[vreihen16]

I found out early last week that the original 12V aux battery finally failed on my 2015 i3, after 6 years and 20,686 miles. Might be a record for battery longevity, based on many reports of batteries failing in 3 years or so.

It went with zero warning after the car sat for a week, and I had to use the emergency key to unlock the door and the manual frunk release cable to get at the dead battery.

Remy battery got the replacement AUX-18L here in two days, and the swap was straight forward following the two-minute instructional video on YouTube. You need a T27 Torx bit to take the frunk bin out, which is not included in some Torx kits. Had to go to my electronics toolbox for the T27, because my automotive kit only has T25 and T30.

Although the car works without registering the new battery, I dropped the $32 at the iPhone App Store for BimmerLink to register it anyway just in case it really does something other than make a note of the replacement for the dealership's scan tools. I already had my trusty Kiwi3 OBD adapter dongle that works with BimmerLink (and BimmerCode), so buying BimmerLink for this one use was cheaper than going to an independent repair shop or the dealership to have them do it.

Just making note here in case anyone was curious, and so that I have a service record to see how long the replacement battery lasts.....

[Coastali8]

Good information,
Thanks

[MsGoGoMoto]

Originally Posted by vreihen16

I found out early last week that the original 12V aux battery finally failed on my 2015 i3, after 6 years and 20,686 miles. Might be a record for battery longevity, based on many reports of batteries failing in 3 years or so.

It went with zero warning after the car sat for a week, and I had to use the emergency key to unlock the door and the manual frunk release cable to get at the dead battery.

Remy battery got the replacement AUX-18L here in two days, and the swap was straight forward following the two-minute instructional video on YouTube. You need a T27 Torx bit to take the frunk bin out, which is not included in some Torx kits. Had to go to my electronics toolbox for the T27, because my automotive kit only has T25 and T30.

Although the car works without registering the new battery, I dropped the $32 at the iPhone App Store for BimmerLink to register it anyway just in case it really does something other than make a note of the replacement for the dealership's scan tools. I already had my trusty Kiwi3 OBD adapter dongle that works with BimmerLink (and BimmerCode), so buying BimmerLink for this one use was cheaper than going to an independent repair shop or the dealership to have them do it.

Just making note here in case anyone was curious, and so that I have a service record to see how long the replacement battery lasts.....

Hey there!
Ice seein you here!

I was too much of a puss to change my own battery in my 2017 when I got it 3 months ago.
I'm in Georgia, so I just took it to the dealer 1 week after buying it and asked for the battery to be changed.

$380 tax included
I figured it's 4 yrs old and as hot as it gets down here, just do it!

Glad to see you got the remy in there. I'll do that next time.

How much is an oil change? I'm going to the dealer to get it logged

[vreihen16]

My i3 doesn't have a REx, so I have no idea what an oil change costs or involves.

I had the two-year brake fluid change and BMW inspection done right after I bought my i3, and that was a bit over $300 at the dealership. Since I did not have a prior service history at our local dealership (never having owned a BMW before), I figured that throwing them a gravy cash job would be a good idea to get in their good graces in case I needed warranty service later.....

[MsGoGoMoto]

Originally Posted by vreihen16

My i3 doesn't have a REx, so I have no idea what an oil change costs or involves.

I had the two-year brake fluid change and BMW inspection done right after I bought my i3, and that was a bit over $300 at the dealership. Since I did not have a prior service history at our local dealership (never having owned a BMW before), I figured that throwing them a gravy cash job would be a good idea to get in their good graces in case I needed warranty service later.....

For the brake fluid change, I only paid $179 at the dealer a few weeks ago.

Ouch to $300

Edit: ooh you also had the inspection with the brake fluid change

[Obioban]

Sounds like mileage is an important factor in 12v battery life. Yours may be the oldest 12v battery we've seen replaced, but also probably the lowest mileage!

[mirms]

Hi happened right after I got the compressor fixed , cost was over 1000$ taxes in

[MsGoGoMoto]

Originally Posted by mirms

Hi happened right after I got the compressor fixed , cost was over 1000$ taxes in

Cost for the compressor or the new battery?

[RP67]

Yes, it's an old thread... anyways, just to confirm, replacing the 12V battery in the BMW i3 is not so complicated, anyone can do it. Sure the dealership trying to sell their service, and I'm not sure how much truth in the warning (by the sales person at the parts department) telling me "..oh you can break things or even fry your computer and it will cost you a lot more...". Ok, I almost made the booking to let them do it...
The symptoms: after a 1000km long trip (cold, rainy weather heater, wiper, headlight on), I had the drive train error warning the next morning, and the car was unresponsive. Well I had a few odd things recently, Headlamp level adjustment error, unable to charge error, and all cleared with a restart. So it seemed to be a good idea to start with the 12V battery. According to the stamp on it it was 6 years old (0218).
Then I was thinking, how? Went home with the new battery from the dealership (it was a few $ more than a generic battery from the cheapest outlet, and cheaper than any other from independent part suppliers), hooked up to the charger to be sure it is at 100% (was 97%). about 5 hours later when it was complete I jumped on to it. Lots of great step by step description around, so most of them is well written, easy to follow. My biggest issue was resetting the HV battery isolator. I have the green one, and I couldn't push it back, even I disengaged the lock (small tab on the side). Finally I realized, the red tongue needs to be pushed slightly towards the center... bam..
I'm not completely convinced the battery was bad, when I pulled out it was sitting on 13.8V (the old one) compared to the new one it was only 0.1V lower. The car was switched off for about a half an hour. About 12 hours later it was 13.4V. It is almost 6 years old, so probably wasn't a bad idea to replace it. Registering with Bimmerlink was straight forward, checked the errors, pretty much all of them was low voltage related, not present, and within the last 20 km. Only one appeared to be present, 805519 (PLC data line, communication error) it says this error not causing any warning. Tried to charge the HV battery, worked fine, no issue during the test drive (TPM came up saying it is active).
So all done within an hour.