The cargo 12 V Socket - Where does it go?

[Onward4x4]

Hello all-
I am wondering where the 12 V Socket in the cargo area is hooked to? Is it hooked to the cranking battery or does it go to the auxiliary battery as I would think it should? I am running a fridge and would like to make sure it is running from the aux battery and not the crank battery. TIA

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[Onward4x4]

Anyone?

 

[sf5211]

Anyone?

I’m not sure NB but from what I’ve read in the forums, evidently if you drain down either battery the Jeep won’t start.

 

[Gee-pah]

Hi:

The 12V socket in the cargo area, if equipped (not all JLs have one) is, by default from the factory, a "battery" versus "accessory" plug. This means it is energized all the time, regardless of whether the vehicle is cranked or not. The behavior can be changed by following the instructions on page 178 of the manual. (page 180 of the PDF file):

https://msmownerassets.z13.web.core...ications/en-us/Jeep/2018/Wrangler_JL/9510.pdf

And yet, that's not what you asked, or even where I think you are going with this question!

As to your question: on the 3.6L JL, the two batteries are in parallel pretty much all the time, (including when the rig is shut down and parked) barring ESS events. (The batteries use to be isolated for an instant at cold cranks as well but since the introduction of the 2019's, FCA seems to have changed that based on people's reports here on the bboard.)

This means that the cargo plug is pretty much hooked up to both batteries at the same time.

As for ESS events, in theory, the cargo plug should be running of the ESS battery, but it seems some things, like power steering are run off the main battery even during ESS events...so I am not certain. Maybe Jerry knows. @Jebiruph more. In my opinion he is our resident expert on such things.

====

And yet, lets get to the heart of what I think is your question, and why even, your goals may not be smart ones (no offense intended).

I take it that you want to run your refrigerator when the rig is shut down in such a way that it doesn't prevent the JL from cranking. Interestingly enough, in the 2018 JL, (at least when it was first introduced), running the refrigerator off the ESS battery is something you DON'T want to do and perfectly wrong! (Go figure!).

Why?

Ok, long story. When the 2018 JL 3.6L was originally released, it had start logic such that prior to a cold crank, the rig would isolate the ESS battery and test it. If that battery lacked a threshold of basic power all on its own the rig would not even attempt a crank, which by the way (if attempted) was energized by BOTH batteries. You could have a dead ESS battery, and a fully charged main battery and the rig would not crank.

In fact, in the 2018 models you could crank your rig with only the ESS battery connected, but not vice versa.



IMHO this was stupid. I think FCA may have agreed. I say this because there is talk on the bboard that the 2019's 3.6L and beyond have logic to crank the rig if either battery has sufficient power. As to why I think it was designed this way (short version of theory: FCA saving $) is a story for another post.

(I can't speak to how other engine models of the JL work in this regard.)

Now: the million dollar question is whether this changed logic was downloaded to the 2018's. I don't know!

But all this is academic. What I think you want to know is how to hook up your refrigerator such that you can still crank when your ready to come home, right?

Under the start logic for the 2018, back when that rig was released, your "play" was to isolate the two batteries (remove all cables from the negative post of the main battery) and then run your refrigerator. The cargo port would tap the main battery then I believe.

You would then crank off the ESS battery whose power you preserved, and after successfully cranking, CAREFULLY reattach the wires on the negative post of the main battery so the alternator could charge it.

This order was important because if you connected the wires prior to cranking, since the batteries would be in parallel, the ESS battery would drain charging the main one and the crank may not happen.

I imagine this still works for the 2019 3.6L and beyond, and even the 2018's if this changed crank logic got downloaded to the 2018s.

I'm sorry for the long winded answer. This turns out to be far less trivial as one might hope.

P.S. There is debate as to whether terminal 5, as shown in the video is the direct connect to the ESS battery. (I think it's N1.) But the rest of the video has merit.

Please see https://www.jlwranglerforums.com/fo...v-socket-where-does-it-go.48115/#post-1059348 for complete details.

 

[Onward4x4]

Hi:

The 12V socket in the cargo area, if equipped (not all JLs have one) is, by default from the factory, a "battery" versus "accessory" plug. This means it is energized all the time, regardless of whether the vehicle is cranked or not. The behavior can be changed by following the instructions on page 178 of the manual. (page 180 of the PDF file):

https://msmownerassets.z13.web.core...ications/en-us/Jeep/2018/Wrangler_JL/9510.pdf

And yet, that's not what you asked, or even where I think you are going with this question!

As to your question: on the 3.6L JL, the two batteries are in parallel pretty much all the time, (including when the rig is shut down and parked) barring ESS events. (The batteries use to be isolated for an instant at cold cranks as well but since the introduction of the 2019's, FCA seems to have changed that based on people's reports here on the bboard.)

This means that the cargo plug is pretty much hooked up to both batteries at the same time.

As for ESS events, in theory, the cargo plug should be running of the ESS battery, but it seems some things, like power steering are run off the main battery even during ESS events...so I am not certain. Maybe Jerry knows. @Jebiruph more. In my opinion he is our resident expert on such things.

====

And yet, lets get to the heart of what I think is your question, and why even, your goals may not be smart ones (no offense intended).

I take it that you want to run your refrigerator when the rig is shut down in such a way that it doesn't prevent the JL from cranking. Interestingly enough, in the 2018 JL, (at least when it was first introduced), running the refrigerator off the ESS battery is something you DON'T want to do and perfectly wrong! (Go figure!).

Why?

Ok, long story. When the 2018 JL 3.6L was originally released, it had start logic such that prior to a cold crank, the rig would isolate the ESS battery and test it. If that battery lacked a threshold of basic power all on its own the rig would not even attempt a crank, which by the way (if attempted) was energized by BOTH batteries. You could have a dead ESS battery, and a fully charged main battery and the rig would not crank.

In fact, in the 2018 models you could crank your rig with only the ESS battery connected, but not vice versa.



IMHO this was stupid. I think FCA may have agreed. I say this because there is talk on the bboard that the 2019's 3.6L and beyond have logic to crank the rig if either battery has sufficient power. As to why I think it was designed this way (short version of theory: FCA saving $) is a story for another post.

(I can't speak to how other engine models of the JL work in this regard.)

Now: the million dollar question is whether this changed logic was downloaded to the 2018's. I don't know!

But all this is academic. What I think you want to know is how to hook up your refrigerator such that you can still crank when your ready to come home, right?

Under the start logic for the 2018, back when that rig was released, your "play" was to isolate the two batteries (remove all cables from the negative post of the main battery) and then run your refrigerator. The cargo port would tap the main battery then I believe.

You would then crank off the ESS battery whose power you preserved, and after successfully cranking, CAREFULLY reattach the wires on the negative post of the main battery so the alternator could charge it.

This order was important because if you connected the wires prior to cranking, since the batteries would be in parallel, the ESS battery would drain charging the main one and the crank may not happen.

I imagine this still works for the 2019 3.6L and beyond, and even the 2018's if this changed crank logic got downloaded to the 2018s.

I'm sorry for the long winded answer. This turns out to be far less trivial as one might hope.

P.S. There is debate as to whether terminal 5, as shown in the video is the direct connect to the ESS battery. (I think it's N1.) But the rest of the video has merit.

No need to be sorry for the long answer. I love it. Thanks for taking the time!

Now, perhaps this will change the answer: I have the Genesis two battery system installed and perhaps I should have made this clear from the getgo. My knowledge about electricity is very limited and so I didn't ask my question properly. So with the two battery system installed, is the cargo plug ends up in the crank battery or the accessory battery? From what I gathered from your answer is that the Genesis should be doing the separation needed to run the fridge at all times without draining the crank battery... right?

 

[four low]

See which battery, main or aux, has the largest draw off when fridge running, vehicle off, after 30 minutes vehicle off.

 

[Gee-pah]

No need to be sorry for the long answer. I love it. Thanks for taking the time!

Now, perhaps this will change the answer: I have the Genesis two battery system installed and perhaps I should have made this clear from the getgo. My knowledge about electricity is very limited and so I didn't ask my question properly. So with the two battery system installed, is the cargo plug ends up in the crank battery or the accessory battery? From what I gathered from your answer is that the Genesis should be doing the separation needed to run the fridge at all times without draining the crank battery... right?

Presence of the Genesis two battery system changes what things a bit OP..

http://www.genesisoffroad.com/2018-2020-Jeep-Wrangler-JL-Dual-Battery-Kit_p_57.html

Like in the stock 3.6L JL, use of the cargo plug when the rig is parked should tap both batteries provided the batteries register at least 13.2 volts. Of course I'd presume that you haven't repositioned the fuse from its factory placement consistent with the owner's manual link I provided prior.

As for the rest, the following is taken almost verbatim from the above link OP:

When your main cranking battery reaches 12.7 volts, a smart isolator built into the Genesis system separates the two batteries, so that (what Genesis refers to as) your cranking battery will have enough power to start the engine. The second battery will continue to power your accessories for as long as it will last.

If your cranking battery is somehow drained down too low to be able to start the vehicle, despite the Genesis System's above protection of same, the Genesis System's Start Boost button can be pressed, and the isolator will connect both batteries together for 1 minute, acting like built-in jumper cables to jump start your engine off your accessory battery.

As long as the accessory battery has enough power, you'll be able to start your vehicle instead of being stranded with a dead battery.

I hope this helps.

 

[Onward4x4]

Presence of the Genesis two battery system changes what things a bit OP..

http://www.genesisoffroad.com/2018-2020-Jeep-Wrangler-JL-Dual-Battery-Kit_p_57.html

Like in the stock 3.6L JL, use of the cargo plug when the rig is parked should tap both batteries provided the batteries register at least 13.2 volts. Of course I'd presume that you haven't repositioned the fuse from its factory placement consistent with the owner's manual link I provided prior.

As for the rest, the following is taken almost verbatim from the above link OP:

When your main cranking battery reaches 12.7 volts, a smart isolator built into the Genesis system separates the two batteries, so that (what Genesis refers to as) your cranking battery will have enough power to start the engine. The second battery will continue to power your accessories for as long as it will last.

If your cranking battery is somehow drained down too low to be able to start the vehicle, despite the Genesis System's above protection of same, the Genesis System's Start Boost button can be pressed, and the isolator will connect both batteries together for 1 minute, acting like built-in jumper cables to jump start your engine off your accessory battery.

As long as the accessory battery has enough power, you'll be able to start your vehicle instead of being stranded with a dead battery.

I hope this helps.

Thanks. That helps. Thanks so much for your assistance and help and citations. Gold star for you!!! <---- adult gold stars!

 

[wolfdog]

This info is great! Gee-Pah, great job of describing this!!

However I wonder why Jeep made the JL a 2 battery ESS thing? I have a 2015 ESS one (large) battery Cherokee Trailhawk and the ESS is faster/smoother than my 2018 JLU? Certainly a lot simpler!

Go jeep!!!

 

[Gee-pah]

All:

I've been reviewing @Jebiruph's posts on this and I want to write out a formal procedure for running off the cargo plug of a 3.6L JL while parked, and still be able to crank your rig and get home--presuming that you're running the stock batteries, not the OP's Genesis System. This approach I suspect likely proves to be neither wrong nor necessary (i.e. superfluous) for 2019 3.6JL's and beyond, and may prove to be superfluous for the 2018's as well if FCA has downloaded updated crank logic to the 2018's whereby the ESS battery having basic charge is no required prior to attempting a cold crank.

• When you arrive to the camp sight, disconnect the wires to the high amp N1 fuse. That's the one closest to the front of the JL, in the PDC (Power Distribution Center) as shown in the video above around 1:26. Doing this isolates the ESS battery from power draw (unless you've managed to direct connect non-factory wires to this ESS battery.)
• Run your refrigerator. It will tax the main battery.
• When ready to return home loosen the nut that attaches all wires to the negative post of the main battery, but don't yet disconnect any of these wires.
• Reconnect the wires to the high amp N1 fuse, but don't yet tighten the nut. Instead, go over to the main battery's negative post and yank all the wires on it.
• Now tighten down N1.
• Crank your rig.
• Once cranked reattach (carefully!) the wires to the main battery's negative post and tighten the nut.

Okay--what's going on here?

• I had you quickly detach the wires to the negative post of the main battery after connecting the wires to N1 on the PDC so that the ESS battery would not be drained charging the main battery otherwise depleted by the refrigerator. You see, with both N1 and the negative wires to the main battery connected, the two batteries are connected in parallel and the weaker one (the main battery) will be charged by the stronger one (the ESS battery.)
• As soon as you cranked the rig though (with the spared ESS battery) I had you reattach the main battery's negative post so the alternator would begin recharging it.
• The quick staggering of the two connections allowed power to flow through the JL at all times.

Cheers.

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