BMW i3: 462-Mile REx Road Trip From New Jersey to Vermont


We stopped at the Big Moose Deli in New York for some coffee. It's about ten miles from the Vermont border.

We stopped at the Big Moose Deli in New York for some coffee. It’s about ten miles from the Vermont border.

462 Mile REx Road Trip: New Jersey to Vermont

Perhaps the most discussed topic of the BMW i3 is the implementation of the range extender for the North American market. In an effort to have the vehicle qualify for the California Air Resource Board BMW set restrictions on how and when the range extender can turn on, effectively reducing the utility of the REx. These restrictions are most apparent when attempting to use the car for long journeys which include drastic increases in elevation.

Recently it was announced that BMW is working on a software update that will allow, under certain conditions, the range extender to come on much earlier than the 6.5% threshold it currently uses. I am actually beta testing that software for BMW now, having had it installed on my i3 just last week. The new software also includes some other updates that will be standard on 2015 i3s and will be uploaded to current i3 owners sometime early next year.

Road Trip Time

Road Trip Time

However, this post will detail a New Jersey to Vermont road trip that I took a few weeks ago, just before I had the new software update. My in-laws live in Vermont, and I had been wanting to take this trip with the i3 ever since I got it, but I just haven’t had the time. Once I knew I would be getting the new i3 software which would be adjusting how the range extender would work, I knew I needed to make the journey before I had it done, so I could perhaps compare the difference in performance the next time I go.

*Editor’s Note: This post appears on Tom’s “The Electric BMW i3” blog.  Check it out here.

The Active Cruise Control is awesome. I don't think I'll buy another car that doesn't have it.

The Active Cruise Control is awesome. I don’t think I’ll buy another car that doesn’t have it.

I have taken the car on a few 200+ mile round trips, having the ability to charge up before heading home, but this would be much further, about 250 miles there and about 210 miles back home. The trip there would be longer because we were meeting at a restaurant farther into Vermont before heading back to the house. A couple of years ago I installed a Clipper Creek CS-40 at my in-law’s house, knowing that the day would eventually come when I drove an EV there, but I had never used it until now. My previous EVs (MINI-E and ActiveE) would have just been too much of a hassle to try to make this long of a trip, but the range extender is perfect for an occasional trip like this – or at least I hoped it would be.

Most of the roads in Vermont were covered in ice and snow. My new Blizzak snow tires performed very well and I definitely recommend them for i3 owners who need to drive in the snow.

Most of the roads in Vermont were covered in ice and snow. My new Blizzak snow tires performed very well and I definitely recommend them for i3 owners who need to drive in the snow.

The truth is, I really didn’t know if such a long trip at highway speeds, which would include an overall elevation gain of nearly 1,000 feet would be doable without the car going into the dreaded reduced-power mode, where the vehicle slows down for a while so the REx can replenish the battery a bit. Also, in the final 50 miles of the journey I needed to climb 500 feet before ascending 500 feet and then climb about 700 feet to our destination.

My wife and I set out early on a brisk morning with the temperature being only 15 degrees when we left. I didn’t precondition the battery or cabin, and the total weight we were carrying was about 450 lbs between me, my wife and the items we were bringing up to her parents’. I topped off the gas tank the night before and left fully charged. The trip is nearly all highway and my plan was to set the cruise control for varying speeds between 70 mph and 75 mph to see how fast we could go with the REx maintaining the state of charge. I would drive the whole way there in Comfort mode and possibly use Eco Pro for the return trip.

A few blocks from our destination we came across some cows.

A few blocks from our destination we came across some cows.

The combination of the very low temperatures, using the heated seats, cabin heat and driving 75 mph meant the range extender turned on after only 48 miles. That’s the earliest I had ever seen it turn on before. I had barely made it to the New York State border and I was already running on gas. So now I had a little over 200 miles to go and it would be all done on the range extender. I figured I’d need to stop three times so we searched the GPS for gas stations that were directly along the route and at the intervals we needed. I wanted to stop when we had about 10 miles of range left and we were able to pretty much get close to that on all three stops.

I needed to stop three times to fill up on the way there.

I needed to stop three times to fill up on the way there.

We made the first stop right about at the 100 mile mark which was about two hours into the journey. My wife laughed at how quickly the tiny gas tank filled up and we came up with the idea that she would time me on future stops to see how long it took to fill up. She would use the stopwatch app on her phone and we would start it when we exited the highway and stop it when we were back on the highway to see just how long the diversion was. We averaged a little over 2 minutes per stop and the best time was one minute, forty eight seconds. All three stops added a total of about seven minutes to the trip – not exactly much of an inconvenience.

The car looked like I was off-roading all day when we arrived. I finally got to test out the EVSE I installed at my in-law's house over two years ago. Thankfully it worked.

The car looked like I was off-roading all day when we arrived. I finally got to test out the EVSE I installed at my in-law’s house over two years ago. Thankfully it worked.

For most of the trip I had the Active Cruise Control set to 70 mph, but I also spent some time with it set to 73 mph and 75 mph. As I expected, 70 mph seemed to be the sweet spot for holding the SOC. Even with inclines that lasted for a mile or two the car never went into reduced power mode. When I set it to the higher speeds it could maintain the SOC on flat ground, but the inclines had the SOC bar graph getting dangerously close to completely evaporating so I kept it at 70 whenever I was going up any kind of hill. One thing I can say, the Active Cruise Control really rocks for long drives like this. It holds the speed, slows down when the vehicle ahead reduces its speed and maintains a nice safe distance. I used it for virtually the entire trip and it is definitely worth the cost if you do a lot of highway driving.

We arrived after nearly 255 miles. About 207 of those miles was done using the range extender.

We arrived after nearly 255 miles. About 207 of those miles was done using the range extender.

So, we made it without ever going into reduced power mode. I guess there is no need to do a comparison trip with the new software since this trip went flawlessly. The only thing I can think of doing is possibly trying the same trip with the ACC set to 75 mph the whole way to see if the new higher REx buffer allows me to maintain the faster speed. As it is now though, 70 mph is definitely the magic number for long distance REx driving. If most of the trip is on relatively flat terrain, the SOC buffer is big enough for sudden bursts of speed for passing and to sustain climbs for a few minutes and a couple of miles. Even though it worked out fine for me, I’m happy that BMW is increasing the battery buffer so longer, sustained mountain climbing will be possible without going into reduced power. I haven’t had enough time with the new software to really comment on how well it works yet but I’ll do that soon.

The final stats for the trip

The final stats for the trip

The trip home the next day was pretty uneventful. I did precondition this time and drove the first half of the way in Eco Pro mode. It was also about ten degrees warmer. All that combined to allow us to go 15 more miles on battery than we had the day before, giving us a total of 63 miles before the range extender turned on. We arrived home with 462 miles on the trip odometer and an average consumption of 3.4 miles per kWh. I filled up with gas about 1.5 miles from my house so we left and arrived with a full tank. Including the final stop to top off we made seven stops for gas (3 going and 4 returning) and bought a total of 9.87 gallons of gas. We drove 111 miles on battery and 351 miles with the range extender running and averaged 35.5 miles per gallon. That’s a little less than what I usually average for the REx, but this was a continuous 70 mph for the vast majority of both legs of the trip so I expected it to be lower than usual. If we had taken our other family car like we usually do for our Vermont trips, we would have needed 19 or 20 gallons of gas or about double what the i3 needed.

Getting ready to leave for the return trip back to NJ

Getting ready to leave for the return trip back to NJ

In conclusion, these kinds of journeys are definitely not what the i3 REx was really developed for. The tiny 650cc motorcycle engine isn’t really engineered to operate for hundreds of miles at a time and I’m sure if it was subjected to this kind of use every week it would certainly have premature mechanical issues. However using it as I do, for the occasional 10 or 20 miles here and there, or the final 3 miles on some days just to make it home plus a road trip every month or two, it’s really a great alternative to spending an additional $20,000 for a battery that’s triple the size of the i3’s. The range extender model is a good stop-gap measure until there is a decent DC fast charge infrastructure in place, which is really the ultimate goal. BMW has some very good news with regards to DC fast charge infrastructure that they will be announcing very soon, perhaps even at NAIAS in January. They are making a significant investment in this area and I believe the EV faithful will be very happy when the news is announced.

Of course we had to return with some genuine Vermont Maple Syrup. The Maple-Walnut PB was a bonus.

Of course we had to return with some genuine Vermont Maple Syrup. The Maple-Walnut PB was a bonus.

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57 Comments on "BMW i3: 462-Mile REx Road Trip From New Jersey to Vermont"

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Meanwhile, a Volt would have made the entire 462 mile trip with 1 gas station stop total…even if the battery was drained from the start.

I don’t think so. The Volt only holds 9 gallons of gas. Even at 40 mpg running it completely dry, you could only expect to go 372 miles.

if you know that you are going on the road, you would of course start with a full tank. under those conditions, it is a true statement that you would have to make only one stop in a Volt. but as tom mentioned, the i3 is not suited for this kind of trip where the Volt is. it’s a difference of philosophy: the i3 was designed for metropolitan area driving where the Volt is designed to provide the kind of flexibility and driving freedom that people have come to expect in ICE vehicles.

It took them 2 minutes to fill the tank. I would have taken longer than that to pick up my drink and snack in the convenient store part of that gas station! Not bad.

It’s funny. I don’t know how the heck other people do it, because I needed to empty my bladder more often than I had to recharge my Leaf on my last road trip (I’d have to admit that I haven’t done a lot of them yet). Maybe I’m different, but these little breaks need to be constructive for *something*.

And maybe people need to think of the stops necessary for quick charging not as inconveniences.

Adding up the filling time was a quaint way of looking at it, but really the energy that adds up is mental. As noted, with battery depleted, the intervals and importance of hitting them just right (10mi remaining), become what I would guess is no small PIA.

It may be flawlessly possible, but BMW has got to appreciate the piece of mind they’ll be giving drivers with an engine over-ride, at >6%. It will mean much less planning stress, to chose where you want to fill the “tank” three times, rather than where you have to do it.

The i3 is a nice vehicle, however, the RE size and the fuel tank size could be better.

I’m fine with the small size of the RE engine. A bigger gas tank would be nice though. And it would be nice if it were cheaper. $4K seems a lot to pay for a 2-cylinder motorcycle engine.

I agree.


Since you can’t pump your own gas in NJ, what is the reaction of gas station attendants when you tell them to fill up your empty gas tank and they can’t even put two gallons in?

Doesn’t seem to matter how many of these stories come out, the i3 haters will continue to say the Rex is a limp-home mode that can only go 45 mph on flat ground.

I tested one of these for 3 days. On the last day I tested the Rex quite a bit and found it to be very capable for freeway driving. I wouldn’t hesitate to take a road trip in an i3 Rex.

I made a trip which required the range extender for the last 50 miles and I noticed no difference when in range extender mode. This was all freeway driving at 75 mph.

Hey David, Merry Christmas to you! Am I an “i3 hater”, or non-biased, i3 observer when I note that 7 trips to the gas station to fill up is pretty nonsensical for a 450-ish mile drive? Come on, man! This and other articles show one thing – it can be done. Is it recommended, no sir. 500ft. elevation gain sounds great in Vermont. What about my state where mountains rise over 14,000ft from sea level? Or how about Colorado, Montana or Idaho, to name a few? Tom’s articles are interesting to be sure, but we must remember that car sells in the ballpark of mid-forty thousand, before tax, license and dealer prep! They also always seem to be great Volt advertisements, and only will get moreso as 2016 Volt rolls out with more EV range. I must add positives here in order to allay all those who claim I hate BMW, Germany or Bavarians in general – 🙂 . Tom, I think your custom wrap cures that strange two-tone, modern art paint scheme i3s have. The front and rear of your i3 look much better than stock, I must admit. So either spend more on your i3, or buy a… Read more »

Again, I’m not trying to say the i3 Rex is designed for this type of scenario. But the point is with the Rex it virtually eliminates range anxiety and the need to locate a working charging station when doing business around town. And people continue to post comments that the Rex can’t drive the car on the highway, when obviously this is not the case.

On the other hand, if you were to remove the range extender and instead add $3,800 worth of extra batteries, you still wouldn’t be able to make those out of town trips under current infrastructure conditions. With the current Rex you CAN.

The point is that the $3,800 option completely changes the versatility of this car and the sales figures seem to bear that out as it would seem most buyers opt for the Rex.

I think the point is that if BMW didn’t decide to play the BEVx game, they could have made this a much more practical car (simply by having a larger tank).

And while offering a REx is a good thing, and people do chose having a REx over one without, it shows nothing about how the REx would fare versus a i3 with a larger battery, because BMW DIDN’T offer one. That’s something that shouldn’t be applauded.

Even Tom says if he was offered a larger battery option, he would have gotten it rather than the REx.

Hmm. Good point. However, after much consideration I think if I had 80-ish miles to start with and I had an option to spend an extra $3,800 on either a larger battery or the Rex. I think I’d still pick the Rex. Now, if the charging infrastructure were there (especially DC fast charge) then I’d possibly reconsider. But it will be years before that is the case.

Tom, thanks for a great post!

Indeed it is good news, esp. for BMW aficionados who are used to go at high speeds, that you can cruise at 70MPH on the range extender, rather than the 50-60MPH needed for long-distance highway hypermiling with affordable BEVs.

That said, note that your description of your typical use:

“However using it as I do, for the occasional 10 or 20 miles here and there, or the final 3 miles on some days just to make it home…”

…means that with a Kia Soul EV and possibly also with a 2014-5 Leaf of the right trim and careful driving, you would be able to squeeze out those 3-20 extra miles without needing gas at all. Surely saving enough money (and gas) over several months, to justify renting a fuel-efficient ICE for that 460-mile winter trip 😉

Happy holidays, Assaf

35.5 mpg at 70 mph is really good for a serial range extender. BMW engineers did well.

Tom, I am curious if the new software with larger buffer will improve gas mileage in some circumstances, because it might be more able to shut off the REx in stop-start driving.

It’ll be interesting to see if they forgo the CARB BEVx credits for this update, or pushed for another change to the rules while keeping the credits.

As always, great write up by Tom. I going to Florida with my Ford Fusion Energi tomorrow. I predict just one stop at a gas station. I drove this car for 600 miles on one tank. Looking forward.

When they make the software change, how much money in terms of CARB/ZEV credits will BMW lose in exchange for making the car run better in Rex mode?…. 5 million per year? 1 million?

I don’t think CARB dictates BMW’s choices in other states. Within the ZEV-MOU, the “EV” classifications for state credits, for instance, are already different. Volt gets full credit in MA (2,500) vs. $1,500, in CA. Prius PIP, and other <10kwh cars get cut back on their rebate checks.

It wouldn't surprise me if CA were stuck with 6% mode. Tom probably knows the skinny on BMW's intentions, and we'll have to wait a month, or so.

Kinda surprised that New Jersey had no problems issuing that license plate. A lot of states have cracked down on any plates with vulgarity.

But then again . . . it is Jersey. 😉

Not everyone is as tuned-in to acronyms and the oil industry as we are. Surely the government employee tapping computer keys at the licensing dept. just thought Tom’s surname or business was called, E.F. OPEC!

🙂 – More likely scenario.

If you have a fifteen minute break and you want a laugh, just Bing or Google (image) , “funny license plates”. You’ll see a lot more ribald or iffy plates get passed licensing departments that you may think.

There’s even a website dedicated to the subject called

Correction: Discovered it’s:

Now imagine the possibilities if BMW made it a 5 gallon tank.

Also imagine the possibilities if Tom had not driven the trip at speeds known to be very wasteful of energy. 70-75 is one sigma to the right of V(max range). I’m not suggesting he do it at 55mph, but I wonder how many gas stops could be eliminated by driving at 65. I totally agree with James that 7 stops and 35mpg is pretty sad. Tom, I enjoy your write ups, but you are beginning to sound a bit like a shill for BMW. Especially considering your recent vehicle history, beta testing relationship etc. And I am quite tired of all the sly disparaging jabs at Tesla in the form of comments about “lugging around” a bigger battery, considering that said battery would have enabled this trip to be non-stop, and enables the car to have far better performance than an i3 DESPITE its size, weight, etc. You can make exactly the same argument about all the soccer moms et al in Amercia “lugging around” all that extra mass, seats, and engine of their giant SUVs, when really all they need is a Vespa. And hey, they can just rent a car for that occasional longer trip, right? But no… Read more »

I don’t have a problem with “lugging around an extra battery” since I’m lugging around an ICE that I rarely use in my Volt. However, what I would have a problem with is paying tens of thousands of dollars for an extra large battery to carry around that I don’t really need on an extra basis. Especially when I can lug around a $3,800 range extender.

I’ll be very curious to see how many large battery detractors still choose to buy a tiny battery Leaf etc. under the “rarely need a big battery” argument when the 200-300 mile battery becomes very affordable. I think it’s really about the money, not how often you need the greater capacity of the big battery.

I’d like to point out also “lugging extra battery” and “lugging an ICE” are false equivalencies. In the latter situation, the ICE serves absolutely no use while the car is in EV mode.

In the former situation, the extra battery still serves very significant uses:
1) It allows proportionally greater absolute charge and discharge speeds (measured in kW). That’s why Tesla is class leading in both charge and discharge power.
2) It reduces stress on the battery because of the above (average power demand in terms of C-rate is lower) and also because the battery sees less cycles per mile.
3) It allows the users to use a narrower SOC window for daily driving, which further reduces wear on the battery.

So “extra” capacity in a large pack is not just extra useless weight when “unused”, unlike an ICE.

…. and no one is discussing that in the cold weather – the larger battery size gives more EV miles.

A 60kwh Model S would need a charge along the way on this trip – both ways. An 85kwh would have needed a charge on the 250 mile leg at these temperatures.

As a person with a Tesla and a Volt, I would make this trip in the Volt. (Until there is a Supercharger route :)) The SC is perfectly timed for my bathroom/rest stop wait.

Interesting point about the duty cycle for the REX – are their guidelines on how much you can use your REX before having to worry about an early grave?

Funny reading EFOPEC and your filling your car up with gas LOL

no hate, just funny, but not the best plate for the car since it still uses gas!

Indeed, I’m with Tom on the fact we all have many varying needs and it’s a positive that at this time and point in history we do have multiple options on eliminating and/or saving a lot of money on gas by purchasing a much more efficient means of transport. The “bridge” cars like Volt, C-Max and Fusion Energis give us varying degrees of freedom from the pump ( and OPEC, and Oil Barons, and fracking..and… ), yet meld this with the convenience we’ve all grown up with and become accustomed to. BEV adopters who press this long-distance point via web documentation only show that it’s still an adventure and early on in hoping for a seamless EV infrastructure of any kind. They do show it can be done, while also showing it’s not for the faint of heart or average of will. Taking a 60-90 mile BEV on a long trip is possible, and so is taking the same trip on a bicycle. I’m not sure what the point is they are trying to stress. One thing becomes evident – it still is a struggle to plan ahead, find an available working charger, and we cannot make most trips over… Read more »

Thanks for the write up and all of your pioneering with the i3. Every new model needs people like you to test and be vocal about your findings.

Don’t sweat the ICE fuel economy. 35mpg is pretty good considering your speed, snow tires and winter conditions. All vehicles suffer in cold weather and snow tires make it worse. I’m a Volt owner and even I can see the value in your testing.

With all the issues related to this car ( BMW i3 Rex), I am amazed by how well it is selling. The sales numbers are the only part that’s not funny.

I wish Nissan would make a pure series hybrid like the i3. I can’t afford a BMW, but I could afford something from Nissan. The Volt is not a bad option, but it burns gas unnecessarily in the winter. Without a temperature sensor mod, I would be burning gas 95% of my commute.

Good fun, Tom, Thanks.
I’m guessing that one detractor missed the ‘BMWBlog’ reference, or your mention of being involved in Both E-Car offerings prior to this. BMW Fan is a tad different than ‘shill’, congrats on your ongoing patience.
God forbid that said detractor ever gives the appearance of ‘Fan’ for Their particular device.. the reaction to their ‘fandom’ might be harsh.

I now understand why you had chosen Not to ‘mend’ the firmware for SOC, nice job of tactful NDA skirting, LOL.

Giving us very high hopes regarding the charging plans. Merry Christmas indeed!

Phr3d, I think you may have misinterpreted my post a little. Or I misunderwtand yours. It is precisely BECAUSE of Tom’s involvement with the other E cars, and his involvement on the blog, and now his invitation to beta test new software for BMW that I am implying that he may no longer deserve “unbiased third party reviewer” status. Exactly what Nameless says below. I like BMW too, but Tom’s involvement goes a few few steps farther than “happy customer”.

And what am I a detrator of, exactly? Ineffective products? Bad engineering decisions? Decisions based on one state’s politics (CARB)? Cars with ineffectively small batteries (and/or missing or poor Rex)? Ok. Guilty as charged. My bad. I’ll get behind any car that does the job well, and right. In 2011 that was the Volt. I’m on my second one. In 2014 it’s the Model S. But I cant afford it.

Hardly an unbiased report as the writer frequently receives “perks” from the manufacturer.

A shill, also called a Plant or a Stooge, is a person who publicly helps a person or organization without disclosing that they have a close relationship with the person or organization.

IMHO, shill is an offensive term to a writer.

As one person who comments here has already chased away (at least) one article contributor, I would hate to have Tom stop being cross-posted here because he is happy with his i3 but must be biased, and therefore unworthy of offering his experience and opinion. (and patience)

Welcome to the jungle. This is a public place, and this is a free country, buddy.