Another ESS/Battery Question

[Gatorized]

Group 48 or group 94R I believe are the options.
aux is Group 400 (AUX14)

https://www.jeepgladiatorforum.com/forum/threads/group-48-and-94r-batteries.53036/

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[Panthers65]

Depends on your options. If you have factory aux switches, you have the larger battery (700 amp)
No aux switches - smaller battery.
Diesels may be different?

Mine has the largest battery they come with factory. Can't get a physically larger battery in there. It fills the tray. My 2020 didn't have aux switches and had the smaller battery with a bit of room on the end of the tray.


I'd never let clowns at a part store diagnose anything. Untrained, especially when it comes to dual battery systems.

And yes, much of what's out there is "internet lore" and started by guessing or one person getting into trouble and not jumping correctly and then blaming everything except themselves.
So much out there that's inaccurate, or even just "not quite right".

Thanks for all your help thus far. Could something I did yesterday have reset the system?

I went to the hardware store to buy an AGM battery charger (I have a se-2158 schumacher charger, but it didn't specifically say for AGM batteries). The hardware store is about a mile from my house. I drove there, no changes. On the way home in the parking lot I saw the message "Start/Stop system ready". When I got to the traffic light, the truck stopped like it was suppose to(first time in a month). Light changed green, drive the mile home with the message "Start/Stop Not Ready" the rest of the way home.

Why would the ESS randomly have worked in the parking lot, but not again for the rest of the trip home?

I have it on the new charger now (disconnected the AUX Ground from the battery, hooked the negative to the Aux ground cable, and clamped the + directly to the main batter terminal, assuming this will only charge the Aux battery right?) charger said the battery was at 60% when I hooked it up. I will do the main battery after.

 

[ShadowsPapa]

Thanks for all your help thus far. Could something I did yesterday have reset the system?

I went to the hardware store to buy an AGM battery charger (I have a se-2158 schumacher charger, but it didn't specifically say for AGM batteries). The hardware store is about a mile from my house. I drove there, no changes. On the way home in the parking lot I saw the message "Start/Stop system ready". When I got to the traffic light, the truck stopped like it was suppose to(first time in a month). Light changed green, drive the mile home with the message "Start/Stop Not Ready" the rest of the way home.

Why would the ESS randomly have worked in the parking lot, but not again for the rest of the trip home?

I have it on the new charger now (disconnected the AUX Ground from the battery, hooked the negative to the Aux ground cable, and clamped the + directly to the main batter terminal, assuming this will only charge the Aux battery right?) charger said the battery was at 60% when I hooked it up. I will do the main battery after.

Sounds like you have it connected fine. The charge will get to the aux battery through the PCR and other wiring.

I wonder if your truck is randomly detecting some misfires or something - it won't necessarily set the light, but will stop ESS from working until the system decides all is ok again - can take one or two big button stops and starts to go again if things were detected.
I'd love to get either JSCAN or AlfaOBD on that truck and see if there's something else going on.

 

[tysongladiator]

That looks like the base battery, no aux switches, etc.

With the aux switches, this is what I have (listed under optional equipment) -

Without the aux switches, this is what an identical Gladiator gets -

A JLU with the "towing and HD electric package" (includes aux switches, and is the only way to get them on the JL)

You can tell the difference by checking the fit of the battery in the tray.
With the 650 amp battery, there will be space between the front end of the battery and the tray. With the 700 the battery will fill the tray front to rear (length of the battery and tray)

You are very correct about the battery tray. Here's another issue with a dealer I had here in San Antonio. I had to replace my batteries the first time at 52,000 miles and then at 132,000 miles. But when I replaced them the first time I replaced them about 3yrs ago, I got a battery from the dealer. When he gave it to me, I told him it was the wrong battery. He swore that the part numbers match. I got home, put the battery in the tray, I noticed that it was too small. Then I noticed the CCAs were wrong. Took it back to them and then the realized they gave me the wrong battery. Even thought they told me the part numbers match.. They didn't have it and I ended up going to another dealer across town to get the correct battery. Ridiculous!!!

So, yes. One way to tell is the size of the battery.

 

[IanNubbit]

YOU did it right if you followed Jerry's ( jebiruph ) bit - he posted about exactly how to do it in this forum months ago.
NO NEED to jump anything!

So I guess I see this making since and working. PERSONALLY. Just personally, i wouldnt run that as a permanent solution. Doing that is asking much smaller circuits in the board of the PDC (fuse box) to back feed power to power multiple circuits. Im also honestly a little confused on how this even works as if you Just pull the wire off N1, you have a dead truck

 

[ShadowsPapa]

Small main battery - no aux switches, etc.
End of battery almost even with rear of PS reservoir
and plenty of space to feed cables and so on->

Larger 700 amp battery - crowded in tray,

 

[ShadowsPapa]

So I guess I see this making since and working. PERSONALLY. Just personally, i wouldnt run that as a permanent solution. Doing that is asking much smaller circuits in the board of the PDC (fuse box) to back feed power to power multiple circuits. Im also honestly a little confused on how this even works as if you Just pull the wire off N1, you have a dead truck

No one is pulling the wire off N1.
They are pulling F42 to prevent the PCR from opening to do the aux battery voltage check when you push the big button to start the truck, and they are removing the aux battery ground cable from the IBS (leaving the other ground cable on the IBS or putting it back on depending on if it's a 2020 or later)
If the PCR can't open during the start cycle (and the ECUs don't know it's not opening) then it lets things function - the ESS works for about 6 cycles then fails apparently because the system saw identical voltages. There's a way around that, too, a simple resistance in the circuit to give a slight voltage difference between the IBS and N1.

People have done this successfully for quite a while. And when the aux battery is going bad, that's how it operates anyway - power goes from the main battery to N1 to feed the cabin electronics, PDC, etc.

N1 is never touched. You don't take anything off of it if using Jerry's quick, easy jumperless method.
There are members here who have done this and it works fine. I seem to recall that as a POC, Jerry has been running his Jeep this way for weeks if not months, no trouble.

 

[Radio Guy]

So I guess I see this making since and working. PERSONALLY. Just personally, i wouldnt run that as a permanent solution. Doing that is asking much smaller circuits in the board of the PDC (fuse box) to back feed power to power multiple circuits. Im also honestly a little confused on how this even works as if you Just pull the wire off N1, you have a dead truck

If you remove the small battery and leave the battery cables intact from PCR to N1 it will still work. If you remove the small battery harness with the small battery you would have to jumper N1 to N3 or something similar. Otherwise part of the truck would be dead.

 

[ShadowsPapa]

Doing that is asking much smaller circuits in the board of the PDC (fuse box) to back feed power to power multiple circuits.

Why does the PDC need to back-feed anything? If the wiring is left in place, the PDC still gets power sourced from original origins.
The system gets operating power via N7 fuse from the charging system, along the high current fuse array bus, then it passes through N3 and the PCR to N1 where it goes out as normal.

 

[ShadowsPapa]

If you remove the small battery and leave the battery cables intact from PCR to N1 it will still work. If you remove the small battery harness with the small battery you would have to jumper N1 to N3 or something similar. Otherwise part of the truck would be dead.

Exactly. And that's how Jerry has laid it out. For a simple jumperless quick bypass - which you can leave that way, pull F42, pull the aux battery negative off the IBS and keep it from contacting anything, and just drive it. The side effect is that ESS only works something like 6 times but there are ways around that as well. It could be fully functional with just a tiny bit more work.
Like you said - only of you remove the PCR and aux battery cables do you need to use a jumper.
Personally I'd go N1 to N3 and jump around N2 because that way it would be fused like it was originally. Going to N2 means no fuse. It's a hot terminal.
It would more closely match the original design in that respect if you went N1 to N3.

But you can leave all of the stuff in place under there with no damage. You could remove the aux battery and just wrap the battery terminal and leave all wiring there. I see no reason to not leave it in place.

 

[Gatorized]

What happens if you leave both batteries connected and remove fuse 42?

 

[Radio Guy]

It disables the ESS and defaults to both batteries in parallel all the time.

What happens if you leave both batteries connected and remove fuse 42?

 

[ShadowsPapa]

It disables the ESS and defaults to both batteries in parallel all the time.

ESS would likely still function for the first 6 times like it otherwise does because it will still be seeing the same voltage because the PCR can't open.
Since the PCR can't open - it would be interesting to see how it behaved as far as charging after an ESS stop event because it wouldn't see the aux battery going down so quickly.
Interesting experiment to try.

 

[IanNubbit]

Why does the PDC need to back-feed anything? If the wiring is left in place, the PDC still gets power sourced from original origins.
The system gets operating power via N7 fuse from the charging system, along the high current fuse array bus, then it passes through N3 and the PCR to N1 where it goes out as normal.

N1 goes straight to Aux battery positive. If you remove the ground from the Aux, you will get no supply voltage from the Aux. Therefore there will be no power at N1, instead at all times main battery power goes through N3 fuse down through the PCR at all times, down to the Aux positive terminal which goes back up to the N1 post and then powering the truck. Normal operation the N3 fuse solely charges the Aux and no more, now it is solely responsible for all power the Aux battery is responsible for. Again, it works, but personally I do not consider this a permanent solution. I might have to show my set up using the factory wiring since it’s free but very permanent just involves more work

 

[Deleted member 28696]

I've ready several of the other threads out there about the Main/Aux Battery, but can't find anything specific to my situation.

'21 Sport S with a S-Tech switch box and a winch. Gladiator was delivered November '21, so 14 months old, and when it was delivered there was an issue with the ESS and the dealership replaced the Aux Batter before I took delivery. ESS worked fine for about a year, and stopped working a month or so ago. Secondary vehicle, a lot of around town trips which I know is rough on a battery.

Getting a plain "Engine Start/Stop Not Ready" message, no other messages/reason.

Engine off, last drove it for a few miles last night:
Voltage across the main battery- 12.4-12.5
Voltage at the N1 Terminal- 11.6

Engine on, right after start:
Voltage across the main battery- 14.7
Voltage at the N1 Terminal- 14.7
Voltage on the dash screen- 14.6

After letting the truck idle for 10 minutes and come to temp, all the voltages are the same , maybe .1V higher. With the switches and winch, I figured the dealership might hassle me about warranty work, so if it's just the Aux battery I'd likely just replace it or bypass it all together myself. Given the low voltage on the N1 terminal with the engine off, and the running voltage staying at 14.7, that would be my assumption. Can anyone confirm if I'm on the right track?

I replaced it with a Genesis. full sized Dual battery system which solved my battery problem & still leaves the Jeep systems as designed. It won't void any Jeep warranty since it doesn't alter the system or how it works in any way. I've heard of others just bypassing the small battery, but I like the Genesis system better. It switches batteries when one gets drained past a certain voltage using a solenoid. It can jump your jeep as well if needed with the second battery. I got full throttle AGM batteries from Genesis when I purchased the system. On my SPOD LCD the voltages usually reading around 14.8v. even after sitting for a while. Prior to installing it I replaced both batteries twice under warranty, but I wanted to permanently solve the issue. Best accessory I've installed.

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