Aux. Battery - How do I know

[sheram]

So……..you do not have an auxiliary battery with etorque but you do have a second battery ie the 48 v etorque battery. Correct?

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[JezzaAllen72]

Wish I had stumbled across this post 45 minutes ago before I did all the work and found an empty box where I thought the Aux battery would be. I have the eTorque (says so right on the sticker). So, before I go looking at the box near the rear axle, what exactly do I have, and is it replaceable? I have a PO562 and PO62F code flashing. and my car battery needed to be jumped several times yesterday.

 

[TheNewGuy]

Wish I had stumbled across this post 45 minutes ago before I did all the work and found an empty box where I thought the Aux battery would be. I have the eTorque (says so right on the sticker). So, before I go looking at the box near the rear axle, what exactly do I have, and is it replaceable? I have a PO562 and PO62F code flashing. and my car battery needed to be jumped several times yesterday.

The 48v eTorque battery is under an 8 year warranty and not customer replaceable. Have you replaced your crank battery or have it load tested? It's probably the culprit

 

[JezzaAllen72]

I had my battery tested at Advance Auto, but was told the CCAs were low but otherwise battery is all good. Put it on a low trickle charge and it's running fine, but still throwing ESS errors. took it to the dealer this morning and he flat out said, change the battery and that should take care of it. I'm online now pricing out an H7 replacement. 3 years/31K miles seems like an early grave for a car battery, but I live in Texas and summers here can kill anything.

 

[Vanburi]

3yrs for OEM failure is common, many threads discussing such failures.

 

[azbikerguy]

I have a 2022 JLU Rubicon with tow package. My window sticker, unlike the one in the earlier post, says nothing about dual batteries. It does say under "Tow Package"

"700-Amp Maintenance-Free Battery"

This is the only mention of battery on the sticker. Does this mean I do not have the aux battery?

 

[Terrymo]

I have a 2022 JLU Rubicon with tow package. My window sticker, unlike the one in the earlier post, says nothing about dual batteries. It does say under "Tow Package"

"700-Amp Maintenance-Free Battery"

This is the only mention of battery on the sticker. Does this mean I do not have the aux battery?

You can easily tell if you have the 48 volt etorque battery. It will be here. About the size of a small suitcase. If you don’t see this battery, your Jeep has (or had) a small secondary 12 volt battery.

 

[azbikerguy]

What is the reasoning for having this second, smaller aux battery? Why wouldn't Jeep simply hook the auto stop/start directly to the main battery? Having this second battery just seems to be another item to go wrong.

 

[Halxen]

What is the reasoning for having this second, smaller aux battery? Why wouldn't Jeep simply hook the auto stop/start directly to the main battery? Having this second battery just seems to be another item to go wrong.

Afaik, and others can correct me if I'm mistaken, the smaller aux battery is to keep your auxiliary devices powered during an ESS event. The engine still cranks from the main battery.

E.g. when the engine shuts off, the system disconnects the batteries from being paralleled and things like your Uconnect, AC, etc. are fused to the aux battery terminal on the PDC. At the end of the ESS event the engine cranks from the main battery and then the system closes the disconnect to put the two batteries back in parallel; which will recharge the aux battery back to balance with the main.

Regarding "Having this second battery just seems to be another item to go wrong.", many users would agree which is why there are lengthy threads on aux battery deletes, etc.

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