Hi all,
Recently replaced my battery, so here is a brief overview.
Batteries tend to last around 5 or so years, and our cars are pretty sensitive to battery issues. I have had a "Battery faulty or worn out" code stored and the battery is original, with a week 10/2015 date stamped on the top of the negative terminal. All batteries will have a date on them somewhere, in the format of WW/YY (WW between 01-52 weeks followed by YY for the year). Since mine was original, I had the stored code, the battery was at 78% of its capacity based on diagnostics, and was starting to see some odd behavior it was certainly time for a replacement.
It's important to get the correct battery for your vehicle; Battery type, capacity (Ah, Amp Hours) and CCA (Cold Cranking Amps).
Without going into much detail, most BMWs will use an AGM (Absorbent Glass Mat) battery. If you're curious, fill your boots:
https://batteryuniversity.com/learn/..._glass_mat_agm Long story short though, they suspend the battery acid in a glass mat so they cannot be spilled if the battery is ruptured.
I purchased a new one from Costco, shipped to my door for significantly less than I could get one from anywhere else. New specs are slightly different, summary below. I was not able to find a 105Ah anywhere but the dealer.
Original:
AGM, 105Ah, 950 CCA
New (Energizer H8 EA95-L5):
AGM, 95Ah, 850 CCA
The most straight forward approach is to match the factory battery type exactly, as it saves you a step. Some people seem to be against registering the batteries, citing it's silly and not required because other cars work fine without this step... I disagree. The vehicle is smart, it charges the battery based on its capacity, age, and likely other factors to stretch the battery life as long as possible and keep the electronics in the car functioning at their peak. To this end, it's very important to register a new battery and if the battery is a different type, code it.
More information on the IBS can be found here if you are interested:
https://www.newtis.info/tisv2/a/en/f...ttery/BdzoqEna
https://bimmerscan.com/bmw-intellige...ry-sensor-ibs/
Procedure:
1. Identify the Factory Battery, source and purchase a new battery
The information is on the battery sticker.
2. Remove the Existing Battery
Open the liftgate, remove the lower trunk liner by lifting via the handle
Next open the battery compartment. At the rear there are two plastic retainers that you can use a flathead screw driver to rotate 90 degrees. The retainer is shaped like a "T" on the bottom and rotating it allows the "T" to slide through the slot.
After that, remove the push pin type retaining clips (4 total). You will need a cats claw or "Y" shaped trim removal tool to remove these. It can also be done with a small flathead screwdriver or pick, but you will almost certainly damage them by not using the proper tools.
3. Remove the Battery
A. Take a picture of everything assembled for reference.
B. Disconnect the Negative battery terminal. The vehicle MUST be completely powered down for this. Ie, ignition fully off. If you have a battery charger it must not be connected. Using gloves is also a good idea when working with batteries and high voltage electronics.
C. Disconnect all cables from the Power Distribution Box (big red box on the left):
https://www.newtis.info/tisv2/a/en/f...older/1M33WCXv
D. Disconnect the cable retainers from the battery retention bracket. These can be removed using a cats claw or trim removal tool. Pry them out; they can be pushed back into place after. Make sure the plastic is warm, it may break if cold. Removing these allows you to move all cables out of the way to access the bracket.
E. Remove the Power Distribution Box by using a flathead screwdriver to pop the shiny metal tabs free at the front/back. There is a 'V' shaped point you slip the screw driver into and pull away from the battery; they will pop free and the box can be lifted out. Make sure the box is first unbolted from the Intelligent Battery Sensor. After this, disconnect the Intelligent Battery Sensor and Positive Battery Terminal.
F. Remove the battery retention bracket. There are two bolts, one at the rear, one at the front. The bracket then lifts up/out
G. Remove the battery holder(s) at the bottom. Mine had only one L shaped holder at the front right of the battery, yours may have one at the front, one at the side. It's held in place by a single bolt, unbolt it and remove.
H. Remove the battery vent tube from the left of the battery. It's a little plastic plug connected to a vent line. You can see it disconnected in the above photo in step 2E.
G. Lift the battery up and out.
3. Install the New Battery
Before installing the battery it's important to install the vent plug in the negative terminal side vent. My battery was supposed to come with one, but did not. I used a pick tool to pull the vent plug from the factory battery and install it in my new one.
Info specific to AcDelco batteries, but the process is universal:
https://www.techconnectcanada.com/bl...ery-vent-plugs
A. Lift the battery in to place
B. Install the vent hose into the positive side vent port
C. Reinstall the battery retention bracket and battery holders at the bottom, torque spec for these bolts is 10nm. I just went hand tight as 10nm is not much.
D. Reconnect the positive terminal/IBS
E. Reinstall the Power Distribution Box by sliding it over the threaded rod on the IBS, it should clip into place with the metal tabs top/bottom.
F. Reinstall all remaining cables, except the negative cable, bolt the Power Distribution Box to the IBS, and bolt the positive cable to the Power Distribution Box. Torque for both is 15nm, I also just did these by hand because again, it's not a high value.
Reinstall the negative battery cable.
G. Reinstall the battery compartment cover / trunk storage bin. The retainer pins are two pieces, gently 'feed' the top of the pin into the seat so it's just started, push the whole assembly into the hole in the metal trunk bed, then push the top of the pin down. It will cause the 'legs' on the bottom to flare out holding the fastener in place. Next push the "T" style retainers you used a flathead on at the start back down, rotate them 90 degrees. Reinstall the trunk liner/lid.
4. Battery Registration
This is the more complicated part, in that it needs a proper scan tool or software. I'm using ISTA+. You can do a google search and find lots of info/where to download it. You will also need an OBD to ENET (RJ45) cable to connect with the car.
The procedure is straightforward, the following video documents the steps. If you have a battery that is different than the factory one, you will need to code the correct values after this step.
5. Battery Coding
Only do this if you have a battery which is different than your factory one.
To do this, I used E-sys, however there are also other options. I believe Carly and BimmerCode have the ability to code a battery but I'm not certain on that. Do some research and decide what software works best for you.
Once in E-sys and connected with the car the process is simple.
A. Access the CAS module
B. Line 3702
C. VCM_BATTERY_CLASS
D. Change the value to the one closest matching your new battery type. My battery was a 105Ah battery, replaced with a 95Ah battery. 95 is not an available value so I coded it to a 90Ah value.
Once complete and the module is flashed, enter ISTA+ again, go to the battery registration procedure and review battery replacement info. The readout from my car is below, you can see this is the first battery change at 98,170km, and that the current battery is a 90Ah AGM.
After this pack everything up, and enjoy your ride again!