Wednesday, June 1, 2016

BMW i3 REx Lawsuit: How'd This Happen & Who's Really at Fault

The "Hold state of charge" feature shown here on this i3 display is at the center of the recently filed lawsuit alleging the BMW i3 REx is unsafe to drive.
Recently news has spread of a class action lawsuit filed in the state of California by MLG Automotive Law alleging that the BMW i3 REx is dangerous and "can result in a catastrophic situation for all those on the road." This, in my opinion, is grossly misleading. However in fairness, to say the vehicle can be driven like any other car while the range extender is in use is also grossly misleading. To understand the juxtaposition of those two statements takes some explanation.

The truth is, the plaintiffs aren't making this up. What they are describing in the lawsuit is called "Reduced Power Mode" and it can happen under certain strenuous circumstances when the vehicle continues, for a prolonged period, to consume more power than the range extender can provide. In this post I'm going to attempt to explain why and when this can happen, how this became an issue, and what could have been done to prevent it from getting to the point of a lawsuit. 

Far and away the most misunderstood aspect of the BMW i3 is its range extender. Ever since early February 2011, when BMW's Financial Officer Frederick Eichinerto announced that the i3 (then known as the Megacity Vehicle) would have an optional gasoline motor to extend the vehicle's range, there have been questions. I remember early adopter electric vehicle enthusiasts speculating over the potential efficiency and power output of the motor on numerous online forums and EV news sites. I was in fact, one of them. 
The 650cc two cylinder range extender sits next to the electric motor over the rear axle.
Fast forward to 2016, two and a half years after the i3 launched and most people still don't really understand the i3's range extender. That's because it's different than anything on any other car sold. No other OEM before or after has offered an optional range extender on an electric vehicle, allowing the customer to decide which form (BEV or extended range PHEV) better suits their personal driving needs. BMW designed the vehicle with as small, as efficient, and as light weight a range extender as they could, while still delivering the power necessary to perform its task. The problem is, it's unclear to many owners what exactly its task is, and therein lies the rub.

If you ask BMW, they'll tell you the range extender is an APU (auxiliary power unit), and its primary function is to extend the range of the vehicle, in order to get the driver home safely or to the next charge point, without worrying about being stranded with a depleted battery. The range extender is not a fully capable large engine, as found in series-hybrid type vehicles such as the Chevy Volt. Vehicles like the Volt can run indefinitely without the need to ever actually plug it in to charge it, while the i3 REx, cannot. However it's unclear if the majority of i3 REx customers actually realize that. It seems many believe the i3's range extender is supposed to operate like the Volt's range extender, to power the vehicle as long as necessary and under any circumstance needed, and that's simply not the way BMW engineered this vehicle. BMW i3 product manager Jose Guerrero once said he viewed the range extender as being “almost like training wheels for the BEV.” I've spoken to Guerrero extensively about this, and he's consistently referred to the range extender as a backup system which is meant to keep the driver from having range anxiety, and worrying whether or not they'll make it home.

The i3 was the first, and still is the only vehicle that is classified by the California Air Resource Board (CARB) as a "BEVx" vehicle.  According to CARB, a BEVx vehicle is,"a relatively high-electric range battery-electric vehicle (BEV) to which an APU is added." Additionally, the vehicle must meet the following criteria:
  • The vehicle must have a rated all-electric range of at least 75 miles
  • The auxiliary power unit must provide range less than, or at most equal to, that of the battery range
  • The APU must not be capable of switching on until the battery charge has been depleted
  • The vehicle must meet "super ultra low emission vehicle" (SULEV) requirements
  • The APU and all associated fuel systems must comply with zero evaporative emissions requirements
I highlighted the third line because this is really the crux of the issue which has caused this class action lawsuit. BMW designed the software on the i3 to allow the customer to manually turn on the range extender once the state of charge was below 75%, recognizing the occasional need to hold back extra energy in the battery pack for later in the journey when they would need it. By selecting this "Hold Mode", the range extender will turn on and hold the state of charge at that level, or close to it, depending on the current power draw. The Chevrolet Volt has a similar feature to accomplish the same result which is to reserve electric power for later in the journey when the driver expects they may need it.  Because of this, a Volt can climb any mountain road in North America without issue, as long as the driver properly uses this feature.

However, if BMW allowed the i3 REx customers in California to have access to a REx hold mode, the vehicle wouldn't qualify as a BEVx vehicle. It would then be classified as a plug in hybrid (PHEV) in the Transitional Zero Emission Vehicle (TZEV) class. In that case, BMW would lose thousands of dollars in zero emission vehicle credits for every vehicle sold, because BEVx vehicles are treated as pure battery electric cars, and thus get the maximum ZEV credits. Of course BMW could have placed the restrictions only on the cars they sold in California and other CARB states to qualify as a BEVx, and sold the car everywhere else with a hold mode as they do in Europe, but it was explained to me that they didn't believe selling the car which operated differently in different states in the same country was prudent. So in order to comply with the BEVx rules, BMW modified the software on all cars sold in the US. This modification eliminated the hold mode option. The range extender therefore only turns on when the state of charge is 6.5%, and the driver has no control over it. They also had to limit the amount of gasoline available from 2.4 gallons to 1.9 gallons to make sure that the all electric range was less than the range while running on gasoline, another criteria of the BEVx classification. So even though the gas tank could hold 2.4 gallons, only 1.9 gallons is available to the driver. This modification caused the delay of releasing the range extended i3 to the US customers back in 2014. I was one of the customers whose car was held up at the port so BMW could modify the software, and print the Monroney label for the window.

Even though the range extender turns on at such a low SOC, the little 34hp motor can keep up with the power demand under most conditions. I've driven my i3 REx on quite a few trips which covered hundreds of miles without any issue, even though it wasn't ideally designed for that type of use. It's been my experience that I can set the cruise control for 70 mph and the range extender can supply the needed power to allow me to drive indefinitely on relatively flat terrain, even climbing a few hundred of feet in elevation from time to time. However, I've noticed if I drive faster than 70mph after a while the state of charge will erode, and the possibility of the car entering reduced power mode is introduced. For that reason, whenever I'm driving long distance on the range extender I keep an eye on the SOC, and slow down a little when I begin a long, sustained climb. For me, the beauty of the range extender is it means I never have to worry about coming up short on range. If I pull up to a public charging station and it's broken or being used, I can still continue driving without having to drastically alter my plans.

Where I live and drive the terrain is relatively flat, and as such a hold mode isn't really as necessary. However driving in areas that have long sustained climbs, especially where the vehicle will be traveling at highway speeds, the operator could certainly benefit from a hold mode. This would allow the driver to engage the range extender at a higher state of charge, reserving the extra energy needed to complete the climb.

Despite calls from some armchair engineers, in my opinion the i3 doesn't need a larger engine. Doing so would add weight and reduce efficiency. The 650cc engine is fine for just about any use, the only exceptions being prolonged high speed (over 70mph) driving, and long, sustained hill climbs which are many miles long at highway speeds. European i3 owners don't seem to have any issues because they can switch the range extender on early if they believe they will need the extra battery reserve at a later time in their journey. So what can US i3 owners do to alleviate the problem? Many have resorted to coding their car which will restore the hold mode. It's a relatively simple procedure, but one that can possibly void the vehicle's warranty. Although whether or not doing so can void a new vehicle warranty has been disputed by some in the vehicle coding community. Coding the car not only restores the hold mode, but can also allow full use of the car's 2.4 gallon gas tank.
Even though the car actually has a 2.4 gallon gas tank, BMW restricted the amount of gas available to 1.9 gallons through software. Had they left the entire 2.4 gallons accessible, the range on gasoline would be slightly greater than the electric range, and therefore not qualify for the BEVx designation.

I've never coded my i3, because I've never had the problem of the car going into reduced power mode. I understand the limitations of the range extender, I watch my state of charge and if I see it getting dangerously low I simply slow down a little. That said, I do understand that many owners don't know how the REx works, and expect it to be able to do anything, under any condition, which it cannot. The APU isn't a large engine that one would expect to find in a car. It's actually a BMW scooter engine which was modified to act as a generator for the i3. That said, with the proper use of a hold mode, the vehicle is capable of climbing any mountain road in North America, as proven by i3 owner and engineer John Higham, when he set out to prove just that by climbing 7,228 feet to Donner Summit in Lake Tahoe last year. John proved the i3's engine is robust enough to power the car up any incline at highway speeds, as long as the operator had access to, and properly used a hold mode.

So what's the problem? Why doesn't BMW just sell the car in the US as they do in Europe, and allow the hold mode and solve the problem. They may eventually have to if the lawsuit is successful, but until they are forced to as mentioned before, it's all about the extremely valuable CARB credits. BMW (along with Chrysler and Volkswagen) lobbied hard to convince CARB to create the BEVx class in the first place. GM was right there with them, but was unsuccessful in trying to convince CARB to relax the criteria enough to allow the Volt to also qualify. The difference between being classified a BEVx vehicle as compared to a PZEV may be as high as $10,000 per vehicle, although that's only an estimate I got from someone familiar with the CARB credit valuation. I don't personally know the exact amount, but I do believe it's many thousands of dollars per vehicle. When you consider BMW has sold nearly 15,000 i3's with the range extender in the US already, you can see how the BEVx qualification may have netted BMW over $100,000,000 already.

It's clear people are buying these cars without really understanding how they work and what the limitations may be, and this lawsuit only further proves that point. I highly doubt many i3 owners in the US even know BMW purposely restricted software that the car has which allows for manual operation of the range extender, and I'm sure the people behind the lawsuit had no idea the car could enter a reduced power mode under certain conditions when they bought it. There's a clear disconnect between BMW and the customer with regards to how the range extender functions, and what its purpose is. Is it an APU designed to keep you from being stranded with a flat battery, or is it a dual-fuel system which allows you the freedom to go wherever you want and at any desired speed? There's really nothing else on the market quite like the i3's range extender, so it's really important that the customer has access to the information necessary to understand how it works. This lack of understanding has been simmering for two years and it's now come to boil in the form of this class action lawsuit.

So is it all BMW's fault? Is this simply a case of a greedy manufacturer putting their customer's lives at risk in order to line their pockets cash? I don't think describing it that way does the whole situation justice. BMW obviously has to take the majority of blame for this resulting in a lawsuit, but to say it's all their fault isn't correct. There's plenty of blame to spread around if you really want to be fair. Here's how I see it:


It's clear the majority of blame has to fall on BMW's shoulders. They built an electric vehicle that was really unlike any other. They included software to allow the operator to turn the range extender on early if they felt they needed to. However, for the US market they disabled that software in order to comply with the California Air Resources Board's strict BEVx criteria. BEVx is a category of electric vehicle that BMW lobbied CARB to create in the first place, and gives the manufacturer full ZEV credits, even though the vehicle burns gasoline in some conditions. It's the only vehicle in the US that is capable of burning gasoline, but is still treated as a pure ZEV by the California Air Resource Board.
An audible warning and this visual alert comes on when the state of charge drops below 3%, warning the driver that reduced power is possible. You can also see the SOC display in the top left corner. That was also added to help the driver avoid reduced power mode.  These warnings were added in 2015, slightly less than a year after the i3 launched in the US.
When the i3 REx was first released, the driver had no warning before the vehicle went into reduced power mode. One minute you'd be cruising along at highway speed, and suddenly it would slow down drastically because the range extender couldn't keep up with the power consumption. Less than a year after the i3 launched in the US, BMW made a software modification to help warn the driver before the car went into reduced power by adding audible and visual alerts.

BMW has provided their dealer network literature to help them understand how the REx works. They have also held BMW i certification training programs, which were deep-dive, extremely informative training sessions for the i3 & i8. The information is there, but does it reach the customer? In most cases I'm afraid it doesn't. BMW's share of the blame: 50%


CARB created the BEVx classification with the hopes of increasing the amount of miles driven on electricity. They view the BEVx vehicle as one that fits a category between plug in hybrid electric vehicles (PHEVs) like the Chevy Volt, and pure battery electric vehicles (BEVs). The goal for BEVx was to increase the amount of miles driven on electricity from 80% (that of an average PHEV) to over 90% and be a "Transitional Vehicle" between ICE and pure BEV. (John Higham went deep into CARBs BEVx classification reasoning in this 2015 post.)

However in doing so, they created criteria so onerous that no manufacturer other than BMW has made a vehicle that fits the stringent rules of the classification. In fact, in order for the i3 to qualify for this category BMW had to disable features that actually prevent i3 owners from using the car more often! The restrictions, and the fear of the vehicle possibly going into reduced power mode actually forces some i3 owners from taking the vehicle on certain days, instead electing to drive their ICE vehicle that day. This is counter productive and acts exactly the opposite of what BEVx was trying to accomplish, which was to facilitate MORE electric miles driven. If CARB needs to feel like they're getting something in return for removing the restrictions on manual control over turning on the APU, then I suggest they raise the all electric range from 75 miles per charge to 100 miles per charge.

I want CARB to make it difficult. I want CARB to continuously increase the electric range which vehicles need to provide in order to qualify for credits, and I want automakers to be forced to innovate to come up with solutions to CARBs mandates. However I also want the criteria to be attainable. The BEVx category has the potential to deliver over 90% electric miles and simultaneously allow the manufacturer to build in software to allow the driver to manually turn the APU on if they feel they need to. CARB may argue that doing so will result in drivers turning on the APU needlessly, and burning gasoline they didn't need to. That may happen on a very small percentage of case, but I contend the net result will indeed mean more all electric miles driven because more BEVx vehicles will be sold, and their owners will use the vehicle for journeys they currently don't for fear of reduced power occurring. People who buy electric cars don't want to burn gasoline unless they really believe they need to, and they aren't going to just turn on the APU for the fun of it. Owner's have paid more money up front to own and drive an EV, to think they would then fire up the gasoline range extender when it isn't needed is nonsensical. CARB's share of the blame: 25%

BMW Dealerships

Whatever transpired behind the scenes with BMW & CARB, once the cars landed into the showrooms it became the dealers' job to make sure the customers understood how the vehicle worked before they drove home with it. 

I know for a fact that early on, when the car first launched BMW dealerships did not have the information or training necessary to explain how the i3 worked. Many client advisers sought help from online forums and i3 enthusiast groups. Through my i3 blog I had dozens of client advisors reach out to me with questions, many of which centered around the range extender. However a few months after the launch BMW caught up and started offering i3 & i8 training programs, along with instructional literature that helped the client advisers immensely. Still, comprehensive electric vehicle information is rarely available at dealers. This isn't a BMW specific problem, though. Most manufacturers selling EVs have struggled to provide information about the cars needed at the dealer level.

However, BMW had a particularly difficult task with the i3 REx since the range extender is complex. Because of the software limitations there are tasks that the vehicle cannot do, but how do you explain that? Can it climb a 5% grade at 65 mph for 5 miles? How about 3% grade at 75 mph for 10 miles? That's just impossible to explain to customers even if the dealer actually knew. I think the best solution given the current circumstances would be to develop a simple "range extender 101" guide that dealers could give to potential customers. I know this may scare some customers away, but isn't the goal to put the client in the vehicle that suits them best? I feel a little bad blaming dealers for this because they have so many vehicles to sell that they can't possibly know everything about every vehicle. However if they did a better job explaining that the range extender does have limits, there might not be a lawsuit pending today. Dealership responsibility: 15%

The Customers

Two words: Caveat emptor. So much has been written about the i3's range extender and it's inability to perform certain tasks that I find it impossible not to place some blame on the customers filing the lawsuit. A simple Google search of "BMW i3 range extender" yields nearly half a million responses, many of which detail the limitations of the range extender. Refine the search to "BMW i3 range extender problems" and there are over 90,000 results that all, in one way or another, speak of the limitations or potential problems it has. I find it very hard to believe that people today buy a $50,000 car without doing even limited internet research, especially when that vehicle is unlike any vehicle they have ever purchased before. If the people in this class action suit had spent even 15 minutes doing some research before they bought the vehicle than perhaps they would have realized the range extender had limitations. I can't help but look at this as another example of "it's not my fault" syndrome, and a clear reminder of how litigious a society the US has become. Customer responsibility: 10%


It will be very interesting to see how this lawsuit plays out. I fully expect BMW to rigorously defend themselves, and I'm sure CARB is also watching this closely. I know it wouldn't hold up legally because nobody forced BMW to comply to CARB's requirements, but I'd love it if somehow CARB could have been named in the suit because I absolutely find them complicit to the root cause of this issue. Whatever the outcome I do expect this issue with the i3's range extender to go away soon. The 2017 i3 will be available in a few months and has a 50% larger battery. I suspect BMW will build a much larger battery buffer into the low end of the i3 REx usable battery capacity. Therefore even without a hold mode the car may very well have so much energy stored in the battery buffer that it will be able to sustain prolonged climbs at highway speeds. It may not be able to climb Pikes Peak at 70mph, but it should be able to just about anything short of that. Of course if BMW loses this suit, and is somehow forced to restore the hold mode on all i3's, then the larger battery buffer in the 2017 i3 wouldn't be necessary.

I have over 50,000 miles on my i3 REx and as mentioned I've never had an issue with the vehicle going into reduced power mode. However as noted, that doesn't mean it isn't a real problem because it does happen to others. The heart of the issue is the question of what's really the purpose of range extender? Is it what BMW designed it to be, what CARB wants it to be, what the dealers sold it as, or what the customers thought it would be? In my opinion everybody involved had a narrow vision of what it was, and saw only what they wanted to see. BMW should have done more to prepare the dealers to sell this unique vehicle. The dealers should make sure their clients know what they're buying before the leave the lot. CARB should have realized the BEVx restrictions are actually hurting EV adoption, and if the plaintiffs in the suit had done even minimal research before they bought the car they would have realized the car has limitations.

Should issue this have ended up in court? Whatever side you're on I think we can all agree it's very unfortunate that it's come to this. The BMW i3 REx is a wonderfully unique vehicle, too bad it's so misunderstood.


  1. Car rapidly slows down when it runs out of fuel? I think you'll find they all do that.

  2. So they are using it wrong, is that BMW's defense? Advertising the car as having a 180-mile range has little to do with it? And BMW did nothing to compromise the function of the car just to get more money? And they continue to do nothing by not offering the battery upgrade, the hold mode and the use of the full tank, all available in Europe while scapegoating the BEVx regulation that they wanted?
    Pardon but it all sounds hollow and something that GM would do. Maybe those i3 REx drivers would have been better getting a Volt after all. ;)

    1. I agree absolutely it is BMW greed at work to the tune of $10000 per vehicle!!!!!!

  3. I drive my rex 130 miles or so a day of 1 charge (goes 75-100 miles on battery every day winter / summer) and then rex turns on. I live in NJ and drive on mostly very dangerous highways and have never one time not had the power I needed. This is totally overblown... if you expect to drive 90 mph, like most i3 drivers seem to think they should, then this is not the car for you. If you want to drive 65-75 then you will be 100% fine always.

    1. Wrong. I've had 2 i3s (2014 and 2015). Neither can sustain the charge of the battery driving 65mph in ecopro+ on a flat highway. It's even worse in the winter with the heater or defroster on. I have experienced turtle mode. It is a real thing. I love the i3 (bought another 2015 after BMW bought my 2014 back for a different reason). BMW should put back the hold mode and ensure customers understand the limitations.

    2. My experience is if I set the cruise @70 mph, I can drive forever (stopping every 50 miles or so for gas, of course) Any higher than 70 mph and the SOC will slowly erode until I get the warning message about reduced power. I've driven it to Vermont from NJ three times and I've done the entire trip @ 70 mph. No problems. Here's the link to a post about the first trip I made (462 miles)

  4. Great article. My few caveats:

    1) I can't imagine that a 800cc motor can't be relatively low cost to implement.
    a. BMW already has one
    b. It is roughly the same physical size as the 650cc motor
    c. Just a few more horsepower would make a significant different on long hills.

    2) "Coding the car" is actually illegal. Yes, it might ALSO void the some aspect of the vehicle warranty, too. Anybody who doubt that coding is illegal is free to call the EPA or CARB hotlines, explain what you're doing, and listen to their response.
    a. Modifications to ANY road legal motor vehicle that affect emissions is illegal, particularly modifications that increase the use of a gasoline motor. Honda was famously sued for this when their hybrid had battery issues, which caused lower MPG. Obviously, emissions went up if MPG went down.
    b. Some people seem to think they just won't get caught (which is very unlikely), but then advertise on public forums with their real names. Not very smart.

    3. Blaming CARB a is pandering to the BMW i3 readership
    a. Yes, everybody wants somebody to blame
    b. Yes, CARB thought BEVx was a good idea, and maybe it is, but none of that excuses BMW's implementation. They could have just as easily built a slightly larger battery vehicle, and/or with a slightly more powerful engine, all of which met the requirements and was safe(r) on the freeways up a hill with a depleted battery. BMW freely chose to offer this car as-is. In addition, as you state, they could have made a CARB a state car and a "rest of the USA" car. We had that situation for DECADES with California cars and "49 state" cars, so this is hardly even new to BMW.

    4. CARB will look closely at this suit
    a. Because they will review the BEVx rules (which are currently valid through 2025) whether there was a suit or not, I suspect they will find BMW's implementation lacking for the consumer.
    b. The lack of oversight from BMW in easily allowing owners to modify their cars counter to BEVx rules will likely be a consideration for CARB.
    c. My recommendation would be to properly put REx (and all gasoline powered cars) in the category with which they properly fit. No gasoline car should be rewarded as a ZEV, in my not very humble opinion. REx is a plug-in hybrid, and should be classified as such.

  5. Great article, lots of much needed detail on this topic.

    I expect it to get tossed out as a frivolous lawsuit but, imagine if it held up. Anyone opting to have their car modified to include hold would, in effect be asking for their car to be re-classified as a 'regular' PHEV and hence should be expected to return their tax credit for a full EV. Net result, a PHEV that performs 'less PHEVy' than, say a Volt at a price higher than a Volt.... Careful what you wish for folks!


    1. But it's not their tax credit, it's BMW's, right? The i3 REx already qualifies for the full $7,500 federal tax credit as the battery has capacity higher than 16 kWh.

    2. He's talking about the California State rebate, vdiv. i3 REx owners get and additional $2,500 there on top of the $7,500 federal tax credit. They only get $1,500 for PHEVs

    3. I see, but it still is BMW that ultimately got paid and arguably offered a "limited capability" vehicle perhaps at a lower price. I don't agree with the "dangerous and catastrophic" claims either, just not happy that BMW limited the capability of the i3 REx for profit reasons and did not properly disclose those limits in order to sell the i3 REx. And if the argument is that they are in the business of making money on the free market then people should be able to freely buy the uncapped version in the US as well.

    4. Indeed, and also, the federal $7,500 is continent on it being classified as an EV. As a PHEV similar to a Volt it's at risk of being dinted at some point as the rules tighten up. Not to mention local state incentives like sales tax elimination in NJ for example or lane access rules. All of these come under fire as the car comes down from 100% electric and I fear that's not been fully considered by all.

    5. Yes, however when the plaintiffs in the case purchased the REx they were eligible for these incentives so they were not thinking they were making a trade-off that they would soon regret. They were led to believe they were getting a capable car for the full range and the incentives.

      Hopefully with the expanded range BEV version and charging network more people will opt to forgo the range extender.

  6. Great article, Tom! It sums up this complex issue very well. It definitely cannot be explained by pointing out that the vehicle is running out of fuel.

    One of the key takeaways from the CARB proceedings was that the APU was supposed to incent the driver to stay in electric mode because the vehicle would not offer the same type of performance. I'm not sure if that's 100% the correct approach. While it's OK to restrict REx operation and range, driving electric has its own rewards. Electric motors result in inherently better driving characteristics. Tesla has demonstrated that with their ludicrous mode.

    I'm also not advocating for a larger APU in the i3. Personally, I wouldn't care if it came out of a Bugatti Veyron. I would not want to use it, unless there was a good reason for it. That said, it might be possible to tune the range extender further and add a few kilowatts. Additionally, in certain situations, such as sustained hillclimbs, REx operation might be permitted sooner. Perhaps at 15 or 20% state of charge.

    I believe that with a few tweaks, the edge could be taken off from the shortcomings in certain scenarios. Although reduced performance in range-extended mode might there be by design, the vehicle needs to be able to handle all use cases safely.

  7. Nicely comprehensive accounting, Tom. It's unfortunate that this had to come to a lawsuit, but that's the mindset of a portion of our society (probably the same mindset that expects their cars to work as they want it to, rather than to work as they was designed to).

    As one of the commenters noted, people run out of fuel in ICE cars everyday in traffic (and the car stops). How does that happen? Human stupidity, perhaps? At least with the REx, it happens more gracefully.

    Driving over the speed limit is also illegal, if we're going to debate legal (coding) niceties.

    I agree with the commenter who suggested no car should be classified as a zero-emissions vehicle if it has an internal combustion engine. In other words, BEVx was a mistake, and created the unfortunate situation we are now discussing. Driven by greed.

    More consumer education is needed about EVs — including the technical details of PHEVs and especially magnetic/regenerative braking. Unfortunately, most people aren't interested (how many read their owner's manuals?), and sales people are ignorant and not interested.


    1. The problem here is that the i3 slows when its NOT out of gas. BIG difference. My i3 did this on the way home from the dealer the day I bought it. I understand the issue now and know how to avoid it but it is an issue.

    2. It slows when the battery charge is depleted. It's an electric car! The REx does not drive the wheels; it charges the battery, but cannot do that if the driver is pulling charge out faster than the REx can replace it. The driver wants the car to behave like something it isn't.

  8. The magnuson-moss warranty act specifically enables after-market modifications made to your car without violating your overall warranty. It could void the warranty on the specific subsystem (eg: if you mod your headlights to be brighter, and they burn out, they will not be required to be replaced under warranty). However, the dealership must prove the after-market modifications caused the problem. Being that the i3 sold in every other market operates differently, it is highly unlikely they could prove that "coding" your car for REX HOLD caused a warranty voiding event, when every other i3 on the planet operates this way. Please stop spreading misinformation.

  9. Great article, thanks.

    I have been driving an i3 REx for about 1.5 years, and I love it. I have encountered this low power mode twice, in very dangerous circumstances. In both situations I was climbing hills with other cars and trucks traveling at high speeds. I was about 1 mile from the top of the hills when the car suddenly lost power and I went from 65-70 miles/hr to around 40 mph. Trucks were fast approaching from behind and there was nothing I could do! I put my hazard lights on and kept my fingers crossed!!!

    If I was able to use the "hold mode" this would have certainly allowed me to avoid these dangerous situations.

  10. It could only happen in California...

    Though the posted speed limit is 65 in most places, the average highway speed in CA is closer to 75-80 (or above). I travel 138 miles from Pasadena to San Diego once a month, and content myself with 'tooling' along in lane 3 or 4 at 68-70mph with cruise to avoid running into the reduced performance mode toward the end of the journey. I too watch the SOC fairly carefully. The only tough part is that I cannot sit in the HOV lane in good conscience since that traffic wants to go at higher speeds.

    BMW did state at most of their media events that the REX was 'auxilliary' power, not designed to do what Tom our I do, but it can be done if you understand the system.


  11. Thanks Tom for taking the time to clear up the 'misunderstanding' behind Rex. I feel more comfortable as an i3 owner now that I am 'educated' of it's purpose and limits ;-)

  12. This seems to be a biased write up. It all boils down to BMW selling the car. The CARB didn't sell it, the customers didn't sell it... BMW sold it with a dangerous flaw. Regardless of the reasons, it's BMW's responsibility to sell a car that is safe. If they compromised it's safety for the sake of tax credits, that is even worse. That indicates putting profits over customer and public safety.

    1. Donut wheels in lieu of spare tires compromise safety too, but they also take less space and save money. These design choices have pros and cons, and it's not unreasonable to expect people to educate themselves about them.

    2. Sure I'm biased, I've been driving one for two years now. I have taken long distance trips covering hundreds of miles and I've never had a problem. If I keep the cruise control at 70 mph (which is actually 5 mph above the speed limit here) I can drive indefinitely without issue. I've driven it from NJ to Vermont three times now and never had a problem.

      As noted that's because I understand how it works, I watch the state of charge gauge and I don't use it for what is wasn't intended to be used for. The real problem isn't that the vehicle can't climb mountains at highway speeds with the REx running, it's that the customers were never told it couldn't so by BMW.

  13. IMO, the only salient question is whether BMW misled buyers into thinking there were no limitations to the system, and not whether it is unsafe, which it is not.

    1. Sudden loss of power or propulsion can be deemed unsafe. Other vehicles have been recalled by the National Highway Traffic Safety Administration for similar reasons in the past.

  14. You see the glass half-full; I see glass half-empty.... BMW hasn't done what is needed to inform / educate the i3 owner and potential buyers.

    The issue is i3Rex has a flawed design, the engine is totally inadequate. There is nothing in CARB's BEVx rules that limit or lead BMW to use this tiny engine. You never had an issue, then come to West Coast and give our mountain a try!

    1. While BMW's education efforts have been pathetic, they designed and ALWAYS marketed the i3 as a CITY CAR, over and over and over again, consistently. So the first thing owners did was test its interstate highway abilities, see how big a mountain it could climb, see how it would handle at 90 mph! And then they complained.

    2. I have said repeatedly that there's a problem, and I've put the majority of the game on BMW & their dealers. But to not also say I have never personally experienced this issue wouldn't be fair.

      I know there are areas, particularly in the Western region where I don't live, where extreme hill/mountain climbing can be part of everyday life. I suspect this issue will be a big problem there.

      The way the software is manipulated to appease CARB, I don't think the vehicle is suited for those areas. The dealers should have been clear about that and informed their clients that the vehicle isn't a god choice if you need it to climb mountains after driving 70 or 80 miles and the battery is flat.

      The engine in the i3 is absolutely capable of providing enough energy to allow the vehicle to drive up any paved mountain road in North America, it doesn't need a larger engine. It just needs to turn on earlier, that's all. And that's where CARB dropped the ball with regards to the BEVx category IMO.

    3. @Chris Liana, I live in the Pacific NW, there are plenty city road with a steep grade. Also bear in mind, unlike in Germany, even if you in the "city", you will have to get on the highway.

    4. Maybe all Electric Car Sales in general should be required to go to a 'Ground School' - like new private pilots due, and then to 'Road Training' in the i3 BEVx (Like - Flight Training - in Aircraft) in their new EV, with a qualified Instructor beside them, and run the vehicle though all conditions it would need to be run in to understand the 'Emergency' Functions and vehicle reactions - again - like all Private Pilots have to do, to get a Licence!

      Maybe BMW - with the i3(Rex) sales need to have drivers get a 'Rex' Classification on their license - proving they have been properly trained! (Like a Motorcycle License is required - in addition to the general Car Drivers License!)

      Personally, If the car has the smarts to have the Hold Mode, and to have it disabled in software, and again be Coded (or Hacked) by users to bring back the Hold Mode, why can't the vehicle - at service - report the number of times the vehicle was put into hold mode above either the current 6.5% SOC - or even - at any SOC above, say 10%, or 20% SOC? Require the BMW Dealers to report that to CARB, and give BMW Credits adjusted accordingly - splitting the difference between the BEVx and the PHEV Category, and not 100% at the sale of the car, but - spread out over the life of the Warranty Period: Like - 25% at the sale - and then 1/Warranty Years(%)[-1] for each year remaining in the Warranty!

      That way - BMW does not 'Dump' a lot of i3 BEV-Rex Models out there as BEV's and Clean up on the cash right away, but they will get it all if users don't need the early switch on of the Hold mod, or less if they have to use Hold a Lot (or just choose to drive it like a Prius PHV, or as a Volt - without Plugging In!)

      Even Further - What if the Buyer - could specify the Base Level of what their Rex would default to turning on, and at set points above the current 6.5% SOC, They would just 'Buy' a new Base for their car: You want a base for the Rex to come on always at 20% SOC - OK - that option is $1200; You want a Rex Base of 30% SOC - that option will cost you $2500, Etc., to - You want a Normal Base where the Rex Comes on - that will cost $5000 (or the Actual Difference that BMW would make between a PHEV CARB Credit - and the current 6.5% Base SOC in their Rex Category!) Between that option, and the further option of intermittent higher settings for the Rex to start up at, with annual 'Upgrade Billings' to the user - at service intervals, they could have a much more flexible solution, and with no loss of funds from their calculations!

      Obviously, American Rocky Mountains, AND Canadian Rocky Mountains, And Coast Ranges, are not the same as the Prairies, and Neither are the Appalachian Mountains - Some of these Mountain roads have Freeways on them, and Speed Limits are quite high! However - for anyone speeding in their EV - Maybe the Car Itself will in the not too distant future squeal on you - either at Service intervals, or by WiFi/Cellular Transmissions, and you will just see the ticket at home in the mail!

      I don't see to many mid-Teens owning and driving BMW i3's, so why are so many 'Adults' still driving as if they were in their teens and early 20's? Sure I have done that stuff back then, and still remember driving speeds much over the posted speeds, but when you get two tickets in one day (even if only one was for speeding), and have your license taken twice, at a time when you had to drive 350 - 500+ miles to get to work, you kind of get the message!!

      So - Most of the complaints boils down to - "Traffic is speeding - so I must also! But - my car can't Speed when Climbing the Hills to Tahoe when the Rex is Running, and that makes my car dangerous! BMW Should pay me!"

      So - Just wait and order a Tesla Model 3, until BMW Get's it 'Right', and Drive a Volt until then!

  15. Hi Tom-

    Thanks for yet another very thoughtful analysis of a complex issue involving our (beloved) i3's. I do wish the discussions/negotiations between BMW and CARB regarding the i3 had been made public, as I suspect they would reveal the fundamental truths behind why things worked out the way they did. I wonder why no one in the EV press has yet filed a Freedom of Information Act request for these files. That said, I must say I can't agree with the part of your report that blames buyers for not having done due diligence in checking out the realities of the REx. In my own experience (I bought my i3 in August of 2014), there was at that time little if any meaningful owner reporting available about the flaws of the REx, and my dealer was actively encouraging me to buy the REx and describing its behavior as essentially equivalent to the Volt except for the more limited range of the gas tank. I came within inches of buying the REx, deciding only at the last minute that the added cost and the lack of certainty about getting an HOV permit were not worth it. I would never, ever have considered the REx had I known at the time about its dangerous performance flaws (which may not be so obvious in the flatlands of NJ but can be very obvious and important here in the hills of CA).

    1. I think all of the discussions are public, Harold. Even if they aren't, it's all documented and you can read the minutes from each meeting, you just need to find them.

      Most of the BEVx discussions that I found were in 2012. Here's one link:

    2. When Pilots make mistakes in Airplanes, and they Crash and Pilots get killed, ever notice they never say the cause was 'Human Error'? they always say in such cases - it was 'Pilot Error' - indicating Pilots are superior to mere Car Driving Humans? Well - Maybe - blaming "buyers for not having done due diligence" is partly like saying - 'Driving Without Due Care and Attention' - and that comes with 6 Demerit points and usually a more hefty fine, than simply 'speeding'!

      Actually - one generally needs to be 'Driving without due care and attention' just to be 'exceeding the speed limit as posted' (Speeding), - unless one has an Emergency, Just Doesn't Care, or Has a Death Wish (on some roads!)

      Some Exceptions are - The road you never drove on before, and for X # of miles - there has been no signs posting the local Speed Limits (But - even then - most States, Counties, and even Cities, have 'Default' Speed limits for when you see no signs posted! Limiting the Validity of any Argument of "Sorry, Officer, I didn't see the Posted Speed Limits since I entered this road!"

      I am not quite sure where the general rule of thumb in driving has become - "I must be in front of the pack, and - I can't let anyone pass me or I am weak!" Nothing wrong with taking the slower lane on multi-lane roads, or even exiting the HOV Lanes now and then when traffic builds behind, and letting it clear, before rejoining it, and carrying on!

      Imagine the Uproar if the USA went Back to the old National Double Nickel (55 Mph) Speed Limits! If that were the case - I don't think the i3 Rex's would have much of these issues! Maybe a few places, but I seem to get the idea that Speeding is the biggest Problem with the Rex - It just was not intended for Autobahn like driving up grades, after the battery was discharged!

  16. Very good write-up that lays out all the issues. A couple of thoughts:

    1) I think your view of drivers is a bit optimistic--around here (CA) a good number of folks look for the cheapest way to get a carpool lane sticker--if CARB eased up on the restrictions, sure folks might take the occasional road trip in their i3, but I also think more daily commuter miles would end up being driven on gas than electric.

    2) You seem to go easy on owners with only 10% of the blame--this seems like an RTFM kind of thing. If I were BMW, I would be arguing that the system works as designed and disclosed in documentation.

    1. In general, I'd agree that part of the problem is poorly informed users. But also, the i3 has one of the worst owner's manuals I've ever encountered. Very few things are explained well, and it's hard to find the info you need.

    2. Maybe it is time in CA to bump up the Carpool Lane Requirements for PHEV's to minimum of two people in the car - and have two people who will be car-pooling - sign the forms, to submit them? Do the Same for the BEVx Category too! That deals with two things, too many cars, and people living across the valley from where they work, having to drive too many miles to get to work!

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  18. An excellent and very comprehensive write up. This will be tried before a jury who drives primarily ICE vehicles and BMW will probably lose as the nuances of EVs will interpreted in an ICE context. In any case, I lay the problems at BMW's feet for these reasons.

    1) In the context of "megacity car", REX makes lots of sense and is never going to be a problem. But when BMW belatedly figured out that megacity residents had nowhere to charge and they turned the i3 into a CARB compliance car to take advantage of a combined $10,000 government subsidy in California, they were stuffing a round peg in a square hole. California freeway driving is about as different from megacity driving (think Rome, London, NYC) as is possible.

    2) The BMW dealer network is at best amused, but usually just annoyed by the i3. My dealer only has i3 qualified maintenance people on site 3 days a week, and I live in Northern California which is awash in EVs. The dealership does not understand the i3 and has no incentive to understand it because it doesn't make any material contribution to their sales. When my 2014 i3 was delivered they actually told me the removable ashtray was a drink cup! They were, and still are, clueless. They will continue to poorly communicate the product to customers and since BMW has made a decision to be reliant upon dealers, they must take responsibility for the dealers incompetency.

    3) In the three years since BMW introduced the i3, they have committed no significant engineering to its development. The 2017 model reflects no new design or engineering effort; it remains an anomaly in the BMW product line for the foreseeable future.

    This lawsuit is the result of BMW trying to change the stripes on the tiger, and failing. It's not the fault of engineering or design who were given the task of designing a car for an entirely different purpose and market. They put "lipstick on the pig" and sold them in volume in California, and now the lipstick has worn off and the pig (for freeway driving) has been revealed.

    It's tragic in the sense that this is a self inflicted wound by BMW. Not as tragic as VW's diesels, but tragic none the less. I would like to see BMW giving Tesla a real challenge, instead they will likely become even more conservative, afraid of lawsuits in California. Tesla is selling an "autopilot" to the accolades of their customers, and BMW has landed themselves a lawsuit just trying to compete with the Volt. BMW needs new management, or we need to accept that they are on a decay curve no different than GM or Chrysler. The existing management can't read the writing on the wall.

    1. One of the primary issues with BEV's is Charging Infrastructure - Charge Rate, and 24x7 Availability, PHEV's - not so much, however - if BEV's with a 22 kWh Battery, like the i3 BEV can have a CCS Charging Option - does this option come available or Standard on the i3 Rex? If not - once again that is part of their design challenge!

      The Tesla Built Toyota RAV4 EV came with no DC Fast Charging - but I believe it had Tesla built 9.6-10 kW AC Charging, which is better than some EV's began with; however - Aftermarket Businesses have stepped in to make CHAdeMO (JdeMO) as an Aftermarket Add-On to the RAV4 EV! So - Why has their not sprung up a hoard of B-I-Y Coders offering their services to unlock the Range Hold Mode for the i3 Rex? Much less hardware cost - Even DVD Training Courses on what to do and how to do it could be sold at the grass roots level! Instead of Suing BMW for the limitations, they could just sue for the rights to 'Improve the safety of their vehicles as they see fit, without repercussions on Warranty Work!' - Meaning - they made the Range Hold option available for themselves, again!

    2. Yes, the i3 REx comes standard with DC Fast Charging, just like the BEV.

  19. As if we didn't know that BMW abandoned electric cars some time ago (Kr├╝ger era), the company has now made it official — remaking the i division (formerly for lightweight EVs) to its center for self-driving cars. See I also read that when BMW gets around to building its next EV (next decade), it will be made of steel.

    1. Count me out! I purchased my i3 REx two years ago this July. I bought it as advertised--as a "city car", a car that would take me neatly from suburb to city and back again primarily on battery with the range extender giving me that final push to the drive way. I've experienced the "great slow down" as my granddaughter calls it twice. The first time was returning from San Diego to Orange County with the car packed with four large men. I anticipated it as I had learned about the possibility. When it occurred, I moved to the right lane and all of us had a hardy laugh. The second time I knew it was coming so I moved to the right lane anticipating that when I reached the top of the hill I would regain speed. In two years, these are the only two instances of a reduced speed occurrence. With a little planning, a very little, the situation will never happen again. Some class action suits are justified; many more are not--the result of competitive interests, greed and/or unrealistic expectations. I look forward to the often mentioned software fix from BMW that will give our vehicles more protection against the great slow down--and by now wonder what happened to it. Many of my friends have coded their cars to give them more control over the REx yet continue to get their vehicles serviced as needed under the warranty. As for me, with regard to the class action suit, count me out! I continue to enjoy my car. I find it safer than most other vehicles I have owned in the past. I do my best to drive it as an electric car, that is, drive it to conserve battery, getting as many miles on battery as possible before the REx kicks in. I also drive it as advertised--as a city car with an occasional straying here or there for a longer jaunt. To everyone who owns an i3 REx, I hope you are too busy enjoying your vehicle to fritter your time with this particular diversion.

  20. Great info as always, Tom. I feel that BMW should have never tried to be all things to all people with the i3. Either you have an EV or you don't. Besides this power issue, REX owners deal with more mechanical issues, inaccurate sensors, and problems. I cannot gauge fault, but whenever a product tries to do it all, it usually is not as good as its pure form. I live in CA and drive the freeways and hills all of the time in my BEV, but if I had to drive over 80 miles and did not want to spend 30 minutes at the DCFC, I would not take my EV.

  21. This is very basic, BMW offered one car to the world and another car to the USA with a lot of restrictions on the REX, and no cost reduction. The early adopters bought it , no sunroof no REX hold and a stupid hold state of charge at 6.5% STUPID and greed on the part of BMW to screw the customers in the non CARB states! FOR BIG PROFITS!!!!!~!!!!

    1. No, it's really not basic, unless you are only capable of thinking in basic terms.

  22. It is real simple, BMW screwed their US customers!!!!

    1. I appreciate the comment, but I disagree. It's really not that simple in this case.

  23. Why anyone with half a brain would believe that the 34Hp REx engine can provide the full power to the 170Hp electric motor plus all of the operational electrical equipment in the i3 and maintain full capability when they let the battery SOC get near zero, is beyond me! That 34Hp is about what the original VW Bug had, and it certainly cannot storm up hills or maintain's physically impossible. The only way this works is if you understand what it is and plan accordingly. It should not come as a surprise, since the computer is telling you what's going on.

    You might be able to remove a nut with a pair of pliers, but a proper wrench is going to work better. Use the car as designed and sold, and you'll be happy...don't, and you might just have problems.

  24. I'm an engineer who researches his purchases extensively, so I knew the i3's limitations going in. I live in hilly San Diego, and I calculated that it would just about make my longest regular trip on electric power, and that has proven to be true. Some I days I make it on EV only, and some days the REx kicks in for the last mile or two (which is up a big hill). But on a couple of slightly longer trips on SD freeways with their usual 75 mph traffic, I have encountered reduced performance mode. I haven't gotten deep enough into it for it to be dangerous (the road leveled out just as the ability to maintain uphill speed was about to go away), but I can see how it could happen.

    The reality is that it's a highly technical vehicle. If you're the sort of person who expects your car to be an appliance that you never think about, but just drive, it's not the car for you. If you're not comfortable with computers or couldn't program your VCR or DVR, it's not the car for you.

  25. US customers can be a very particular bunch...I mean, bucky balls (magnet balls) are banned in this country.

    Thanks BMW for pushing it and creating the only EV that I'd buy. Sorry for silly people.

  26. An excellent article, with three things you need to do: 1. Get your car CODED. I drive an Australian spec i3 and being able to switch on the range extender early is a god-send. You'll find it transforms the car on long trips. 2. Locate BMW i3 product manager Jose Guerreroe and kick him in the head. BMW has no reason for cars outside of California not being able to activate their range extenders when the battery is 25% depleted. Being "prudent" is not a valid reason! 3. Lobby BMW to offer 10mm wider tyres. Twice I've scratched my wheels on kerbs and its annoying. There is no question that the rims are actually capable of handling wider tyres. Overall my i3 is perfect for me, with my only comments being that I'd like better steering feedback and the ability to fit roof racks.

    1. Thanks for the comment. I have to stick up for Mr Guerrero, though. I've had the opportunity to speak with Mr Guerrero on a few occasions and he isn't the reason the range extender has these limitations in the US. When that decision was made back in 2013 Guerrero was a product manager that reported to BMW i Manager of Operations, Jacob Harb. I'm not even sure Harb is entirely at fault, either. This may go back to Munich.