Drained Battery, Any jumpstart tips??

[Gee-pah]

Scott, like (I think) Jerry @Jebiruph, your non 3.6L JL is simply beyond my knowledge.

I too hope you'll share your findings so I can learn more about this system.

Thanks

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[CoolToys]

Scott, like (I think) Jerry @Jebiruph, your non 3.6L JL is simply beyond my knowledge.

I too hope you'll share your findings so I can learn more about this system.

Thanks

I don't know how much I really want to know about the Hybrid system. What I learned is don't let it sit for more than a week. Thats all I need. FCA should have a voltage cutoff so that you preserve enough to start it. It's not like the clock needs to know the time.

I did find a thread on another forum that said the NOCO Genius 15A charger will bring this beast from dead to startable in about 3 hours. So I am off to buy one at Long Beach Battery in a bit.

I am going to wire in the harness with the plug run to front grill behind the bumper unless I can find a cool connect kit.

In dreamland I'll trade it in next year for the EcoDiesel if the bugs get worked out of that drivetrain, if not maybe I'll go back to a CJ5 or CJ7 or two door unlimited TY. The Defender 110 looks pretty good on paper, but I already have an F-Pace Diesel.

 

[Jebiruph]

I talked prior about the easiest way to test the ESS/Aux battery on a 3.6L JL is, with engine off, is to temporarily yank the negative cables off the main battery post, and put your tester's negative side to these dangling cables, and its positive side to the main battery's positive post.

IMHO the best way to facilitate quick jump starts in the 3.6L is to buy an Anderson hook up to eyelits cable like this:

https://www.polepalsolarlightingsys...ndard-size-winch-2-ga-wire-0.364#.Xh4TXndFy1s

Put the positive on N1 (and ONLY N1) in the PDC. The negative can go on the main battery's negative terminal. (You may have to bend the positive eyelit 90 degrees to get the PDC cover to close.)

Then get an Anderson hook up to alligator clips cable. It looks like the shorter cable here on the right. This vendor will sell you cables of any length with anything on the ends you want (eyelits, Anderson connectors, alligator clips, etc.)

If your rig won't crank, temporarily connect the two cables at their Anderson connectors and the alligator clips to those of a working power source and crank.

You've direct connected to the ESS/Aux battery. Try cranking as soon as you'd like.

Put the Anderson connector to alligator clips cable away thereafter.

I think trying to jump start from N1 is a bad idea and it's discussed here. https://www.jlwranglerforums.com/fo...al-ess-aux-battery-jumpstart-dangerous.42570/ . Not mentioned in that post, but it's also possible you could blow the 150 A PCR (ESS) fuse.

 

[Gee-pah]

I think trying to jump start from N1 is a bad idea and it's discussed here. https://www.jlwranglerforums.com/fo...al-ess-aux-battery-jumpstart-dangerous.42570/ . Not mentioned in that post, but it's also possible you could blow the 150 A PCR (ESS) fuse.

This is well taken Jerry @Jebiruph....thanks.

Perhaps I should explain my logic.

The very diagram in the link to the thread you provide shows N1 directly connected to the ESS/Aux battery--and it's why I choose N1 as place to hook up directly to the ESS/Aux battery.

In the 3.6L, this method of hookup I suggested, which differs from the owner's manual recommendation on jump starting to the main battery's terminals, focuses any charging the jumping source can provide directly on to the ESS/Aux battery alone, rather than both batteries (as the manual's method effectively does because both batteries are connected in parallel while the rig's at rest.) Still more, as the jumping source and the ESS/Aux battery are direct parallel connected in my approach, this means it might allow the rig to "see" the ESS/Aux battery as having adequate charge ASAP (because the ESS/Aux battery and jumping source are hard wired in parallel and seen by the rig "as one") and attempt a crank when the start button is pressed.

Putting a small power pack of questionably adequate charge to crank the rig on the main battery terminals and waiting (as per the manual) depletes the power pack of charge for the crank as its power flow empties, in part, also into the main battery during the owner's manual's "waiting period" method, rather than focusing on the ESS/Aux battery reaching a threshold of power for the crank to even be attempting by the rig. Why waste limited power pack current on a main battery not even needed to effect the crank was my logic. The goal is to get the rig to "see" the ESS/Aux battery of having adequate power to even attempt the crank when the ESS/Aux battery (and anything directly parallel connected to it) is tested in isolation by the rig pre-crank, to even see if the ESS/Aux battery has enough power to even attempt the crank.


This said, assuming my method a reasonable approach (maybe you disagree) it seems to me the only other option is to bypass N1, dig out the ESS/Aux battery, and attach the positive end of a permanently installed jumper cable under the hood to the positive pole of the ESS/Aux battery instead of using N1.

Getting the cable to fit in the PDC and shut the cover was enough of an obstacle. I'm afraid that getting a cable to fit when on top of the ESS/Aux battery compartment lies the PDC box, may prove difficult.

This leaves me with the following questions for you.

• Do you concur that my approach to adding a permanent jumper cable under the hood that maximizes the chances that the rig cranks, even if the jumping source may have just enough power to do so, makes sense both schematically and in focusing current directly on the ESS/Aux battery, even if you think going through N1 is a bad idea?
• If so, in lieu of attaching to N1, where would you hook the positive side of a permanent jumper cable under the hood to--the ESS/Aux battery positive post as suggested, someplace else?

My goal is to maximize the chances that an owner, stranded from civilization with a power pack, maximizes their chances of successfully cranking, while not blowing fuses should such failure to crank occur on their driveway and some tow truck with extra large jumping power be the power source (much that with the tow truck the owner's manual method of jumping can be followed as more than ample current is likely provided by the tow truck.)

Installing a permanent cable to the ESS/Aux battery under the hood to which a jumping source can attach, to my way of thinking was like (to make a metaphor) putting an IV into a hospitalized patient's arm, through which juice (electrical current/medication) could directly flow to where it's needed most (the ESS/Aux battery.)

Please critique my approach. Thanks.

And as for the other reason to not bypass the main battery:

"Only use the positive battery post on the main battery to jump start your vehicle. Serious injury or death could result if you attempt to jump start using the supplemental battery."

Why on earth so--which was basically your take on this too?

 

[Jebiruph]

When you are trying to jump start your jeep, the critical hurdle is getting enough power to the starter to crank the engine. Connecting the jump starter as close to the starter as possible reduces power loss caused by the accumulated wire and connection resistance. @Gee-pah, as you can see in this diagram, your method goes B (N1) - aux - PCR - N3 - PCR fuse - N2 - main - starter. This puts you as electrically far away from the starter as possible, putting the maximum amount of power robbing resistance in the path of the jump start. You also risk blowing the 150A PCR fuse. It is better to jump start using the main battery positive terminal (A) and manage the batteries with the negative cables, N1 to N2 jumper or unplugging the PCR as necessary.

 

[Gee-pah]

When you are trying to jump start your jeep, the critical hurdle is getting enough power to the starter to crank the engine. Connecting the jump starter as close to the starter as possible reduces power loss caused by the accumulated wire and connection resistance. @Gee-pah, as you can see in this diagram, your method goes B (N1) - aux - PCR - N3 - PCR fuse - N2 - main - starter. This puts you as electrically far away from the starter as possible, putting the maximum amount of power robbing resistance in the path of the jump start. You also risk blowing the 150A PCR fuse. It is better to jump start using the main battery positive terminal (A) and manage the batteries with the negative cables, N1 to N2 jumper or unplugging the PCR as necessary.

Thanks for your reply Jerry. And it's not that I didn't appreciate your thoughts about creating proximity between the jump starting power source and the starter...

...rather it's this:

Your method, i.e. the conventional owner's manual method of jump starting, necessitates that you sit for a while with what might be a questionably powerful enough jump starting source--like say some portable power pack you took into the wilderness with a now "dead rig," connected to the main battery, while it depletes itself in part, charging both batteries (as N1 and N2 are connected when the rig's at rest, correct?).

Such portable power packs (as I suspect you know) are inherently deep cycle type devices--with tendencies to delivery lots of charge in short periods of time--such as required to overcome the inertia of cranking an engine. Battery charging is often not their forte. And if a power pack actually had enough power in it at the onset trying to jump start a 3.6L, it may not have enough power to do so if time is spent depleting it on first charging, in particular, the main battery, technically not needed for the cranking to occur.

As I understand it, this whole waiting process in jump starting the 3.6L is really about charging the ESS/Aux battery enough, that when examined by the rig in isolation, pre-cold crank request by the owner, its power level is adequate enough for the rig to attempt a crank. To my way of thinking, maybe incorrectly, charging the main battery as well "robs" the ESS/Aux battery and a portable power pack.

I sought to hard wire a power source to the ESS/Aux battery so the 3.6L's diagnostics would "see" the ESS/Aux battery as having power--given that it is "sistered" to the power pack, ASAP, with little time wasted to devote the power pack's limited power to effect a successful cold crank rather than charge the ESS/Aux battery.

But I think you get my approach---good or bad.

~~~~~

I'd like to suggest something else that involves combining my approach with something you've said before. I'm curious to your thoughts on it.

Owners can, consistent with your previously posted hack, where N1 and N2 are hardwired to each other (but where a fuse lies in between to protect N2) can combine this with your approach of attaching a jumping source to the main battery.

https://www.jlwranglerforums.com/forum/threads/3-6l-ess-dual-battery-consolidated-information.25377/

and specifically https://www.jlwranglerforums.com/forum/threads/3-6l-ess-aux-battery-bypass.17293/


This, as I see it, perhaps prevents the ESS/Aux battery from being isolated during its pre-crank test of power, (if not during ESS events as well.)

For the purist, such a connection between N1 and N2 could be with an on and off switch to turn "on" just for jump starting quickly, especially of the power source has limited power.

I may be wrong, but would this solve issue with having to wait on a jump starting source, while it charges the ESS/Aux battery enough to pass the pre-crank testing of its power by the 3.6L when its examined in isolated from the main battery (because now it's hard wired parallel connected to the main battery), all while protecting N2 given the fuse that's part of your hard wiring hack?

Thanks in advance for your thoughts on this.

 

[Jebiruph]

I sought to hard wire a power source to the ESS/Aux battery so the 3.6L's diagnostics would "see" the ESS/Aux battery as having power--given that it is "sistered" to the power pack, ASAP, with little time wasted to devote the power pack's limited power to effect a successful cold crank rather than charge the ESS/Aux battery.

If I connect my power pack to the main terminal, then I do have that same long path back the other way to aux battery to power the cold start ESS test. The difference is, the amount of power lost due to the accumulated resistance of the wiring is directly related to the amps going through the wire. Since the starter draws considerably more amps than the ESS cold start test, connecting the power pack to the main battery terminal, close to the starter, is more efficient use of it's limited power. If you use the fused jumper between N1 and N2, you've effectively connected your power pack to N1 anyway. So connecting it to the main battery terminal and using a fused jumper between N1 and N2 looks like the most efficient use of a power pack's limited power.

 

[Gee-pah]

If I connect my power pack to the main terminal, then I do have that same long path back the other way to aux battery to power the cold start ESS test.

Fair.

The difference is, the amount of power lost due to the accumulated resistance of the wiring is directly related to the amps going through the wire. Since the starter draws considerably more amps than the ESS cold start test, connecting the power pack to the main battery terminal, close to the starter, is more efficient use of it's limited power.

Fair--but doing so, without your fused jumpering of N1-N2 (I realize you cover this below) would necessitate time spent depleting the power pack on charging the ESS/Aux battery enough to pass the pre-cold crank test by the 3.6L because as per factory, that ESS/Aux battery is going to be tested pre crank, in isolation.

Further, such power pack charging of the main battery--which while tapped if available to effect the crank, isn't needed if the ESS/Aux battery (in combination with a power pack parallel connected to the ESS/Aux battery) has sufficient power.

If you use the fused jumper between N1 and N2, you've effectively connected your power pack to N1 anyway.

I'm sorry if I didn't make myself clearer above sir, but the above sentence of yours is precisely, and the essence of my point.

So connecting it to the main battery terminal and using a fused jumper between N1 and N2 looks like the most efficient use of a power pack's limited power.

Agreed, and for what I hope we concur are the following reasons:

• Your fused N1-N2 jumper hack protects N2 from being blown. It's much less expensive to replace your hack's fuse than the entire high order fuse bar in the PDC, which is the cheapest remedy when any of this fuse bar's fuses are blown--let alone having to buy a whole new PDC with a new fuse bar in it.
• Your fused N1-N2 jumper hack hopefully allows the pre cold crank test to see the ESS/Aux battery not in isolation, but as 3 batteries: itself, the main, and the power pack.
• Your fused N1-N2 jumper hack allows the power pack to be hooked up to the terminals of the main battery, to create, as you mention, the shortest route to the energy demanding starter.
• This approach would in theory, allow minimal time for the power pack to be spent charging the ESS/Aux battery (worse the main one not needed here), robbing the pack of precious power needed to effect the cold crank. It would make for a situation in what is most convenient for the 3.6L owner (not having to wait as per the manual) also increases the chances that the crank would be attempted and be successful.

Thank you for your time.

 

[Jebiruph]

Fair--but doing so, without your fused jumpering of N1-N2 (I realize you cover this below) would necessitate time spent depleting the power pack on charging the ESS/Aux battery enough to pass the pre-cold crank test by the 3.6L because as per factory, that ESS/Aux battery is going to be tested pre crank, in isolation.

To be honest, I kept missing this point you were trying to make because with as much discussion as there has been on this system, it didn't occur to me that someone would attempt to charge the aux battery from a power pack enough to pass the cold start test as opposed to bypassing the test with the fused jumper or PCR unplug.

 

[2Wander]

Sunday my battery died after leaving in ACC overnight. Long story short, much like others here, charger did nothing, quick jump got a turnover and then nothing, prolonged charging via the jump start brought her around to start. YAY! Bad news.. and I need to ask the dealer more about this issue, once started and run for an hour, the ESS WARNING light came on and said take to dealer. My infotainment system never came back on. No radio, backup camera (although the sensors still worked on the display cluster), no display of heat controls, no USB port connections etc. Took it to the dealer and they said “an underlying problem with the system caused the aux battery to go bad and that somehow shorted the head unit and a hood pin switxh”. They are replacing the battery, hood pin, and ordering a new head unit which I was told by them would take 1-2 months to get in. Guess I will be practicing my whistling skills for a few months.

 

[CoolToys]

Bummer and interesting that could all happen. Maybe a bluetooth speaker duct taped to the roll cage?

I did as others suggested and added a permanent battery tender connection that can be plugged in without opening the hood.

My wife's Jag F-Pace died in the same way, so my apologies to the Jeep Wave agent that took the brunt of my frustration. it appears all the car companies are overloading and under powering their standby electrical systems.

But then again, really Jeep? Even if ACC mode left on (easy to do w keyless) battery should self shed to protect enough voltage to start. I do travel 8-10 days straight sometimes shooting the show, and the JLU stays home because I do not want to arrive at midnight to find a dead battery that wont start with a single 1400 CCA rescue battery.

 

[Cthehentz]

So, with all the drama regarding small jump boxes would it be best to carry the old school 90lb jump box?

 

[wolfdog]

Wow I have a 2018 JLU and have not had a Jump situation...oops should not have sais that!! I do however have a 2015Cherokee Trailhawk that has one large HD battery and ESS. Regular jump works fine and best of all ESS work faster and smoother that the JL??? I heard the JL with 2.0 has it's batteries under the vehicle...wha'ts with that, you lay on the ground to initiate a jump????

Ohhh Jeep what's happened to you?? I thought with my 27th Jeep (JLUS) we'd be really uphill with all this crap!!

Go Jeep!!!

 

[CoolToys]

So, with all the drama regarding small jump boxes would it be best to carry the old school 90lb jump box?

we did get two of the Dewalt 1400 cca jumpers to work. Just connect both, wait 5 min and off you go.

OR

drive it more that once a week and make sure you didn’t leave it in ACC mode.

Maybe, if the doors are locked ACC mode could turn off after 30 min? There might be a setting in there somewhere. I’ll look next week.

 

[roaniecowpony]

So, with all the drama regarding small jump boxes would it be best to carry the old school 90lb jump box?

My guess is no. I don't believe it matters whether the battery is a lead acid or lithium. What I believe matters is total energy in the jump pack battery and voltage.

A battery like a lithium, nickel-cadmium, or nickel-metal-hydride, that has the capability to discharge at very high rates, I don't believe will be hindered when called on to discharge at low rates. That's why an Emergency Locator Transmitter (ELT) in a modern airplane that has a lithium battery, will work very well to long periods of transmitting a signal, at low discharge rates.

Also, when batteries are hooked together, they will seek equilibrium. That is: they will seek to balance their voltage. Hook up a dead car battery to charged lithium battery and a lead acid battery, both with the same voltage and same total energy, and they will both seek balance with the dead car battery(s). I believe only a very low discharge rate capable battery would be a hinderance in jump starting, not a high discharge rate.

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