BMW i3 REx Top Speed With Depleted Battery – Video


110 km/w or 68.4 mph

110 km/h or 68.4 mph

It’s often been asked “How does the BMW i3 REx perform when its battery is depleted?”

Well, if you’re interesting in knowing its top speed when the battery is empty, then this video provides an answer – beginning at the :53 mark.

Video description:

“German Autobahn – full throttle shortly before and while the battery is empty.”

i3 REx owners largely confirm that 70 MPH is the max speed the car can maintain when the battery is depleted. If pushed beyond 70 MPH or so, the battery depletes itself even more, which leads to a reduced-speed condition where the car will begin to slow well below 70 MPH until it can replenish the battery enough to pick up the pace.

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95 Comments on "BMW i3 REx Top Speed With Depleted Battery – Video"

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Preparing to hear from all the BMW hater trolls…

I think a car should at least be able to keep up with a u haul truck.

It can Easily keep up with a U haul truck if you rent the 0ptional Trailer hitch & hook the BMW to the u haul. l m a o

You asked for it! No, seriously, I have nothing against BMW, only against ill designing a serial hybrid on purpose. A well designed one would have a more powerful REx, software controlled to never let the battery entirely depleted, and so always providing a sufficient power reserve to still use the entire power of the electric drive train. Unfortunately, the i3 REx is the only one on the market. The main reason why we have only parallel hybrids istead of more efficient serial hybrids, is that serial-hybrid by definition, (a well designed one) have all the full fledged electric power train running alone, and would have provided the full superior experience/joy/qualities of the all electric to the users, and therefore amplified the demand for more electrics. And everyone knows(!) that ICE car makers do NOT want to sell good electrics and shoot themselves in the foot doing so. The message sent by BMW (and the petro-auto cartel by the same occasion) is : here is a serial hybrid, and it sucks! So don’t bother. The message sent by the Prius wave was : Here is an Half electric, so don’t bother to ask for full electrics. With the rare short… Read more »

I don’t think there’s nefarious gas car cartel. More likely, BMW wanted to minimize gas engine use, so they wait until battery is very low. If gas engine kicks in when battery is 3/4 full or 1/2 full, people will complain that gas engine is kicking in all the time (perception).

Having said that, I don’t like Rex. They should’ve made pure BEV, and pure serial hybrid. What they have now with Rex is hodge-podge.

However, a simple fix by BMW would be to allow the user to turn on the gas engine sooner if they expect to go farther with software option.

The petro-automobile cartel is more than a century old. It began with John D. Rockefeller and Henry Ford.

Right you are; and, the history is a fascinating business lesson on what American business is all about…control of the market.

I should’ve been more clear. Yes, of course there exists bunch of idiots undermining EV, no question about it. But i3 issues, probably not so much due to them.

Idiocy is a convenient place to hide schemes.
Real idiots i n power are very rare, conspirators acting like idiots to lure us are common.
Every body says the GM marketing sucks. On the contrary, GM’s anti-marketing is brilliant!

This is actually one part of the I3 that appeals to me… Basically an electric car but a very small (under 700 cc) engine to help it along to the destination, where, presumably, it would charge up a bit under most circumstances. Scale this up to a 3/4 ton pickup truck, the most popular American vehicle. Lets say GM used the same 1500 cc engine they are using in the volt, but redesigned the electrical and planetary gearsets to withstand double the power of motors 2 times the size (in other words an MGA (small motor), and then a large motor (MGB – make it 170 kw as opposed to 85 kw at in the ’16 volt). Lets further state the vehicle has a 36 kwh battery and has a 60 mile all electric range. So most work days would use no gasoline at all. Extended trips would run out the battery and would make the engine run most of the time, and on the freeway, it would run flat out often (lets say, a top speed of around 70 mph, which would be acceptable). The engine life would be acceptable, since although it is being pushed hard, there won’t… Read more »

You just described the Via EREV trucks.

You must be believing their ad brouchures.. For some reason, most of the information keeps changing, or is constantly incorrect. They used to claim they’d use a 4 or 6 cylinder engine, but now the van has a v8. They claimed ’15 kw’ auxilary power, but that’s rather hard to obtain from a 30 amp twist lock. A ’50 kw’ ‘utility grade’ (whatever that means) upgrade has been ‘just around the corner’ for years. They say to plug in using a 110 outlet, or charge at a 220 outlet (showing a non-descript twistlock) or evse in “Half the time”. Taken literally, that would be a 3.0 kw charger. But then supposedly the vehicles are being fitted with 6.6 kw chargers, except if you buy special vans, which then supposedly can charge at 15 kw. None of this is in the brouchure, which constantly changes things like battery sizes, generator output and drive motor horsepower. Maybe one of the VP’s 10 year old kids made the brouchure, except now he’d be 14 and hopefully start correcting the mistakes. And their roll out makes Tesla look downright speedy. They also advertised a “Presidential SUV”, but then discontinued it before even trying. Even… Read more »

My Chevy Volt has a dashboard selectable “Mountain mode” which fires up the ICU when there are about 10 miles left on the battery. I travel regularly between Baltimore and Chicago and have no degradation in performance on the Pennsylvania Turnpike mountains. 70+ is no problem.
I’m surprised that the BMW doesn’t have a similar mode. Maybe if you complain they’ll give you a good trade in deal on an I8.
That said, passing on a hill is not the Volts strong suite. I’d hate to drive that route with an I3 and a dead battery. If you pull off at a turnpike service station to fill up and notice a semi close behind, I’d suggest you park behind a State Trooper and have a cup of coffee first. Also, make sure your Obamacare is up to date. Buying gas may be the least of your problems.

It does have a SoC hold mode, but in America you need to code the car to enable it, elsewhere in the world it can be enabled starting from 75% SoC.

Thanks for that info. What does it take to do the code thing? Is it something the owner can do or can and will the dealer do it?

The dealer will not do it, since modifying the i3’s software this way is tampering with the federal emissions control system and thus, illegal. But it is something an owner can easily do after some Googling.

I found it. $20 for a cable, a laptop, some software and it looks like the I3 will have the same “mountain mode” as the Volt. I wonder why it’s legal for a Volt but not an I3. There’s also a way to increase the capacity of the tank with a code change. Maybe it has something to do with the EV credit.

We never bomb oil-rich countries unwilling to share at our terms either πŸ˜›

Serial hybrids are NOT more efficient! They are simpler and possibly lighter but once you need to run the ICE, they are less efficient than parallel hybrids. You seem to actually think BMW built a sh*tty serial hybrid on purpose for … some reason.

Are you just trolling?

Give me some numbers to prove that, beside the i3. All the home made serial hybrid we find are powerful.
It’s simple as “enough batteries to get a good AER plus an optimum point running REx to recharge regularly on long trips, exactly like “diesel” trains and heavy duty mining trucks.
If parallel were more efficient, they would use them.

It is simple physics, and it is why the Volt has its parallel-like mode despite being a fully electric drivetrain… Greater efficiency than a simpler always-fully-serial hybrid.

It’s not a parallel-like mode. It is a true parallel hybrid. With all three clutches engaged, the Volt has a direct connection between the engine and the motors and the drive train.

Actually, the parallel mode is using both the engine and the electric motor(s) at once.
So yes, it is more powerful, IF you use the same motor than the serial version.
It is more powerful, but most more efficient.
The electric motor is ~5 times more efficient than an ICE.

A good serial hybrid would gate a more powerful electric motor and a smaller ICE always running at its peak efficient RPM. (But not weak as the i3’s. )

It would be more powerful AND more efficient.

It’s not hard to understand, just think of why the standard hybrid is more efficient than an ICE?

Because there is an electric motor added.

GM CHOSE to make a complex multi mode hybrid
It is the best because there is not even one well designed serial hybrid to compete with.

Should have written : “but not more efficient” sorry.

You always compare the Volt to some magical unicorn car that doesn’t exist.

The Volt is definitely more fuel-efficient and power-efficient than both the Fisker Karma and the BMW i3 REx. Your only explanation for this is that GM is intentionally sabotaging the Volt, but BMW (and Fisker) are somehow sabotaging theirs more, all in service of the great petroleum conspiracy.

No, Fisker just didn’t have a clue on how to make good cars.

Well, on an earlier post I examined ‘efficient’ series hybrids at some length (Diesel Electric locomotives and Ocean Liners).

ON those devices, higher efficiency compared to the simplicity of the serial hybrid is expensive to obtain, especially when considering the engine’s ‘sweet spot’ is a much more confined range, than the volt engines.

Helical Gearing is usually around 98% efficient, and even though part of the torque of the engine does go through a double reduction (triple if you include the main driving chain on the 2016 volt), most of the power only goes through a single reduction, and for this part, the volt, excuse the expression is at times a ‘Partially serial hybrid’, since part of the engine out does the electric double conversion thing’.

But the efficiency is high enough, and the gears are cheap enough to be compensated by the lower cost, high speed motors used, and the gearing forms a ‘poor man’s transmission’ to find the ‘sweet spots’ of all the motors and the engine sooner and under a greater percentage of driving time.

It is the opposite. The Volt has a serial hybrid-like mode, it has always been a parallel hybrid with software controlled modes.

BUt it is easy to get confused, There was supposed to be another pure electric after the EV1, the Volt was announced as a true serial hybrid in 2007.
Then in 2010 the marketing sold it as a pure electric while in fact it was a parallel hybrid.
Remember “the electric car that goes further”
and even now dealers still say that there is a separate small generator but it is a real electric! That’s what my neighbor was told a month ago.

RexxSee said:

“All the home made serial hybrid we find are powerful.”

It both amazes and amuses me to so frequently see posts from people who have cobbled together a conversion EV, and have thus convinced themselves they know all about EV design. One guy even called himself a “design engineer” because he had gotten his conversion vehicle to work!

On paper, a serial hybrid looks like it should be more efficient and easier/cheaper to make than a combined parallel/serial hybrid like the Volt. But there’s no nefarious plot to prevent auto makers from producing a compelling serial hybrid EV. The reason the Volt isn’t a pure serial hybrid is that GM engineers discovered their PHEV works better, performs better and is more energy-efficient, by having the option of engaging the ICEngine directly into the drivetrain.

The reason we haven’t seen a well-designed pure serial hybrid from any auto maker is because they can’t compete in the very competitive new car market. Contrariwise, one combined parallel/serial hybrid PHEV, the Volt, works very well, and is one of the top-selling plug-in EVs.

“In theory, there’s no difference between theory and practice. In practice, there is.”

So explain to me why trains, and enormous mining trucks don’t use parallel designs?

You laugh at some people who worked hard and learned making a good conversion, but what do you have to offer Mr. “I know all” ?

I explained that ICE car makers protecting themselves did not put on the market good serial hybrids because it does give the crave for the all electric car.

For the same profit protecting reason, they don’t yet give us good ranged EVs, even if they did 15 years ago. There is a lot of progresses that have been done in all fields of sciences in 15 years, and what we have doesn’t even match what they have done 15-18 years ago!

The technology permitted it then, and not now?!?

Same reason why Tesla dropped the 2 speed transmission from the Roadster.. Torque breaks gear-boxes.

There’s no practical way to create a multispeed transmission that will permit a million lb train to accelerate from rest. Further, the train use case is far simpler than that of a car. It accelerates (gradually) to a speed and stays there.

“So explain to me why trains, and enormous mining trucks don’t use parallel designs? ”

They do it for other reasons. Lack of affordable or small enough gear boxes that can handle the torque with those applications.

Mining trucks and trains require enormous low end torque which would break most transmission gears.

So, the series configuration was due to for a reliability reason, not your misunderstood efficiency reason.

If the parallel design was more efficient and powerful, since they exist, engineers would have implemented them to save money to the companies. They can put the electric motor on one set of wheel directly and the engine on the other set, for example.

The serial design is more efficient, more powerful, cheaper and simpler

“The serial design is more efficient, more powerful, cheaper and simpler” That is far from the truth. Parallel hybrid loss is mainly from the engine and the transmission. Under high power or high load applications, the high gear ratio will increase the loss at transmission. The high varying load also make the engine less efficient. Combined with difficulties in designing a mechanical transmission that can handle the torque, designers tend to go for series-hybrid. Series hybrid tend to leave the engine in a more efficient operation range. But it adds additional loss in the generator, motor controller and electric motor. The loss varies based on the rating of the system. Under high power application such as mining trucks or train, the amount of mechanical loss can over come the electric loss in the series hybrid. But in light load application, the opposite is true. You will always have lower loss with parallel hybrid than series hybrid given a particular set of powertrain. Now, the superiority of the Voltec is that it allows you to have the superior efficiency of parallel hybrid while retaining the constant load efficiency of the series-hybrid on the engine. So, it is effectively the best of… Read more »

I’d wager these hommade contraptions never did a controlled EPA test. Nor did they comply with any emissions regulations. That makes it kinda hard, you know?

Fisker Karma. Pure serial. 20mpg compbined.
Mercedes S500e. Parallel. Bigger. Heavier. Faster. 26mpg. THIRTY PERCENT.

Here’s the number you want: 2. As in the second law of thermodynamics.

In order for a serial hybrid to be as efficient as a parallel hybrid (not MORE efficient, just EQUALLY efficient), the gasoline->electric->motor conversion would have to be 100% efficient.

By converting gasoline into mechanical power, then converting that mechanical power into electricity and converting that electricity back into mechanical power, you LOSE EFFICIENCY. It really is that simple.

“A well designed one would have a more powerful REx, software controlled to never let the battery entirely depleted, and so always providing a sufficient power reserve to still use the entire power of the electric drive train.” This seems like a great idea if you don’t think about what it actually means. How can you software control something to never let the battery be depleted? If someone floors the i3 and never lets up, or is trying to climb a mountain at 80 mph, etc, how can you design the car to never run the battery down even when you’re using the full power of the electric drivetrain. The ONLY way to do so is to have an ICE that produces as much power as the Electric motor. Period. Otherwise, the electric motor can always outrun the engine and that won’t meet your requirement. Regarding the i3, a 170hp (plus inefficiency) ICE would be completely idiotic. The purpose of the i3 was to be extremely efficient and it had to offer BMW-esqe driving dynamics. That ICE would be huge and heavy and rarely run, just like the current one. You might argue that the REx should be a little… Read more »

I disagree, on long trips, the adequate REx
Would be sufficient to give full power for hundreds of miles before emptying the batteries enough to effect power. All of this can be software selectable options like all EVs.

There are a lot of other choices between 34 and 170 hp! Don’t have to be so heavy as you describe.

Only a 170hp REx with a big gas tank will go hundreds of miles and offer indefinite use of the full 170hp Electric motor, in which case you’ve added hundreds of pounds and numerius packaging issues. Those were your requirements, not mine. I’m just explaining what it would take to meet your requirements and why BMW didn’t go that direction.

You disagree? You said it needs a REx that can indefinitely provide full electric power, which is 170hp. It’s extremely simple. If you want to always have 170hp, no matter what the situation, then you need a 170hp REx. Period. Could a 75hp REx hold the i3s charge better than a 34hp REx? Sure! But if you are using all of your 170hp electric motor, you are using battery and could theoretically run it dead, which doesn’t meet your original criteria.

I agree the American REEV version without SoC sustain mode is somewhat pointless but elsewhere this is currently the best BEV/REEV car on the market. Its only problem is the price tag (too high for a car of this segment) but I guess that was a deliberate move by BMW.

The car has everything a good REEV should have:
– good EV range covering extended commuting
– lack of range anxiety in EV mode
– infinite RE range in SoC sustaining mode
– small, light, quiet and apparently reliable RE
– good performance and handling (low mass)

And nothing it shouldn’t have:
– efficiency optimizations for REEV mode
– extra performance boost in REEV mode
– ICE-only mode

The last point may look like a limitation but it is a giveaway that it is a well balanced REEV. If a car can drive on ICE only, its EV range, utility, reliability and cost had to be necessarily compromised. I wish Leaf or Volt were available with such REs.

This isn’t a troll. I own.a 2014 ReX. And, yes, slightly less than 70 mph can be maintained on a FLAT highway. Go up a grade and your speed will plummet like mine did just 2 days ago. I was traveling in southern Oregon just north of Medford and I was on ReX power. The battery went from 5.0% to 1.0% in no time at all and my speed then dropped from 65 (the posted limit) to 40 mph. If you don’t think driving on an interstate at 40 mph isn’t dangerous, try it sometime. Do it a lot and have your next of kin let me know how it worked out for you.

More than serves its purpose. And sure beats those early attempts of LEAF owners pulling generators behind them!

Did that work? Any web-link to what they did?

Do a search for AC propulsion’s range extending trailer. This was in the late 90s if i remember correctly. They used a Kawasaki Ex500 motorcycle engine powering a generator that worked quite well. There was also a gas turbine engine on a trailer hooked to a Leaf by a member of the mynissanleaf forum. It worked quite well and i believe it was Phil (ingineer) who is also Nissan reps even visited a local eaa chapter meeting to check it out. Also, do a search for “pusher trailer”. i remember quite a few being built and even one by jb straubel of Tesla fame.

Thanks. I found many of them. I was always curious why there’s no market, and it seems price is the answer. They cost more than SparkEV! Also, I share some concerns that people will abuse them: use them all the time even if they could use charging, just like free charging is causing abuse.

Oh well. I guess we’re stuck with what we have until Mr. Fusion comes to market.

Yawn. So you can go about 15 mph faster than folks should be going on the highway, if we cared about energy use, anyway.

I know YOU are way too important to drive that slow. But trust me, nobody will notice ten minutes after you reach room temperature. πŸ™‚

I think the speed limit should be 85mph like it is in some parts of texas. A $45k car should be able to keep up with a semi truck

Do you drive your gas car around on empty? No? The. Why would you drive your electric i3 around with a dead battery?

It’s meant for getting you to a charger, not for driving on exclusively. Does a damn fine job of that, I’d say.

If you were to take an extended trip in the i3, it will (nearly) deplete the battery THEN start the engine to keep up with demand. You don’t have to start your trip with a dead battery.

I am more interested in a video with still mountain, is it possible that the Rex didn’t make a specific gradient?

I would like to see that test repeated in mid-winter including driving up a reasonable highway uphill gradient. My main concern with the Rex is in winter the waste heat from the Rex is wasted, so the little Rex generates electricity at say 1/3 thermal efficiency which is then used for heating. To make matters worse, the Rex is fitted where the heat pump is fitted in the BEV, so the Rex seems to have only resistance heating. This is really inefficient, which is contradictory as the i3 is all about efficiency. The Rex sounds cheap too. Meanwhile the frunk is wasted space because it lacks seals. This would all be solved by putting a real BMW flat twin motorcycle engine under the hood, with water-cooling connected to the cabin heater. A choice of power outputs would be nice. I guess it depends on what you are looking for. If you want the most efficient EV that you can charge from your solar PV on a net zero basis, the BMW i3 offers that with sporty performance provided you live in a warm climate. If you commute less than 60 miles a day & can charge at work, or commute… Read more »

I hardly ever drove faster then 100 km/h with my ICE car before, so for somebody like me this is a non issue.

I tested REx up the mountain freeway from Salt Lake City to Park City on I-80. It rapidly slowed down to 35 mph and I barely made the first possible exit. After waiting for a while for the battery to recharge until REx turned off, I followed a loaded semi truck to the next exit. After exit hopping 3 times, I made it to the top, but not without having to stop on the shoulder before the last exit because I was down to 25 mph half way between exits, and even loaded semi truck was going 45-50 mph.

Why test a city car on mountain passes? Do you test motorcycles ability to pick up a new sofa?


Maybe he lives in Salt Lake City or Park City, which are near mountain passes. Wouldn’t you drive your city car on a mountain pass if the city you lived in was located right next to a mountain pass?

A city car like the Smart would be able to make it up a mountain pass at highway speeds. Why should the i3 city car be hobbled by design?

The REx makes 34hp. So, if you intend on using it with a constant load like driving up a mountain, you better make sure 34hp is sufficient. Or, crazy idea, don’t try to climb a mountain with near-dead batteries. You wouldn’t show up at the base of a mountain pass with a half-gallon of fuel in an ICE car, would you? If you know you’re going to be doing lots of mountain pass driving or 85 mph speeds in Texas, then be a responsible person and do some research about the car you’re buying. The are plenty of cars that would be a bad choice for those conditions.

The part of the video I don’t understand is that the car is clearly in ECO PRO mode. In that mode (which is configurable), you’ll get “encouraged” to drop down below the set speed. (I have mine set to 70 mph.) I would love to see the test performed in COMFORT mode. I would also like to see the the SOC percertage displayed while the test is conducted. Finally, the Euro models have additional charge-sustain capabilities that are not available in the US.

I’ll have to do the test sometime, but given that I’m very rarely using gas, it’ll be awhile before I can do this myself.

Why Even bother.with a car like that …,Who cares anyway ,there are other choices & more to come…..Just Forget About It!

You are right! The BMW i5 is due to come out.

Since the i3 REx’s range extender uses a scooter motor — not a car motor — it’s amazing that the car can maintain even 70 MPH on flat ground.

As has been noted in many reports, where the i3 REx really falls on its face is in climbing to a higher altitude, such as driving up a mountain or a long steep hill. It’s not that BMW engineering is inept overall; it’s just that with the i3 REx, they they weren’t even trying to make a fully functional PHEV.

It’s better to think of the i3 REx as BEV with a limp-home range extender, rather than as a car intended to function as both a gasmobile and an EV.

SparkEV uses 16kW to 17kW at 70MPH on flat road in my testing (rough estimate of flat). That translates to 23 horsepower. With 85% efficiency from engine output to battery charging, you need 27HP engine. Make it even 30HP (22.5kW). BMW has 25kW engine, which should be more than enough to push it 70MPH on flat ground.

Ok. I’m a total EV nerd to Nth degree. πŸ˜‰

If Rex starts the engine sooner, such as when battery is 75% or even 50%, they would work fine. Problem is, BMW wants to turn on gas engine only when the battery is much further down.

I thought your 17kw at 70mph sounded low as most cars use 12-15kw to maintain 55mph, so i double checked. A Leaf needs an average of 25kw to maintain 70mph. I can see the i3 or the Spark needing a little less but not that much. It takes alot of energy just to overcome wind resistance at high speeds like 70 mph. So the scooter engine would likely need to be 30kw to maintain 70mph. Here’s a link to the kw consumption at speed and a bunch of other specs for a Leaf. There are also other cars tested including the Spark and i3.

SparkEV shows about 10-11kW at 55MPH (5 mi/kWh). 16-17kW at 70MPH (4.11 mi/kWh). That’s assuming what’s displayed is accurate. 55MPH got me close to 95 miles range on 19kWh battery, so it’s probably close.

I think I know the discrepancy. 70MPH testing was done on short stretch of “flat” road. Typical 70MPH would have hills. Since going up the hill would lose more energy than made up going down, typical driving would need more than flat road. There’s also various wind and big-rig-buffeting to consider.

Original comment was that rex gas engine would have hard time pushing it 70MPH on flat road. I think it can based on my estimates, but it could have hard time on typical driving.

But now I’m curious what 70MPH on SparkEV would take for typical driving.

SparkEV said:

“70MPH testing was done on short stretch of ‘flat’ road. Typical 70MPH would have hills.”

That is highly dependent on where you live. In western Kansas, where my grandparents lived, you’d be very hard pressed to find any hills, even small ones. But here in eastern Kansas, where I live now, you can’t find any long stretch of flat road.

FWIW, someone with an i3 did a bunch of testing and came up with 18.9kW for 70mph on constant mild hills with 3 passengers and mild heat use.

The REx is certainly sufficient for cruising flat-ish ground at 70mph because I’ve done it for 50 miles at a time on multiple occasions. It was holding SOC at ~6%, so I was able to use additional battery power when necessary to pass.

SparkEV said:

“If Rex starts the engine sooner, such as when battery is 75% or even 50%, they would work fine. Problem is, BMW wants to turn on gas engine only when the battery is much further down.”

If I understand correctly what I’ve read, the European version of the i3 REx does have a Mountain/Hold mode, to do the very thing you’re suggesting here. Unfortunately, as with other aspects of the American version of the REx, BMW chose to cripple it so that they could earn more carbon credits.

Bottom line: BMW treated the American version of the i3 REx as a compliance car, and cynically crippled the range extending mode to an astonishing degree to achieve that.

It’s too bad that so much attention gets focused on the crippled American version of the REx version of the i3. Without that optional crippled range extender, the BMW i3 is a highly rated, well engineered BEV.

It must be a magical place where some of you live. My Leaf probably hasn’t seen since 70 mph since i last visited the drag strip. Speed limits where i live are largely 55 mph with a few short sections limited to 65 mph but traffic is usually too heavy to do it. Any anything pulling a trailer whether its an 18 wheeler or my Leaf pulling my jetskies to the lake is limited to 55 mph max anyway. I owned a gas car for a few years (automatic 3cyl metro) that could just barely hit 70 mph. It’s funny that some of you consider the i3 rex at 70 mph a limp home mode. If it can maintain 55 mph, thats perfectly adequate for anywhere i go. Once a year i drive my Leaf to Penn State University (200+ miles away) and the top speed i reach is still only 55 mph. I think a few of you may be exaggerating unless there are magical US autobahns out west.

This may be shocking to you – I hope you’re sitting down – but in most places traffic flows faster than the posted limits. A nation of scofflaws, I tell you!

Regardless, read Ivan’s post above. Try taking that “70mph” i3 up a significant incline and you might find yourself going 25mph. As it slows down, it inexplicably *reduces* engine RPM according to reports. I’m guessing they don’t have enough airflow over the radiator at low speeds.

My Volt needs to go 70 – 90 mph on a daily basis just to keep up with highway traffic here in NC. Maybe it has to do with living too close to the birthplace of NASCAR.

You would hate South Jersey and Philly. A hopped up Nev (35 mph?) would most likely not slow down my commute. It takes me an hour or more to go about 27 miles at the times i goto work and come home. Lifetime average in my Leaf over 80,000 miles is not quite 30mph.
Be careful speeding in NC though, i got pulled over on my motorcycle on the way to Myrtle Beach, SC going 86 in a 70 and i had to post $200 bail on the spot at the local barracks before the statey would let me go. Im just glad they didnt tow my bike. Did have to drive down a month later for mandatory court appearance though. Got half of my $200 back, but had to then wait for them to mail me a check. Learned my lesson about speeding through North Carolina on Rt 95 though.

HA! I lived in Myrtle Beach for about 6 years and they do hate motorcycles… They even imposed a helmet law that was struck down by the Supreme Court because there is no helmet law in SC. Someone allegedly saw my 2005 Pontiac GTO doing 150 mph on HWY 31 once… Allegedly…

I agree there is a bit of exaggeration here. I have drive. My i3 80mph and with the narrow tires and short wheel base it felt okay- but not sure footed as my old 3 series coupe. In NM our top speed is 75mph, but everyone drives 10 mph faster. My i3 is only used for urban driving.

Ken, there are magical US autobahns out west.

I didn’t call the i3 REx in range extender mode a “limp home” mode because it has a top speed of 70 MPH. I called it a “limp home” mode because of the ridiculously tiny gas tank (made even worse by BMW artificially limiting how much of the fuel can be used!), and because when climbing a long hill or a mountain, its speed falls so low that it becomes unsafe to drive.

Yep, it’s a BEV with a gas generator meant to save you from running out of charge. It’s not a Volt.

The thing that would be important where I live is what is the maximum speed with the Resistance heater on ‘HIGH’?

For some reason no one ever checks that.

The comment under the photo reads:
110 km/w or 68.4 mph
Should this not be 110km/h ??

That would be incredibly efficient if it was 110km/w. Even the i-MiEV would have 1.76 million km range on a single charge. πŸ˜‰

The 25 kW would be much better for climbing hills if the engine was used at full power. It isn’t. This is maybe the biggest design flaw of i3.

The range extender operation is designed so that it doesn’t run at high rpm at low speed, because high rpm engine noise would be annoying at low speeds. This is completely OK on flat ground as you don’t need much power at low speed, but uphill is different. When you are running out of power in uphill you start losing speed and therefore the ICE rpm, and thus power, starts to drop. This will reduce your speed even more, which will reduce the rpm even more. Right when you would desperately need all 25 kW capacity.

So next time you are crawling uphill, desperately trying to get some speed and scared of getting rear-ended, remember that your i3 is doing this for you so that you wouldn’t get annoyed by engine noise.

The very least they should do is add inclination sensor and disable rpm reduction in uphill.

Or they reduce power/RPM due to reduced cooling. Less speed = less airflow.

Could be, but there is a topic on BMW i3 forum where actual BMW engine document is referred, and it says it’s for noise reasons (I haven’t seen the engine document).

You can check out the topic. There is interesting information and a chart copied from engine document (on page 3 of the discussion):

The chart is titled “W20 engine, acoustics and range strategy”

I understand the principles of insideevs to publish any news about EV. But if it was a guy that drove his car in incoming traffic and resulted in a accident and just happen to drive an electric car?

If you published that as news about EV, I assume you would put a warning saying the guy is stupid and don’t try this with your car.

Well this is the same here, this is stupid. I have driven over 1000 miles on the REX, guess what, no restriction, no reduce power. No I didn’t code my i3, because I want to maximize my EV miles.

The REX gets you to your destination, with a proper DCFC network, you can drive what ever speed you like and get to the next DCFC.

But, hey, it seems you like to be scared of being scared and it creates clicks to your site.

Put the warning “This is not a normal use, we don’t recommend speeding in any car”.

What makes you think that the driver was speeding?

154Km/h, 95mph: that’s illegal in most country/state.

I have driven that speed twice in 30 years of driving (I was young and stupid), I did it only for a very short distance (it was still stupid to do so). And anyone saying this is a safe speed on public road need their brain to be check. It’s not. Even if you assume (and that’s a big if) you are a good driver, most people around you aren’t.

Even worse, he is doing that while holding his phone… He may as drive his car drunk.

The Average speed driven on the major freeways around where I live (when traffic is not backed up) is around 85MPH. The Legal Speed Limit is frequently 75MPH once you are away from the cities.

95MPH Is hardly an insane or even dangerous speed.

Whats your problem?? This part of the german autobahn was without speed limit and there was somewhat cars. I can daily drive far over 95 mph, this is NOT dangerous!!!

Of course it was only one test. What happend. Also it was a rental car ;-)) I’m attired in.

This is on the German Autobahn so very likely he isn’t speeding as there are sections that do not have speed limits.

I would like to see the i3 REx climbing the Rockies or Sierra Nevada without battery buffer.

Then we will understand how unsafe that US version of the i3 REx is.

Or maybe all you’ll see is a person who is using the wrong tool for the job. What kind of idiot would try to climb the Rockies with only a 34hp engine and a 1.9 gallon gas tank. It would be like showing up to Mt Everest wearing just a windbreaker and then blaming the windbreaker for not being a parka.