Battery problems?

[lookitsapples]

Has anyone had freak battery problems? I currently own a 2016 m3 and this past Wed, it appeared my car battery was completely dead. Key fob wouldn't work, car wouldn't go into ignition mode, absolutely no power whatsoever.

This is my daily driver and I drove to work and home completely fine the day prior. The only thing that would even drain my battery is bm3 wifi agent that I leaved plugged in. However I've left it plugged in since day 1 without any issues.

Anyway, I attempted to jump start the car with my wife's accord, had her rev her engine a few times and the car refused to start. We attempted this for quite a while then gave up as it was not working.

On Saturday, I wanted to try to jump it one more time. After I moved my wife's car closer to my car, I turned off her car, and literally right when I connected the jumper cables from her car to my car, my car suddenly came back to life. Immediate error codes were battery charge malfunction.

Once the engine was up and running, I decided to drive it around to charge the battery. And then throughout the weekend and today, the car is back to it's normal self. I used the battery charger to check voltage and its at 13.4v with car off, alternator had no issues.

Any idea what could be the cause of this? I opted to not buy a replacement battery for now as it seemingly is back to normal again

[tom @ eas]

Just replied to a similar situation. It's the ETS circuit of the lithium battery battery doing its job:

Electronic disconnect switch (ETS):
The (dual storage system) 12 V lithium ion battery features an electronic disconnect switch (ETS) that can switch off the battery to protect it. The voltage at the battery terminals cannot be measured when switched off.
Consequently the (dual storage system) 12 V lithium ion battery is not necessarily faulty if it is no longer possible to measure voltage at the battery terminals.

If the electronic disconnect switch (ETS) has activated, it is necessary to diagnose the (dual storage system) 12 V lithium ion battery using the diagnosis system.

If it is necessary to apply a voltage at the battery terminals to reactivate the electronic disconnect switch (ETS) as per the aforementioned table, this can be carried out using a charger with a suitable voltage setting or by jump-starting with a running donor vehicle. As a result of the insufficient voltage output it is not possible to reactivate the electronic disconnect switch (ETS) using a second battery.

When using a charger it must feature a mode for deep-discharged batteries or manual starting of the charging procedure (so that U>13.6V) as otherwise the battery is not detected and the charging procedure is not started.

It's likely the agent draining a ~5 year old battery, in addition to all other background activity from the BMW itself. You'll need a code scanner to clear codes.

[lookitsapples]

Thanks Tom! Yea it freaked me out. Seeing how the batteries on our car is touted to last 3-5 years, how exactly do we know when it is actually time to swap out? Would this lithium battery just suddenly stop working? I'm used to conventional car batteries where things would begin to slowly show signs of failing

[tom @ eas]

Originally Posted by lookitsapples

Thanks Tom! Yea it freaked me out. Seeing how the batteries on our car is touted to last 3-5 years, how exactly do we know when it is actually time to swap out? Would this lithium battery just suddenly stop working? I'm used to conventional car batteries where things would begin to slowly show signs of failing

Eliminate the variables first, by unplugging the agent when not in use.

With the new iOS app, the Rpi-based agent is really kind of obsolete.

[Prossx]

Originally Posted by lookitsapples

Seeing how the batteries on our car is touted to last 3-5 years

7-10 years on this battery. Still doesn't make up for its cost.

[Fan2z_M3]

Had a battery issue as well. Bought one of those ctek lithium ion battery chargers. Now whenever I disconnect the charger the car says that the battery is not being recharged? Can anyone give info on this?

[khoa@x-ph.com]

Scary story!! So does everything feel normal with your car now OP?

I also daily drive my 16 M4. Hopefully I don't bump into the same problem.

[lookitsapples]

Originally Posted by khoa@x-ph.com

Scary story!! So does everything feel normal with your car now OP?

I also daily drive my 16 M4. Hopefully I don't bump into the same problem.

Yea everything is back to normal now. I'm keeping jumper cables in the backseat because if it dies again I won't be able to open the trunk lol. But yea not too sure with these lithium batteries if they give us a warning if it's time to change. Was about to be $2,200 or so for battery and install cost, sigh lol

[wdskukm3]

I just want to know if there is a way to use a regular agm or standard battery when it comes time to swap these batteries out. I know I can get a oem lithium battery for cheaper but still over 1k. Just seeing if anyone out there know of a solution to this.

[SD ///M4]

Originally Posted by wdskukm3

I just want to know if there is a way to use a regular agm or standard battery when it comes time to swap these batteries out. I know I can get a oem lithium battery for cheaper but still over 1k. Just seeing if anyone out there know of a solution to this.

The short answer is no. This has been discussed many times on this forum in the last 5+ years.

[ONEof500]

...but there are other lithium options other than OEM correct?

[The.slowest.g20]

Originally Posted by Fan2z_M3

Had a battery issue as well. Bought one of those ctek lithium ion battery chargers. Now whenever I disconnect the charger the car says that the battery is not being recharged? Can anyone give info on this?

Having this ame problem