[everson38]

Hey all,

new to the forum so apologies if any faux pas in advance.

I have a 2018 5 series petrol hybrid and got a warning light / code for my auxiliary battery 'aged battery'. I was hoping could tell me are there any writes up on how to get this replaced, or are thier any other models that have the same procedure that i can check their write up as wanting to get this changed sooner rather than later.

Thank again.

Everson

[vinniea]

Hello, I also need to get the instruction on how to replace the front auxiliary battery on a 540i. Specifically on how to make room to get the battery out the car. There is an alluminum bar on the way and I wonder the proper steps to remove it.
Thanks
Vinnie

[vinniea]

540i G30 Auxiliary Battery Replacement
The Main Battery located in the trunk, under the floor mat. AGM 90AH / 900CCA. The replacement of this battery is no hassle and requires to be registered with the vehicle.

The Auxiliary Battery is under the hood of the car. AGM 60Ah / 680 CCA:
1. Open the hood. Remove Wiper Arms, mark wiper blade position on windshield. Use a puller if available, apparently these are really hard to remove.
2. Remove the Windshield Cowl Panel, detach holding latches as shown in graphics. I was able to reach the bolts by lifting the cowl and. Not remove it
3. Remove the Torx screws on the front and back side to remove reinforcement aluminum bar away
4. Remove battery holder. Replace Battery. Insert plug in right side vent hole
5. Secure battery and connect +/- cables. 1-2Nm is spec but rather handtight.
6. Installl Battery holder
7. Reinstall Aluminum bar, apply 56Nm torque.
8. Reinstall Cowl Panel, engage latches.
9. Reinstall Wiper Arms. Apply 35Nm torque as specified. It seems too much force I applied 30Nm.
10. Measure new battery voltage (12.7V), turn on engine, measure charging voltage (14.72V)
11. Clear Error code with BimmerLink App

Here is a link to a video of the work:

[kampod]

thank you! this was super helpful. I followed the instructions and never had any issues except jamming the battery ventilation hose under the battery, and then having to take it out and putting back again. Make sure that hose is attached before securing the battery.

[Tpriest7893]

What battery did you use for replacement for the auxiliary battery?

[vinniea]

Originally Posted by Tpriest7893

What battery did you use for replacement for the auxiliary battery?

The Auxiliary Battery is under the hood of the car. AGM 60Ah / 680 CCA.

[Tpriest7893]

Originally Posted by vinniea

The Auxiliary Battery is under the hood of the car. AGM 60Ah / 680 CCA.

Yes I know the location I was curious what brand as I was going to replace mine with a non oem and there’s several brands and haven’t found what is best

[OnlyGerman]

Do we need to disconnect the neg terminal for the main battery in the trunk before proceeding?

[OnlyGerman]

Originally Posted by Tpriest7893

Yes I know the location I was curious what brand as I was going to replace mine with a non oem and there’s several brands and haven’t found what is best

Did you end up locating a sufficient aftermarket battery?

[Tpriest7893]

Originally Posted by OnlyGerman

Did you end up locating a sufficient aftermarket battery?

I did not. It’s still on my list to do. I kinda forgot about it to be honest. My cars been fine tho, part of me wonders if my battery was even low. I have a voltage tester at home that I should hook up and test it to see if bmw was bullshitting

[OnlyGerman]

Originally Posted by Tpriest7893

I did not. It’s still on my list to do. I kinda forgot about it to be honest. My cars been fine tho, part of me wonders if my battery was even low. I have a voltage tester at home that I should hook up and test it to see if bmw was bullshitting

I ended up getting one from advance auto and changed it.

My failing aux battery left my car stalling on the highway, with no real prior warning of a failing aux battery. I would recommend replacing if it’s old!

[Tpriest7893]

Originally Posted by OnlyGerman

I ended up getting one from advance auto and changed it.

My failing aux battery left my car stalling on the highway, with no real prior warning of a failing aux battery. I would recommend replacing if it’s old!

Which brand did you use?

[OnlyGerman]

Originally Posted by Tpriest7893

Which brand did you use?

Diehard AGM H5
680 CCA

60 amp hour

100 reserve

[430Scud]

Originally Posted by OnlyGerman

I ended up getting one from advance auto and changed it.

My failing aux battery left my car stalling on the highway, with no real prior warning of a failing aux battery. I would recommend replacing if it’s old!

Best advice is to buy an inexpensive battery tester and test your battery a couple times a year. This will catch it as it begins to become weak, and hopefully before it leaves you stranded. I have been doing this for the past 15+ years and have been able to prevent premature replacement. I got 14 years out of one battery. Both of my M550ix batteries are 8 years old, no issues so far.

https://www.amazon.com/dp/B01M0ARG3X...x=battery+test