My i3 is completely dead

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ma1as

i3 120ah 2019 and 418d gran coupe 2016
Joined
Jan 24, 2024
Messages
2
Hello,

I have problem with my 2019 BMW i3 120ah. First strange thing happened when i came to take a car from charging station. When i unlocked car only one side blinker turn on, normally headlights turn on. When i got in to car, it was like car was after reset, trip showed 0 kilometres and time and dates was not set. I drove to my house and left it over night.

In the morning i walked to the car and it didn't unlocked, got into car by manually unlocking it and tried to push start button but nothing was happening.

Removed 12v battery and put it on charger it showed 4 lights out of 8, after charging it over night got the battery in the car but the car was completely dead anyway. Tested battery while it was connected tester showed 13 volts and didn't drop.

All fuses under glovebox are good, tested the power on main electric motor in the trunk, only 3 volts of power is coming to motor.

I am not really that good in car electronics but did what i could.

Anywhere i look in internet they say that 12v battery is bad, but it charged full so i think there is very small chance that the 12v battery is bad. I bought new battery 6 months ago.

Does anyone had some similar problem? Or have any ideas how to fix it?

Update: went to mechanic to test battery, computer showed 100% good.
 
Last edited:
Are you able to get mains power to where it currently is? If you can get a granny charger (i.e. a low-power AC charger) plugged in and leave it for a few hours, you may find that everything will reset itself.

If that is not hard to do where it currently is, it's worth a try before you get it towed to a garage for diagnostics.
 
Are you able to get mains power to where it currently is? If you can get a granny charger (i.e. a low-power AC charger) plugged in and leave it for a few hours, you may find that everything will reset itself.

If that is not hard to do where it currently is, it's worth a try before you get it towed to a garage for diagnostics.
I tried charging for about 20 min, but not even that ring around charging port lit up and charging port cap i opend manually.

I guess i need to try leaving it for longer
 
I tried charging for about 20 min, but not even that ring around charging port lit up and charging port cap i opend manually.

I guess i need to try leaving it for longer
According to BMW's documentation there should be an unquantified delay before the chrging module (in the car) decides that it's OK to reconnect the HV battery - during that delay you will see no apparent activity and no status lights.

Some people report having to leave it a long time (e.g overnight) but I'm not sure why it would need to be that long, unless the 12V battery was really moribund - that should not in theory apply in your case...
 
Tested battery while it was connected tester showed 13 volts and didn't drop.

All fuses under glovebox are good, tested the power on main electric motor in the trunk, only 3 volts of power is coming to motor.
Is there 12V power entering into the fuse panel under the glove box? If not, the problem is likely at the battery terminal itself.
 
If your 12v actually went "dead" then it is "bad" and you need a new one. The car will not allow the 12v battery to drain like that unless there is something wrong with the battery or the car. Also- once the 12v dies for whatever reason, it messes up a bunch of computer things and nothing works right until you clear all the error codes and/or leave it plugged in overnight so the computers can work it out. This usually automagically "fixes" everything. Unless you have some issue that is draining the 12v battery.
 
Testing a 12v battery requires it to also be load tested. It is possible to have a 12v battery (actually closer to 13.8v) to test good for voltage, but still be bad. It is also possible to buy a brand new battery and it be bad out of the gate. Extremely less likely. But not completely unheard of. This is my first EV and my background is in classic vehicle resto/retro. But I bet my fathers old lesson still holds true. If the problem isn't obvious, always check for bad grounds.
 
I have also a problem with 12v battery. My i3s is '18 and at 118.000km. It's the first time I have this discharge problem with the 12V battery. In fact, I was totally forgot having one :)

Is it a defect, or something I did caused the battery to fail... I don't know.

The battery is not in stock. The service said it will be available in 20 days after the order. In the mean time I am trying to use my car, by locking/unlocking -like doing hard reset on old computers- :) No problem during the drive so far...

Until having the new battery I would not leave it unconnected to power source more than several hours...
 
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