"Increased battery discharge when stationary" and other errors

[DRK002]

Hello everyone,
Can someone explain to me the meaning of these messages? This is from a 2014 BEV that I went to inspect (a prospective buy)
1)
”Increased battery discharge when stationary.
Start Engine.
If the problem recurs have the problem checked by Service.” (on the main screen)

https://ibb.co/d9JOcy

2) “Battery discharged. Start engine” (small screen)

https://ibb.co/if8Ocy

3) Red icon of the car with front highlighted (small screeen. Sorry about the lighting conditions)

https://ibb.co/iwQEjd

4) service requirement – emission inspection, Brake fluid, Vehicle check, vehicle inspection. (following pics)

https://ibb.co/d07S4d

https://ibb.co/nu4UHy

https://ibb.co/kQekqJ

https://ibb.co/gBnGxy

I usually check the VIN from hidden service menu accessible from the small screen and use that to check 13.08 Batt.Kapa.Max reading. However, the vehicle doesn’t let me access the menu (pressing and holding the button for 10+ doesn’t change a thing) I suspect the car doesn’t let me access the menu because of these errors.

Searching for “increased battery discharge” in the group returns few results and I’m not sure whether it completely matches with this trouble/warning. I was going to take the car for a Diagnostic scan from BMW ISTA+ software. But what I witnessed today was disturbing. I hope you all would be able to edify me about the scale of the problem.

Best case scenario : it needs brake fluid flush, and 12v battery replacement. Worst case scenario: there is something wrong with HV battery, drivetrain and/or electronic modules.

Has anyone of you has encountered any of these messages problems?

Thank you in advance!

 

[jadnashuanh]

Most modern BMWs have numerous modules that communicate via the CANBUS. If one or more of them doesn't get the shutdown message, it can continue to operate as if the car is on, and thus draw far more power than it should. Diagnostic software at the dealership should be able to identify what's going on. If the 12vdc battery gets discharged, things can get confused, so it may just need a new 12vcd battery. All of the computers run off of the 12vdc battery, and that doesn't get recharged from the main battery except under certain specific circumstances.

 

[graememwl]

I'd bet the 12v battery needs charged. All sorts of weird, wonderful and completely unrelated errors get thrown when the 12v battery is low or bad.

 

[DRK002]

Most modern BMWs have numerous modules that communicate via the CANBUS. If one or more of them doesn't get the shutdown message, it can continue to operate as if the car is on, and thus draw far more power than it should. Diagnostic software at the dealership should be able to identify what's going on. If the 12vdc battery gets discharged, things can get confused, so it may just need a new 12vcd battery. All of the computers run off of the 12vdc battery, and that doesn't get recharged from the main battery except under certain specific circumstances.

Thanks! In fact, I was keen to know your opinion in particular and I was hoping that you would reply. I wonder whether there is a way to determine the health of HV battery in this condition without replacing the 12v battery. Because the vehicle is not mine yet, I don't want to replace the 12v battery before purchasing and I'd rather do it myself after the purchase, than letting the current owner do it.

I m planning on taking the car for a scan using ISTA+ software. Do you think that would be in vain? I mean without replacing the 12v battery would the CANBUS be inaccessible even for ISTA+ ? I was hoping that keeping the vehicle in "Ready" state and driving around will recharge the 12v battery at least to an extent that it would allow us to access the service menus and run diagnostic tests.

If I can somehow verify that the HV battery and electronic modules (like EME, BDC, EDME, KAFAS etc...) are in good condition, I would buy this car. The question is how to verify that without replacing the 12v battery

 

[DRK002]

I'd bet the 12v battery needs charged. All sorts of weird, wonderful and completely unrelated errors get thrown when the 12v battery is low or bad.

I guess so and i just hope that that alone will resolve these problems. The question is how to verify whether it need any additional work (like hv battery repairs / electronic modules etc...)

 

[jadnashuanh]

IF the car gets to the READY state, the 12vdc battery isn't dead, as all of the computers run off of that. That doesn't mean that it's not weak, though. Testing that battery is a little tricky, too, as you can't test it in the car like you would a typical ICE...you have to use the disconnect switch to disconnect the HV battery first. Getting the car into READY, and then maybe adding a bit more load might drop the 12vdc enough to create a problem or if the DC-DC converter has issues.

The 12vdc battery gets charged when the car is in the ready state, or when low and the EVSE is connected and the brains think it needs it.

 

[DRK002]

IF the car gets to the READY state, the 12vdc battery isn't dead, as all of the computers run off of that. That doesn't mean that it's not weak, though. Testing that battery is a little tricky, too, as you can't test it in the car like you would a typical ICE...you have to use the disconnect switch to disconnect the HV battery first. Getting the car into READY, and then maybe adding a bit more load might drop the 12vdc enough to create a problem or if the DC-DC converter has issues.

The 12vdc battery gets charged when the car is in the ready state, or when low and the EVSE is connected and the brains think it needs it.

No no. i just want to check the condition of the High Voltage (HV) battery (and the electronic modules). I fully intend to replace the 12v battery once i buy the car (if i buy)

Correct me if i m wrong. Based on what you said, I guess having the car in "READY" state will recharge the 12v battery to a sufficient level that it will allow the Scanner and ISTA+ software to access the CAN bus and perform diagnostic tests.

I'd like to know whether you know of any specific tests that can be performed in ISTA+ to check the condition of High Voltage battery. Checking the 13.08. Batt.Kapa.max reading is the only thing i know that can give an indication (maybe inaccurate but still) about the HV battery. And i m sure that there are better methods available using a scanner and ISTA+

 

[vinc]

I got this (hilarious) message about turning on the engine on my BEV i3, which makes me suspect that the 12v battery needs to be replaced.

Is this something that any BMW mechanic can do, or do I have to take it to the dealer. I checked their price and the dealer seems to charge an arm and a leg…

 

[Anonymous]

Most BMW mechanics should be able to do the battery swap, if they have access to the online BMW service docs for the steps. Involves taking out the frunk box for access to the battery, which sits behind it on the passenger side.

Also not hard to do it yourself, following several YouTube videos on the task.

Important steps:
- Make sure the new 12v is fully charged up before the swap - many ship under charged.
- Disconnect the HV battery before the swap - disconnect switch is in the Frunk
- Shut off the car with the Frunk open, and let is sit for 15 minutes so all the systems go to sleep, and leave the key fob away from the car when you come back to swap the battery.

In in the USA the OEM battery is the AUX 18L made by East Penn Manufacturing. Available at their regional warehouse outlets, or online under the Remy brand name.

https://www.eastpennmanufacturing.com/contact/where-to-buy/?division=186
https://remybattery.com/start-stop-aux18l-auxiliary-battery.html

 

[alohart]

I got this (hilarious) message about turning on the engine on my BEV i3, which makes me suspect that the 12v battery needs to be replaced.

If you've not been driving as much as you normally do over a significant period (e.g., during the pandemic), the 12 V battery could have slowly discharged as the battery in our 2014 BEV did. This could happen to ICE vehicles as well. So your 12 V battery might not need replacing. Instead, charging it with a standard 12 V battery charger could fix the problem as it did with our i3 which still has its original almost 7 year old 12 V battery. I ordered a replacement 12 V battery 2 years ago which I keep charged and ready to be installed when needed.

 

[vinc]

Thank you! I will start by getting a charger from Amazon and trying that. I assume that an 8A Charger/Maintainer would work? Although it is true that we have not been driving as much as we used to, we still drive about a couple of miles a day to get the kid to and from school, so I will report back.

Today things got more interesting. The car would not start and it was giving all sort of random errors (no ABS, drivetrain, steering...). I switched the lights from automatic to off and that seemed to do the trick, at least for now.

 

[alohart]

I will start by getting a charger from Amazon and trying that. I assume that an 8A Charger/Maintainer would work?

I have an 0.8 A CTEK charger that works fine with the i3's low-capacity 20 Ah 12 V battery, so your 8 A charger will be way more than necessary.

 

[vinc]

At the end, when I was ready to try the charger, we found a BMW mechanic that gave us a very reasonable estimate for replacing the battery. It was about $100 plus the cost of the battery.

I went with it and all issues went away.

Thanks for your help!