ESS Dual Battery Management

[Jebiruph]

While I don't know that the ESS battery is for sure tested for voltage prior to an ESS event, why would you think it not possible to separate the batteries for an instant prior to an ESS event so that the ESS battery's voltage could be tested? The alternator and main battery on the 3.6L are clearly more than enough to run any electrical needs while this extremely quick test of the the ESS battery's voltage, as you correctly report required in isolation, is effected (hypothetically or not)?

More recent 3.6L JL's which fail the ESS battery test at crank disable ESS as you describe, and take this battery out of the picture (correct?) for the rest of the trip, and things run fine on the main battery and alternator alone, right?

(Maybe I misunderstand what you are talking about.)

I suppose I could test this. I could attach a battery cutoff switch like you use in your setups Jerry to the negative cable that leads from the ESS battery to the main one--initially when the 3.6L cold cranks, with that circuit closed/intact.

My 3.6L is on a trickle charger when at rest. Getting ESS to kick in once it's warmed up shouldn't be a problem. I could then put the rig in park, get out, open the hood, and use this switch to disconnect the ESS battery from the main one and drive some more, coming to a braked stop.

I hope your wrong about only testing the ESS battery's voltage upon cold crank, but if you're right Jerry, I'd agree. The vehicle should die once the ESS event is attempted to be engaged, shutting off the engine with no alternator, main, or ESS battery to energize appliances off of.

I don't see anyway to quickly separate the batteries on a running vehicle to check the ESS battery voltage before separating them for an auto stop. That's why there is a pre start test. If the ESS battery is tested before an auto stop, you don't need a pre start test.

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[Rhinebeck01]

Here is another tidbit of important info that has been thrown into the mix so to speak.

Do read here:
https://www.jlwranglerforums.com/forum/threads/alert-high-amp-fuse-array-related.65085/

 

[MacJack]

Here is another tidbit of important info that has been thrown into the mix so to speak.

Do read here:
https://www.jlwranglerforums.com/forum/threads/alert-high-amp-fuse-array-related.65085/

I just ordered this to have onhand... This is what the website said for:
Part Number: 68368854AA The 100 Amp.
[Aux Switches], [Aux Switches] 100 Amp, [Aux Switches] AND/OR [Trailer Tow Group], [Aux Switches] AND/OR [Trailer Tow Group] 100 AMP, 100 AMP.
Fits Gladiator, Wrangler

Hope this helps all.

 

[Rhinebeck01]

When you want to.....

 

[Rhinebeck01]

As I have gotten older my vision is not what it used to be. When looking at the PDC cove for certain fuse #/ relay locations, I have to really work at it , lets say.

Now a days, I keep this pic of the inner side of the PDC cover on my smartphone...

Allows me to zoom in lets say and take a clear looksee...

 

[Redbaron73]

Here's a schematic of how this is wired.

Here's some pics showing more details of the latest version. I mounted the gauges in 1 1/4" PVC pipe endcaps and color coded the gauges and wires - blue= aux green = main.

I am going to be installing your setup. This is a genius design that fits the way I use my jeep.

I really appreciate the time you have taken in documenting this.

I don't use ESS, so I plan on charging the aux, and keeping it as a jump start when needed.

My question is how do you start with a dead main and fully charged aux in your design? Assuming 12.6v on aux, and less than 11.8 on main, is it simply adding the fuse between f1 and f2?

 

[OldGuyNewJeep]

I am going to be installing your setup. This is a genius design that fits the way I use my jeep.

I really appreciate the time you have taken in documenting this.

I don't use ESS, so I plan on charging the aux, and keeping it as a jump start when needed.

My question is how do you start with a dead main and fully charged aux in your design? Assuming 12.6v on aux, and less than 11.8 on main, is it simply adding the fuse between f1 and f2?

I keep this note on my phone. I got this procedure from @Rhinebeck01

To start from AUX:

• Pull fuse out of jumper
• Connect AUX negative
• Take whole negative assembly off battery and start vehicle

Bill or Jerry might have additional info.

 

[Gee-pah]

I keep this note on my phone. I got this procedure from @Rhinebeck01

To start from AUX:

• Pull fuse out of jumper
• Connect AUX negative
• Take whole negative assembly off battery and start vehicle

Bill or Jerry might have additional info.

@OldGuyNewJeep, IMHO that which you write above is both correct, and for parts of it, superflous (unnecessary).

From my way of seeing things, removing the fuse in the jumper in your describe situation is neither wrong nor necessary in the 3.6L. Here's why I believe so.

The presence of the fuse directs all electric flow on terminal N1 to terminal N2 (the main battery's positive terminal) as well.

N2, as the main battery, is something you've already taken out of the rig's electrical system when you took all cables off the negative terminal of the main battery anyway.

To put this yet another way, removing the fuse is another way to prevent electric from terminal N1 to N2 to flow, that would be necessary, not superflous, had you not vacated all the cables from the negative terminal of the main battery.

None of what I write he lies in the spirit of "ha, ha, you weren't completely correct!" That's B.S. I make the notes I do so people UNDERSTAND what's going on.

 

[Redbaron73]

So using Jerry's setup - the dial would be switched to "CONNECTED/ON/ENGAGED", which connects the Aux Ground to the main battery. You are then removing the main battery ground wire assembly from the MAIN battery negative terminal, but keeping the individual ground wires connected on that assembly and doing the start. Is that correct?

This makes sense, in such as you are going to eliminate the dead main from draining (aka trying to charge from ) the aux. Once started, then reconnecting the ground is the right action to recharge the main battery. Do I have this right?

***edited for clarification

 

[Redbaron73]

I thought I'd post a picture and info on some of the different battery switches I've acquired while working on this project.

The top left switch is a dual battery switch rated for 900A cranking (30 sec), 500A (5 min) and 300A continuous.
https://www.amazon.com/gp/product/B0070YEEI8/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1

The bottom left switch is single battery switch rated for 1250A cranking, 455A intermittent and 275A continuous.
https://www.amazon.com/gp/product/B07XTDSD4B/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1

The bottom right switch is a single battery switch rated for 300A.
https://www.amazon.com/gp/product/B082W24S4F/ref=ppx_yo_dt_b_asin_title_o07_s00?ie=UTF8&psc=1

The top right switch is a battery switch rated for 75A intermittent and 50A continuous.
https://www.amazon.com/gp/product/B08612YVG9/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

@Jebiruph I see that you already tested a dual battery switch, or at least purchased it. Is there a reason why you did not integrate that into the design? It looks like a very easy way to determine which battery is in use with a simple dial. Was this too bulky or too complicated?

 

[Gee-pah]

So using Jerry's setup - the dial would be switched to "ON", which connects the Aux Ground to the main battery. You are then removing the main battery ground wire assembly, but keeping the individual ground wires connected on that assembly and doing the start. Is that correct?

This makes sense, in such as you are going to eliminate the dead main from draining (aka trying to charge from ) the aux. Once started, then reconnecting the ground is the right action to recharge the main battery. Do I have this right?

Ronnie--if you get nothing else from this, please understand that it is NOT my intention to be some pedantic sh*t. Rather, I seek to inform forum members so they are armed with correct information upon which to make informed decisions.

Ronnie, I think Jerry @Jebiruph brilliant. But some of Jerry's setups involve more than one cutoff switch so I'm confused as to your words. Still more, I want to make a distinction here between ground and negative terminal. As you may realize, one cable leads from the ESS/Aux battery's negative terminal and connects to the main battery's negative post, not to body ground. I completely get that you *may* be using the terms interchangeably.


If Ronnie, what you are saying is that you've switched Jerry's dials such that the ESS/Aux battery's negative cable is not connected to the main battery' negative terminal AND, the ground from the main battery's negative terminal is not connected to the main battery's negative terminal, BUT (and this is key) a complete circuit lies between the negative terminal of the ESS/Aux battery and the body ground (in other words the two disconnected factory cables from the main battery's negative terminal are in fact themselves connected together,) then, YES (!!) you have created a one battery 3.6L running solely on the ESS/Aux battery. Let's define complete circuit here Ronnie. You have NOT removed any cables from the body ground and you have NOT removed the cable attached to the negative terminal of the ESS/AUX battery.

Yes Ronnie, once you have successfully cranked you can reintroduce the main battery's negative terminal to BOTH the cable leading to ground AND the one leading to the negative terminal of the ESS/Aux battery to get the now working engine spin the alternator and charge both batteries.

I hope this helps. I am not trying to be a sh*t. I'm trying to make sure you walk away with this with not only crystal clear instructions on what to do, but equally important, the electric foundation as to why things are what they are here

 

[Gee-pah]

@Jebiruph I see that you already tested a dual battery switch, or at least purchased it. Is there a reason why you did not integrate that into the design? It looks like a very easy way to determine which battery is in use with a simple dial. Was this too bulky or too complicated?

By all means Ronnie please solicit Jerry for a reply. @Jebiruph. One answer though that he might provide is the wiring was simpler the way he did it given his interest in having two voltage meters, one on each battery.

Perhaps with more complex switches and wiring, one switch and one voltage meter may have been sufficient to configure no, one, both all the time, or factory settings (both batteries all the time but an instant at crank and during ESS events).

 

[Redbaron73]

Ronnie--if you get nothing else from this, please understand that it is NOT my intention to be some pedantic sh*t. Rather, I seek to inform forum members so they are armed with correct information upon which to make informed decisions.

Ronnie, I think Jerry @Jebiruph brilliant. But some of Jerry's setups involve more than one cutoff switch so I'm confused as to your words. Still more, I want to make a distinction here between ground and negative terminal. As you may realize, one cable leads from the ESS/Aux battery's negative terminal and connects to the main battery's negative post, not to body ground. I completely get that you *may* be using the terms interchangeably.


If Ronnie, what you are saying is that you've switched Jerry's dials such that the ESS/Aux battery's negative cable is not connected to the main battery' negative terminal AND, the ground from the main battery's negative terminal is not connected to the main battery's negative terminal, BUT (and this is key) a complete circuit lies between the negative terminal of the ESS/Aux battery and the body ground (in other words the two disconnected factory cables from the main battery's negative terminal are in fact themselves connected together,) then, YES (!!) you have created a one battery 3.6L running solely on the ESS/Aux battery. Let's define complete circuit here Ronnie. You have NOT removed any cables from the body ground and you have NOT removed the cable attached to the negative terminal of the ESS/AUX battery.

Yes Ronnie, once you have successfully cranked you can reintroduce the main battery's negative terminal to BOTH the cable leading to ground AND the one leading to the negative terminal of the ESS/Aux battery to get the now working engine spin the alternator and charge both batteries.

I hope this helps. I am not trying to be a sh*t. I'm trying to make sure you walk away with this with not only crystal clear instructions on what to do, but equally important, the electric foundation as to why things are what they are here

Thanks -- Yes, my lazy use of words "on" and "ground" are definetly not proper when talking something this complex. You answered my question, and it makes sense.

THis also explains why @Rhinebeck01 went to all of the trouble he did to be able to remove the ground cables from the main negative terminal so easily, and in a package that keeps the bundle of ground cables attached to each other.

Understanding this battery system is so crucial for anyone that might find themselves off grid and with a dead battery. Most people think that having a fully charged NOCO Booster is all they would need. I really appreciate all the input here.

 

[Redbaron73]

By all means Ronnie please solicit Jerry for a reply. @Jebiruph. One answer though that he might provide is the wiring was simpler the way he did it given his interest in having two voltage meters, one on each battery.

Perhaps with more complex switches and wiring, one switch and one voltage meter may have been sufficient to configure no, one, both all the time, or factory settings (both batteries all the time but an instant at crank and during ESS events).

The simplicity was my guess, and hard to fault, espically seeing how easy it is to isolate the aux. The aux is too small to ever be normally the "primary" battery, so a dual really doesn't make sense.

 

[Jebiruph]

@Jebiruph I see that you already tested a dual battery switch, or at least purchased it. Is there a reason why you did not integrate that into the design? It looks like a very easy way to determine which battery is in use with a simple dial. Was this too bulky or too complicated?

When I'm experimenting with something new, I end up buying lots of stuff that either doesn't work or I just never implement. I found that dual battery switch that should work, I just never implemented it. I posted it incase someone was looking for one, so they could avoid buying junk like I did before I found this one.

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