Jump starters: who’s got one and what’s good?

jjs3845

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I expect that the only thing that changes with the firmware upgrade is the ESS/Aux battery test only runs once. This would not change any other aspect of starting or jump starting, both batteries are still in parallel and each would still have the same impact on starting or jump starting. Except with the old firmware, there is never an attempt to crank the starter if the ESS/Aux fails the test. With the new firmware, it will attempt to crank the starter with a bad ESS/Aux battery.
Jerry:
I too have a portable battery pack I bought a while ago for my previous vehicle and now have a 2021 Unlimited Sahara. The 2021 owners manual does state that a portable battery booster pack will work. Do you think this a new? and something changed?





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Gee-pah

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Jerry:
I too have a portable battery pack I bought a while ago for my previous vehicle and now have a 2021 Unlimited Sahara. The 2021 owners manual does state that a portable battery booster pack will work. Do you think this a new? and something changed?
Hey Joe:

Not Jerry @Jebiruph , but I have to laugh at what you report the owner's manual to say, as I have been hypothesizing this all along.

Here's what I think the deal is. I could be wrong. Jerry, if you know otherwise, please chime in. (BTW: much of this I learned from Jerry's initial work so cudos to him.)

The story involves some historical context. Sorry that this is long.



Stroll back to 2018. 3.6L JL's had to have adequate power in their ESS batteries for a cold crank to be attempted. Never mind that cold crank was energized by both main and ESS battery, it would never be attempted if the ESS battery didn't hold at least some charge (even if not enough charge to put the vehicle into an ESS event at a stop once the engine warmed up.)

Jerry actual developed a hack for this (links upon reference) hooking up the two batteries in parallel 100% of the time with simple straight forward wiring and a fuse. It was brilliant but may result in the vehicle's tests of the ESS battery being a composite test of both batteries. This could result in ESS events happening when the ESS battery tested alone (hard wired to the main battery now vis a vis the hack) wouldn't have had the current to permit the event, and taxing of the main battery during the ESS event, possibly robbing it of the cranking power it normally has after an ESS event because the ESS battery is **pretty much running the electrical needs of the vehicle during an ESS event when Jerry's hack isn't implemented, where both batteries run the ESS event when his hack IS implemented.

The hack could possibly also let ESS events run too long as tests of the ESS battery for power depletion during ESS events, that might cause the events to end early if the ESS battery is taxed too much, might be a composite test of both batteries with Jerry's hack allowing the ESS event to run longer than it should, robbing cranking power from the main battery.

The morale: the hack is awesome but might not be best used with letting ESS engage; the latter easy enough to turn off by ESS off button push, hack, or the purchase of tech (e.g. SmartStopStart).

(** Jerry, didn't you seem to think that power steering ran off the main battery during an ESS event, much that, with the wheel turned, ESS doesn't engage???)

That 2018 3.6L JL model year's owner's manual recommended during jump starting, the placement of energized jumper cables on the main battery for a time and waiting, before attempting a crank. I believe this was because of the fact that both batteries are connected in parallel when the rig is at rest (all model years BTW) and that this waiting period was really about putting a charge into the ESS battery (which could happen by virtue of the parallel connection to the main battery where the jumper cables are connected), so that tiny ESS battery would have enough power for the crank to even be attempted.

Most portable power packs are designed to release lots of current in small periods of time to overcome the inertia of getting the starter going, not as chargers (to an ESS battery.) So it's quite possible that many portable chargers spent some of their energy during this charging phase on juicing up the ESS battery (and the main battery as well BTW) and leaving inadequate charge in the power pack to help with the crank that followed.

Come model year 2019 and beyond and it seems that the design of the cold crank has been changed by FCA (again, thanks to Jerry's findings) such that if the ESS battery lacks adequate power, rather than strand the driver (as the case in the 2018 3.6L,), subsequent presses of the start button (with the brake pedal pressed of course) throw up a diagnostic code to tell the driver about the bad ESS battery, but switch the vehicle over to the main battery and attempt the crank.

Jerry also reported what appears to be a flash that gets model year 2018's to behave the way the 2019 3.6L JL's and newer do.

https://www.jlwranglerforums.com/forum/threads/3-6l-ess-bad-aux-battery-no-start-firmware-fix.53608/

Also note, as discussed and shown above in a prior thread, a fully charged ESS battery can alone crank a 3.6L JL.

~~~~~

So what are all the possible implications of these things related to you Joe?

It seems that this waiting period, if in the 2019 owner's manual (you tell me what's in the new manual) may not be (as) necessary anymore because the ESS battery getting charge isn't a prerequisite to crank the engine. So maybe your portable pack can be used shortly after it's connected to the main battery terminals without getting depleted in part with this aforementioned pre-crank charging/waiting phase.

And a portable pack that may have failed on a model year 2018 3.6L JL (without the aforementioned flash) spending its time charging the ESS (and main) battery may in fact work on a 2019 or newer 3.6L JL because the cold crank can be attempted right after the portable pack is hooked up to the main battery.

I keep on qualifying my remarks to pertain to the 3.6L because the 2.0L's electronics I am to understand are different.

What does the 2019 manual say on this waiting period Joe?
 
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Jebiruph

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Jerry:
I too have a portable battery pack I bought a while ago for my previous vehicle and now have a 2021 Unlimited Sahara. The 2021 owners manual does state that a portable battery booster pack will work. Do you think this a new? and something changed?
In theory portable battery packs have always worked as long as long as their level of charge was enough to over come the batteries level of depletion.
 

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Dkretden

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Jerry:
I too have a portable battery pack I bought a while ago for my previous vehicle and now have a 2021 Unlimited Sahara. The 2021 owners manual does state that a portable battery booster pack will work. Do you think this a new? and something changed?
Joe, can you post a picture of the page in the 2021 manual that says this? I would like to see what it says and compare the page to the 2020 manual.

thanks in advance if you can.
 

Gee-pah

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I would love all batteries packs to be tried this way on a 2018 3.6L JL without the previously mentioned flash (where the engine won't attempt a crank if the ESS battery lacks too much power):

1) charge pack
2) hook battery pack positive to ESS battery's easiest exposed positive cable and battery pack negative to ESS battery's easiest exposed negative cable. (@Jerbiruph Jerry knows what these are; I'll try to look them up.) N1 on the Power Distribution Center and the main battery negative post with all its cables connected.
3) try cranking immediately.

I would not be surprised if some battery packs succeeded doing this where following the advice in the 2018 3.6L JL's owner's manual would have failed them.

And I say this because:

1) The battery pack doesn't have to first charge the ESS battery, which by the 2018 owner manual technique also further depletes the battery pack by charges the main battery as well, because
2) When the ESS battery is tested for power prior to the crank it is hard wired parallel connected to the ESS battery by virtue of step 1) above, and doesn't to nearly as much acquire a charge of its own, so
3) the battery pack's full power (along with less wait time) can go towards cranking the engine, something a fully charged ESS battery (and/or with the battery pack "sistered" into it) can do without the main battery.

Once the rig is started the battery pack can be removed and the alternator can take over charging the batteries provided they accept charge.
 
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jeepdabest

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i have a 2019. Disconnect aux negative and jump main. You will throw a code which can be cleared with a obd11 reader and torque software.
 

Gee-pah

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Joe, can you post a picture of the page in the 2021 manual that says this? I would like to see what it says and compare the page to the 2020 manual.

thanks in advance if you can.
Any year's owner's manual can be found here.

https://www.mopar.com/en-us/my-vehicle/owners-manual.html

Having just looked both the 2018 and 2021 owner's manuals here, essentially each say the same thing, but it is possible it could mean different things for each of the model years; I don't know.

Let me clarify what I mean by that.

Both procedures provide for the acceptable use of a power pack or a donor vehicle, but for the donor vehicle, call for a wait period on the donor's cranked engine to idle.

Is this to let the donor's battery charge, and maybe for the 2018 3.6L JL the ESS battery tocharge?

I don't know. The verbiage is missing the reasons for this wait period, which in the post 2018 model years may only be about the donor battery working up charge, given the previous posts discussion on how the cold crank procedure may differ among model years..
 

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i have a 2019. Disconnect aux negative and jump main. You will throw a code which can be cleared with a obd11 reader and torque software.
Does the first crank attempt fail and throw the code, and subsequent crank attempts succeed, or is it something else?

Was/is a waiting period necessary?
 

jjs3845

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Hey Joe:

Not Jerry @Jebiruph , but I have to laugh at what you report the owner's manual to say, as I have been hypothesizing this all along.

Here's what I think the deal is. I could be wrong. Jerry, if you know otherwise, please chime in. (BTW: much of this I learned from Jerry's initial work so cudos to him.)

The story involves some historical context. Sorry that this is long.



Stroll back to 2018. 3.6L JL's had to have adequate power in their ESS batteries for a cold crank to be attempted. Never mind that cold crank was energized by both main and ESS battery, it would never be attempted if the ESS battery didn't hold at least some charge (even if not enough charge to put the vehicle into an ESS event at a stop once the engine warmed up.)

Jerry actual developed a hack for this (links upon reference) hooking up the two batteries in parallel 100% of the time with simple straight forward wiring and a fuse. It was brilliant but may result in the vehicle's tests of the ESS battery being a composite test of both batteries. This could result in ESS events happening when the ESS battery tested alone (hard wired to the main battery now vis a vis the hack) wouldn't have had the current to permit the event, and taxing of the main battery during the ESS event, possibly robbing it of the cranking power it normally has after an ESS event because the ESS battery is **pretty much running the electrical needs of the vehicle during an ESS event when Jerry's hack isn't implemented, where both batteries run the ESS event when his hack IS implemented.

The hack could possibly also let ESS events run too long as tests of the ESS battery for power depletion during ESS events, that might cause the events to end early if the ESS battery is taxed too much, might be a composite test of both batteries with Jerry's hack allowing the ESS event to run longer than it should, robbing cranking power from the main battery.

The morale: the hack is awesome but might not be best used with letting ESS engage; the latter easy enough to turn off by ESS off button push, hack, or the purchase of tech (e.g. SmartStopStart).

(** Jerry, didn't you seem to think that power steering ran off the main battery during an ESS event, much that, with the wheel turned, ESS doesn't engage???)

That 2018 3.6L JL model year's owner's manual recommended during jump starting, the placement of energized jumper cables on the main battery for a time and waiting, before attempting a crank. I believe this was because of the fact that both batteries are connected in parallel when the rig is at rest (all model years BTW) and that this waiting period was really about putting a charge into the ESS battery (which could happen by virtue of the parallel connection to the main battery where the jumper cables are connected), so that tiny ESS battery would have enough power for the crank to even be attempted.

Most portable power packs are designed to release lots of current in small periods of time to overcome the inertia of getting the starter going, not as chargers (to an ESS battery.) So it's quite possible that many portable chargers spent some of their energy during this charging phase on juicing up the ESS battery (and the main battery as well BTW) and leaving inadequate charge in the power pack to help with the crank that followed.

Come model year 2019 and beyond and it seems that the design of the cold crank has been changed by FCA (again, thanks to Jerry's findings) such that if the ESS battery lacks adequate power, rather than strand the driver (as the case in the 2018 3.6L,), subsequent presses of the start button (with the brake pedal pressed of course) throw up a diagnostic code to tell the driver about the bad ESS battery, but switch the vehicle over to the main battery and attempt the crank.

Jerry also reported what appears to be a flash that gets model year 2018's to behave the way the 2019 3.6L JL's and newer do.

https://www.jlwranglerforums.com/forum/threads/3-6l-ess-bad-aux-battery-no-start-firmware-fix.53608/

Also note, as discussed and shown above in a prior thread, a fully charged ESS battery can alone crank a 3.6L JL.

~~~~~

So what are all the possible implications of these things related to you Joe?

It seems that this waiting period, if in the 2019 owner's manual (you tell me what's in the new manual) may not be (as) necessary anymore because the ESS battery getting charge isn't a prerequisite to crank the engine. So maybe your portable pack can be used shortly after it's connected to the main battery terminals without getting depleted in part with this aforementioned pre-crank charging/waiting phase.

And a portable pack that may have failed on a model year 2018 3.6L JL (without the aforementioned flash) spending its time charging the ESS (and main) battery may in fact work on a 2019 or newer 3.6L JL because the cold crank can be attempted right after the portable pack is hooked up to the main battery.

I keep on qualifying my remarks to pertain to the 3.6L because the 2.0L's electronics I am to understand are different.

What does the 2019 manual say on this waiting period Joe?
I did not see anything in the manual about a waiting period but I will look it over again. In the section about jump starting it does mention there's two batteries, but that's all. It just mentions it. Makes me wonder why they put that in.

I'll check it out
 

Gee-pah

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I did not see anything in the manual about a waiting period but I will look it over again. In the section about jump starting it does mention there's two batteries, but that's all. It just mentions it. Makes me wonder why they put that in.

I'll check it out
IMHO, it's carefully written code speak that in 2018 meant that the 3.6L JL had a waiting period where 1) the donor battery charged the ESS battery, and that, by the way, 2) as in all good jump starts allowed the donor vehicle's cranked engine to charge the donor battery, that in 2019+ model years and beyond, as well as flashed 2018's, has only "2)" apply.

In short, you don't have to charge the ESS battery if the testing of its charge in isolation prior to crank is no longer a necessary condition to crank the vehicle, as appears to be the case in flashed 2018 3.6L JL's and model years that are newer.

This is just theory but backed by reports on the forum.
 

jjs3845

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IMHO, it's carefully written code speak that in 2018 meant that the 3.6L JL had a waiting period where 1) the donor battery charged the ESS battery, and that, by the way, 2) as in all good jump starts allowed the donor vehicle's cranked engine to charge the donor battery, that in 2019+ model years and beyond, as well as flashed 2018's, has only "2)" apply.

In short, you don't have to charge the ESS battery if the testing of its charge in isolation prior to crank is no longer a necessary condition to crank the vehicle, as appears to be the case in flashed 2018 3.6L JL's and model years that are newer.

This is just theory but backed by reports on the forum.
Who would have ever thought that some poor soul stuck somewhere with a dead battery would be such an issue?
 

yngrshr

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I have the NOCO GB70 that I use for work. It jumped 18 small cars off without a recharge and still was showing full charge when I decided to charge it. I really like it.

https://www.amazon.com/NOCO-GB70-Ul...coding=UTF8&psc=1&refRID=MTGNXDKD6MM0TTGF805A
I know a number of people have said that they have this, but I'll chime in and say the same. Phenomenal product and has worked more than a few times on batteries in either my car or SUV that have been sitting for a while at various times depending on use (or lack thereof). Super portable as well, so great for road trips.
 

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This does work.... BUT the key is let the donor battery vehicle has to be more then a lawn mower... I did this with a Toyota 4 dr sedan and after 15 to 20 minutes started the Jeep. I did more then idle, I race up the engine in the donor vehicle because the donor vehicle needed to put some juice into the Jeep battery to get it from 0 voltage to some voltage...

I do have the jumper wire for adding big battery jumping to smaller battery but just jumped it after PM with the author of the jumping wire.

Keep the faith and fallow the suggestions and your Jeep will live to tell about it.


Dollars to donuts, your power pack will not be able to do the job with any JL or JT, regardless of 2018, 2019, 2020. Sure with a single 12v battery, stock, JK, it will...

Power pack (even a top notch one) just doesn't have enough oomph, lets call it, to do the job.

I have friends that are Techs at dealerships and even they , long ago, gave up trying to jump start JL's with battery packs.

For pretty much a sure thing in regard to jumping starting a JL, just hook up the JL with the depleted battery(s) to a 12v donor vehicle, with quality (not el cheapo jumper cables)jumper cables and have the donor vehicle's engine running.

Now, leave the JL and donor hooked up to the running 12v donor, like that for 10-15 min., and then try to start/ start the JL.

More often then not, the JL will start with this method...

With battery power pack your chances are say 1 in 10 that the power pack will do the job.

Note: I'm not saying no one ever has been able to start a JL with a top notch battery pack but again, not all that often doing so is successful.
 

Gee-pah

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This does work.... BUT the key is let the donor battery vehicle has to be more then a lawn mower... I did this with a Toyota 4 dr sedan and after 15 to 20 minutes started the Jeep. I did more then idle, I race up the engine in the donor vehicle because the donor vehicle needed to put some juice into the Jeep battery to get it from 0 voltage to some voltage...

I do have the jumper wire for adding big battery jumping to smaller battery but just jumped it after PM with the author of the jumping wire.

Keep the faith and fallow the suggestions and your Jeep will live to tell about it.

Jack, what you write above regarding waiting may be a technique that works for you on your 2018 3.6L JL, but I'm of the believe there are two better courses.

In order to appreciate why, understanding of what's happening when you sit with energized jumper cables on the main battery is required. If you do know, perhaps others don't.

The real underlying purpose in what your doing, IMHO, is charging the ESS battery. In 2018 3.6L JL's that haven't been flashed https://www.jlwranglerforums.com/forum/threads/3-6l-ess-bad-aux-battery-no-start-firmware-fix.53608/ prior to the vehicle attempting a crank, the ESS battery will be tested in isolation for basic power. (TSB 18-092-19 )

If it lacks it the crank won't be attempted--even if the main battery, (which if the above test is passed the ESS battery is then connected to in parallel) has all the power in the world to crank the engine. Both batteries energize the crank. In fact a charged ESS battery can do it alone, but in a 2018 3.6L the main battery (with the ESS battery disconnected) cannot for the reasons just described.


Think about that. If the ESS tiny battery can crank the 3.6L JL alone, then perhaps atomic power packs are not as important as the technique used to jump start. (read on)

And this charging that your doing, which is possible because the two batteries are connected in parallel at all time but for this aforementioned test and ESS events, is also charging the main battery.

That could deplete a power source other than a donor vehicle (e.g. a power pack) whose engine is on and its alternator is charging the donor battery, leaving inadequate power to effect the crank in the case of a power pack.

So yes, power pack strength matters, but technique matters too.

And this technique involves connecting your donor to the negative terminal on the main battery and (this might take putting a lead on it--its hard for alligator clips to only attach to it), the N1 terminal (connected to the ESS battery) in the PDS (power distribution center). This N1 is closest to the front in the PDS on the driver's most side.

https://www.jlwranglerforums.com/forum/threads/3-6l-ess-battery-diagram.14401/

This allows the ESS battery to be the only one charged by your donor and probably will allow for a quicker time before attempting a crank because when the ESS battery is tested, it is parallel to the donor power source, whose power is read in the pre-crank test.

This behavior of no crank if ESS battery dead in 2018 3.6L JL's seems to not be in 2019 model year and later JLs, and addressed with the flash linked above. When the ESS battery is dead in these other vehicles, it appears that the driver is not left stranded, but rather subsequent crank attempts occur from the main battery. I would guess in these JLs that waiting on the donor battery, at least for the JL side of the jump start, is not as essential.

The owner's manual has said to wait on the donor vehicle since 2018. It's my belief in 2018 it was primarily to charge the ESS battery, and today, it's more to make sure the donor vehicle's alternator is given time to charge the donor battery, and overall less necessary.
 

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