[chassis]

Hello all,

Is a BMW procedure, with torque specs, posted on this site for main battery replacement on the G01 B48 variant? I searched using the site search tool and also with Google. Nothing came up.

I understand the windshield cowl trim and chassis strut need to be removed.

mattsheng is this something you would have at hand?

Thanks for any input.

[mattsheng]

It seems that you want the repair instruction for replacing the 12V AGM battery located underneath the trunk cover. If that's the case, this is the repair instruction for that:
Replacing 12V AGM vehicle electrical system battery REP-REP-P-6121017-G01.pdf
Disconnecting all negative battery cables REP-REP-P-6120900-G01.pdf

This won't require removing the cowl cover and the engine bay strut brace unless your car also has a 48V battery. The 48V battery and the additional 12V lithium-ion support battery are located underneath the right engine cowl if they are fitted. Their replacement instructions are here:
Replacing 48V battery REP-REP-P-6121007-G01_B48.pdf
Replacing 12V lithium-ion vehicle electrical system support battery REP-REP-P-6121070-G01.pdf
Replacing 12V dual storage battery REP-REP-P-6121004-G01.pdf

I can't work out what is the difference between the 12V lithium-ion support battery and the 12V dual-storage battery. As far as I know, 2018 G01 xDrive30i in the US only has the 12V AGM battery. Anyhow, here are some notes on the different batteries
Notes on AGM battery REP-ALG-RAF0161-6120AGM.pdf
Notes on 48V battery REH-HIN-P-6120-48V.pdf
Notes on 12V lithium-ion support battery REH-HIN-P-6120-EMARS.pdf
Instructions for 12V dual-storage system REH-HIN-P-6120-DSSDUAL.pdf

[chassis]

Thanks mattsheng !

I learned something today. There are two batteries in my April 2018 build G01 xdrive30i US market vehicle.

I saw the smaller 12V 50Ah VRLA/AGM Pb Varta battery in the right/passenger side cowl area during normal cleaning, oil change and spark plug projects. Part number 61219364596. I erroneously thought this was the only battery because it looks about right. Then I looked under the trunk liner and saw the large main battery - surprise (to me)! I didn't get the part number or capacity of this battery, but will need to do this when I buy a new one.

OK then.

[X3rd Time Is a Charm]

I also have a battery under the hood .This is what I found. Not sure how much information it gives though. My rear battery is a 105AH

[mattsheng]

Originally Posted by chassis

Thanks mattsheng !

I learned something today. There are two batteries in my April 2018 build G01 xdrive30i US market vehicle.

I saw the smaller 12V 50Ah VRLA/AGM Pb Varta battery in the right/passenger side cowl area during normal cleaning, oil change and spark plug projects. Part number 61219364596. I erroneously thought this was the only battery because it looks about right. Then I looked under the trunk liner and saw the large main battery - surprise (to me)! I didn't get the part number or capacity of this battery, but will need to do this when I buy a new one.

OK then.

Hmm... I don't recall seeing the 12V 50Ah auxiliary battery on my US 2022 G01 xDrive30i. Maybe they got rid of it at some point in time. BTW, 2018 G01 xDrive 30i either comes with a 105Ah AGM battery (part #61 21 7604808) or a 92Ah AGM battery (part #61 21 6806755) and these batteries are also used on LCI cars.

[chassis]

Videos showing nearly all of the steps to replace both batteries:

https://www.carcarekiosk.com/video/2...eplace_battery

In my haste to find the front battery video I neglected to watch the full length of each video. Everything is included in the link above.

The only step not shown is detaching the cowl plastic trim. Does it simply pull/snap off?

[R BMW]

Why does this model need 2 batteries? Are there more electronics than other versions.
If this is a dumb question, excuse me. Mines a X3MC.

[rob175]

My 2020 X3 xDrive30i has ONLY one battery in the rear...no other battery. It does appear to have a smaller battery attached to the right side.

Question.....when disconnecting and pulling the battery are all of the settings erased? (such as: radio presets, iDrive settings, phone pairing etc etc) Or are they retained in memory?

For other cars I've owned, in the past, I've used a second 12v battery with a jumper cable plugged into the cigarette lighter socket to retain settings while changing the battery.

[mattsheng]

Originally Posted by rob175

My 2020 X3 xDrive30i has ONLY one battery in the rear...no other battery. It does appear to have a smaller battery attached to the right side.

Question.....when disconnecting and pulling the battery are all of the settings erased? (such as: radio presets, iDrive settings, phone pairing etc etc) Or are they retained in memory?

For other cars I've owned, in the past, I've used a second 12v battery with a jumper cable plugged into the cigarette lighter socket to retain settings while changing the battery.

Not sure about iDrive settings but all fault memory will be erased after disconnecting all negative terminals.

[jeff3820]

Originally Posted by rob175

My 2020 X3 xDrive30i has ONLY one battery in the rear...no other battery.

My 2020 X3 xDrive30i has two batteries. One in the rear and one in the engine compartment in the right cowl. Must be the difference in equipment selection...

[chassis]

Originally Posted by jeff3820

My 2020 X3 xDrive30i has two batteries. One in the rear and one in the engine compartment in the right cowl. Must be the difference in equipment selection...

Wife's 2018 xDrive30i has two batteries as yours does. I think start-stop is supported by the second battery, likely among other functions.

If a 2020 xDrive30i has only one battery, it is likely a "dual storage" battery listed in one of the scenarios early in this thread.

[mattsheng]

Originally Posted by chassis

Wife's 2018 xDrive30i has two batteries as yours does. I think start-stop is supported by the second battery, likely among other functions.

If a 2020 xDrive30i has only one battery, it is likely a "dual storage" battery listed in one of the scenarios early in this thread.

If I remember correctly, 2018-2019 G01 30i came with B46TU0, which has different fuel and timing systems than B46TU1, which are on 2020 and onward. Maybe the start-stop function got changed a bit during the technical update and it now requires less energy and so 2020 and onward G01 no longer require a secondary battery in the engine bay to support the start-stop function.

[glennbk]

LiIon battery under the hood is exclusively for start/stop and performance booster. H8 AGM in the back supports everything else. Confirm battery size as BMW uses both H8 and H9.

[mattsheng]

Forgot to mention, you can actually use a vin decoder to figure the battery size. For example, SA A105 is 105Ah AGM battery.

[glennbk]

Website?

[rob175]

I removed the right side rear plastic cover looking for a "second battery" in my 2020 X3 xDrive i30 and here's what I found. Just a small black box was there....is that the second battery? The box is about 2"x5" (finger pointing to box)....looks awfully small for a battery.
Nothing else is in the area......

[mattsheng]

Originally Posted by rob175

I removed the right side rear plastic cover looking for a "second battery" in my 2020 X3 xDrive i30 and here's what I found. Just a small black box was there....is that the second battery? The box is about 2"x5" (finger pointing to box)....looks awfully small for a battery.
Nothing else is in the area......

The additional battery is much bigger than that. What we have there in the photo is the jump start terminal (Item 1 in the part diagram).

[mattsheng]

Originally Posted by glennbk

Website?

Any BMW vin decoder website should work. For example, this one: https://www.mdecoder.com/

[Qsilver7]

Originally Posted by glennbk

Website?

For VIN decoder? See either of the two sites below. You will need to input your 17 digit VIN:

1. www.mdecoder.com
2. www.bimmer.work

Also...be careful to use the websites actual fields...sometimes these sites get targeted with spam VIN sites and if you use their fields...you'll probably get a request for a fee to get the info.

So just input your VIN in the websites' actual field and answer the CAPTCHA puzzle or questions to indicate you're not a bot.

[rob175]

SO....I'm correct in saying my car DOES NOT have a second battery in the engine compartment under the right side plastic cover.....correct?

[mattsheng]

Originally Posted by rob175

SO....I'm correct in saying my car DOES NOT have a second battery in the engine compartment under the right side plastic cover.....correct?

Yup, you are right! 😉

[R BMW]

Can anyone answer WHY they decided 2 batteries were needed? Did they just under size the alternator and charging system?
Seems odd others with much more electronic add ons along with ASS didn't need the additional battery.