New software update

Hi there...I just purchased a 2105 BMWi3..this is my third. My wife also bought one. After going to the dealer here in London Ontario, they claimed there was aftermarket software on the car and when I tried to explain that it was previously coded to include the Hold state of charge and the increase in fuel capacity, they simply would not listen and stuck with their story. After their software update, ive had issues with the car seemingly reporting erroneous voltage numbers. First it would take forever to get to 100% from 99.5. When I let the car sit after lets say 90% within an hour the voltage would be down to 87.5%. I would drive the car and it would seem to act normally (about 1.5kms per 1%), but when sitting it would again lose voltage. I then got the "electrify" app and with the Bimmer Dongle I could now see the voltages. VIOLA!!..when the car was sitting at 87.2 volts (via the electrify app) it had 388 volts and each cell was 4.04. 45 mins later and the voltage is down to 85 volts, BUT the actual voltage was still 388 volts and 4.04 volts each. Letting the car sit for a while longer the voltage dropped again to 84 volts yet 388 volts and 4.04 volts each remained. I thought that the car was losing voltage just sitting so was alarmed, but now I can see its the BMS reporting not actual voltage percentages. I am going to request BMW remove the update although I dont think they can, and when my wife gets home I am going to do the same test on her car to see, if this voltage drop occurs with hers as she did not get any updates (hers is a 2014).I am going to drive it untill the BMW reports 10% and see what the actual voltage is and report back here. Is anyone else having this issue especially after a new software update?

Do some more Electrified checks at various % states of charge.

The cell voltages don't drop linearly with the % SOC -- their voltages are very stable mid-charge.

For instance, at 50% SOC, you'll likely see that they're only 3.96 volts.

There could be some balancing going on, or the pack is simply stabilizing, achieving is "resting" state after a drive or a charge.

I'll agree it's disconcerting seeing % SOC bounce around like that, but often this figure is artificially stabilized in software (just like a fuel quantity needle and miles-to-empty readout is artificially stabilized in an ICE vehicle). Mid-pack states of charge are particularly difficult to nail and rely on a few different tricks.

At the end of the day, the number of miles that can be reliably driven on a charge are what counts when judging the battery's health.

Thanks for the reply. Ya after looking at the voltages, the % the car is telling me is obviously a calculation. I can get between 110 and 120 kms at 90 KPH and easily get 150 kms in the city so im happy. Now if I can get the DC fast charging fixed. I bought this car 10 days ago and if you lift up on the handle it will start DC fast charging MOST of the time. BMW thought it was the charging lock but after $650 it didnt work, so now are quoting $2700 to replace the charging port and cables. The dealer agreed to reimburse me, but now hes hesitating. Not a good start. If anyone else has had this issue Id be grateful for any feedback, I might have to post this on a new subject.