[rgomez]

Hello,

Totally going crazy about my BMW F10 520d 2010.

Issue started by a warning when turning off engine "Battery charge too low" (something like that). It would just cut off all lights, CIC, etc. After that when opening the car no lights were on also. This happened some times and then went way.

A few days back it came again and now it doesn't go away. Even another error that shows up when car is running which is the known "battery disrcharge while stopped" issue.

I went to car service and they measured the battery leves while running, with ignition on and off.

Car running - 14.5V right after car start
Ignition on - 11.70V
Ignition off - 11.89V

They removed the negative cable, diassembled the IBS and car drove for couple hours just fine without any additional charge of the battery.

Then it came back to the error again.

What I did, drove for a couple time and with vehicle off, ignition off the battery would read 12.35v and after a few hours with vehicle locked it would read 11.80v even reached 10.xx with ignition on after a few measurements.

I drove again and stopped the car during the night, last read right after engine off was 12.45 and in the morning 11.80v again.

Right now the negative cable is off and IBS plug also off (for around 4/5 hours) and battery is at the same level, 12.40v.

I remembered that my bluetooth doesn't work (option is greyed out) so I decided to remove cables from MULF2 also.

I'm getting to a point where I think some module is not shutting down correcly.

What confuses me is how after IBS "reset" it drove ok even with 11.70v.

Any ideas would be appreciated.

Thanks

[Surly73]

I notice that at no times do you mention plugging the car into a charger for a long time, like overnight, charging through the IBS, and then seeing what happens. Do that...

A "charge battery" message means that your battery's state of charge is low and it needs charging. It's not going to "go away" by starting and stopping your car a few times.

A "discharge while stopped" message means you have something draining the battery when the car is supposed to be sleeping and you probably need to repair something. Reading codes with a BMW tool like ISTA should point you in the right direction.

As I said - I'm surprised you're fooling around disconnecting IBS but not simply charging the battery first. Unless the IBS is faulty (and your voltage measurements don't point to that) all you're doing by disconnecting the IBS is allowing the car to "lose track" of the current state of charge and battery conditions. It won't be able to cut off a parasitic drain on the system, and it won't know that you might be unable to restart the car.

Your running voltage is fine. If it stays like that you don't have an alternator problem. Your not-running voltages are low meaning either your battery is discharged, worn out, or both. A drop to 10.xx is a magic number meaning that one cell is completely dead. It could be shorted by deposits or totally worn out. When you keep fooling around at those voltage levels you're running current through that cell effectively reverse charging it, making things even worse. Don't be doing that on purpose.

[rgomez]

That was my next step and it will be done tomorrow with a decent charger which I didn’t had at hand.

The latest test I did before asking for the charger was, after put everything back and drive for while car stopped with no high discharge when stopped message.

After a few hours it returned. I left during the night the MULF2 (Bluetooth broken) disconnected and in the morning no error showd up. After reconnecting MULF2 a few hours later the issue showed up again.

Would it possible the module is not “hibernating” correctly due to the issue it has?

Anyhow, tomorrow battery will be charged and I will have ISTA and ENET cable. Anything specific I would be looking for in ISTA? Because regular OBD tool gave no issues that could be related.

[DonJkZ]

Had a very similar experience last week with my 2010 F10 too! Similar voltages to what you mentioned and exactly the same error messages about the charge being too low and the battery draining while stopped. My battery was 8 years old and never had any problems before. I tried charging it fully but the error came back within a day or two when the car had been sitting for few hours. The message would stay away if I drove a long distance, as expected. I think the battery discharging message could just be the fact that the battery is old and cannot hold charge as well as a new battery so the car sees the drop in voltage and shows up the battery discharging error?

Anyway, I changed out the battery for a new one last week and registered it to the car, have had no error messages since and all is good!

How old is your car battery?

[rgomez]

I did the same, charged it fully and the car has been stopped for almost 48h and still no error (usually it would be noticed by just unlocking the car and no lights). But I'm also suspecting it will come again in few days.

Probably I would say 8 years also. Not sure.

Did you ever felt you card was having issues to start? I didn't at least which feels strange but I think the most reasonable change would be the battery since it's 8 years, not much to complain about.

[DonJkZ]

Monitor it for a few days in that case. I never noticed the battery was weak apart from the warnings from the car which caused the lights to go off. I agree that this would make it seem like there is another issue and the battery is fine but those voltages you listed when the battery has been resting are deifnitely too low (similar to mine)

I did notice though, that after installing a new battery, the start up was ever so slightly quicker. (This was mainly noticeable on a cold morning first start)

ISTA will have the mileage of when your current battery was registered to the car - mine said 0km as battery was the original from factory.

If it is indeed around 8 years old it's likely to need replacement I'd say.

[rgomez]

I agree. Let's see for a few days.

I would love to check that. Still fighting to make ISTA to work hopefully I will get some help on that on other threads and if I get the same 0km reading as you I won't give it a second thought next time warning comes up.

[BMelchner]

Originally Posted by DonJkZ

ISTA will have the mileage of when your current battery was registered to the car - mine said 0km as battery was the original from factory.

Same here when i checked it. Seemed very odd.