gqpixel
Posts: 14
Joined: Thu Oct 14, 2021 7:12 am

12v battery dying?

Sat Oct 16, 2021 4:21 pm

Hello,

I was wondering how can you tell if the 12v battery is dying? Today I tried to turn on the car and it would not get into gear. dashboard would light up. check engine light came on. I did see a YouTube video about how someone else's i3 died and he had a feeling it was the battery. I'm feeling the same. Wondering if someone has seen something similar?

Only thing that changed was that I got 240v charger installed and changed the 120v setting on the i3 to Maximum. I did purchase a level 2 charger. BMW 120/240v charger.

appreciate any insight. thank you.

Arm
Posts: 178
Joined: Tue Jan 07, 2020 5:53 pm

Re: 12v battery dying?

Sat Oct 16, 2021 7:31 pm

I've luckily not had first hand experience of this issue but yes it sounds like that may be the issue.

marvintherepairman
Posts: 10
Joined: Tue Jul 20, 2021 2:08 pm

Re: 12v battery dying?

Sun Oct 17, 2021 10:13 am

No offense intended, by chance did you forget to press your foot on the brake pedal when turning on? I have done this a couple of times when I was not paying full attention. I had turned on the auxiliary power to the car, but not turned on the high voltage power. It’s an easy mistake to make if not paying full attention.

From my experience with a 12 V battery dying, the car itself started acting odd. I never had a problem turning it on as is it would not when it finally died. I can’t remember as of now any of the other odd things the car did. Personally, I’m glad to have the battery replacement process completed.

As the 12 V began its decline, the car would turn on sometimes, and I would get to drive as usual. I hoped that I would not be out on an errand and be stranded. When it became clear to me the car was acting odd, I made the decision to go ahead and order a new battery. The car was already four years old, so to me that was an easy decision. When the new battery arrived, I attached it to a trickle charge and it sat for a couple of weeks before I was forced to change it out. I did not experience flashing lights or the dashboard lights doing anything unusual.

I have had no other issues with the car since replacing the 12 V battery.

gqpixel
Posts: 14
Joined: Thu Oct 14, 2021 7:12 am

Re: 12v battery dying?

Mon Oct 18, 2021 7:54 am

marvintherepairman wrote:
Sun Oct 17, 2021 10:13 am
No offense intended, by chance did you forget to press your foot on the brake pedal when turning on? I have done this a couple of times when I was not paying full attention. I had turned on the auxiliary power to the car, but not turned on the high voltage power. It’s an easy mistake to make if not paying full attention.

From my experience with a 12 V battery dying, the car itself started acting odd. I never had a problem turning it on as is it would not when it finally died. I can’t remember as of now any of the other odd things the car did. Personally, I’m glad to have the battery replacement process completed.

As the 12 V began its decline, the car would turn on sometimes, and I would get to drive as usual. I hoped that I would not be out on an errand and be stranded. When it became clear to me the car was acting odd, I made the decision to go ahead and order a new battery. The car was already four years old, so to me that was an easy decision. When the new battery arrived, I attached it to a trickle charge and it sat for a couple of weeks before I was forced to change it out. I did not experience flashing lights or the dashboard lights doing anything unusual.

I have had no other issues with the car since replacing the 12 V battery.

hA! that was it. patience is the key.

also did you do the 12v replacement yourself? and was it the Remy battery you bought?

Arm
Posts: 178
Joined: Tue Jan 07, 2020 5:53 pm

Re: 12v battery dying?

Mon Oct 18, 2021 8:42 am

There's a LiPo alternative that's about 10lbs lighter and probably lasts a lot longer.

https://www.reddit.com/r/BMWi3/comments ... 4_upgrade/

I'm a little hesitant to do the swap on my own due to possible coding requirements/issues. The OP of that thread claims he didn't have to do anything at all...just a straight swap. No coding, no special anything.

marvintherepairman
Posts: 10
Joined: Tue Jul 20, 2021 2:08 pm

Re: 12v battery dying?

Mon Oct 18, 2021 3:29 pm

Yes, I chose to replace the 12 V battery myself after watching numerous videos on YouTube, and reading of others on their process here on this site. I purchased the Remy. I watched multiple videos to make sure that the process was pretty well uniform across all the videos, just trying to be cautious in case someone “accidentally “ left out an important step, e.g., if they forgot to mention to disconnect the high voltage battery. You don’t want to skip that step.

To bless/authorize the battery, I also purchased the Foxwell device. I think I have read that others may have skipped this step in process, but I can’t be sure about what their results were. I did not try to use Bimmercode to authorize the new battery.

I wrote all the steps down to keep me organized since I had not done this before. I went so far as to place a cover over the bay so as not to lose an errant screw or bolt. A screw still fell down there, twice. I am now the proud owner of pliers with a magnet taped to it. Luckily, I was able to retrieve what I dropped into the bowels of the bay.

I checked with the dealer first to see what they would charge to replace the battery when the oddities appeared. They are 60 miles away. My vague recollection was that they wanted somewhere near $500. It was a wash for me, as a new battery and the Foxwell device was just shy of that number. But I reason that I now I have a Foxwell device if I need to run a diagnostics on the auto. Also I had no idea if the car would actually make it to the dealer or if it would cut out on me halfway.

So your experience may vary, and I can say I hope I don’t have to do this again too soon. At least I know how to do it now.

marvintherepairman
Posts: 10
Joined: Tue Jul 20, 2021 2:08 pm

Re: 12v battery dying?

Mon Oct 18, 2021 3:39 pm

And yes, patience was a key. When I installed the new battery it was hot as you know what outside and humid. So it was very frustrating that I had to deal with the heat.

Arm
Posts: 178
Joined: Tue Jan 07, 2020 5:53 pm

Re: 12v battery dying?

Mon Oct 18, 2021 3:50 pm

Frankly speaking, I was considering doing it too but given how many steps are involved and the whole "coding" thing, it's much much easier for me to take it to the dealer and have them do it. Yes, I know...it's more expensive but I get a 12 month/12k warranty on the thing and know that any issue that may arise is on them and not me. That extra piece of mind is worth the $$ if you can fork it out. Amortized over a number of years, it's not that much.

marvintherepairman
Posts: 10
Joined: Tue Jul 20, 2021 2:08 pm

Re: 12v battery dying?

Mon Oct 18, 2021 4:03 pm

Sounds like a good decision, Arm.

The dealer did not make the additional warranty clear, from what I recall, when I inquired about the service.

Arm
Posts: 178
Joined: Tue Jan 07, 2020 5:53 pm

Re: 12v battery dying?

Mon Oct 18, 2021 4:08 pm

marvintherepairman wrote:
Mon Oct 18, 2021 4:03 pm
Sounds like a good decision, Arm.

The dealer did not make the additional warranty clear, from what I recall, when I inquired about the service.
They usually don't but pretty much any work they do is backed by 12 months, 12 miles. It's pretty standard unless things have changed.

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