Incorrect State Of Charge Readings Causing Problems For i3 Owners

With the i3 REx, Reduced Power can occur if the operator continues to use more energy than the REx engine can produce. Examples of this would be continued high speed (over 70 mph) driving or long, sustained hill climbing. However this new problem that has plagued some i3 owners isn't caused by over-taxing the REx. 

Someone once said, "You could always tell the pioneers by the arrows in their back."  A recent software bug has cropped up that seems to be affecting many of the early build and higher mileage i3s that are mostly driven by the early adopters. The problem causes the car to go into reduced power mode, or in some cases shut down without warning when the display shows about 5% - 6% battery remaining.

In mid 2016, BMW released a software update, (version 16-07-501) that was supposed to correct the issue, but for some unknown reason it didn't work on all of the vehicles. They then sent out letters to the early buyers to inform that they need a software update. Recently though, the problem seems to have become more and more common, with many owners reporting it. I'm not 100% sure if that initial software update did what it was intended to, or if it actually exacerbated the issue, because it really seemed that the problem became more widespread once people had the new software installed. 

Perhaps it was just timing that made it seem that way because the cars are getting older and natural battery capacity loss is occurring. Also, the colder weather came and that could have played a role in magnifying the issue. BMW did realize the new software didn't do what it was supposed to, and quickly issued a new version, as well as a service bulletin (B61 20 16) which informed the service centers of the problem and how to correct it. However, some centers haven't been quick to pick up the problem, and I've had more than a few i3 owners ask me for help getting this problem resolved. 

There are probably dozens of service bulletins issued by BMW every month, so it's understandable that some centers might be a little slow to catch every one, but it's now more than six months into the problem and there are still many centers that aren't able to diagnose the problem when a car comes in with it, and that's just too long. One potential reason they were having trouble diagnosing the problem is that the symptoms of this issue are very similar to how the car may act under normal operation when the range extender is over-taxed. It's been well documented that the range extender has limits. If you drive at highway speeds up continuous steep inclines then there will come a point that the range extender cannot supply enough energy to maintain the speed. The car will then go into reduced power mode and slow down to about 40 mph. However, speed or excessive hill climbing isn't the root cause of this issue, it's actually an incorrect adaption value of the battery's state of health, even though the results are similar. 

A simple explanation of the problem is that the affected cars are incorrectly reading the battery's state of charge (SOC), and slightly overestimating it. This doesn't present any real problem unless you discharge the battery to well under 10%. At such a low state of charge, it's very important to have as accurate of a reading as possible, since every percent counts when you're trying to make a destination. Calculating the precise state of charge of a battery is very difficult, and with all EVs, the displayed SOC is a close approximation of the actual SOC, it's not a perfectly accurate value. 

The 2014 to 2016 i3s have about 19 kWh of usable battery capacity, when new. Like all batteries, as they age they lose capacity. If an i3 battery loses 10% of its original capacity, then the usable capacity is roughly 17 kWh. If the car doesn't properly recognize the loss of capacity, it can miscalculate the remaining state of charge. That is what's happening with some of the older i3s. The onboard battery management system (BMW calls it the SME High Voltage Battery Module) isn't adjusting quickly enough to the capacity loss, and it is overestimating the actual remaining level of charge. 

What this means is, if you drive an older i3, you may think you have slightly more range left than you actually do. There have been reports of a few i3 BEV drivers having the car slow down to reduced power mode, then crawling to a halt when the SOC gauge states that there is another 5% or 6% battery available, and 4 or 5 more miles of range still "in the tank." Most i3 BEV owners don't drain the battery to such a low state of charge, so they'd never even know their car is affected by this issue. 

It's not as simple for the i3 owners that have the ranger extender option, and the majority of people reporting the problem are indeed i3 REx owners. That's because unlike BEV owners, it's not unusual for them to drain their battery way down to only 6.5%, since that's the set point for the range extender to turn on. Because the SME module is slightly misreading the battery's state of health (capacity), the REx is actually turning on at around 1% to 3% while the car thinks it has 6.5% remaining. Once the REx does turn on, it doesn't operate at a high enough output to sustain driving at highway speed because it thinks the SOC is at 6.5%, while the battery is struggling to supply power at less than 3%. In some cases the car will continue to drive along at reduced power mode, but others have seen the car simply slow down and shut off shortly after the range extender operation began. 

In most cases a BEV owner will be very close to their destination when they realize they have the problem, since they only had a few miles of range remaining anyway - or so they thought. On the other hand, REx owners could be many miles from their destination, as they were relying on the range extender to allow them to complete their trip. Either way, it's not a pleasant experience, and I know because it happened to me back in December. I have one of the early 2014 i3s (the first REx delivery in the US, actually), and also one of the highest mileage i3s with over 67,000 miles on the odometer. Luckily, I was able to get home. Since I had heard of others experiencing this issue, I knew exactly what was happening. I took secondary roads home, kept the speed under 45 mph and I made it without a problem. However most other i3 owners aren't necessarily as informed as I am about the car, and they won't understand what's happening or how to mitigate the issue and get to a plug. 

Recommendation:

I'm recommending all 2014 i3 owners that haven't already had their car reprogrammed, take it to their dealer to have it checked for this problem. Tell your service writer to look up service bulletins B612016 and B612116. These bulletins will instruct the dealers on how to correct the problem. You should also make sure you have software version 16-11-502 or later. in the meantime, if you drive a BEV i3, then try not to let the SOC drop below 8%. If you have a REx, closely monitor the power bars when the REx turns on. If you see any of them disappearing, then slow down and get to a charging station as soon as possible because you can't rely on the REx until this is fixed. If you have a 2015 or newer i3, then I wouldn't worry about this. By the time your car might experience these symptoms, you'll have had newer software updates that will proactively eliminate the problem before you've experienced it. 

Recently, BMW HQ has stepped up their game and has been reaching out to their service centers to make sure they are aware of the issue and can identify it quickly.  Service bulletins B612016 and B612116 have been updated with a new procedure to perform an ISTA capacity adaptation test after programming (This is a new function in ISTA 4.04.3). It should prevent future cases of range extender not turning on when the SOC drops below the threshold. At the very least, this will allow REx owners to get home if they encounter this problem because the range extender will turn on and replenish the battery enough to allow driving. However, so far what I've witnessed is the uptake has been uneven; some dealers are on it, and others are still struggling to identify the issue when a customer comes in. The one thing I've noticed is that when the owner knows the exact issue, and gives the service writer the bulletin numbers, then in nearly every case I've followed it's been fixed on the first visit. Don't let the dealership tell you there's nothing wrong with the car. Forward them this post, if you must. There have been cases where the software update didn't work for some reason. When that happens, the dealership needs to connect the car to BMW HQ and perform a remote IRAP session. The IRAP reprogramming will definitely resolve the issue if the software update doesn't.

I know this because many i3 owners reach out to me for advice with their car, often when there's an issue. In this case, I've had more than a couple dozen i3 owners ask if I could help them out. They have been driving the car for more than two years now, so they know this isn't how it usually works. Yet, when they bring it in for service, often the service team tells them there's nothing wrong. Here's an example of what one service center told an i3 REx owner that had the issue once while driving, and another time when he tried to turn it back on to continue driving:

Hi Xxxxxx,

"It appears that you are driving the car down to a very low charge.  Once it is stopped, the charge is so low that it will not let you go anywhere. They’ve told me that when the range extender kicks in, it does not charge the battery.  It keeps the battery charged to get you another 10-30 miles down the road depending on driving conditions.  The vehicle will reduce power and loads to help get the battery to last a little longer, how I understand it.  But after you reach your destination, the car needs to be charged."

That's just an incorrect diagnosis, and not really a proper explanation of how the range extender works. The only reason the state of charge is too low when the vehicle stopped is because of this problem. Under normal operation, the REx will keep the SOC above the low charge threshold that prevents startup. The fact that the owner can drive it to the point that it won't restart should immediately be a red flag that there's a problem. In the case of this issue, the range extender is actually working properly. Its operation is based on the state of charge. The lower the state of charge, the harder the REx works to produce energy to maintain the SOC. If the car is telling the REx that there's more than 6.5% SOC, than the REx won't turn on. But if reality there's actually less than 1% SOC, then the car won't turn on. The misdiagnosis and improper response to the customer is really a microcosm of the challenges dealerships have dealing with a car like the i3 REx, that operates unlike any other car in production today.

An i3 with the range extender option exposed. The electric motor and power electronics are on the left, with the jumper cables attached. The REx motor is on the right under the black heat shield.

There may be some adventurous i3 owners who want to cheek for themselves if their car has this problem. The only way to test it, is to exhaust the battery and see if the issue appears. The good thing is you don't necessarily have to wait until you're stuck to see if you are about to go into reduced power mode. The ePower display will let you know before it's too late. There are 11 small blocks on the right side of the driver's display screen. (See pictures of the power blocks above) Under those blocks is the word "ePower." As the car begins to go into reduced power mode, one by one the blocks disappear, starting from the top. To test if you have the problem, you want to:

A) Drain the battery down below 7% SOC, and then 

B) Keep driving but watch the ePower gauge. 

If you see the ePower blocks disappearing from the top, before your SOC drops below 3.0%, then you probably have this problem. You shouldn't experience any reduced power with more than 3.0% state of charge. To protect yourself from getting stranded during this test, do it within a mile of a charging station, or drive up a long hill -- you can always turn around and descend to regen some power back into your battery. If you get the battery down to 3.0% SOC with no loss of ePower blocks, then you don't have the issue. To display the battery SOC, tap the BC button on the end of the turn signal stalk and watch the upper left corner of the driver's display. However, even if you don't seem to have the problem, I'd advise having your dealer update your version of software and check the state of health adaptation value. 

Finally, I don't want owners to freak out over battery capacity loss. This is completely normal for any electric car and that's not the problem here. The car needs to properly adjust to the capacity loss over time to give a proper state of charge reading and therein lies the cause of this issue. Once BMW updates the software, there is no issue. As I mentioned above, I have close to 70,000 miles on my i3 now and my battery is nearly as robust as it was when it was new. My range seems just as good as it was in May of 2014 when I took delivery. Perhaps I've lost 4 or 5 miles or range but honestly, I can't tell. BMW has an eight year, 100,000 mile battery capacity warranty for the i3 that guarantees at least 70% capacity. Based on what I've seen so far, I highly doubt that they will have many claims on that warranty, if any. 

Hit tip to fellow i3 driver Chris Campbell for providing information used here, and for prodding me to post about the problem so other i3 owners affected by the issue know what to do. 

i3 Software Update 15-11-502 Fixes Flaws, Adds Features

Details of the November software update (15-11-502) for the i3 and i8. Click to enlarge or download.

BMW has just rolled out another software update (15-11-502) for the i3 in the North American market. Since the i3 launch, these updates have been coming out about once every six months, and as with previous i3 software updates, they are free of charge. Hopefully this time around BMW dealers know these updates are indeed free. Last year when BMW introduced an i3 software update, for some reason there were some dealers that charged their customers for the service. Once BMW realized what was happening, they reached out to their dealer network to inform them that these i3 updates are indeed free, and they were instructed to refund the money to anyone who was charged for it. If you were one of the people who unfortunately paid for an i3 software and wasn't reimbursed, please contact your dealer and they will refund what you paid.

This new update is a combination of fixing some nagging issues, as well as adding a couple of new features. Below is a detailed description of what the added enhancement and fixes of this update are all about.

Fixes:

"Broken motor mount potential"

There have been a few cases since the i3 has launched, where the left side motor mount has failed.  Basically, this failure is caused by an excessive shock to the driveline, such as a sudden loss of traction or underbody impact, during hard acceleration. For instance, if you get the rear axle airborne (going over the bump while accelerating) while still keeping your foot on the acceleration pedal, the electric motor, without any load, will quickly reach very high speeds - up to 11,000 rpm. When tires hit the ground while the motor is freewheeling at such a speed, the impact force from the drivetrain may compromise motor mount bolt (it's the left side mount in a BEV and possibly both sides in REX). It's obviously bad if this happens, but if you continue driving then extensive damage to high voltage components (EME, KLE) can occur. The 15-11-502 update will reduce the electric motor speed when the rear axle freewheeling situation is detected. 

Picture of a broken motor mount from an i3. Photo credit Roger Klemm

Some i3 owners, upon seeing this line item in the update were concerned that BMW's solution may have been to reduce power in an effort to reduce the strain on the motor mounts. Luckily, that isn't the case. This update is not going to affect motor output or torque during normal driving; only when the car has lost traction and the wheels are spinning without load. 

 
"Low Cost Charging complaints"

This issue concerned the Low Cost Charging feature which allows the owner to set a delayed charging session so they can take advantage of lower cost electricity pricing. There were complaints that for some customers it only worked sporadically, and for others it didn't work at all. This is the kind of feature that many people won't use, but for those who do, it's very important because it can lower the cost of charging their car significantly.


One i3 owner posted a video of his EVSE clicking. This should be solved with the software update.

"Clicking noise from Level 2 charger during charging"

This issue was definitely strange and annoying. When i3 owners set their car to precondition, often it would cause a contactor in the EVSE to open and close every few seconds. It would happen with various brands, including the BMW i branded Wallbox Pure, which was made by Bosch. Depending on the brand of EVSE, the clicking noise would vary from every couple of seconds to clicking once every 15 or 20 seconds. It didn't present any immediate problem, but the contactor would eventually wear out and fail if this were allowed to continue for years unresolved. Besides that, it was really annoying and many customers could hear the clicking noise throughout their house. The video above was made and posted on YouTube by i3 owner, George Betak.

"Various fault codes will set a check engine light (CEL)"

Basically, BMW cleaned up some errors in the code that have caused the check engine light to illuminate when there really wasn't a problem. Phantom check engine light warnings have been an ongoing problem with the i3 REx cars since the launch. The majority of the time when they happened there wasn't anything wrong with the vehicles. Hopefully with the new software update these false warnings will be a thing of the past.

Enhancements:

"Addition of Hospitality Charging Feature"

This is a feature that owners of other electric vehicles will appreciate as much as the i3 owner does. This issue centered around the fact that the i3's connector would lock itself to car if the doors were locked and wouldn't release until the doors were unlocked. On the surface it sounds like a good idea. Nobody wants someone else to be able to unplug their car while it's still charging at a public charging station, right? Well, in in the majority of instances most people don't, but there are exceptions.

The issue of charger sharing dates back to the early days of the recent generation of electric cars in California. Back about a decade ago when GM had the EV1, and Toyota had the first generation RAV4 EV, there were very few electric vehicle charging stations, and the small group of EV drivers took it upon themselves to come up with methods of sharing the few stations available. They would leave notes that would say something like, "You can unplug me anytime after 1:00," or "I'm opportunity charging. If you really need to charge, just unplug me." These charger sharing methods allowed the users to get the most out of the few stations available.

Hospitality Charging in action! These hang tags help make hospitality charging possible and efficient. But that's only if the connector will unlock.

Fast forward to today. There are hundreds of thousands of plug in vehicles on the roads here in the US, and not nearly enough public charging stations, especially in EV hotbeds like California. So charger sharing has continued in many different forms, especially for workplace charging. Often, the number of plug in cars in a workplace parking lot greatly exceeds the number of charging stations they have. So by playing nice, and sharing the chargers, everyone gets their fair time on the plug. However, if the connector is locked to your car, even when the car is finished charging, then the charging station cannot be utilized by the next person.  One electric vehicle owner, realizing the need for them, created hang tags specifically to assist in public charger sharing and now sells them on his website.

Also, if an i3 owner is charging in a public parking lot, they cannot leave a note allowing the next person to unplug them and use the station at a certain time, when they know the car will be finished. BMW fielded many complaints about this issue, and I've even heard people call the i3, "The most hated electric car at the office," because of this. Earlier in the year, when the last i3 software update came out, this issue was addressed, and the cars then unlocked the connector once the vehicle was finished charging. However, for some reason the update only worked on cars with a build date after March of 2015. This update corrects the issue on all i3s built before March, so all the i3s now have Hospitality Charging. This was the first thing I checked when I had the software update, and I have confirmed it does work.

BMW i European Type 2 charging cable. Notice it has connectors on both ends. We don't use cables like this in the US - though I think we should. Personally, I prefer this method of public charging rather than having the cables tethered to the unit as we use here.

However this feature will not be added to European i3s. That is because the majority of public charging stations throughout Europe do not have the charging cable tethered to them as they do in the US. In most European countries, the owner of the car brings the cable which one one end plugs into their car, and the other end plugs into the EVSE. If the connector automatically unlocked, than the cable could be easily stolen. I believe this is the reason all i3s were initially delivered without the Hospitality Charging feature. BMW, being a German based company, was just more in tune with the charging needs of European customers than they were with US customers. However thankfully, they listened to their US customer base and added this feature.

I'm glad BMW added this, but there is one thing about it I'd like to see them improve upon. As it is, you cannot turn off Hospitality Charging. Once the car has finished charging, the connector will unlock, you cannot stop it. I would prefer a setting in iDrive where I can check or uncheck a box that will determine if Hospitality Charging is utilized. I want this for the times I may plug into a basic 120v outlet with my Occasional Use Cable while the vehicle is in a public space. As it is now, once the car finishes charging, the connector will unlock and someone can steal the portable EVSE which is worth a couple hundred dollars. There are ways to lock the OUC to the car, but that means carrying a padlock along with you and taking the time to lock it to your car whenever you use it which is cumbersome and time consuming. Adding the option to iDrive would be the best solution, giving the driver full control over when the connector unlocks or not.

Charge Port Flap Open Warning

Interestingly, this new feature isn't included on the 15-11-502 service bulletin list, but it is indeed part of the new software. I like this feature a lot and am happy to see it now added on the car. There have been many times in my six years of driving electric when I did not realize that I left the charge port open until I arrived at my destination and needed to plug in. Usually that doesn't really present a problem, but it can. In fact, back in 2010 I left the charge port of my MINI-E open while driving home from work one night in a pouring rainstorm. So much water got into the charging socket that even after a couple of days of letting it air out (and even taking a blow dryer to it), I had to take it to the dealer where they replaced the charge port. This new added warning is really appreciated and I believe it should be standard on all electric vehicles.

I'm happy to see BMW updating the software frequently to fix issues, and actively adding features that the customers have asked for - you may remember that last year they added the numeric state of charge and low battery warning after receiving numerous customer requests. Tesla in particular has been praised for how they offer frequent updates, and over the air no less. While the i3 needs a trip to the dealer to perform the update, the fact that they are pushing them out, and frequently, is good news indeed.