Odometer reading and Battery capacity indicated in menu - Tampering?

HI everyone,

I have been teasing with the idea of buying a used i3 which are becoming available at good prices in the local market due to depreciation. Unfortunately CPO vehicles are not available where I live as the authorized BMW dealer only brings down the REX version whereas a number of 2014 and 2015 BEVs used in UK are imported and used alongside the REX version in local roads. Hence I’d have to rely on visual inspection in making a buying decision to a greater extent.

I’m curious as to how reliable are the digital odometer reading and the battery capacity reading [menu (13.08 Batt.Kapa.max)] that can be accessed from the BMW i3 menu. I have read in forums that the battery capacity reading above, can of course vary by as much as 2kWh from time to time, due to various conditions. What I want to know is whether it is possible for someone to deliberately hack into the menus and tamper the battery capacity reading and odometer reading (and any other information accessible from the menus of i3) and if yes whether there is a way to detect it.

To my knowledge the battery capacity reading above is the only way you can get an idea of the state of the health of the battery pack (unlike a vehicle with an ICE where you can start the engine and inspect/look for signs of trouble) and its effective capacity which IMO is the main factor that determines the overall value of the vehicle, and having to make the decision based on this single information makes you wonder how reliable that single reading is.

Thank you very much!

I follow i3 forums pretty closely and have never read of any hack of an i3's computer systems. Of course, anything is possible. If the odometer reading had been hacked, the distance limit of the battery warranty would have more distance remaining.

The remaining battery pack capacity would be way down my list of concerns because the battery pack remains under warranty unless an i3 has been driven much farther than average. I am much more concerned about the out-of-warranty failure of expensive electronics modules. Used modules should become more available but BMW dealers aren't likely to install used modules and independent mechanics don't seem to have the expertise or confidence to work on i3's.

i3 battery pack degradation over time and distance seems to be very slight in most cases. There are a few reports of unexplained higher than average degradation that does not reach the 30% level that would trigger a warranty fix (in the North American market, at least). So paying attention to the Batt. Kapa. max reading would make sense if it is seems particularly low.

The reset of the battery management system triggers a return to the initial battery pack readings for a while, until the car puts some additional mileage for the system to reassess the battery condition. This is true for Nissan Leaf, and cases with 100% state of health and all 12 bars on the dashboard are common for second hand Leafs imported to Ukraine from the US. Hence, few people trust these indicators, they’d rather choose a full day test drive option before purchase instead.

Such a reset is necessary for battery swap cases, it’s done via OBD2 port, but some sellers meticulously use it for the pre sale conditioning as well. I believe the same could be done with BMW i3 theoretically. Will keep an eye on it - in case it’s possible to tinker with Batt.Kapa.max, it will certainly be done in Ukraine or some other similar market flooded with used cars not covered by the manufacturer warranty.

alohart said:

I follow i3 forums pretty closely and have never read of any hack of an i3's computer systems. Of course, anything is possible. If the odometer reading had been hacked, the distance limit of the battery warranty would have more distance remaining.

The remaining battery pack capacity would be way down my list of concerns because the battery pack remains under warranty unless an i3 has been driven much farther than average. I am much more concerned about the out-of-warranty failure of expensive electronics modules. Used modules should become more available but BMW dealers aren't likely to install used modules and independent mechanics don't seem to have the expertise or confidence to work on i3's.

i3 battery pack degradation over time and distance seems to be very slight in most cases. There are a few reports of unexplained higher than average degradation that does not reach the 30% level that would trigger a warranty fix (in the North American market, at least). So paying attention to the Batt. Kapa. max reading would make sense if it is seems particularly low.

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Thanks! I also have noted that all users forums, blogs etc... consistently reports the degradation is minimum in i3 battery pack. However I have came across couple of 2014 model i3 that had been sitting there idling until both HV and 12v batteries have completely depleted. Mind you I couldn’t start the vehicle and check the menu information. Well afterall it’s the sales guy who told me that it cannot be started because the battery is depleted and I cannot think of any other reason as to why it could not be started. And this one was bought from UK and imported by an individual who is not the authorized BMW agent in the country. Hence no battery warranty! Such rare but shocking cases makes you extra cautious.
I also have not come across anything about hacking into i3 systems. But I guessed if there is any such method, this forum will probably have someone who knows about or at least heard about it.

Oleksiy said:

The reset of the battery management system triggers a return to the initial battery pack readings for a while, until the car puts some additional mileage for the system to reassess the battery condition. This is true for Nissan Leaf, and cases with 100% state of health and all 12 bars on the dashboard are common for second hand Leafs imported to Ukraine from the US. Hence, few people trust these indicators, they’d rather choose a full day test drive option before purchase instead.

Such a reset is necessary for battery swap cases, it’s done via OBD2 port, but some sellers meticulously use it for the pre sale conditioning as well. I believe the same could be done with BMW i3 theoretically. Will keep an eye on it - in case it’s possible to tinker with Batt.Kapa.max, it will certainly be done in Ukraine or some other similar market flooded with used cars not covered by the manufacturer warranty.

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Thank you! This is very useful information.

But since such a reset will always indicate full 100% rating (which I believe is 18.8kWh in BMW i3) I guess it’s safe to assume that if the menu indicates Batt.Kapa.max to be something less than 100% like say 18kWh or something less, that is most likely will be the correct value. Isn’t it?

I would think so as well. Unless the car was driven for some time after the reset, so that the BMS started readjusting itself towards the correct value.

DRK002 said:

However I have came across couple of 2014 model i3 that had been sitting there idling until both HV and 12v batteries have completely depleted.

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I suspect that only the 12 V battery was fully discharged due to the usual parasitic loads typical with all modern cars: keyless entry system, burglar alarm, clock. The Li-ion battery pack isn't connected electrically to anything when an i3 is parked and not charging except briefly when a door is unlocked, for example, and its self-discharge rate is very low, so it is likely not fully discharged. But without sufficient 12 V voltage, the various electronic modules that must boot for an i3 to "start" (i.e., enter "Ready" mode) cannot boot.

alohart said:

DRK002 said:

However I have came across couple of 2014 model i3 that had been sitting there idling until both HV and 12v batteries have completely depleted.

Click to expand...

I suspect that only the 12 V battery was fully discharged due to the usual parasitic loads typical with all modern cars: keyless entry system, burglar alarm, clock. The Li-ion battery pack isn't connected electrically to anything when an i3 is parked and not charging except briefly when a door is unlocked, for example, and its self-discharge rate is very low, so it is likely not fully discharged. But without sufficient 12 V voltage, the various electronic modules that must boot for an i3 to "start" (i.e., enter "Ready" mode) cannot boot.

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I see. What i thought was that the main HV battery is programmed to recharge the 12v battery when it's SOC drops. THanks for the clarification

DRK002 said:

What i thought was that the main HV battery is programmed to recharge the 12v battery when it's SOC drops.

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The HV battery pack can charge the 12 V battery only when the HV system has been activated. This occurs when an i3 is being actively charged (an EVSE being plugged in insufficient if the battery pack is full) or when the car's state is drive readiness, operating readiness, or, I believe, radio readiness. So when an i3 is resting with its HV system inactive, the 12 V battery won't be charged and is being discharged by parasitic loads.

There is an emergency backup to recharge the 12vdc battery if it has been depleted, but it only works when attached to an EVSE since without the 12vdc battery providing enough, the main computers won't turn on, and those can't activate the high voltage logic unless running. It can take awhile for that backup system to charge the 12v battery enough to then start working normally. And, if the 12v battery is too far gone, nothing will work until it is replaced.

You cannot simply put jumper cables on the 12vdc battery, either. There's a very specific procedure that must be performed - one step is to actually disconnect the HV battery from the rest of the system (there's a disconnect for that buried in the back). Not following proper procedures can fry some electronics.