has yet to site some protective mechanism in the JL that cuts the batteries off, outside of the crank event, if one is dead. Of course I may have missed that, or it may exist and have yet to be cited.

To @allieboy's point, with that jumper the aux/ESS battery can be taken out of the picture, but if you don't turn the ESS system off, I suspect it will drain the main battery when engaged. I'm not certain. In theory, the ESS battery is checked for good current before an ESS event, which with this jumper one might conclude is now the current in both batteries, or just the main one if the ESS battery is disconnected, after the N1-N2 jumpering.

And if one battery goes bad, as you say, defining that as a defective battery with parasitic drain of the other but not accepting that charging, yeah, I'd agree with you about them possibly both having no charge afterwards.

I guess parallel connections bring out the best and worst in batteries: coming to another one's aid, or the defective one sucking the other dry.

: - )

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Maybe wise to carry a spare ess battery of I'm up 75 miles into death valley or out in the senoran desert? That would start Jeep in a lonely dead isolated place... Not that I want to be out there alone. Thinking out loud to all your great info.

 

[Rahneld]

Maybe wise to carry a spare ess battery of I'm up 75 miles into death valley or out in the senoran desert? That would start Jeep in a lonely dead isolated place... Not that I want to be out there alone. Thinking out loud to all your great info.

I've been thinking about your scenario regarding the best ways, and their costs, for maximizing the chances that a 3.6L has the energy to crank in the middle of nowhere.

* One approach is to install the jumper on N1 and N2 highlighted at the top of this thread. You could keep the fuse of this link in the glove box so the wire's there (but disabled) to enable with the insertion of a fuse mere seconds before the "2nd crank" (the 1st failing)----which would prevent the batteries from being isolated at the moment of crank.

This hot (fuse inside) jumper would insure that both batteries signal the starter relay, not just the ESS. But again, your point about parasitic drain of the main battery by a defective ESS, or vice versa, is noted, and apt to occur with this jumper or not. 99.9% of the time those batteries are in parallel. The jumper adds the .1%: the moment of crank when the batteries are isolated, and/or during an ESS event.

* Another approach is your ESS battery backup idea, which sounds smart--although I'm no expert. It's bound to be less expensive to buy that smaller battery given the size of the main one. With your backup you could, in this order, 1) disconnect the main battery (so it doesn't drain your backup ESS if the main battery is your problem, or the main battery ran dry trying to charge your defective ESS one, 2) replace the failed ESS battery with your backup, successfully crank and be on your way. Again, a charged ESS battery alone should be able to crank your 3.6L

* In another approach you could acquire a dual battery kit discussed above, but with the new batteries required of it, it's expensive as "insurance policies" go, less so though if your desert trip includes taxing your batteries on appliances while, say, camping,

Most people don't have ESS battery problems I'm glad to report.

Nevertheless, this little thing....this "toy battery" if its not working, can leave you stranded. Like I've said before, it's like, to my way of thinking, an airplane being rendered unable to fly simply because one of its toilets clogged.

There are things the really knowledgeable owners (I'm not one) don't yet know about this system, let alone me. But I'll say this...

If I had one question I could ask the engineers who designed this it would be:

"On cold startup attempt, why not first isolate the batteries and test the ESS battery? If dead, why not then NOT isolate the batteries while energizing the starter relay, and allow either or both batteries to energize this critical engine starting component?"

And the beautiful irony, to my understanding, is that this is exactly what happens when stopped at a traffic light with the ESS system not shut off (i.e. the ESS button on the dash NOT illuminated.)

To point, assume every condition that permits ESS to happen is good, except the ESS battery is low (it is tested by the vehcile prior to an ESS event.) In that case ESS doesn't engage because if it did, at the end of that ESS event, the ESS battery, when isolated to fire the starter relay, may lack the juice to do so--especially since vehicle appliances might have drained it further were the ESS event to occur.

There may be reasons why FCA designed a cold crank this way that I'm too ignorant to understand why they're smart. I wonder if such crank logic changes I describe, if correct and useful, could even be downloaded to vehicles as software upgrades.

Thanks for the scenario Vic. It really solidifies a lot of the points trying to be conveyed in this thread.

: - )

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[Blu bi Kong]

Yeah I really do not anticipate an issue honestly. I carry a $54.00 cooler that runs when Jeep is running and not while Jeep is off. Never had an issue keeping suplies cool. ARB fridge/freezer takes up to much room. Winching, three times all with engine running, (Obviously). My thot was just a off the beat and path bit of knowledge to have in my brain! And there is ALOT of it here related to these batteries!
I may just put new batteries in every couple years. Their lifespan ise yets to be determined I guess.
This build is a process that just keeps on going!

 

[nerubi]

I've seen a video of what you have to do to replace the second battery and seems it would be easier to just get a new Jeep.

 

[Blu bi Kong]

I've seen a video of what you have to do to replace the second battery and seems it would be easier to just get a new Jeep.

What, taking the hood, the fender, the upper control arm and maybe the windshield off is to much work!!

 

[nerubi]

What, taking the hood, the fender, the upper control arm and maybe the windshield off is to much work!!

When he took off the rear bumper and both rear tires to get to it I decided that was too much.
To change the oil in new Bugattis you do have to disassemble half the cr, it takes 3 days and costs $21,000 so I guess shouldn't complain about a half day and $300 labor charge to change the battery.

 

[Rahneld]

I've seen a video of what you have to do to replace the second battery and seems it would be easier to just get a new Jeep.

Yeah, it's tucked away under the Power Distribution Center (PDC) I think. You've got to remove a couple of bolts--and know which ones, but I get the "funny."

Stranded, I'd like to think though that we whip out our charged Aux/ESS battery, complete with its own leads, disconnect the existing ESS battery without having to dig it out https://www.jlwranglerforums.com/fo...cables-jump-starting.24419/page-2#post-581867 , hook up ours and its leads to the same connection points, quickly crank up (to avoid parasitic drain,) shove the fresh Aux/ESS battery into some empty space under the hood, and hightail it back to town for the dealer to figure out the rest.

Heck, you could disconnect the main battery too before hooking up the replacement in case it's the culprit for parasitic drain. We seem to only need a working ESS battery for engine crank, which makes sense from what we know, but probably only a good idea in a pinch--because all isn't known about doing this.

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I'd just like to see someone offer a compatible larger battery to replace the Aux/ESS one, along with the space/hardware to fit it. From videos, it seems that even if the dual battery kit mentioned above was free, that it's installation, comparatively speaking, makes access to the Aux/ESS battery a picnic. : - )

~~~~~

 

[Mojito!]

What is the factory recommended lifespan , say in general way of the ess battery?

I received my latest Jeep-VHR report and it recommends factory battery maintenance. I've had mine since September 2018 and both batteries replaced in September 2019 under warranty.

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