Jumping your Jeep..... who has done it with a battery pack?

[roaniecowpony]

...to state another way: the extent to which your JL's battery[ies] are charged, even if unable to crank the engine, can vary even if you could keep the power pack's power constant between tests.

At least on the 3.6L JL, Jerry and I discuss here how one might, with Jerry's fused jumpering of the N1 and N2 high amp fuses in the Power Distribution Center hack, connect a power pack directly to the ESS/Aux battery to increase the chances that a pack will get the 3.6L to crank.

https://www.jlwranglerforums.com/fo...-any-jumpstart-tips.12316/page-11#post-986785

Seems like the easy way to go is to just buy a higher capacity jump pack, or buy two small ones and put them in parallel. That Audew pack looks like it cranked a small tractor by itself.

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[Gee-pah]

Bobby, while this YouTube contributor is in "my book," an A+ thorough "Consumer Reports Clinical" like guy, at least on the 3.6L JL, his testing may have limited applicability when jumping the rig using the owner's manual method of connecting a jumping power source to the main battery's terminals and waiting.

Perhaps known to you, these power packs tend to be engineered to delivering a large amount of power in a short period of time for getting over the inertia threshold needed to crank an engine, as they should be.

But the 3.6L, and that wait period, is about charging the ESS/Aux battery to a threshold that below which, the 3.6L's computer will not even attempt the crank...even if, for argument sake, the main battery is fully charged.

(Let's set aside the fact that both batteries are connected in parallel on this version of the JL when it's at rest, and a fully charged main battery would charge an ESS/Aux battery with less charge, and not defectively unable to accept that charge.)

This waiting period robs the power pack of power to crank the engine. Further more, using the owner's manual method, you're also wasting precious power pack power charging the main battery was well.

You see, the 3.6L tests the ESS/Aux battery alone before attempting a crank, and if it has suitable power it then attempts the crank using both batteries "if available." These quotes address the fact that a 3.6L can crank with a charged ESS/Aux battery alone, but not a main battery alone.

It is these very facts that prompted discussion of how one might connect the power pack (safely) directly to (and only) the ESS/Aux in parallel to not only increase the chances for a successful crank, but do without the waiting period. That discussion is linked in my immediately prior post.

 

[Gee-pah]

Seems like the easy way to go is to just buy a higher capacity jump pack, or buy two small ones and put them in parallel. That Audew pack looks like it cranked a small tractor by itself.

Here's the rub. Power packs, even the one you reference, are designed more to deliver lots of charge quickly, more so that charging batteries---

--which at least on the 3.6L is what happens during the owner's manual waiting period, on the ESS/Aux battery.

I'm not saying this high end pack won't work, or the parallel idea is without worth (I hope it does.) Clearly the big one on wheels dealers lug around to charge 3.6L JL inventory do.

Rather I'm saying that the 3.6L design of first requiring charging (of the ESS/Aux battery) often doesn't mesh well with how power packs are designed to delivery quick high power.

This is why I discuss how to optimize the nature of a power pack's fast charge design, in the aforementioned link, to direct connect with the ESS/Aux battery on 3.6L JLs.

 

[roaniecowpony]

Here's the rub. Power packs, even the one you reference, are designed more to deliver lots of charge quickly, more so that charging batteries---

--which at least on the 3.6L is what happens during the owner's manual waiting period, on the ESS/Aux battery.

I'm not saying this high end pack won't work, or the parallel idea is without worth (I hope it does.) Clearly the big one on wheels dealers lug around to charge 3.6L JL inventory do.

Rather I'm saying that the 3.6L design of first requiring charging (of the ESS/Aux battery) often doesn't mesh well with how power packs are designed to delivery quick high power.

This is why I discuss how to optimize the nature of a power pack's fast charge design, in the aforementioned link, to direct connect with the ESS/Aux battery on 3.6L JLs.

A few questions:
When the JL starter is engaged, does the system use the main battery only, ESS only, or join the main battery and ESS together?
When accessories run on the system (radio, fridge, etc.) does the power come from the main, ESS, or both?

 

[uawho]

I have a Gooloo 20800mAh model.
I just got my JLUR, so I have not needed to jump start it.
But I think this thread is a great resource to start to nail down some specs that will/could/may work on a completely dead main battery.

It sounds like the focus is shifting (appropriately) to the "capacity" of the charger, and not necessarily the short term peak flow capability.

 

[jeepdabest]

Bobby, while this YouTube contributor is in "my book," an A+ thorough "Consumer Reports Clinical" like guy, at least on the 3.6L JL, his testing may have limited applicability when jumping the rig using the owner's manual method of connecting a jumping power source to the main battery's terminals and waiting.

Perhaps known to you, these power packs tend to be engineered to delivering a large amount of power in a short period of time for getting over the inertia threshold needed to crank an engine, as they should be.

But the 3.6L, and that wait period, is about charging the ESS/Aux battery to a threshold that below which, the 3.6L's computer will not even attempt the crank...even if, for argument sake, the main battery is fully charged.

(Let's set aside the fact that both batteries are connected in parallel on this version of the JL when it's at rest, and a fully charged main battery would charge an ESS/Aux battery with less charge, and not defectively unable to accept that charge.)

This waiting period robs the power pack of power to crank the engine. Further more, using the owner's manual method, you're also wasting precious power pack power charging the main battery was well.

You see, the 3.6L tests the ESS/Aux battery alone before attempting a crank, and if it has suitable power it then attempts the crank using both batteries "if available." These quotes address the fact that a 3.6L can crank with a charged ESS/Aux battery alone, but not a main battery alone.

It is these very facts that prompted discussion of how one might connect the power pack (safely) directly to (and only) the ESS/Aux in parallel to not only increase the chances for a successful crank, but do without the waiting period. That discussion is linked in my immediately prior post.

Uh, I can start my Jeep without the aux connected and jump it without the aux connected.

 

[roaniecowpony]

I'm not an electrical engineer, but it seems to me any battery with a high discharge rate capability would not be a limitation when connected to a depleted battery with a lower discharge rate, when attempting to "charge" the depleted battery. The batteries should seek equilibrium at a rate based on voltage delta and sum of individual component resistance between the two. I believe a battery with a high discharge capabilities is indicative of low internal resistance. That should mean less electrical energy is converted to heat within the battery itself when charging or discharging. No?

 

[jeepdabest]

I'm not an electrical engineer, but it seems to me any battery with a high discharge rate capability would not be a limitation when connected to a depleted battery with a lower discharge rate, when attempting to "charge" the depleted battery. The batteries should seek equilibrium at a rate based on voltage delta and sum of individual component resistance between the two. I believe a battery with a high discharge capabilities is indicative of low internal resistance. That should mean less electrical energy is converted to heat within the battery itself when charging or discharging. No?

You had me at voltage delta.

 

[roaniecowpony]

You had me at voltage delta.

voltage difference

 

[jeepdabest]

voltage difference

Shhhh....say no more

 

[Ma$$iveDebtAche]

Jumping your Jeep.....

 

[jeepdabest]

Jumping your Jeep.....

 

[Cthehentz]

So if I understand what you guys are saying is this is not a simple jumpstart? The main battery can have full charge but the small ess battery is dead so basically your dead in the water? Now I've had older diesels that had two batteries in parallel and if one was weak it would drain the other. But you guys are saying this is separate right?

 

[Dkretden]

Bobby, while this YouTube contributor is in "my book," an A+ thorough "Consumer Reports Clinical" like guy, at least on the 3.6L JL, his testing may have limited applicability when jumping the rig using the owner's manual method of connecting a jumping power source to the main battery's terminals and waiting.

Perhaps known to you, these power packs tend to be engineered to delivering a large amount of power in a short period of time for getting over the inertia threshold needed to crank an engine, as they should be.

But the 3.6L, and that wait period, is about charging the ESS/Aux battery to a threshold that below which, the 3.6L's computer will not even attempt the crank...even if, for argument sake, the main battery is fully charged.

(Let's set aside the fact that both batteries are connected in parallel on this version of the JL when it's at rest, and a fully charged main battery would charge an ESS/Aux battery with less charge, and not defectively unable to accept that charge.)

This waiting period robs the power pack of power to crank the engine. Further more, using the owner's manual method, you're also wasting precious power pack power charging the main battery was well.

You see, the 3.6L tests the ESS/Aux battery alone before attempting a crank, and if it has suitable power it then attempts the crank using both batteries "if available." These quotes address the fact that a 3.6L can crank with a charged ESS/Aux battery alone, but not a main battery alone.

It is these very facts that prompted discussion of how one might connect the power pack (safely) directly to (and only) the ESS/Aux in parallel to not only increase the chances for a successful crank, but do without the waiting period. That discussion is linked in my immediately prior post.

Except, what I learned from another thread is that the Jeep JL (at least 2019s and 2020s, it appears) WILL start from the main battery if you disconnect the aux battery. So, in the case of a bad aux battery, disconnect the negative aux battery lead and jump the main battery as normal with a jumper pack.

https://www.jlwranglerforums.com/forum/threads/3-6l-ess-aux-battery-bypass.17293/page-20

 

[jeepdabest]

So if I understand what you guys are saying is this is not a simple jumpstart? The main battery can have full charge but the small ess battery is dead so basically your dead in the water? Now I've had older diesels that had two batteries in parallel and if one was weak it would drain the other. But you guys are saying this is separate right?

You have a 2019 so you can remove negative aux cable from main and jump the main battery normally. You can start your Jeep that way as well, however, you will have an ESS service warning come up that can be rectified by clearing the code. This has worked for me.

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