[philooo]

After a very happy year of ownership with plenty of long distance trip and great electric only trip, I am coming into a weird issue.


SHORT VERSION:
My 2021 X5 45e 12V battery was completly drained twice 7 days apart for no good reason. And each time after a rather long highway trip and totally normal operation in the 7 days prior to the incident. I plug my car every day in my garage, and I always have a few electric range miles left at the end of the day.

LONG VERSION: ...

It is now the second time this happens to me.

- I drive the day of the incident a relative long highway trip 45min to 1h30.
- I park the car
- I once left the car sitting for 3 hours, and second incident I left it parked for 1 minutes.
- I get in the car, press the start button and nothing happens. I try again pressing the button and still nothing then dashbaord start to blink. Try again and error message start popping up, about various malfunctions: drivetrain, driving assitance etc etc
- after a few try I get the 'battery charge very low
- and then nothing.

few interesting symptoms:
- each time I press the brake pedal the dash turns off and the pedal push back
- I heard a weird clunk noise under the car, only once.
- I hear a double bip coming from the trunk area

Once I had zero mile on the EV battery, the other time I had 20 miles.

To get back on the road:
- I used a portable battery booster, connect it under the hood to the terminal and the car starts.
- On both occasions I removed the booster after car started, and put the car in sport mode (gas engine on), and the engine would die as soon as I remove the battery booster
- After driving a few miles I can remove the battery booster, and even restart the car and all works well.

After the first incident, I drove the car for a week before without any issues or message before it happened again. This time I will bring it to BMW to check the various error logs.

I have no idea what is going on.

I have not done anythign different these past few week sthan the past year. Car sits most of the time in my car garage pluged to the EV battery charger (110v supplied charger, not high speed charge.)

I'd be curious to hear any feedback, that may help to start the talk with my service advisor...

thank you in advance.


PS: After the first incident, I drove back the back home for an hour without any assitance, all light on dash were on. heavy steering wheel, jerky transmission and no assistance. The next day the car worked without any messages at all...
I was expecting the computer to 'reset' after a while driving but that didn't do it. When I arrived I stopped the car was able to restart it but all messages were still there. The next day they were gone.

PS2: My car fans often run very hard in my hot miami garage... may be this is too much for the battery and after only a year may be it is too weak... Note that when this happen the car is always plugged in the wall via tha bmw charger...but are they smart enough to recharge the 12v battery during EV battery charge...who knows

[LogicalApex]

I assume you're still under warranty on a MY2021. You should drop the car off to a dealer and let them repair the vehicle. The 12v battery is maintained by the HV battery system so it shouldn't be dying out like you're experiencing. There is no alternator in the PHEV so the ICE engine won't charge the battery at all.

People here can probably help you try and hunt down what parts to replace, but there is literally zero reason for you to waste time figuring out why the IBS system appears to not be working in your car.

Not sure why you need something to help you start the conversation with your service advisor. This should be enough as the car logs a lot of data and I'm sure this is in it. If that doesn't work... Find a new dealership... Yikes.

[jad03060]

Most things in the vehicle are commanded to turn on/off via one or more computers. When you shut the vehicle off, if one or more of them do not get the message, they can continue to run in operate mode which can, depending on which and how many (there can be multiple devices on one serial CANBUS), the battery may not last long. Repeated deep discharge of the 12vdc battery tends to severely shorten its life.

All of the computers are fed from the 12vdc bus, and that 12vdc needs to have enough voltage and current to get the rest to function, including to run the starter motor, which might be needed if there's no HV battery left. Unlike most other systems, braking in the 45e is literally brake by wire and not just the rear brake lights, that computer and hydraulic pump puts a fairly big load on the 12vdc system, so pressing the brake pedal could drop the level enough if things are low to literally shut things off.

So, they really need to run diagnostics to find out what's going on, and likely replace the defective module, and probably the 12vdc battery as it may no longer be viable. There's likely lots of error codes stored in the computer, and deciphering exactly what's wrong is now dependent on how good the computer software program is, and the skill of the tech in interpreting them. Might be easy, but getting the required part(s) may take some time.

[biterror]

"second incident I left it parked for 1 minutes" - there's no way the 12 V batteries could be drained in just 1 minute unless they were empty (or faulty) already. Something wrong with the DC/DC converter or the batteries maybe.. strange that the car doesn't give any error messages about this.

[philooo]

Originally Posted by biterror

"second incident I left it parked for 1 minutes" - there's no way the 12 V batteries could be drained in just 1 minute unless they were empty (or faulty) already. Something wrong with the DC/DC converter or the batteries maybe.. strange that the car doesn't give any error messages about this.

That second time I litterally parked my car, got out of it to find out the car was sticking out from the parking spot and went right back in the car. and would not start.

And this was after a 45 minutes highway drive, and I had 8-10 miles remaining on the EV range before parking the car. Everything working perfectly inside the car (AC, assist... )

I am bringing the car to South Motors BMW (Miami, FL), tomorrow morning, we'll see what they have to say.

[philooo]

Got the car back from the dealer...

They said 'software update' is the fix... I find it super strange. See below the service paperwork. Curious to see if anybody else had

"performed a SIB 61-16-21 programming and coding"....

I am not feeling it ...

[philooo]

Ok so unfortunatly after taking the car back from the Dealer (south Motor BMW Miami Florida), I had some check engine light coming on and off for a few days. some day nothing some days the light would come on. But no message on the car status screen...

Car worked perfeclty for a week...

And then trying to go to diner with my wife, after the car being plugged in the garage, fully charge.

And the car started the gas engine with a very rough idle, sounding like a V8 or firing on 3 cylinders only !

Then the dashboard started turning on and off.

I turned the car off and when I tried again to start I got the 'power supply' warnig on the dashboard

See the video link below to hear the engine rumble and my annoyed self :S

https://youtube.com/shorts/inc6HcnHnpc?feature=share


Looks like I will need more than a software reprogramming for that one....

Could it be that my battery pack is bad ? I am within the production months of the recall but my VIN was not recalled...

I am trying to find in the forum anybody with similar problem but so far I seem to be the only one struggling with that random power supply problem !

Anyways the car is back at the dealer... And still no loaner car provided...
I thought I had bought the BMW for the dealership experience but now I am getting tesla like drive-through service. Sucks...

[philooo]

I'll just reference this interesting thread here

https://g05.bimmerpost.com/forums/sh...+supply&page=3

Sounds like a lot of issues with car stopping and then driving fine the next day... to then break down again and dealership taking a few "trips' to figure it out.

[nZtiZia]

Keep us posted. I'm sorry you're going through this

[biterror]

My guess is that the HV battery is ok but you have run out of 12 V power again. The 12 V batteries have gone bad and/or the DC/DC converter producing 12 volts is not working properly.

[philooo]

SOLUTION from the dealer, new 12volt battery...

It's been a month and no more issue, I have no idea why my battery died within a year. I do drive very short distance everyday and I feel that may be the battery doesn't have time to recharge enough when I drive

funny enough I had the same problem with my previous X5 (V8)... I was hoping the EV version would not have the same issue...

[e61it]

So should we start using a cteck to keep our 12v charged if we do mostly short trips even though we charge the hv to keep it full?

[nZtiZia]

i do short trips 5 days a week… my work commutes are 9 miles each way. I've had no 12V battery issues in 18 months *knock on wood*

[jad03060]

Some of the potential issues may come with where you live, the ambient temperature, and how you drive the vehicle. Heating, especially on the 45e where it all comes from the battery, puts a big load on things when you consider the seats, steering wheel, mirrors, rear window, and cabin. Throw in heavier light use in the winter when the days are shorter, your battery use goes way up when you the throw in low-speed and stop and go.

The ICE models all have the alternator on a clutch, and while it's a quite high-capacity device, there are limits on how hard you can charge a cold battery. On the PHEV, the HV batteries through a DC-DC converter maintain the 12vdc one, and it generally doesn't charge it up to full, which, in the cold is potentially an issue. While recharging the HV batteries, it might charge the 12vdc ones, but it at least maintains it where it was, as the computers need 12vdc to monitor that process.

The i3 had an interesting bit in its logic...if the computer (i.e., 12vdc battery driven) couldn't run, there was a trickle charger built in to charge it up when plugged into an EVSE or CCS charging unit that would try to bring the 12vdc battery up, and then, once it could fully run the computers, it would turn the EVSE on to charge the HV batteries and compete the charging of the 12vdc battery through its DC-DC converter. I don't think the X5 is that sophisticated in that aspect.

[philooo]

UPDATE 3 month later, the problem did NOT re-occur, the car is working perfectly since battery change, no other things have been changed.. so I am pretty sure in my case this was the issue.

[hazboocom]

I'm also having similar issues with my 12V battery - https://g05.bimmerpost.com/forums/sh...2#post29567742

[JohnAnderton88]

See attached screenshot for my battery issue. This was back in June, no issues so far almost 3 months later

[philooo]

happy to report that a year later after the incident and after a new 12V battery. I have had NO PROBLEM.

I saw a couple of firmware updates mentioning battery drain as well, so I guess they figured it out.

I have to say that I also try to avoid getting my EV battery fully drained, by using the battery minimum charge option.

[nZtiZia]

Originally Posted by philooo

happy to report that a year later after the incident and after a new 12V battery. I have had NO PROBLEM.

I saw a couple of firmware updates mentioning battery drain as well, so I guess they figured it out.

I have to say that I also try to avoid getting my EV battery fully drained, by using the battery minimum charge option.

this step isn’t necessary as the HV battery never fully depletes; only the usable capacity depletes. the unusable capacity is untouched for the purposes of battery longevity related to its warranty

[philooo]

Unfortunatly today the exact same issue is coming back. 1.5 years after the previous battery replacement, it seems to have failed yet again...

I pressed the start button
- gas engine turned on with very irregular idle rpm,
- could not put the car in gear
- pressing the gas pedal did nothing
- multiple of error messages on dash / secodn screen
- check engine light up (orange icon)
- battery light appeared (blue icon)

A fun message appeared at some point saying someting like "go drive the car now to recharge the battery" ...

I plugged OBDII plug to read all error messages (attached) and after clearing all error codes I can actually now move the car, hopefully i'll reach the dealership tomorrow.


For context,
HOW I STORE THE CAR
the car is always parked in my garage, miami warm weather, plugged to the bmw charger 110v to full every night.
HOW I DRIVE THE CAR
I work from home and most trip are done in EV mode during the week. Only engaging the ICE engine in the weekend longer trips. I drive only in the city during the week. I drive 10k miles per year.

LONG TRIP?
I had another road trip 3 days ago (before todays' incident), 4 hour drive to orlando and back 4 hour to miami, car sitting for 2 days in hotel parking. I am mentioning this because last time the issue appear in similar fashion after a little road trip... I am starting to think that a potential cause would be on long road trip the EV battery usually go down to 0 and then the 12V battery may not be recharged properly because there is no alternator on the 45e...pure speculation but I find it strange that this happens again after a little road trip.. could be pure coincidence... but other have reported suspicion about driving with 0% EV battery could cause issue with the 12B battery: https://g05.bimmerpost.com/forums/sh...2#post29567742






posted a video on youtube..

[philooo]

And they did it AGAIN, a year and a half later the 12V battery needs to be replaced again under warranty... pffu if these BMW warranty dont' last more than that it is pathetic !! there is something wrong in the way the programming drain and charge the battery. What a waste! ... we'll see how long that one stays alive !

[philooo]

battery cost for reference in case you are out fo warranty