Car & Driver Posts Intrumented Test Results For BMW i3 REx


U.S. magazine Car and Driver spent some time with the BMW i3 REx, the Range Extender variant of BMW’s first fully electric car.

At 3,135 pounds, the range-extender-equipped i3 is almost 300 pounds heavier than the pure-electric model. In their instrumental test, they recorded a 0 to 60 mph time in 7.0 seconds and through the quarter-mile in 15.8. That’s quick, especially considering that this is a segment in which many cars need 10 seconds to hit the mile-a-minute mark.

They also concluded that the BMW i3 is still a …BMW. “The strongest hints of BMW are found in the handling feel. The steering is quick at 2.6 turns lock-to-lock,” says the review.

*Editor’s Note: This post appears on BMWBLOG.  Check it out here.

In order to reduce range anxiety, BMW i3 REx comes with a rear-mounted 650cc, 34 hp, two-cylinder, gasoline- powered Range Extender generator is available, which roughly doubles the vehicle’s range. When the battery gets to a certain level, the Range Extender starts and maintains the battery’s current state of charge.

The Range Extender never directly drives the vehicle’s wheels. The Range Extender adds roughly 330 lbs. to the vehicle curb weight and has a fuel capacity of 1.9 gallons. Pricing (before federal or local incentives) starts at $41,350; $45,200 for Range Extender model.

Here is the full review from Car and Driver.

And here’s a handy graphic showing the test results from Car and Driver for the BMW i3 BEV, BMW i3 REx and BMW i3 REx in charge-sustaining mode:

BMW i3 Tests Results

BMW i3 Tests Results

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30 Comments on "Car & Driver Posts Intrumented Test Results For BMW i3 REx"

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So they never found out what the top speed was in RE mode?

If the battery is depleted when using the RE,top speed and even more acceleration fall into the dead parrot range: ‘ I thrummed along at 70mph, but it soon became clear that at this kind of speed our comfortable range between fill-ups was more like 40-50 miles. Still, it was impressive how, even when it says it’s flat, the car maintains enough battery power to give an instant shove of torque. Only if you really run it down, which you’ll have to try pretty hard to do (or so I’d been told), would you compromise the performance. Which is what happened next. I’d just come through a heavy but localised rain storm on the M20 when the i3 started to slow. It was a gradual process, from motorway cruising speed all the way down to 44mph. By this time I was travelling up a slight incline and had effectively become a slow-moving obstacle.’ In Europe the driver can control when the RE is switched on, and so appropriate use ie turning it on way before the battery is flat can mitigate the problem. Unfortunately in the US the wisdom of Californian legislators means that to qualify they have had… Read more »

kdawg: I don’t think it’s any different than in all electric mode. I’ve had mine up to 85mph in RE mode quite a few times and it could have gone higher.

Tom, was that with the battery flat or charged though?
The problems only come in when the battery gets low, and can provide a sudden unpleasant surprise.

Dave: That’s with the flat battery. The RE only comes on when the battery is under 6.5% Once the REx comes on if I were to getit up to 90mph it wouldn’t be able to sustain that speed for more than a minute or two because of the tremendous energy demand. But lets say your cruising along at 70-75mph in RE mode (under 6.5% SOC), there is plenty of power to punch it and accelerate up to 90mph for a sudden burst, but you would then have to slow down under 75 mph in order to continue driving without reduced power. I’ve driven it about 600 miles now at highway speeds (65mph to 75mph) and it’s never gone into reduced power because the roads are mostly flat here. My wife just took it on a 260 mile trip to Pennsylvania last week without any issue. Driving in RE mode you just need to keep an eye on the SOC. If I accidentally creep up over 75mph for a while and the SOC drops below 2% I slow down a few mph and it quickly gets back up to 5-6%. If you are driving long distance in RE mode it’s better… Read more »

It sounds as though it is perfectly workable – journalists can get themselves in a tizz.

For me it works perfectly. I never have to worry about the unexpected trip, detour or the occasional long trip. Since the roads are mostly flat here (there are definitely hills, but no mountains to climb) I can do anything with it, including 200-300mile trips if needed. I just need to keep it under 75mph and I can drive it all day without any worry.

That being said, there are plenty of cases where it isn’t sufficient for lots of other folks. If you need to climb long, sustained hills or mountains at highway speed, there are instances where you will have a problem. I just happen not to need the vehicle for those circumstances. BMW is working on a solution in a few months there will indeed be a change that allows the REx to turn on at a higher SOC. Stay tuned…

In CA the REx can’t run with the battery charged. You know that.

Check the C&D review:
“On the highway, the i3 buzzed happily at 80 mph, the engine humming audibly but not intrusively.”

They said uphill they couldn’t go above 65 mph (and that other areas of the country could have more extreme cases).

If I had remembered I would have said so, wouldn’t I?

BMW presumably hope that they will have more energy dense batteries able to give better range by around 2017, which would improve the car immensely.

BMW are working with Toyota on their fuel cells.
The weight would work OK for the i3, as the Rex is around 300lbs more than the non Rex, which is enough for a 50kw fuel stack and a CF tank able to hold enough hydrogen for hundreds of miles of range.
That would still qualify as a ZEV in California, and would not need a stupidly small tank as the petrol Rex does.

Packaging is more of a challenge for such a small car, and of course the availability of hydrogen filling stations, but the latter would apply to whatever fuel cell car BMW made and they certainly intend to build one, whether as a version of the i3 or not.

In fact both the long electric range and good range using hydrogen would work to mitigate the filling station problem for the i3, and it would be a heck of a lot smoother, more powerful and quieter when the fuel cell was being used instead of the present motorbike engine.

50kw of fuel cell would work fine to provide power for the car to top up the batteries, as cruising only takes around 30kw, so 50kw would include a good allowance for not running the fuel cell flat out but in its sweet spot.

Nissan for instance has always built half size stacks for RE use as well as full size ones.

Dave, you’re dreaming. BMW is not going to make a fuel-cell REx. Nobody will. It’s utterly pointless.

The purpose of the i3’s REx is to have the security of the existing gas refueling infrastructure. There is no H2 refueling infrastructure now, and it won’t get near the coverage of gasoline for 20 years, if ever. Until then, an FC REx will be far less useful and far more expensive.

The reason Tesla can cover the US with superchargers is that they only need a to put them between cities. They don’t have to be 5 minutes away from most of their owners. H2 stations have to be *everywhere* to avoid being an inconvenience.

I already layed out the math for you before under optimistic circumstances. FCPHEVs will not happen.

Your notion that you are in a position to instruct is fallacious, as is your information.
If you wish to discuss the subject please drop the attitude of superiority and do some reading of what is actually happening, outside of whatever you have drafted on the back of an envelope.
Funnily enough the industrial chemists who design fuel cells are rather good at adding up, considerably better than most of their critics.

The fact is that you have an opinion, not sole possession of the truth.

Nissan have build half size stacks with precisely that purpose.

VW have told us that they plan PHEV FCEVs.

The US Government is funding fuel cell range extenders for goods vehicles, and Renault is already running them in Kangoo vans.

So not even the basis of your calculations is founded on facts.

I’m talking about the mass consumer market, not niche applications or PR projects. There is no business case for them.

VW is going to produce a fuel cell plugin? I’ll believe it when I see it.

VW will make a FC car for PR purposes to show it’s not behind Toyota or others. If by some chance they make a plug-in version, who will buy it when all of other VW’s PHEVs are right next to it for thousands less?

Here’s what I posted before:

Take a PHEV that goes 200k miles over its life, and does 20% on gas at 40 MPG. That’s 1000 gallons of gas, and assuming WTW emissions of 11kgCO2/gal, that’s 11 tons of CO2.

Toyota’s non-plugin FCV will cost $50k more than a non-plug-in Prius, but I’m going to make life easy for you with magical assumptions:
-a mere $5k premium for that 30kW FC
-renewable H2 costs the same as gasoline per mile
-no CO2 emissions to build H2 infrastructure

Even with all these optimistic assumptions helping your case, your solution to eliminate a PHEV’s CO2 emissions costs…

$454 per tonne.

What a joke? Fuel Cells? Yeah, there’s 12 fuel cell gas stations in the US. Only a Fool would put a fuel cell in this car.

Slogans are wonderful things, as they cater for the proportion of the population who are unfairly disadvantaged by intelligent debate.

What a wonderful thing, to be able to air views needing neither wit nor intelligence!

Keep it up.

I don’t think a fuel cell would help this car. The Rex only adds $4000, you probably can’t buy hydrogen tanks for much less than that let alone add a fuel cell stack. The idea here is you can get gas anywhere, while hydrogen would probably take a huge amount of effort. It would be nice if bevx regulations died, and they did it by range alone, allowing a button and a larger gas tank.

Whatever they use for the first fuel cell car they make, the cost of the fuel cell is going to be high to start with, although costs are dropping very fast.

It would make a great base for one, so long as it is not too small to get it in, as fuel cell cars have needed bigger bodies to date.

First of all, I own this car with the range extender. I am not a BMW fanboy despite comments made by others. This is the first BMW that we have owned. We really love this car. It looks better in person than in pictures. Everywhere we go people stop and want to look at and ask questions about the car. In fact, my wife was pulled over by DPS just so they could look at the car. This car fits our needs. Where we live, the pure electric version would not give us the range we need. For the electric purist, most BEV’s don’t work for everyone and not everyone wants to or can afford a Tesla. For all of you performance enthused, this car is quick and handles well. I suggest before you bad mouth this car you may want to go and test drive one.

AFAIK just about everyone loves this car, so I am not sure who you think is bad mouthing it.

The only thing I have seen much criticism of is the range extender, for instance in the article I excerpted in answer to a very specific question on it.

I test drove one yesterday. I dispise BMW as a carmaker but liked the Rex a lot. I was considering trading the imiev and leaf for the rex…..

Why not wait a couple of months for the final specs of the Gen 2 Volt to be revealed at the NAAS in January? Would 50ish mile AER be short for your specific needs/situation? I’m hoping GM surprises us all, and knocks it out of the park with 55-60 AER.

Thanks for that but I will not buy a new car from GM ever. Plus I can barely fit in the 2014 Volt and it is uncomfortable. The Leaf is much better for me. I am selling the Imiev because the seat is terrible for my back but I have plenty of headroom even at 6’5″.

OK, fair enough. Being uncomfortable while driving is a dealbreaker for me also.

“Thanks for that but I will not buy a new car from GM ever”


So the rest doesn’t matter.

You can always buy an used one then… How do you know that 2016 won’t fit you?

They need to put a warning sticker on the Rex that you may lose speed going up an incline carrying your family. Or they can wait until they get sued.

I don’t see the problem. I’ve driven gasoline vehicles before that were as bad. I remember borrowing an old Blazer from my parents that had trouble climbing a local hill for than 45 mph. In fact, I started to lose more speed towards the top. That actually used to be very common on older cars. I don’t recall anyone being sued over that.

I guess you don’t live in California…

Try to drive at hwy speed on some of those major interstates across the Sierra Nevada…

The difference is that in the i3 REx, the loss of power is sudden and relatively unpredictable.

If it were slow all the time, that would be one thing. It’s the unexpected transition from fast to slow that’s the problem.

I wish the Volt did 0-60mph in 6.5…. 🙂