Consumer Reports On BMW i3 REx’s Inability To Maintain Speed On Hills


Full Specs On BOTH The i3 And i3 Range Extender Option

Full Specs On BOTH The i3 And i3 Range Extender Option – Click To Enlarge

Is the REx engine in the BMW i3 the up to the task?

Initially, Consumer Reports (owner of a BMW i3 REx) would have answered that question with a yes, but now the leading consumer magazine has doubts:

“The electric BMW i3 we’re testing is the version that comes with a range extender—a small two-cylinder gasoline engine that fires up when the drive battery is near depletion, acting as a generator to keep the electric drive system running. Relying on that gas engine when the main battery is depleted works well in most cases, including high-speed steady cruising, but not, we’ve discovered, if you demand more of it.”

Consumer Reports tells the story of the REx’s inability to maintain pace as follows:

“Recently, one of our drivers tromped on the pedal to pass a truck on a hilly two-lane highway. The i3 began to lose power without warning, subjecting the driver to more exposure in the oncoming lane. It then recovered rather quickly upon coasting, which converts energy and uses it to fill the battery. But losing power just when you need it most is disconcerting to say the least.”

“Further tests revealed that after a prolonged use of the throttle with little or no speed varying and no gentle braking to regenerate energy to the battery, acceleration ability falls off dramatically. In that state, we measured a 0-60 mph acceleration time that ranged from 27 to 40 seconds—as opposed to 9 seconds in normal range extending mode. For the record, when the car is running purely on electric power it sprints to 60 mph in 7.5 seconds.”

With its depleted power and inability to maintain speed, this becomes a safety issue (not just a performance issue).

Consumer Reports reached out to BMW to notify the automaker of this safety flaw, stating that at the very least, the BMW i3 needs to warns drivers of its reduced power state.

“Asked for a response, a BMW spokesman, Matthew Russell, said that an enhancement is coming in spring 2015 that will address our concern. It will include a battery state-of-charge indicator, an early alert prior to potentially experiencing a temporary loss of power, and a proactive boosting of the battery level based on the car’s navigation prior to encountering hilly terrain. This enhancement will also be available as a retrofit for existing i3 owners.”

Separately, Manny Antunes, BMW client adviser at JMK BMW in New Jersey, states the BMW will make the following changes related to REx operation for 2015:

“…There are some other minor tweaks besides these programming bits but the biggest will be how the REx will engage prior to a large sustained climb, I can’t elaborate but REx owners will love it.”

Basically, BMW will up the threshold for when the REx can kick on.  We don’t know what the final value will be, but it should be high enough to prevent occurrences like Consumer Reports experienced.

Source: Consumer Reports

Categories: BMW

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100 Comments on "Consumer Reports On BMW i3 REx’s Inability To Maintain Speed On Hills"

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Law of unintended consequences in action.

BMW crippled the US version of the i3 Rex to game CARB compliance regulations with this unforeseen result.

Luckily there seems to be a solution, so the i3 will improve. Sad for current i3 owners that have to wait until Spring for a fix.

This ‘solution’ seems like it would violate the regulations. If I’m not mistaken, the reason that the i3 ReX comes with a 1.9 gallon tank is to satisfy a requirement (CARB or something else) that requires the gas-range to be less than the electric range. If the fix that is hinted here “a proactive boosting of the battery level based on the car’s navigation prior to encountering hilly terrain” could potentially cause this to be a problem with the gas range < electric range requirement. Or will this 'feature' only work when someone has a route entered in GPS? If so, this is still a safety hazard. Most of my trips I do not use GPS, even long-distance drives I regularly take to visit friends and family.

I wonder if BMW will have to program in a reduction of the amount of usuable gasoline if you want to be able to pass safely on hills with an i3 Rex?

Right good points.

When I read that I was thinking what if the GPS signal is non existent for a period of time. This can be the case for large areas with big old trees, such as the Coastal range in OR/WA. Dead reckoning may not work especially if you make stop, something resets, or you change routes on your drive.

You’re citing the wrong part of the regulation.

The “BEVx” category (that BMW lobbied for) has two relevant qualifications:

1) gas range must be less than EV range
2) REx may not engage until battery is below 5% SOC

It’s regulation #2 that’s the problem, and I don’t see how BMW can get around it without giving up those sweet, sweet zero emission credits they get for the i3 REx.

Yes, depending on how you drive, and terrain, it should be 10%-20% SOC.

SMH, forgive my ignorance, but I’m pretty sure the Volt SOC doesn’t drop below 5% before its engine kicks on. Why is that a problem for BMW and not Chevy?

Two reasons:

1) The Volt was designed before the BEVx category existed

2) The Volt already fails BEVx classification based on its gas range (which is nearly 10 times the Volt’s AER), so even on newer Volts, there would be no benefit to restricting Hold to 5% SOC… and even without Hold mode, Voltec is designed to kick on the REx at ~20% SOC

Basically, Volt doesn’t qualify for BEVx, so these restrictions don’t apply.

But the solution still isn’t to just give people a HOLD function. It’s going to use the GPS and do all manner of stupid trickery to avoid having to implement the simple and obvious fix.

Please Note:

After all of the gobbledygook about how BMW will fix this Problem,,,,please review the final words,
“Basically, BMW will up the threshold for when the REx can kick on.”
In other words, you will no longer have your
“normally reduced” EV range consistent with the Rex, you will now be given even less Ev range than before. Now the Rex will kick in earlier, leaving you with a larger residual
battery charge.
Which by the way you can still exhaust going up hill and attempting to pass.
I hope Consumer Reports scolds BMW for this feeble effort before someone gets killed.

Finally the truth comes out. I’m surprised it took so long.

Exactly like other car makers but Tesla, crippled, rare and expensive EVs on purpose.

It’s actually something I would expect and understand if I owned one of these. The traction motor can take upwards of 100kw. We know going up any decent grade in a LEAF can take 40-60kw. So given that, we know with only a 25kw generator and depleted battery, full acceleration will not be available. When I drove the i3 on range extender, I knew to drive it very economically, partially because the idea of running on and wasting gas didn’t appeal to me in the first place.

Sounds like the anemic REx could lead to some “wrecks”. Hope they find a way to fix it.

“the biggest will be how the REx will engage prior to a large sustained climb”

Hold/Mountain mode? What do I get for solving the riddle? $1,001 off??

The problem with your solution is that the i3 still has a less than 2 gallons fuel tank which will only give you about an 80 mile range using the hold mode like it would be used in the Volt. No matter how you see this car, it looks to be a good city car but not suitable for long distance driving as filling up every 80 miles can get annoying fast.

What they essentially need is what the Volt calls “Mountain Mode.”

Yes, and the BMW would need a much larger buffer given the smaller size of the BMW’s engine compared with the Volt’s.

That is, if the BMW is expected to climb things like Pike’s Peak without hesitation just like the Volt can.

The EU-spec i3 REx already has this feature, in the form of Hold Mode. And in Europe, BMW has specifically advised i3 REx owners to activate Hold Mode before running out of battery, so as to avoid this exact phenomenon.

However, in the U.S., BMW successfully lobbied CARB to create a new category of vehicle (BEVx) that cannot engage the REx above 5% battery SOC remaining and cannot have more REx range than EV range, then crippled the U.S. i3 REx’s features and gas tank to meet that standard. But hey, BMW gets more CARB ZEV credits out of the deal!

Reap what you sow.

They don’t actually get more CARB credits… they managed California HOV lane access.


An i3 REx gets the same (green, PHEV) sticker as a Volt, Plug-in Prius, or Fusion Energi, all of which can engage the gas engine at any time. BMW had hoped that the i3 REx would qualify for the white (BEV) sticker, but CARB rejected that idea. So it’s not about the stickers.

The reason why the BEVx category exists (and why BMW crippled the U.S.-spec i3 REx) is because BMW gets the same amount of zero-emission credits for selling an i3 REx as they do for selling a BEV i3, instead of the reduced ZEV credits of a PHEV. And given BMW’s model portfolio, they can use every ZEV credit they can get.

Voltec is still the best gas+electric powertrain on the market, and GM’s engineers are vindicated with each new competitor.

To elaborate on that statement, so as not to sound like cheerleading:

GM’s decision to include bigger batteries than Ford or Toyota (that only operate between 20-80% SOC), and a bigger engine than BMW, have been criticized as unnecessary expense. But Voltec is unique in it’s ability to give full performance in EV mode and full performance in REX mode.

Too bad GM leadership accompanied that top-notch engineering effort with mediocre-to-pitiful marketing.

Hopefully they’ll learn better soon, but I wouldn’t bet on it ;(

true, yet thanks to that I was able to get my 2014 with great discounts and incentives.

non-existant marketing.

Volt charging motor is papa bear (too big). BMW i3 charging motor is baby bear, too small. Would be nice for there to be a “just right”. (Crossing fingers for Volt II version).

There really is no need in the real world to be able to drive to the top of Pike’s Peak starting from the bottom with a discharged battery like they did when developing the Volt. (It isn’t even a real road. It is a paid private tourist attraction that dead-ends at the top. You can take the Tram if you don’t want to drive to the top of this tourist attraction).

Even GM knows that. The publicly stated that the only reason why they were going with a 4 cyl instead of the 3 cyl outlined in the concept car, was because GM already had an emissions certified 4 cyl. Certifying a 3 cyl was going to take too long for their timeline.

How about the sustained hwy driving from SF to Lake Tahoe in CA along hwy I-80 (major interstate)? That is a major climb from sea level to 9,000 ft at hwy speed…

Pikes Peak climb starts at around the altitude that the SF-Tahoe trip ends, and goes to 14,000+ feet. There is a reason why the car makers all go to the namesake of Brigadier General Zebulon Montgomery Pike to do their testing. It is unlike any road anywhere in the US. They don’t just go there because it is fun to say “Zebulon”.


So if it starts at 9000ft and ends at 14000ft, that would make it a 5000ft climb (i.e. less than the climb from SF to Lake Tahoe).

Pikes peak is actually a 6000+ foot climb, I was rounding to make a point about the altitude. Altitude matters to gas engines. It matters alot.

A Volt’s gas engine starts with 84 HP in SF. By the time it hits Tahoe it has dropped to 66 HP due to thin air.

By the time you make it to the top of pike’s peak, you are down to 49 HP. Nearly the entire trip up pikes peak you have less horsepower than the SF-Tahoe run.

The point I was trying to make, was that the altitude of the end point of the SF-Tahoe trip, is around where the start is for pikes peak. Meaning that nearly the ENTIRE trip has to be done with much, much less HP being available from the engine. Less HP==less electricity being generated.

The reason that SF-Tahoe climb is tough is due to the fact that is interstate hwy speed and you start the main climb with your charges already depleted…

The entire trip is about 200 miles with 150 miles at hwy speed with fairly flat terrain and then the climb comes with the last 50 miles or so…

MMF — GM tested with the entire run up pikes peak in extended range mode. They started with an intentionally already depleted battery running only on gas power. They intentional were testing the worst-case scenario, on the worst case location in the US. That is why they chose that place. In the real world, if you knew you were going to climb pikes peak, you would hopefully be smart enough to punch the hill mode button and save some juice for the climb. If you didn’t, it wouldn’t be the car’s fault, it would be yours. I agree that the first 150 miles or so or so of the SF – Tahoe run doesn’t really matter. That part isn’t a test of the charging motor. It might be a test of the gas tank size, but that’s it. Only the last 50 miles is the part where the range extender really gets tested. But on pikes peak, that same amount of altitude gain is done in less than half that distance!! It is a brutally constant up, up, up, up with absolutely no chance for a range extender battery to catch up. No dips, not flats, nothing but up followed… Read more »

Though 65% of my driving is “city” driving, I regularly drive my Volt from my home base in Redding, CA west over the coastal mountains to Eureka, east to the top of the Sierras at Portola, and north over the Siskiyous to Mt Shasta and southern Oregon. This can involve 3,000-6,000 feet of vertical climb, at 55-70 mph, with little respite. For me, the Volt’s Hold mode and 57 kW engine-generator is JUST RIGHT….

GM designed the Volt to be able to handle any mountain terrain in N. America and it did all the testing to verify that…

HVACman — The Volt was actually built to do much harder climbs at much higher altitude, for even more altitude gain, straight up with no let up at all, without the benefit of hill mode. In fact, without the benefit of having any initial battery charge at all.

GM ran up pikes peak starting with a discharged battery at the bottom, with all the power being provided by the engine. They ran 800 miles worth of trips up and down pikes peak without ever plugging in.

The Volt with the benefit of a smartly applied hill mode button, could do your drive with one cylinder tied behind its back.

>>”Volt charging motor is papa bear (too big). BMW i3 charging motor is baby bear, too small. Would be nice for there to be a “just right””

Not really, but if so, the Volt is way closer to just right than the BMW i3-rex that took 4 extra years to come up with.

For a first-generation product, the “just right” level of Reduced Propulsion Power is… never. These cars are supposed to sell the technology to the public, and suddenly losing power in the middle of a pass does not sell a car.

Would you know if there’s anything to back up my suspicion that the 2nd generation Volt might use an OPOC engine from Ecomotor? I drool thinking about it.

Dr. Kenneth Noisewater

Indeed, and hopefully Volt 2.0 rectifies the problems with the off-the-shelf iron motor and can get 50+ mog in CS mode…

Meh. They are both good and each has its own advantages and disadvantages. The current Volt certainly has more power. But this i3 is much more efficient, has a longer electric range, and has a fast-charge port.

Dr. Kenneth Noisewater

i3 in REx mode is 1mpg highway more efficient than Volt. Talk about embarrassing! REx should be getting more like 60mpg highway!

The first i3 customers were naturally, early adopters who knew going in that the range-extender had it’s limitations. It is true, however, that anyone can make mistakes, and since our entire driving lives, we’ve been able to jump out and pass someone if needed – this could be dangerous, indeed. Surely BMW needs to put a bright yellow warning sticker on the steering wheel or dashboard of i3s stating the cautionary information regarding this limitation. Imagine the horror of an i3 driver pulling out to pass and >bonk!< nothing! It's well and fine for BMW to say they're working on it, and there'll be improvements – but for today, nobody should count on a salesperson to inform the i3 buyer about said deficiencies. I live in mountainous Washington State. I've never had hill/power issues with my Volt. I've used mountain mode before, and it would be great if there were a topographic feature built into the nav where I could log my trip and it would advise me to use mountain mode – but so far I haven't needed it and I've traversed some steep mountain highways. Even so, I know I'm not in a V-8 pony car. So as… Read more »

As a temporaty solution BMW will provide loaner grannies who will sit in the back seat telling you to “slow down!” on a regular basis.


Dr. Kenneth Noisewater

Problem is, they only speak German..

Yes but you quickly learn not to mess with a German grandma. I know this from a lifetime of experience (ps I say this with the upmost of love towards my grandmother)

Good one! :-0

I hope this settles it once and for all; people calling for the next volt to have a less capable range extender are seriously mistaken.

I call for the next Volt to have a smaller range-extender…and to keep HOLD MODE.

Heck, with 70 miles of range i’d take a Briggs & Stratton. My lawn mower has a Kawasaki twin. That’d get’r done, too.

If you want to drive around in water, buy a fish. If passing trucks, across double-yellows, uphill, with a dead EV battery, presumably after 70 miles, is something you really need to do, than maybe the non-updated i3 isn’t the best choice.

Dr. Kenneth Noisewater

The current Volt gets 55kW out of its 1.4l iron-block off-the-shelf motor. That is incredibly suboptimal, especially given the (lack of) fuel economy. A task-specific range extender would reduce the # of cylinders and use aluminum and/or magnesium to reduce block size and mass, along with direct injection, VVT, and Atkinson/Miller valve timing (the difference between the two is forced induction, which would be optional with a turbocharger/generator that could either charge the battery or force air depending on demand). Or, a compacted graphite iron block turbodiesel of 1l with an electric turbocharger/generator to squeeze a bit more juice out of a gallon of fuel.

And which existing engine accomplishes these goals?

Isn’t this kind of like criticizing the motor in the Model S for not being efficient and powerful enough?

Dr. Kenneth Noisewater
At the very least, a modern Atkinson-only motor gets the Honda Accord hybrid into the high 40s/low 50s on the highway, and that’s not even mentioning Prius. Making it an Atkinson/Miller multimode range extender with a turbocharger/generator would eke out a few extra kW from the exhaust gas stream or provide boost for extreme demand situations. The goal of the modern Atkinson cycle is to allow the pressure in the combustion chamber at the end of the power stroke to be equal to atmospheric pressure; when this occurs, all the available energy has been obtained from the combustion process. For any given portion of air, the greater expansion ratio allows more energy to be converted from heat to useful mechanical energy meaning the engine is more efficient. The disadvantage of the four-stroke Atkinson cycle engine versus the more common Otto cycle engine is reduced power density. Due to a smaller portion of the compression stroke being devoted to compressing the intake air, an Atkinson cycle engine does not take in as much air as would a similarly designed and sized Otto cycle engine. Four-stroke engines of this type with this same type of intake valve motion but with a… Read more »

ICE motors that deliver power directly to the wheels will obviously get better fuel efficiency than converting gas to electricity and back to power through an electric motor. If the Volt’s gas engine didn’t link up to the wheels through the planetary gearset at 70+ MPH, the MPG would be even worse than it is.

I notice that you listed a bunch of hypothetical ways to increase efficiency, but not an actual existing engine that functions as a generator and does better at that job than the Voltec setup. To my knowledge, the only real competitors to Voltec that qualify are the Fisker Karma and the i3 REx, both of which are clearly worse.

The Honda Accord Hybrid would seem to prove otherwise. But I’m thinking more of city driving when the car is constantly stopping and going. On the highway, a direct link would be more efficient.

The engine in the Accord Hybrid cannot act as a generator, and therefore does not perform the same function as the engine in the Volt.

As I previously asked: name another engine that does the same thing as the Volt (but better) and we can talk about the shortcomings of the system the Volt uses. Otherwise, it’s hard to seriously consider criticism of the best currently-existing implementation.

Dr. Kenneth Noisewater

Wrong, as noted below.

Dr. Kenneth Noisewater

I don’t care about what’s already out there, I want to see improvements, not lazy laurel resting.

BTW, the new Accord system is basically Voltec Lite, and it gets 10+mpg better economy than Volt on the highway:

If the Accord Plugin Hybrid had a 16kWh battery, it would still likely get at least 5mpg better on the highway due to the Atkinson cycle.

Dr. Kenneth Noisewater wrote: “BTW, the new Accord system is basically Voltec Lite, and it gets 10+mpg better economy than Volt on the highway”

“10+mpg better on the highway?”! You’re greatly exaggerating one-sidedly which doesn’t help your credibility. Let’s fact check this: The Volt highway EPA rating is 40 mpg. Accord hybrid highway rating is 45 mpg. That is a 5 mpg difference, not 10+. You exaggerated by over 100%.

Also, the Accord Hybrid (3,550-pound curb weight) is ~250 pounds lighter than the ~250 pounds lighter that the 3,791 pound Volt.

A 16 kWh Accord would weigh ~4000 lbs (since the current 3,799-pound Plug-In Hybrid’s 60% smaller than Volt battery) and, over 200 lbs heavier than the Volt.)

You’re trying to change the laws of physics for only one car if you think it’s going to do any better than a few mpg highway better simply due to the different engine type.

I suspect that the 2nd generation Volt may use an OPOC engine from Ecomotor. Do you think it’s possible? What are your thoughts on it for this application? I think it’s a great match.

The next generation Volt will use a simpler version of the Opel 1.0 L 3-cylinder engine, which is now used in the Opel Adam. It can generate up to 85 HP (63 kW), whic is enough as a range extender.

Compare and contrast to the Chevrolet Volt or Tesla S. If this Consumer Report news were about those cars – it would be the headline today in the Wall Street Journal, hourly BREAKING NEWS on Fox, fodder on Bloomberg, the New York Times and Washington Post.

Since it’s a BMW, it’ll probably never make their news cycle.

The short’s aren’t paying for bad press for BMW, yet.
Rupert will print it if they want it.

“Since it’s a BMW, it’ll probably never make their news cycle”.I agree.

With the popularity of autonomous driving aids today – BMW could just program the car not to allow you to pull out of your lane when the power is not there to pass. This could lead to all sorts of stories of people fighting with their cars. Can you see the guy at the rest stop kicking his i3 and shouting “*&^%!, you have NO RIGHT to tell me what to do! I should be able to pass WHEN I WANT, that’s it, I’m trading you in on a iMiev!”

That would be funny to see.

Not here to defend the i3 Rex but we should be careful to distinguish “hills” from steep and sustained inclines. The i3 is a city car and such it was not designed to climb mountains. Sure the city of San Francisco has some steep hills, but the elevation change is minor as compared to climbing a mountain.

Does BMW make it clear to buyers that their car is not made to climb mountains? Many of us live near them.

The Chevy Spark EV is a city car but it can whip that BMW’s ass for less money!

thats what ya get for using a pos 2 cylinder enine hahahaha lol

The solution? No rex, more batteries, more range.
Like GM should have done with the Volt, no ICE crap, no pollution, no money to big oil.

How do you drive across the country then without enough charging station coverage?

Even Tesla doesn’t cover all the route with its supercharger and it cost way more than what a Volt cost.

Sometimes, the desire for all electric is good, but don’t let that desire (emotion) cloud your logical thinking.

There are a lot of charging points and it is growing. 200 miles is quite enough, and ALL car makers can do it! NOW!

forgot the link

And free charging is also included in many hotel room price.

Your map link proves ModernMarvelFan’s point.

Make sure to uncheck the checkboxes for wall outlets and L1-L2 crap, and just check high power stations. You’re not going to drive across the country waiting for L1-L2 charging, without serious delays in a BEV rated for 200 miles.

They would need to be closer than 200 miles. You can’t discharge to 0 in a BEV w/out a tow, and range fluctuates with temp, so winter range is lower. You’d need them every 100 miles or so to account for fluctuations and being able to see anything along the way.

Sure, there have been some well organized trips to run a (P85) Model S’s along a few specific paths. For 200 mile BEV’s there are gaping holes like Dallas to Kansas City, Seattle to Minneapolis or Phoenix to San Antonio, and many other routes.

It is funny that you mention plugshare. Without Supercharger, can you even make it from Seattle to San Diego in 2 days with a 200 miles BEV?

So, until we have a public “supercharger” that covers every major interstate every 50 miles, it is just NOT going to happen…

Once that infrastructure is there, then we can talk about 200 miles BEV being capable for cross country trips… Until then, EREV is the way to go.

In my opinion though, even with the improved infrastructure you describe, 200 miles isn’t enough AER range for cross country trips, if we honestly want them to compare to the same lengths of time other cars take. The time it takes to get more than 80% charge on a Leaf or a 50% charge on a Model S is much more than the 20 minutes it takes to get a partial charge. If you don’t take the extra time to get the full charge, you will under best case scenario needing to stop every 160 miles. This is a very noticeable change when you are use to cars able to go 450 highway miles between stops that can be less than 20 minutes.

I’m interested in an affordable 200 mile EV, but I don’t have delusions the first ones out will be all that great for road trips even with an improved infrastructure.

BMW went to great lengths to say the REx was not a limp home mode – but that is exactly what it is.
They also didn’t provide a SOC indicator
They set the expectation, but cannot deliver.
The really sad part is that this is only a software change – but good old BMW (bless them) are still stuck in the old-guard methods and not doing OTA updates.

I’m at a loss to see the safety problem. So you pull over into the passing lane while climbing a steep incline and realize the car doesn’t have enough uumph to get you around the vehicle you are trying to pass. Big deal.. get back in your lane behind the car where you started. It isn’t like you are committed to passing once you get over into the passing lane.

You don’t see the safety issue with losing power just as you are about to complete a pass?

If the car flat out restricted your power, that would be safer than giving you acceleration power and then snatching it away unexpectedly.

You are committed once the car behind you speeds up.

“There really is no need in the real world to be able to drive to the top of Pike’s Peak starting from the bottom with a discharged battery like they did when developing the Volt”

Maybe for Florida buyers, but not if you want to sell the car across the US and other countries. The bottom of Pikes Peak is far from sea level. What kind of elevation gain do you think a car should be able to have? Do you think plug-ins be crippled?

(that comment was in reply to Nix’s previous comment)

GM designed the Volt, so this problem never comes up.
It’s overcapacity for most drivers, but, for the ones who would have the problem, this could troll the car out of existence.

BMW should program the car like they have it in Germany and give up the extra CARB credits. Safety first. After all, they are supposed to be an Engineering company.

BMW won’t give up the CARB credits because, at its core, the i3 is a compliance car.

We will certainly find out for sure in the coming months.

Speaking in my capacity as President and Founder of the Corps of Compliance Car Pilots as well as a big fan of the type, please do not label this cynical attempt at a compliance car a compliance car.

No, it isn’t. BMW sells the I3 here in Puerto Rico and we have no CARB rulings. I can post a link to the BMW dealer so you can see the I3’s in their inventory.

Climbing pikes peak starting with a fully discharged battery is definitely way overkill for any actual real highway situation anywhere in the US.

GM could very safely shrink the gas engine without coming anywhere near crippling the Volt for actual real roads anywhere in the US. Pikes peak is a private tourist attraction road specifically built to rise in altitude to the top of a mountain in such an impressive way that people will pay good money just to drive it. It in no way resembles any real road that was built to get from one side of a mountain pass to the other side.

I don’t think that folks who have never driven pikes peak really understand the difference between their local road they think is steep, and a tourist attraction built specifically to launch you as quickly as possible up a fourteener right to the top, opposite from a Swiss-style slant cog rail trolley.


I’ve been saying this for a while . . . there is no way that little 2-cylinder would be able to provide enough power zip up hills when the battery is fully depleted. That said, I don’t see this as a serious problem, just something that the drivers need to be aware of.

And that awareness has to come from the car with an in-dash warning. With an emergency update they could add a power available and power demanded bars on the screen in charge sustaining mode. As the battery approaches complete depletion the driver will see the power available bar getting shorter.

If this “fix” requires a destination to be programmed into the nav system to give proper warning it’s mostly useless.
98 to 99% of trips involve no pre programmed destination.
For me I would want control over my Rex engage point.
Max EV range for my flatland low speed commute
And an early Rex kick in for that trip to WV mountains to ski.

Btw I predicted almost 6 mos ago this Rex 5% kick on would result in loss of power and a major safety issue requiring a change in operation software.

We already knew this.

Those that don’t like the ability of the REx in the i3 can buy a Volt.

They miss the point.

The whole idea of the i3 REx was as an emergency device.

There were parts of the envelope that were excluded in order to keep the cost of the REx down.

That was the whole idea.

You got a bigger battery instead.

More EV miles and less RE

get over it

+1 George

Not only can they buy a Volt instead, but they can also save $10k at the same time!

I agree.

That is why i3 REx is a BEVx instead of a true EREV like the Volt.

The REx in the i3 is preventing you from getting stranded, but it is NOT designed for you to drive across the country.

Beside the power reduction, the fuel tank size speaks LOUDLY about its true intention. I don’t understand why BMW fans keep try to make it into something that it is NOT.

Even if the hold mode is available, do you want to stop every 1.2 hrs to fill up the gas tank?

No you did not understand at all. Just unlocking the tank blocking software adding AM radio, and hold mode release will make this car safe, more useful, as European model software. Easy like a pie. California let use another software, because they are green – like Al Gore driving Humvee with Arnold. I will unlock mine, and do not care about the BMW fix for US. I spent My money and I want at least it behave like European model.

Hi George, I have never seen anywhere, in BMW literature or in their advertisements where they referred to the generator in the BMW i3 Rex as an emergency device or “for emergencies only”. It (the BMW i3 Rex) has always been referred to as a range extender with the only limitations is the frequency with which you would have to refuel (because of the small fuel tank). If I am wrong, show me?

It is a shame that they had to depower the thing just to get those credits. However as someone mentioned earlier this is more about snatching that instant torque away without warning. The car can get up and go in EV mode, so if you are used to that than you should NOT ever have to expect it not to. If you bought a dog to begin with, say a Prius, then you are used to having no balls, hence you don’t pass. Epic Fail BMW.

BMW can and will fix the problems with the BMW i3 Rex, but they will not do so until a few people have died and they are called before congress to testify as to what they knew and when they new it. They will pay a small fine and apologize to the families who have lost love ones, and life goes on. There is too much money to be made in California at this time, and that is their focus. When they are pulled before congress not only will BMW be on trial, but electric vehicles will be and that will not be fair. There are three auto manufacturing companies and thousands of individuals who have tries very hard to promote the cause of electric vehicles. BMW going before congress will set the cause back. I have read on the Internet of a BMW i3 Rex review, the car lost power and went from highway speed to 25 miles per hour. It is just a matter of time when people will be killed, and that is sad.