My thoughts on the auxiliary battery

[Andy29847]

What literature could possibly claim that?
What startup load does the alternator need to be shielded from? They can't be serious.
If this were the case, that alternators needed to be shielded from something, then the automotive world would be in a heap of trouble. Many engines take a whole lot more to crank and start than these do. There's no load on the alternator until the startup sequence is finished and it's in charging mode - and even then, it's charging two batteries - similar load to one larger battery (as you already understand)

If the main battery were much larger, there'd be no load to shield it from. It could handle it.

So that "literature" is from who, or what? Hope not a forum, or one of those "i used to be an engineer for......" types.

Those are fair questions. I was just reading through this thread again and lamenting the amount of mis-information shared here. Now it turns out I might be guilty too. I can't seem to google that article up again. It might be that I confused the RV side of my brain with the Jeep side.

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[ShadowsPapa]

Those are fair questions. I was just reading through this thread again and lamenting the amount of mis-information shared here. Now it turns out I might be guilty too. I can't seem to google that article up again. It might be that I confused the RV side of my brain with the Jeep side.

My gut tells me that if we were to meet, compare some notes and chat a bit - we really aren't THAT far apart on some things.........

 

[Wageslave]

For the aux battery that makes sense because there is NO regulation or charge handling of the stock AGM aux battery. The only sensing is done for the main/crank battery. the aux gets whatever is tossed out there.
With the built-in electronics, it will hopefully make that battery less prone to failures from being over or under charged because the charging system doesn't really directly monitor that battery for temperature or state of charge.
Seems a reasonable replacement direction.
Would be interested in long-term results over some time.

I do hope you did a full charge on the main/crank AGM battery when you reset the IBS.
Otherwise, sound theory.

I left the main battery on the trickle charger with the AUX disconnected until it switched over to float charge.

 

[ShadowsPapa]

I left the main battery on the trickle charger with the AUX disconnected until it switched over to float charge.

So you actually reset the IBS and installed it back onto the fully charged main battery with surface charge removed?
Resetting the IBS should see it then installed on a fully charged battery, rather than resetting it, installing it and then charging the battery.
So still confused - did you charge the main battery before reinstalling the IBS - you said you reset the IBS - that means disconnecting it and setting it aside for a while.

 

[Wageslave]

So you actually reset the IBS and installed it back onto the fully charged main battery with surface charge removed?
Resetting the IBS should see it then installed on a fully charged battery, rather than resetting it, installing it and then charging the battery.
So still confused - did you charge the main battery before reinstalling the IBS - you said you reset the IBS - that means disconnecting it and setting it aside for a while.

I pulled main battery out of truck, put it on trickle charger while I was replacing AUX battery with the new one. I touched positive and negative clamps together for a few seconds to reset the IBS while both batteries were disconnected from truck. I then installed the AUX battery, and once the charger switched over to float I installed the main battery.

Once everything was buttoned up I took it for a 30 mile round trip of highway driving. During that trip the ESS stayed in the not ready state for the entire trip (I am assuming the IBS was relearning). The next day and every day from then to present, the ESS has switched to ready as soon as the engine hit 170 degrees and would reliably switch back to ready as soon as I hit 35mph after a stop event occurred.

I seem to get about 5 minutes of stop time with lights and heater fan on before the AUX battery is discharged enough to automatically restart.

 

[ShadowsPapa]

while I was replacing AUX battery with the new one. I touched positive and negative clamps together for a few seconds to reset the IBS while both batteries were disconnected from truck.

To reset it, you remove the IBS from the battery and and remove the ground clamp from the IBS and set the IBS aside.
Not sure where you got the touching the clamps together part.

But it likely reset by virtue of the fact you had it out of the truck and away from all power. That's how they get reset, lay it aside while charging the main/new battery, disconnected from the system. The small connector is the LIN network connection, how the IBS communicates to the BCM.

Lots of bad info out there.

proper procedure is to:
*Remove IBS from both the ground cables and the main battery negative terminal (touching clamps together isn't needed and doesn't do anything for the IBS)
*charge the main battery,
*Reinstall main battery if necessary,
*Reinstall IBS.

See above for how it relearns.............. 1 to 2 key cycles, 2 to 4 hours of quiet sleep time with no charge in or out of battery and minimal draw from battery (no added accessories running)

The bit about installation of a new IBS applies to reinstalling a reset IBS - on a fully charged battery.

 

[Lost1wing]

I pulled main battery out of truck, put it on trickle charger while I was replacing AUX battery with the new one. I touched positive and negative clamps together for a few seconds to reset the IBS while both batteries were disconnected from truck. I then installed the AUX battery, and once the charger switched over to float I installed the main battery.

Once everything was buttoned up I took it for a 30 mile round trip of highway driving. During that trip the ESS stayed in the not ready state for the entire trip (I am assuming the IBS was relearning). The next day and every day from then to present, the ESS has switched to ready as soon as the engine hit 170 degrees and would reliably switch back to ready as soon as I hit 35mph after a stop event occurred.

I seem to get about 5 minutes of stop time with lights and heater fan on before the AUX battery is discharged enough to automatically restart.

I actually cringed reading the part where you touched the two cables together. Then I saw that you had both batteries disconnected. I thought for sure that your next sentence was going to be about the shower of sparks and now nothing works.

I'm glad it worked out for you. Good dral!

 

[Wageslave]

To reset it, you remove the IBS from the battery and and remove the ground clamp from the IBS and set the IBS aside.
Not sure where you got the touching the clamps together part.

But it likely reset by virtue of the fact you had it out of the truck and away from all power. That's how they get reset, lay it aside while charging the main/new battery, disconnected from the system. The small connector is the LIN network connection, how the IBS communicates to the BCM.

Lots of bad info out there.

proper procedure is to:
*Remove IBS from both the ground cables and the main battery negative terminal (touching clamps together isn't needed and doesn't do anything for the IBS)
*charge the main battery,
*Reinstall main battery if necessary,
*Reinstall IBS.

See above for how it relearns.............. 1 to 2 key cycles, 2 to 4 hours of quiet sleep time with no charge in or out of battery and minimal draw from battery (no added accessories running)

The bit about installation of a new IBS applies to reinstalling a reset IBS - on a fully charged battery.

Touching the terminals together simply grounds out any possible sources of voltage that may be back feeding from the cabin, such as a USB charger in the cigarette lighter port or an aftermarket car stereo amplifier. IBS sensors only have surface mount capacitors that will drain out after a second or two of being shorted to ground.

The correct way is to follow the procedure that you listed, but it can be done my way as well.

 

[ShadowsPapa]

I actually cringed reading the part where you touched the two cables together. Then I saw that you had both batteries disconnected. I thought for sure that your next sentence was going to be about the shower of sparks and now nothing works.

I'm glad it worked out for you. Good dral!

Yeah, I even read it twice to see that both batteries were out.
Just so much easier and safer to take it off the cables and battery - then it's reset.
Once you take it off the battery and the ground cable, it's dead.
Someone is going to forget or misunderstand and blow things up some day.

 

[Borismtngoat]

I was literally just looking at this. My amperage as not gotten over 14v in the last week while watching. I assumed the lights added by the prev owner was the cause for the extra battery issues and disconnected at the fuse until I have time to remove it and do it correctly. I've owned my JT since the end of August 2023 and have continuously seen where the ESS will not work because it is "charging" and had the main battery tested at O'Reilly's to make sure it wasn't an issue there. I'm going to try this NOCO out as well. Spec wise, it matches and surpasses the AGM on the market with higher CCA, amerage, and watt hours. Also, with just 1 - 1in spacer is the exact came size as the OEM Aux battery.

Have you had any issues since this post?

 

[ShadowsPapa]

and had the main battery tested at O'Reilly's to make sure it wasn't an issue there.

Did they disconnect the ground cables from the top of the crank battery to isolate it from the aux battery before testing? (hopefully leaving the IBS on the terminal and testing through it)

I don't generally trust parts stores to test batteries unless they are fully disconnected.

My amperage as not gotten over 14v in the last week while watching. I assumed the lights added by the prev owner was the cause for the extra battery issues and disconnected at the fuse until I have time to remove it and do it correctly.

I assume you mean voltage....... there's a lot of reasons for the running voltage to not go over that level. You don't know what the prior owner or anyone else did as far as charging batteries, pulling load from under the IBS instead of through it and so on.
Lights won't cause a problem - unless turned on.

 

[Borismtngoat]

Sure didn’t. I just bought it and ultimately thought I was over analyzing it so let it be. I will go ahead and swap and when the old comes out, I’ll run a test on it. Whether it’s bad or not, it’s 3 years old and likely worth replacing as a precaution anyways.
The aux lights wired in are coming out. I had to order new cowl bolts since they were removed for others with spacers. I’ll be adding the factory switch in later when I put in my tazer mini on top of a few other gadgets.

 

[Borismtngoat]

In my case, the AUX battery has failed on me both times coming into cold weather. I replaced both batteries as a precaution the first time but that main battery lives on 'til this day in my Grand Cherokee with no issues. I replaced the AUX battery with an ES-TX14-BS motorcycle battery the first time due to availability issues with the AUX14 battery (Same guts, nut and bolt posts instead of stud posts). No more issues and ESS readily available through fall of this year. Original AUX battery tested bad.

This week I started getting getting Aux switches unavailable errors again any time I hadn't ran it or had it on the trickle charger for more than 24 hours. Main battery tested good, AUX battery needed charging but tested good afterwards. I threw it in my motorcycle and haven't had any issues cold starting it with that battery so it seems to have nearly all its rated CCA still available.

This time around, I decided to try out a theory that I had and installed a NOCO NLP14 LiFePO4 battery in the AUX battery position. My theory is that when cold weather hits and possibly even in warmer weather, the charge profile for low temperatures is correct for the main battery but is too conservative for the AUX battery and the computer ends up holding it at a lower than ideal voltage. This fatigues the battery over time and shortens the life a battery that is probably designed for a 3-5 year service life in the best case.

What should make the NLP14 special is the fact that it is a retrofit Lithium battery that has a charge controller that is programmed to simulate an AGM lead acid battery. This should mean it can be connected in the same way with no modifications to the truck and the charge voltages will be compatible.

The internal charge controller should regulate the battery separate from what the PCM is doing with the main battery, allowing it to basically protect itself.

I installed the NLP14 a week ago and reset the IBS, and after it relearned my ESS has been showing ready as soon as it was up to full temperature. I have had it stop the motor for 2 minutes at a light, then stop again a few blocks down the road so capacity doesn't seem to be an issue. After sitting for 48 hours, there was no abnormal issues with voltages at startup and no extended wait times for the ESS to become ready.

Unless there is a very slow draw between the batteries that shows itself after weeks of sitting, I don't see any reason why this setup wouldn't have superior reliability to the AGM battery for the same price (-ish) as an AUX14.

It looks like you’ve a diesel as do I. I just swapped this out after both my main and aux batteries were bad. I’m. Or getting an ESS unavailable and to service after it charges enough. I think I need to reset the IBS to read it again because it was working. I’m curious if you’ve had good luck or any issues and did you charg the batteries separately or other when you topped them off? Let me know how it’s going.

 

[Wageslave]

It looks like you’ve a diesel as do I. I just swapped this out after both my main and aux batteries were bad. I’m. Or getting an ESS unavailable and to service after it charges enough. I think I need to reset the IBS to read it again because it was working. I’m curious if you’ve had good luck or any issues and did you charg the batteries separately or other when you topped them off? Let me know how it’s going.

When I replaced my batteries, I charged each new one individually on my trickle charger until it registered a full charge/float charge, then installed them. You should unplug the IBS for a few minutes to reset it as well.

As far as my current situation, the NOCO battery has been doing well. Once I put a few miles on it, ESS becomes ready and seems to work even after repeated uses.

 

[Borismtngoat]

When I replaced my batteries, I charged each new one individually on my trickle charger until it registered a full charge/float charge, then installed them. You should unplug the IBS for a few minutes to reset it as well.

As far as my current situation, the NOCO battery has been doing well. Once I put a few miles on it, ESS becomes ready and seems to work even after repeated uses.

Thanks for the info. I had topped off my old primary and the aux battery separate till full outside of the truck, but was told the primary was good when tested originally. When I took it in to the dealer they tested both originals were bad and the truck sat while I ordered a better primary battery and I’m sure that drained off the noco. It’s showing a service light for the ESS if it tries to charge and I’m sure that and an IBS reset will do it. I appreciate it!

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