i3 Battery charging - Degradation real life experience

BMW i3 Forum

Help Support BMW i3 Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
It's good to try something after you get the car - when I did six months after buying mine, I found that the dealer or previous owner had installed a GPS tracker in the OBD port!
A U.S. i3 would normally sound the alarm a while after it is shut down if an OBD dongle remains plugged in. I don't know how long after shutting down the alarm would sound. I participated in a state of Hawaii pilot program whose goal was to base the annual registration fee on the distance driven with maybe the vehicle's weight considered as well. An OBD dongle was used to transmit distance driven data via a cellular data connection to the DMV. The dongle set off the burglar alarm on our 2014 i3 sometime during the night. To prevent this, the value of the following coding parameter in the Roof Function Center (FZD) could be set to inactive:

OBD socket alarm (BimmerCode expert mode)
3002->OBD-Alarm: active (default)

However, setting this parameter to inactive is considered to increase the risk of an unknown OBD dongle being installed in one's i3. Maybe that change had been made to your i3 when the GPS tracker was installed.
 
A U.S. i3 would normally sound the alarm a while after it is shut down if an OBD dongle remains plugged in. I don't know how long after shutting down the alarm would sound. I participated in a state of Hawaii pilot program whose goal was to base the annual registration fee on the distance driven with maybe the vehicle's weight considered as well. An OBD dongle was used to transmit distance driven data via a cellular data connection to the DMV. The dongle set off the burglar alarm on our 2014 i3 sometime during the night. To prevent this, the value of the following coding parameter in the Roof Function Center (FZD) could be set to inactive:

OBD socket alarm (BimmerCode expert mode)
3002->OBD-Alarm: active (default)

However, setting this parameter to inactive is considered to increase the risk of an unknown OBD dongle being installed in one's i3. Maybe that change had been made to your i3 when the GPS tracker was installed.
Now that you mention it, I was getting spurious alarms, but perhaps that was related to super hot summer days. I have only tried BimmerLink so far but will try BimmerCode at some point in the next few months. In any case, no dongle installed now.
 
A U.S. i3 would normally sound the alarm a while after it is shut down if an OBD dongle remains plugged in. I don't know how long after shutting down the alarm would sound. I participated in a state of Hawaii pilot program whose goal was to base the annual registration fee on the distance driven with maybe the vehicle's weight considered as well. An OBD dongle was used to transmit distance driven data via a cellular data connection to the DMV. The dongle set off the burglar alarm on our 2014 i3 sometime during the night. To prevent this, the value of the following coding parameter in the Roof Function Center (FZD) could be set to inactive:

OBD socket alarm (BimmerCode expert mode)
3002->OBD-Alarm: active (default)

However, setting this parameter to inactive is considered to increase the risk of an unknown OBD dongle being installed in one's i3. Maybe that change had been made to your i3 when the GPS tracker was installed.
I think that also means a new key can be coded on the steering column with suitable software/hardware via theOBD. Hence why it alarms if it detects current drain on the OBD port whilst armed. Was an issue in UK some time back with cloning kits. Required access to car via some other means usually blocking the locking request from the fob.
 
Now that you mention it, I was getting spurious alarms, but perhaps that was related to super hot summer days. I have only tried BimmerLink so far but will try BimmerCode at some point in the next few months. In any case, no dongle installed now.
Either a wasp or current drain on OBD for sure.
 
I'm coming back from a journey that I knew would be dangerous: 150 km on the highway with my i3 120Ah. 20 km from home: loss of power... I exit the highway and finally end up 500m from home with no power and 13% remaining. Here are the data at this moment.
 

Attachments

  • IMG_6084.jpeg
    IMG_6084.jpeg
    2.1 MB
  • IMG_6080.png
    IMG_6080.png
    300.1 KB
… Finally a neighbor was able to pull an extension cord and I charged for 20 minutes / 0,5kWh. I was able to leave and strangely with no loss of power for the last 500 meters. The data at this moment:
 

Attachments

  • IMG_6086.png
    IMG_6086.png
    301.9 KB
It looks like you had a relatively large difference between minimum and maximum cell voltage in the first readout, with the minimum improving a fair bit after your short extension cord charging.

Could it be that the car wouldn't drive because the lowest-voltage (emptiest) cell was too low and the system wanted to prevent battery damage?

Seems like your pack could use some cell balancing; I'll leave it to the more expert here to make suggestions on how best to accomplish that.
 
It looks like you had a relatively large difference between minimum and maximum cell voltage in the first readout, with the minimum improving a fair bit after your short extension cord charging.

Could it be that the car wouldn't drive because the lowest-voltage (emptiest) cell was too low and the system wanted to prevent battery damage?

Seems like your pack could use some cell balancing; I'll leave it to the more expert here to make suggestions on how best to accomplish that.
I agree with your analysis. This seems to be more evidence that the BMS doesn't calibrate very well for a decreasing usable capacity. Maybe @jfk68 rarely drives to very low charge levels, so the BMS has not had an opportunity to calibrate.

@jfk68, do you typically charge to less than 80%?

It would be interesting to learn the minimum and maximum cell voltage difference when the battery pack's charge level is 100% which is where top-balancing tries to minimize the voltage difference. If a 0.1V difference remains, or even a difference greater than 0.01V, cell charge level balancing should be attempted. Unfortunately, there's nothing that an i3 owner can do to accelerate this process other than to charge to 100% and allow the car to rest at a high charge level as long as possible. Although cell charge level balancing apparently occurs at charge levels less than 100%, it probably occurs most rapidly at 100% because the balancing current would higher at higher voltages. If you drive daily, maybe charge it to 100% at the end of each day before parking it overnight.
 
I've received my Vgate icar pro wifi today and tried to use it with the mi3 app. Connected it with the wifi of my iphone.
The data is shown correctly. Nice. SoH from battery was 98% (after 110.000 km). That was what I was looking for.

But a few seconds after leaving and locking the car, the alarm of the car started making a horrible noise. I never heard the alarm before, so it's probably normal alarm sound.

So, can I not just leave the OBD in the car and do I have to remove it during regular use of the car? Is it only ment for testing now and then? Or is there a setting somewhere to be changed?
 
As I understand it, that is an intentional feature of the alarm system - IIRC referred to in the Owner's Manual somewhere?

I believe you can change the coding of the car so that the alarm is not triggered by activity on the OBD port while the car is locked, but I can recall a suggestion that leaving an OBD device plugged in can prevent a complete shutdown into power saving mode when the car in unused. That probably depends on the exact type of OBD device used.
 
So, can I not just leave the OBD in the car and do I have to remove it during regular use of the car? Is it only ment for testing now and then? Or is there a setting somewhere to be changed?
It's only meant for testing now and then. Leaving an OBD dongle plugged in could make an i3 less secure and might result in increased energy consumption because the 12V pin of the OBD port never powers down like 12V accessories do after several minutes.

When I was part of a pilot program to evaluate using distance driven as a factor for determining the annual registration fee, the program supplied an OBD dongle with a cellular radio that reported odometer readings periodically. This triggered our i3's alarm after shutting off our i3, usually not immediately, though. I was able to disable this alarming behavior by changing a FZD (Roof Function Center) parameter value using BimmerCode in expert mode:

3002->OBD-Alarm: set to inactive

However, I decided that doing so wasn't worth the risk, so I changed the parameter's value back to the default "active".
 
Back
Top