Replacement Auxiliary Battery

[Recon3D]

Looking for assistance with replacing my auxiliary battery for my 2016 750i xdrive.

The original battery specs are 12v 12Ah 200CCA AGM, however, I was wondering if there would be any issues if I put in a 12v 14Ah 200CCA AGM battery?

Would I need to code the new auxiliary battery?

[TheNine90]

Not sure if you can change the battery capacity, but the new battery would need to be registered for replacement

[Qsilver7]

Originally Posted by Recon3D

Looking for assistance with replacing my auxiliary battery for my 2016 750i xdrive.

The original battery specs are 12v 12Ah 200CCA AGM, however, I was wondering if there would be any issues if I put in a 12v 14Ah 200CCA AGM battery?

Would I need to code the new auxiliary battery?

Not sure why you’re changing the size of the battery…but if you have the software that allows you to code and/or register a new battery…simply connect to the software and pull up the auxiliary battery to see if you have the capability to code or register it. Pulling it up to check what can be done won’t hurt or change anything…UNLESS you change the parameters.

Some BMWs may require coding/registering of the auxiliary battery and some don’t. If the aux battery has an IBS (intelligent battery sensor) built into the negative battery lead…then more than likely you will have the capability to register it since the IBS facilitates communication of that battery in the vehicles electrical charging system.

If the aux battery does NOT have an IBS…then more than likely you won’t see a way to register the battery. When the aux battery doesn’t have an IBS attached to it…it is usually monitored by a PCM/PCU (power control module/unit).

My f15 X5 has an aux battery that sits next to the main battery and it DOES NOT have an IBS attached to it…but it’s connected to a PCM that sits between the aux & main battery. My coding & registering software doesn’t list anything for this aux battery. Again, it doesn’t have an IBS attached to it.

[Raimo5]

Looking at the specifications of the battery in opening post, it indicates that we are talking about Integral Active Steering battery, not just additional electrical system battery. I cant be sure, but I think there was no service function, or need to register HSR battery replacement. It's only function is to step up the voltage to 24v for HSR by being connected in series to basic electrical system.

I would be rather comfortable equipping the 14Ah battery.

[Recon3D]

Originally Posted by Raimo5

Looking at the specifications of the battery in opening post, it indicates that we are talking about Integral Active Steering battery, not just additional electrical system battery. I cant be sure, but I think there was no service function, or need to register HSR battery replacement. It's only function is to step up the voltage to 24v for HSR by being connected in series to basic electrical system.

I would be rather comfortable equipping the 14Ah battery.

Correct, I am referring to the battery in the trunk, next to the main. I was getting EPS faults before swapping the battery and it has now remedied that issue.

Do you happen to know if that same AUX battery handles the compressor? If not, would it be the battery under the hood?

[Raimo5]

Air suspension compressor is handled by basic electrical system, which would be your 105Ah AGM in the luggage compartment.

Additional electrical system battery (60Ah) under the bonnet doesn't run anything directly. It is connected to PCM (Power Control Module) which is a DC/DC converter and feeds power back to basic electrical system during start-stop procedures to relieve system load and cycling.

[Roland2024]

[QUOTE=Recon3D;30672094]Correct, I am referring to the battery in the trunk, next to the main. [COLOR="Red"]I was getting EPS faults before swapping the battery and it has now remedied that issue.

Reading your comment about the aux battery... I'm getting this message from my scan "4822E2 EPS voltage supply: Failure of 24 volt level (auxiliary battery disconnection element), and of course on the dash the yellow warning steering light. Is this what you were seeing? Is it the battery or the power module?
How hard is it to replace the battery - dealer only type of thing ?? ThanX! Roland

[M_Bimmer]

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[TENCHI]

I bought my car used and the dealer swapped out the OEM 12ah battery with an aftermarket 14h battery. while some things worked, it caused a lot more faults. Wound up having to pay over a grand to replace