Charging and Jump starting of Jeep JL Wrangler Batteries

[jeepdabest]

Ok....what is the DEFINITIVE answer regarding charging our batteries? Do we charge them together or separated? At what voltage? How do we jump start when the aux battery poops its pants? How do we jump start when there is a bad cell in the main and it takes a dump? What does JEEP want us to do in these situations? Does @JeepCares know? If not, why not?? Should the alternator be stuck at one charging rate forever? Or should the IBS be regulating alternator output according to state of battery charge? There shouldn't be a need for jumpers and other work arounds that some of our very bright (sincerely mean that!) members (not throbbing) have discussed.

Sponsored

 

[KnG818]

Ok....what is the DEFINITIVE answer regarding charging our batteries? Do we charge them together or separated? At what voltage? How do we jump start when the aux battery poops its pants? How do we jump start when there is a bad cell in the main and it takes a dump? What does JEEP want us to do in these situations? Does @JeepCares know? If not, why not?? Should the alternator be stuck at one charging rate forever? Or should the IBS be regulating alternator output according to state of battery charge? There shouldn't be a need for jumpers and other work arounds that some of our very bright (sincerely mean that!) members (not throbbing) have discussed.

Did you just say "..poops its pants.." !?

 

[jeepdabest]

Did you just say "..poops its pants.." !?

I was gonna say shits its pants but thought you would be offended.

 

[INCRHULK]

Ok....what is the DEFINITIVE answer regarding charging our batteries? Do we charge them together or separated? At what voltage? How do we jump start when the aux battery poops its pants? How do we jump start when there is a bad cell in the main and it takes a dump? What does JEEP want us to do in these situations? Does @JeepCares know? If not, why not?? Should the alternator be stuck at one charging rate forever? Or should the IBS be regulating alternator output according to state of battery charge? There shouldn't be a need for jumpers and other work arounds that some of our very bright (sincerely mean that!) members (not throbbing) have discussed.

I'm taking mine in shortly (as soon as I can find the time) because the voltage has been showing +14v for weeks. I'm definitely driving long enough to have the batteries charged, and the voltage drop down to the 12.x range I was seeing previously. I suspect one of my batteries is bad, or the IBS is failing.

 

[KnG818]

I was gonna say shits its pants but thought you would be offended.

Lol...I'd be the last person to get offended bud

 

[fat_head]

I was gonna say shits its pants but thought you would be offended.

Triggered and reported for foul language.

 

[JIMBOX]

I leave my battery('s) on BATTERY MAINTAINER, WHENEVER I'm GONE FOR OVER A WEEK--

Charging both at the same time takes longer, but works AOK !

No Problemo

W.E.

JIMBO

 

[jeepdabest]

Lol...I'd be the last person to get offended bud

bud? LOL wanna buy some?

 

[KnG818]

bud? LOL wanna buy some?

No need...legal where I'm at.

 

[Stormin’ Moorman]

There’s a massive, in-depth thread on how the battery system works on the forum somewhere. Try looking it up

 

[Gee-pah]

Ok....what is the DEFINITIVE answer regarding charging our batteries? Do we charge them together or separated?

I'm assuming that you are talking about the 3.6L JL. For reference ESS battery=aux battery=supplemental battery; they're all one and the same.

Some people have suggested--and I think them purists--that because the 2 batteries are of different types that it's best to charge them separately. But I don't think your rig does, so why should you?

Barring an instant at cold crank and during ESS events those batteries are connected in parallel, so putting jumper cables on one--heck--putting the positive jumper cable lead on one battery or its leads (or vice versa) and the negative jumper cable lead on the other battery or its leads is fine.

At what voltage?

Are we talking trickle charging or jump start charging. If the latter I imagine 12V is fine--give or take a bit.

How do we jump start when the aux battery poops its pants?

First I'll answer your question strictly, then I'll comment.

The easiest way to charge your aux battery in isolation would be to temporarily disconnect all the negative leads that attach to the main battery's negative post and put your positive jumper cable lead on the main battery's positive post, and your negative jumper cable lead on the now isolated series of wires that you distanced from the main battery's negative post.

Make sure to put things back!

~~~~

This said, life is rarely this easy. You see, there's a bit of a downside that both batteries are connected in parallel most of the time in that a defective battery (either) could become parasitic to the other. Envision two columns of water of dissimilar height. The taller column is the battery with greater charge. Connecting those columns with a pipe at their bases (i.e. connecting the batteries in parallel) will seek to equalize the height; height being a visual metaphor for voltage here. The analogy isn't perfect as a bad battery can drain both, while in the water column example the amount of water doesn't change.

How do we jump start when there is a bad cell in the main and it takes a dump?

There isn't one answer I don't think, but one right initial thing to try first. Remember above where we disconnected on the wires on the negative post of the main battery? Try that. The reason why is that your 3.6L is fine to operate only on the aux battery. The converse (operating only on the main) is not possible.

The 3.6L checks the aux battery in isolation prior to cold crank. If it lacks sufficient power the crank won't be attempted despite--funny enough--that said crank is energized by BOTH batteries.

So, if you truly know the main battery is bad, and the aux battery is not--but both are dead--have your jumpers connected as described above when charging the aux battery in isolation.

Someone would know better than me if any of those dangling wires, along with one on the positive post of the main battery directly connects to the aux battery. If they do the wait time in the manual probably shouldn't matter. On the other hand if those cables first are controlled by the PDC (Power Distribution Center): that black box on top, near the fire wall (under the hood) closest to the front passenger's seat, then let the jumper cables sit for while like described in the Owner's Manual. This is because the PDC will test the aux battery all on its own, separating it from the jumper cables for an instant, and if it lacks sufficient power on its own, no crank will be attempted.

What does JEEP want us to do in these situations?

I'll define JEEP here as the Customer Service arm of the organization, including Jeep Cares, who monitors posts here. If fact it's not fair to talk behind their backs. @JeepCares .

My guess is that they would want you to, barring being able to start the rig with jumper cables applied for a few minutes to the main battery posts consistent with the Owner's Manual, to have the vehicle towed to your nearest dealer for service. And if you can get the rig started, to drive it there yourself.

@JeepCares Does know?

I think you're asking if Jeep Cares knows what to do to refer you to those who can get you up and running again---and facilitate that...

...which is a separate question from do they know how to resolve these problems with step by step instructions.

The first question's answer is definitely. They're refer you to the manual and a dealer.

The second question: I think Jeep Cares is very good at facilitating the resolution of rig problems by connecting you with those at FCA (including the dealer) in the know and "greasing" that process. Do I think the team is former mechanics that can say, "attach this wire here," ….maybe some of its staff but likely not the majority--nothing disparaging meant to them.

If not, why not??

I don't think you're going to like my answer. Because if management staffed the Jeep Cares team with automotive engineers with advanced degrees in mechanics, fluid science, etc. our rigs would cost $1000 more each. Their people are trained in relating to people and are able, need be, to facilitate tapping into those people at FCA, often on behalf of a dealer, to diagnosis hard problems.

Should the alternator be stuck at one charging rate forever? Or should the IBS be regulating alternator output according to state of battery charge?

I don't know. I do think it's kind of funny though that the system and its at time unpredictable nature steals an acronym from the equally unpredictable Irritable Bowel Syndrome.

There shouldn't be a need for jumpers and other work arounds that some of our very bright (sincerely mean that!) members (not throbbing) have discussed.

Agreed.

 

[jeepdabest]

There’s a massive, in-depth thread on how the battery system works on the forum somewhere. Try looking it up

I've read everything. Nothing definitive.

 

[jeepdabest]

I'm assuming that you are talking about the 3.6L JL. For reference ESS battery=aux battery=supplemental battery; they're all one and the same.

Some people have suggested--and I think them purists--that because the 2 batteries are of different types that it's best to charge them separately. But I don't think your rig does, so why should you?

Barring an instant at cold crank and during ESS events those batteries are connected in parallel, so putting jumper cables on one--heck--putting the positive jumper cable lead on one battery or its leads (or vice versa) and the negative jumper cable lead on the other battery or its leads is fine.



Are we talking trickle charging or jump start charging. If the latter I imagine 12V is fine--give or take a bit.



First I'll answer your question strictly, then I'll comment.

The easiest way to charge your aux battery in isolation would be to temporarily disconnect all the negative leads that attach to the main battery's negative post and put your positive jumper cable lead on the main battery's positive post, and your negative jumper cable lead on the now isolated series of wires that you distanced from the main battery's negative post.

Make sure to put things back!

~~~~

This said, life is rarely this easy. You see, there's a bit of a downside that both batteries are connected in parallel most of the time in that a defective battery (either) could become parasitic to the other. Envision two columns of water of dissimilar height. The taller column is the battery with greater charge. Connecting those columns with a pipe at their bases (i.e. connecting the batteries in parallel) will seek to equalize the height; height being a visual metaphor for voltage here. The analogy isn't perfect as a bad battery can drain both, while in the water column example the amount of water doesn't change.



There isn't one answer I don't think, but one right initial thing to try first. Remember above where we disconnected on the wires on the negative post of the main battery? Try that. The reason why is that your 3.6L is fine to operate only on the aux battery. The converse (operating only on the main) is not possible.

The 3.6L checks the aux battery in isolation prior to cold crank. If it lacks sufficient power the crank won't be attempted despite--funny enough--that said crank is energized by BOTH batteries.

So, if you truly know the main battery is bad, and the aux battery is not--but both are dead--have your jumpers connected as described above when charging the aux battery in isolation.

Someone would know better than me if any of those dangling wires, along with one on the positive post of the main battery directly connects to the aux battery. If they do the wait time in the manual probably shouldn't matter. On the other hand if those cables first are controlled by the PDC (Power Distribution Center): that black box on top, near the fire wall (under the hood) closest to the front passenger's seat, then let the jumper cables sit for while like described in the Owner's Manual. This is because the PDC will test the aux battery all on its own, separating it from the jumper cables for an instant, and if it lacks sufficient power on its own, no crank will be attempted.



I'll define JEEP here as the Customer Service arm of the organization, including Jeep Cares, who monitors posts here. If fact it's not fair to talk behind their backs. @JeepCares .

My guess is that they would want you to, barring being able to start the rig with jumper cables applied for a few minutes to the main battery posts consistent with the Owner's Manual, to have the vehicle towed to your nearest dealer for service. And if you can get the rig started, to drive it there yourself.



I think you're asking if Jeep Cares knows what to do to refer you to those who can get you up and running again---and facilitate that...

...which is a separate question from do they know how to resolve these problems with step by step instructions.

The first question's answer is definitely. They're refer you to the manual and a dealer.

The second question: I think Jeep Cares is very good at facilitating the resolution of rig problems by connecting you with those at FCA (including the dealer) in the know and "greasing" that process. Do I think the team is former mechanics that can say, "attach this wire here," ….maybe some of its staff but likely not the majority--nothing disparaging meant to them.



I don't think you're going to like my answer. Because if management staffed the Jeep Cares team with automotive engineers with advanced degrees in mechanics, fluid science, etc. our rigs would cost $1000 more each. Their people are trained in relating to people and are able, need be, to facilitate tapping into those people at FCA, often on behalf of a dealer, to diagnosis hard problems.



I don't know. I do think it's kind of funny though that the system and its at time unpredictable nature steals an acronym from the equally unpredictable Irritable Bowel Syndrome.



Agreed.

Thank you for taking the time to write your great and informative response! I truly appreciate it.

 

[Compression-Ignition]

I don't think you're going to like my answer. Because if management staffed the Jeep Cares team with automotive engineers with advanced degrees in mechanics, fluid science, etc. our rigs would cost $1000 more each. Their people are trained in relating to people and are able, need be, to facilitate tapping into those people at FCA, often on behalf of a dealer, to diagnosis hard problems.

Possibly worth it........

 

[Gee-pah]

Possibly worth it........

Roy, I say this with a smirk I bet you and others can relate to. Much as I wish that first line customer service people knew answers like NASA ground specialists....

In work it's been my experience that the guy (or gal) with the true expertise is some subject matter...

...the one who knows the answer to your question before you ask it

..the one who corrects the form of your question to perfection--because they're pedantic

...the one who sighs because he/she gets this question so frequently and thinks people with merely average intelligence are idiots

...but yet the one you come to with trepidation because your other smiling fellow workers don't know "ship from shinola" the answer to your question.....but's are great with people

...don't often make great customer service reps.

Sponsored