AUX battery delete/bypass - Which method is proper?

[AndySpill]

I'm not sure I agree. To me KISS would indicate keeping as much of the factory wiring intact (as in not destroyed) as is readily possible and keeping positive terminal connectors as robustly protected as possible.

I think we actually agree in a different way. You see I'm for keeping the ESS/Aux battery in place, just taken out of the electrical schematic of the vehicle...for those that is wishing to abandon ESS. So my positive cable never gets touched, just the negative between both batteries negative posts get disconnected at the main battery, and that end insulated.

The aux positive wire terminal connector crimps around 2 wires, one to N3/PCR and the other to N1. Attaching the aux battery cable terminal connector to the main battery terminal effectively jumpers N1/N2 and bypasses the PCR.

Ok, here's the fly in that ointment for me. I don't disagree with your wiring observation, I just wonder if its moot. You see anyone taking the ESS battery out of the schematic should either be pulling Fuse 42, so the PCR never can engage, and N1/N2 can never separate anyway, or they're going with the original fused jumper approach between N1 and N2 (or both methods if their redundant) and in either case, N1 and N2 are to never be separated again anyway. Maybe I am mistaken and/or miss your point Foster. If so, my bad.

Doing so also helps prevent the stock terminal connector between N3 and N1 which is exposed when the aux battery is removed from shorting (better than wrapping it in electrical tape and leaving it floating around the battery tray, anyway).

Here again I take no issue with this except to say I never concerned myself with an insulated but dangling cable connected at one end originally to the positive of the ESS battery because unlike you (which is fine, different strokes different folks) never considered it worth it to remove the ESS battery or this cable's connection to its positive terminal.

As a sealed AGM battery I'm not too worried about it staying in place neither tapped nor charged. But you would certainly have a fair point in saying that the battery which is removed is certainly the battery, if it is compromised, that never causes issue in the vehcile.

Granted, this arrangement creates an extraneous connection between the main battery positive terminal and N3 (through the PCR), but that seems worth the tradeoff of avoiding permanently altering the factory wires/connectors.

For those removing the ESS battery like you, I have no issue with your logic.

The Genesis dual battery system installation recommendation jumpers N1/N2 by attaching the aux battery cable terminal connector to the main battery positive terminal (as I described above). There's no mention of fuse F42 because the PCR is bypassed so the relay closed/open state is irrelevant. The recommendation isn't related to anything specific about the functionality of the Genesis system, it's because the system deletes the original aux battery and it's a clean way to manage (or "groom" as Shane would say) the stock battery cables.

To which I'd like to talk about why. Shane runs ESS and regular stuff off of one battery, saving the other for managing overland appliances particular with the engine off, right?

With one battery doing regular and ESS work, separating N1 from N2, i.e. taking the two factory batteries out of parallel no longer becomes required.

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[THAW]

I think we actually agree in a different way.

I agree we agree ?

There's just so many different variations, it's hard to keep track.

For those removing the ESS battery like you, I have no issue with your logic.

I was perfectly happy to run my JL with the ESS battery disconnected in place (negative wire disconnected from main and insulated) until I removed the factory battery tray to install the Genesis tray (just the tray).

Shane runs ESS and regular stuff off of one battery, saving the other for managing overland appliances particular with the engine off, right?

The Genesis system runs everything off both batteries while the Jeep is running (thereby "charging" the aux battery). The two batteries are connected in parrellel, and the connection between the battery positives is opened when the Jeep ignition is off (or when voltage drops in older versions) so auxilary loads don't touch the start battery. The battery positives are reconnected after a brief delay post ignition/start, I believe.

 

[THAW]

@AndySpill

I realized there is one other wrinkle in attaching the factory aux battery terminal connector to the main battery positive terminal: the 150A PCR fuse is bypassed.

Assuming the fuse is designed to protect only the PCR, taking the fuse out of the path between the main battery positive terminal and N1 (to factory electronics) doesn't have any negative consequence, and prevents the possibility of blowing the fuse when jump starting using the main battery positive post. On the other hand, if the fuse is designed to protect anything downstream of N1 (which seems somewhat unlikely given the stock unfused connection between the aux battery and N1), bypassing it is problematic...

 

[bobholthaus]

Good morning folks: I’ve ready this entire thread but I’m still asking for clarification please. Are one of you willing to shorten the options to as few bulletpoints as possible for those of us considering this mod, with a pro and con of each? My aux battery is shot (but im still under warranty) so im just about to do this.

so far, i think my options are:

A Leave Aux Battery in:
1. Disconnect neg term for Aux battery from main battery post
2. Insulate removed negative terminal
3. Pull fuse F42
Question: what are the pros and cons of this method?

or

B. Pull Aux Battery out:
1. Remove negative wire from aux battery altogether
2. (I think) hook pos terminal that went to aux battery to main battery terminal
3. (I think) Pull fuse F42
Question; am I correct, and what are the pros and cons of this method?

or

C. Buy a dual battery setup like a Genesis system

Lastly: if I delete the battery using any one of these methods, how will it affect my original warranty, and could it affect the 8 yr - 125k Mopar Max Care Warranty that I have already purchased?

thanks guys. Also, a link to a YouTube video if I decide to do B would be appreciated (Which is what I’m leaning towards)

 

[AndySpill]

Good morning folks: I’ve ready this entire thread but I’m still asking for clarification please. Are one of you willing to shorten the options to as few bulletpoints as possible for those of us considering this mod, with a pro and con of each? My aux battery is shot (but im still under warranty) so im just about to do this.

so far, i think my options are:


A Leave Aux Battery in:
1. Disconnect neg term for Aux battery from main battery post
2. Insulate removed negative terminal
3. Pull fuse F42
Question: what are the pros and cons of this method?

Pros: easiest method IMHO to take the ESS/Aux battery out of the electrical schematic of the vehicle. Also, see your warranty concerns below.

Cons: you probably shouldn't run the ESS system. (Some would consider that a pro.) You'll be obligated to turn ESS off each time you cold crank, via a push of the button, or acquire after market tech to do so.

Con: I seriously doubt a sealed AGM battery like the ESS/Aux is going to cause you problems just sitting there. But I can't deny that the ESS/Aux battery this is removed is the one, that if it causes issues, can't cause problems. Then again, this battery rides the lowest of all components in the engine bay and gravity is likely, even if it is compromised, to be on your side.

or

B. Pull Aux Battery out:
1. Remove negative wire from aux battery altogether
2. (I think) hook pos terminal that went to aux battery to main battery terminal
3. (I think) Pull fuse F42
Question; am I correct, and what are the pros and cons of this method?

Foster @THAW https://www.jlwranglerforums.com/fo...ss-which-method-is-proper.123845/post-2586730 had some intelligent thoughts on rerouting the positive cable that originally connected to the aux battery.

IMHO, if you are leaving the ESS Aux battery in place, and you yank the negative cable between the ESS/Aux battery's negative post on the main battery's negative post you are abso freakin lootely breaking all electrical connections between the ESS/Aux battery and the world around it. An electrical connection needs a connection: two wires. You have disconnected one: a minimum but also completely sufficient method of disconnection that would find you also rerouting this positive cable a pain in the ass to get to its ESS/Aux battery end, with no pros in doing so.

The cons, like with the first method involving turning ESS off.

If you were to remove the ESS/Aux battery, as I think Foster did, I might find it indicated that you yank or reroute this positive cable. That said, the cable's end isn't going to touch anything that would create a problem. It's attached to the disconnected ESS/Aux battery's positive post forever more.

or

C. Buy a dual battery setup like a Genesis system

Shane's product offerings, like Cholesterol lowering Statin medications are great. They're also not for everyone. We don't take Statins if we don't have high cholesterol and we don't spend the money on Shane's kit unless we are overlanders who want to run appliances with the engine off, and manage our power/have enough power to get home after our camping trip.

Especially If you are at the point of battery replacement and are, or see yourself being a overlander, I can't recommend this kit enough. If not, save your money for other things. There are no shortage of things to buy for your JL that WILL offer you benefit.

Lastly: if I delete the battery using any one of these methods, how will it affect my original warranty, and could it affect the 8 yr - 125k Mopar Max Care Warranty that I have already purchased?

I'd think most dealers could not care less. For those that do, there's the Magnuson-Moss Act, which prevents dealers from denying warranty claims simply because you have an aftermarket part or modifying your vehicle, unless that change led to something breaking on the vehicle.

Of course enforcing the Magnuson-Moss Act requires attorney's fees.

Worried? Okay. Before service put a battery charger's positive on the main battery's positive post. Put its negative on the dangling cable you temporarily took the insulation off of. This will only charge that ESS Aux battery, even though, yes, the positive of the charger sits on the main battery. Put Fuse 42 back, take it to the dealer and side step this issue all together.

thanks guys. Also, a link to a YouTube video if I decide to do B would be appreciated (Which is what I’m leaning towards)

I think you should do "A."

 

[THAW]

Good morning folks: I’ve ready this entire thread but I’m still asking for clarification please.

You appear to have a solid understanding of the aux battery delete/bypass information.

I agree with @AndySpill's assessments, including the pros/cons.

Option A is best for most people. It's simple, closest to factory, and accomplishes everything required to prevent aux battery related issues.

Option B requires pulling the PDC (fuse box) or the fender (the inner liner at minimum) to access the aux battery. I've realized it may be easier to non-destructively remove the positive aux battery cable than I originally believed, if you disconnect it from the PCR (located on the firewall below/behind the battery tray). Doing so requires a jumpered N1/N2 (or N1/N3 to include the N3 fuse)

As for option C, I am a fan of the Genesis dual battery product (I own only the tray), but note that a cab-located lithium ion aux battery is a popular alternative. Also, the Genesis system discoonects and re-connects it's batteries in a way similar to the factory system, so while it's (differently proposed) aux battery is more robust the system doesn't eliminate the original concern regarding strain on the main battery. Personally, I use a DCDC charger in conjunction with my Genesis tray.

 

[JLfromCA]

Can’t you also , do Step A , but also remove the aux battery, insulate the battery ends, and let them hang ?

 

[THAW]

Can’t you also , do Step A , but also remove the aux battery, insulate the battery ends, and let them hang ?

Yes. That's option B, but an alternative to part 2. Insulate any metal and secure the wires to prevent chafing (don't let them "hang" ).

 

[AndySpill]

You appear to have a solid understanding of the aux battery delete/bypass information.

I agree with @AndySpill's assessments, including the pros/cons.

Option A is the best for most people. It's simple, closest to factory, and accomplishes everything required to prevent aux battery related issues.

Option B requires pulling the PDC (fuse box) or the fender (at least the inner liner) to access the aux battery. I've realized it may be easier to non-destructively remove the positive aux battery cable than I originally believed, if you disconnect it from the PCR (located on the firewall below/behind the battery tray). Doing so requires a jumpered N1/N2 (or N1/N3 to include the N3 fuse)

As for option C, I am a fan of the Genesis dual battery product (I own the tray only) but it should be noted that a popular alternative is a cab located lithium ion aux battery. Also, the Genesis system connects and disconnects it's batteries in a similar way to the factory system, so while it's (differently proposed) aux battery is more robust it doesn't eliminate the original concern regarding the strain on the main battery. Personally, I use a DCDC charger in conjunction with my Genesis tray.

Foster:

You seem to have taken a route I'm considering: that being the purchase of Shane of Genesis Offroad's battery tray, and perhaps two batteries that fit in it, (rather than the entire kit) making one the "main" and the other the ESS. battery....even ideally, having them periodically switch roles every "x" number of cold cranks.

I call this "the way Stellantis should have done ESS in the first place" with two identical batteries in parallel.

Could you talk more to what you've done here? Perhaps I/we can glean some insight for your work.

Thanks

 

[THAW]

Could you talk more to what you've done here? Perhaps I/we can glean some insight for your work.

I respect your ambition to optimize the ESS power source(s)!

I don't use ESS. My ESS is fully functional (start battery only), but I have a Tazer to provide ESS button memory and haven't enabled it since turning it off (I rarely encounter stop lights or sit in traffic - situations where I'd at least consider using it).

I'm doing something more like the Genesis system, for auxiliary/house loads (e.g. a fridge). As mentioned, I have the Genesis tray, but didn't purchase their electronics/wiring. Instead, I use a Redarc BCDC1225d which keeps my 2 AGM batteries electrically isolated (technically they share a common ground), provides a proper charging profile for the the deep cycled house battery, and adds supplemental solar charging. The BCDC ignition wire is connected to an alternator sensing relay.

I also have an onboard/hardwired NOCO GenPro for monthly maintenance charging on the start battery. I've considered running a trickle charger from the (solar charged) house battery back to the start battery.

Since I have 2 isolated batteries, each with enough capacity to function as a crank battery - and because I have voltmeters to monitor status, plus solar charging - I'm not particularly concerned about a dead start battery. I should see early warning signs and/or be able to self recover.

I'm not a fan of the effects of ESS paired with alternator "charging" on AGM batteries. With my system, I figure even if ESS were enabled I can achieve long battery life with regular maintenance charging on the start battery (which I do regardless of ESS usage).

I'll have to think on your "Stellantis should have" ESS concept, and I'm curious to see what you invent.

 

[PrimeTime4370]

So, I did the bypass. Pulled the fuse and disconnected the negative Aux battery cable. I still have a "service ESS" warning light and message. Bad main battery?

 

[THAW]

Bad main battery?

I'm not familiar with the "service ESS" warning light (just chiming in until someone more knowledgeable comments), but your intuition is probably correct.

Can you check the main battery voltage with a multimeter? Or on the dash (with the engine off)?

 

[PrimeTime4370]

I'm not familiar with the "service ESS" warning light (just chiming in until someone more knowledgeable comments), but your intuition is probably correct.

Can you check the main battery voltage with a multimeter? Or on the dash (with the engine off)?

Don't have a multimeter. I can run out and check

I'm not familiar with the "service ESS" warning light (just chiming in until someone more knowledgeable comments), but your intuition is probably correct.

Can you check the main battery voltage with a multimeter? Or on the dash (with the engine off)?

No multimeter unfortunately. With the engine off in ACC it reads 12.5v.

So, what happened was, I almost always hit the button upon starting the engine. Last weekend I stopped to grab a drink. Forgot to hit the button after I left. Stopped at a light and engine shut off. No big deal ESS was on. Light changed and when I released the brake, the engine started but sort of lurched. It kicked into park and I had to move the shifter to park and back to drive. after which the light came on the cluster and the message "start/stop unavailable. Service start/stop system" appeared. Assumed the Aux. battery was bad so, when I got home I did the bypass method. But the message still appears each startup and the A with a circle light stays on. The Mopar main battery has a date of 2021. This is on a 2019. So, assuming the batteries were replaced at some point after only 2 years of service.

 

[THAW]

With the engine off in ACC it reads 12.5v.

12.5V is good, but doesn't necessarily confirm a healthy battery. I'd put a charger on it if you can.

I wonder if you have to clear a code?

 

[PrimeTime4370]

12.5V is good, but doesn't necessarily confirm a healthy battery. I'd put a charger on it if you can.

I wonder if you have to clear a code?

Cleared it with JScan and it came back immediately with the next start up.

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