BMW i3 Range Extender To Offer Up to 87 More Miles, Decreases Performance

JUL 29 2013 BY JAY COLE 36

According To BMW USA Boss, About 80% Of Buyers Will Opt For The Extender

According To BMW USA Boss, About 80% Of Buyers Will Opt For The Extender

As BMW has put the focus on the debut of the i3, there has been a lot of details on what the all-electric component of the Bimmer can do, and not so much on what the extended range option adds, or in some cases takes away from the vehicle.

BMW i3 Range Extender Gives...And Takes Away From The Package

BMW i3 Range Extender Gives…And Takes Away From The Package

Given that this particular author is lining up to buy the Range Extender (REx) edition, and that BMW North America CEO, Ludwig Willisch himself thinks 80% of i3 buyers will choose this option,  lets ignore the all-electric version for awhile and focus on the REx.

Of interest is the fact that adding the extender increases the weight, and the air resistance somewhat (.29 vs .3o), making the all-electric range shorter and the performance less sporty…especially at speed.  A not unexpected reality…there is always a trade-off.


  • Range Extender: $45,200  (+3,850 over the standard $41,350)


  • 1,315 kg/2,900 lbs  vs 1,195 2,634 (DIN), an official increase of 259 lbs (despite the US press release saying aprox 330 lbs)


  • the internal combustion engine adds up to 140 km (86 miles) to the total range of the i3
  • when adding the REx package, the all-electric range of the i3 falls by about 10%.  In the US, BMW says range is between 80-100 miles, and we expect an EPA rating of just over 90
  • on the Euro-NEDC cycle the all-electric i3 is rated at 190km (118 miles) of electric driving, while the i3 REx will go 170 km (106 miles) on electricity


  • 34 hp/54lb ft of torque (4,300RPM)


  • 0-62 mph:   7.9 seconds (7.2 all-electric)
  • 0-37 mph:   3.9 seconds (3.7 all-electric)
  • 50-75 mph:  5.5 seconds (4.9 all-electric)

Check out the full specs of what we know are the differences between the two below:

Full Specs On BOTH The i3 And i3 Range Extender Option

Full Specs On BOTH The i3 And i3 Range Extender Option


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36 Comments on "BMW i3 Range Extender To Offer Up to 87 More Miles, Decreases Performance"

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Much better performance than I thought it would be with the REX.
0-60 with the REX is still almost a second faster than with the ActiveE! The 20% buffer should easily handle all but the longest of grades at freeway speeds.
Very impressed. Still leaning towards the all electric but it will be interesting to see what kind of option packaging goes on.

I think you misunderstand. The 0-60 time for the Rex version is not on the Rex itself, but the time for 0-60 on electric, same as the non-Rex version. The increased time is due to the increased weight and drag with the Rex. On pure Rex only, the 0-60 time would be much greater.

Great work, Jay
No way there will be 80% gas lovers, i think.

Did you notice the octane rating? It says the RON95 is recommended. I don’t know much about it and googling it helped a little. But it seems like the octane rating in the US is about 4-5 points lower than the RON rating. Does that mean that the BMW will require a 91 octane gas to use?

Dr. Kenneth Noisewater

Presumably, like the Volt, they recommend premium in order to prolong the life of a tank of (rarely used) fuel, and have periodic burnoffs to keep it fresh and to work the engine and related hardware.

Great info, Jay. Thank you!

Looks like BMW is following the route of other automakers and allowing the free rental of ICE vehicles for longer trips.

This sentence was also interesting (and I’m skeptical).
“Chief Executive Officer Norbert Reithofer is convinced the car, which the company says will be profitable from the start”

yeah there is a video about it

Profits from the start, so long as the first chump is willing to pay the 2+ billion, in R&D. That’s been the standard by which EVs uniquely seem to be measured.

Yeah, I was thinking of that too. And even if you ignore that BS, I don’t see how a large battery, a carbon fiber body, and range extender, with a $47K price tag will be “profitable from the start” for BMW; but the Volt was supposedly losing money when it debuted at $42K.

Thanks for the specs. The more I read, the more I see that this car is a refined, more-powerful, range-extender-capable i-MiEV: (North American measurements shown)

Wheelbase: 2570mm vs. 2550mm
Length: 3999mm vs. 3675mm
Height: 1578mm vs. 1615mm
Weight: 1195kg vs. 1171kg
Turning Circle: 9.86m vs. 9.4m
Passengers: 4 (both)


That’s interesting thought. How goes the i3 compare to the LEAF and Volt?

The LEAF is a 5-passenger vehicle. The Volt is a 4-passenger vehicle. The reason the Volt is 4-passenger is that its battery intrudes into the passenger compartment. The LEAF’s doesn’t. Neither does the i-MiEV’s. Both the i-MiEV and i3 have a 4-passenger limit, though, because of the size of the vehicle.

Here are the comparison on the LEAF (S):
Wheelbase: 2570mm vs. 2700mm
Length: 3999mm vs. 4445mm
Height: 1578mm vs. 1551mm
Weight: 1195kg vs. 1477kg
Turning Circle: 9.86m vs. 10.4m
Passengers: 4 (i3) vs. 5 (LEAF)

Note: The LEAF S is lighter than the SL/SV models.

And for the Volt comparison:
Wheelbase: 2570mm vs. 2685mm
Length: 3999mm vs. 4498mm
Height: 1578mm vs. 1439mm
Weight: 1195kg vs. 1715kg
Turning Circle: 9.86m vs. 11.0m
Passengers: 4 (both)

It’s interesting how much heavier the LEAF and Volt are.

This is great, thanks for pulling the numbers together.

I note that you omitted width from your comparison. The i3 is nearly a foot wider than the iMiEV, which is significant, I believe.

This article is not clearly stating what it means by “performance with the REX”. My guess is that this 7.9 seconds (0 – 62 mph) is the performance within the all-electric range and the 0,7 s difference with the pure electric model is caused by the heavier weight.

What you should still ask your contact at BMW is what the performance and speed are AFTER the battery has come down so far that the REX is needed to generate extra electricity for the extended range. In other words: what are the top speed and performance above the 170 km all-electric range?

Thats not really a good question either because it can use a buffer in the battery to give full performance for a short while.

The question would be what is the top speed on level ground that can be sustained while using the REX, meaning that its not draining the battery.

With a perfect conversion of power into electricity (which isn’t possible), the REx should deliver around 25kw of power. For my i-MiEV, that would work up to around 45-50 MPH. Since the i3 has better (“stated”) aerodynamics but other dimensions are very similar, that number would be slightly more, probably closer to 50 MPH.

In Chevy Volt average electroc motor power 25 kW the battery with 10,5kWh shall be emtied during 15 min.Chevy Volt AER 38 miles within 15 min.That means speed should be 152MPH- not possible. That means 25 kW ICE is far enough with battery covering peaks.

Are you sure? The LEAF needs between 10 and 11 kW to sustain 50 mph. It requires about 25 kW to go 75 mph on flat dry road. I can’t imagine that the iMiEV would do worse in this respect.

Looks like a DESIGNED-TO-FAIL vehicle to me.

Not only ugly, but weird looking – the way they do with most of the EV’s, except the Tesla which is designed to win. The Leaf is not that bad either.

I can’t understand why, with the great designers BMW has, the car comes out looking pathetic, except that there is a lot of effort from big oil to make sure that EV’s fail.

I’ve seen lots of comments today about the car being ugly. I think it is worth mentioning that for every car on the market, there are a group of people that think it is ugly and a group of people that think it is attractive. No single car can please everyone.

Well G, forgive me but the only thing I find pathetic is the pessimism and small mindedness. I’m grateful that the powers-that-be at BMW let some of their more progressive designers get a little wild and risqué with the new i line. I suspect BMW has now set the bar, at least to a certain degree, for the next couple of EV releases from everyone else.
G, this subset of the auto industry is new and requires thinking that is “outside of the box”, and admittedly I too wasn’t initially sold on the design. Just in the last week, however, I’ve concluded otherwise. I didn’t think that my next car purchase would again be a BMW, but the release of this car has me revisiting that.

Kudos to BMW for resisting the temptation to succumb to all the naysayers and negitive nancies!

Dr. Kenneth Noisewater

Well that’s, just, like, your opinion, man..

The i3’s looks/packaging are pretty decent to me, but it seems that the battery tech is a bit old compared to Tesla, if they had Tesla-level densities it’d be more like 35-40kWh for a 150mi or thereabouts range. And the ReX efficiency may be no better than that of the Volt’s archaic 1.4 non-DI iron lump + 0.5t added weight!

Interesting that the REx version has different size tires for the rear axle.

Meh. The very small range-extender is interesting. But beyond that, the current crop of small EVs seem just as good, much cheaper, and available now. This is an EV for BMW badge-hounds.

And this is supposed to compete with the Model S? What are they smoking?

The i8 seems to be more of the Tesla competitor . . . but it is barely electric.

So the REx, adds 259 pounds, and reduces the electric range by 10%. They could have offered an additional 9 kWh pack option for that money, and it would have made for a solid 120 mile EV.

Probably not weight is reducing AER but required bufer for CS mode.

I find the commitment BMW has made to carbon fiber to be impressive, and look forward to seeing how it is incorporated into future cars. The styling…I’m okay with it, especially the interior. The REx is an interesting option, adding utility, even if only accessed sparingly. Personally out of my comfort price range, and probably not enough bang for the buck to make this be my choice when my 2012 Leaf lease expires in Dec. 2014. Hoping for an affordable Gen. III Tesla…even if I have to walk for a year before it comes out.

You know for a couple hundred bucks I could buy a small diesel or gas generator that I could keep in the back. Maybe with some clever plumbing the exhaust could be routed out a window an you could charge while driving. Then add on more dangerous gas tanks and you have unlimited range! I have several other bad ideas if you are curious.

Can someone please explain to me how REx works? Is it constantly running or kicks in when battery is running low? I’m wondering if there’s an option to turn off the gas engine and only use it for longer road trip

See my post below. The REX really does not make the i3 viable for a long trip.
The gas motor just charges the battery and only adds 86 miles to the range. Once the batt is dead, you are going to visiting gas stations very often if you are on a highway drive.

The REX defeats the purpose of the i3 entirely!
The problem with the REX option is that it still prevents a long distance (>100 mile) drive. It really only adds 86 miles to the range ONCE per charge. After the battery is dead, you are then stuck with a gas car with a very short (~100 mile) range!

So the REX is really there to get you out of a jam on rare occasions. If you think you will need a longer than 100 mile range per day, and you don’t have access to fast charging stations, the i3 (REX or no REX) is not for you.

It looks like it will have 440v quick-charge capability to allow longer trips. Also, the REX’s may be good in that they will provide a safety net “bridge” into BEV adoption. As the general populace comes to realize how little they use the REX, BEV’s will get more and more popular.