Here’s How Long It Takes To Refuel The BMW i3 REx – (w/video)


I know many readers here have spent countless sleepless nights pondering the the age-old question: How long does it take to refuel a BMW i3’s tiny gas tank?

Well maybe not, but I have had people argue that driving the i3 REx on an extended trip would be very inconvenient because they would have to stop to fill up the gas tank every 50-60 miles. I’ve done quite a few road trips with my i3 REx, and stopping once an hour for a couple of minutes to refill the tank never really bothered me much.

I wrote a post last year which detailed a 462 mile round trip I made to Vermont from my home in New Jersey and refueling was one of the topics that many people commented on. On that trip, I had to stop for gas a total of seven times, as I only recharged the car once, which was at my destination. I drove 111 miles on battery, 351 miles on the range extender and used a total of 9.87 gallons of gas, averaging 35.5 mpg.

Image Credit: Tom Moloughney

It was snowing in Vermont when we arrived- Image Credit: Tom Moloughney

In that post, I wrote that I found it funny how quickly the gas tank fills because it’s only 1.9 gallons. My wife started timing how long it took to stop for gas and we averaged a little over two minutes. I remember wishing we had recorded one of the gas breaks so we could demonstrate just how quick you can pull off the highway, fill up, get back into the car and back out onto the highway. I made a note that the next time we drove back up to Vermont, we would do just that.

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

So last week we made the Vermont trip again, and as planned we recorded one of the gas stops:

As you can see, I started the stopwatch before we exited the highway, and stopped it when we were back on the highway. I didn’t jump out of the car and rush like a NASCAR pit crew filling up. I took my time and even spent a couple extra second topping off so I’d get every drop that I could into that tiny tank and we still did it in under two minutes.

The point of the exercise was to demonstrate that it’s really not that inconvenient to make a quick gas break about once every every hour. I will qualify that statement with the fact that here in the Northeast there are gas stations everywhere. It seems that I’m never more than a couple miles from one, so when I’m doing these long drives I can plan the stops at convenient intervals when the tank is nearly empty. While that is the case for many large city and suburban areas throughout the country, there are plenty of rural areas where gas stations aren’t as prevalent, and the small gas tank would be a problem. The i3 REx most likely isn’t well suited for use in those areas. But hey, BMW calls it a “city car” after all.

Trips Figures - Image Credit: Tom Moloughney

Trips Figures – Image Credit: Tom Moloughney

As I mentioned above, when I made the trip last year I only did 111 miles on battery and drove 351 on the REx. This year I was able to drive 270 miles on battery, and needed only 184 miles with the range extender maintaining the battery state of charge. This was possible because of the always improving charging infrastructure.

I was able to stop twice (once each way) at Prestige BMW in Mahwah, NJ and use their new DC fast chargers. Also, on the way home I stopped for a couple hours at a friend’s house who just recently installed a 240v level 2 EVSE in his garage. These stops allowed me to more than double the all-electric miles for the trip, and I only needed 4.9 gallons of gas for the 184 miles I drove with the range extender running, as I averaged 37.5 mpg.

I used the recently installed DC Fast Charger at Prestige BMW on both legs of the trip. - Image Credit: Tom Moloughney

I used the recently installed DC Fast Charger at Prestige BMW on both legs of the trip. – Image Credit: Tom Moloughney

I now have over 36,000 miles on my i3 after seventeen months of ownership, and only about 1,750 of those miles were on the REx. The range extender has been a great feature and I’m still very happy I got it. It does what it is supposed to; it gets you home without worrying about finding a charging station on the rare days that the electric range isn’t enough, and it enables the occasional long road trip.

There are limitations though, and extreme hill climbing while the REx is running for prolonged periods at highway speeds, can result in reduced power. Fortunately I’ve never had that happen to me but I don’t really have any big mountains which I need to climb. On my Vermont trips I set the Active Cruise Control to 70 mph and have never had an issue yet, even though there are some prolonged climbs at the end of the trip.

I did get the “Reduced Power Possible” warning once though, as the state of charge hit a low point of 2% once. However it held there until I crested the climb and once I was on flat ground the SOC climbed back up to about 6%. I left the cruise at 70 mph because I actually wanted to see at what point it would go into reduced power mode, but it never happened.

On one climb, I was able to get the SOC down to 2% and at that point the car warns you that reduced power may occur if you continue without altering your driving. Basically it's saying "Slow Down!" - Image Creidt: Tom Moloughney

On one climb, I was able to get the SOC down to 2% and at that point the car warns you that reduced power may occur if you continue without altering your driving. Basically it’s saying “Slow Down!” – Image Credit: Tom Moloughney

Still, in a perfect world I’d prefer a 150 mile, all-electric-range i3 combined with adequate DC fast charge infrastructure. Personally, I really don’t need 250 or 300 miles of range, and I’d rather not pay for it. However, even though the infrastructure is improving, I think 200 miles of range is probably more acceptable until DC fast chargers are ubiquitous.

It appears with Nissan and Chevy poised to bring 200 mile EVs to market in the coming year, the “affordable” electric vehicle market is going to get very interesting. BMW’s CEO recently announced that the 2017 i3 will have a longer all electric range also, but didn’t comment on exactly how much more. That’s good news because as much as I like how the REx works, and how quickly I can refill the gas tank, I’d still much prefer going on battery alone.

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44 Comments on "Here’s How Long It Takes To Refuel The BMW i3 REx – (w/video)"

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The real inconvenience is the little power, a hold battery power button would be more helpful, than a 20 gallon tank.

I’m surprised Tom hasn’t done the “hack” to enable the European modes and allow for a “hold” mode.

I think he has, he just doesn’t want to admit it 😉

Even if it wasn’t needed I would itch to unleash the full potential of the car as it was designed especially since the incremental cost and risk of doing it is very little.

Thanks Tom for the very informative post about the rex. I would say it works exactly as BMW intended and allows a much longer trip than would normally be possible without long charge stops.

Great video. I love the i3 and if it were more affordable, I’d probably have one. Of course I wouldn’t even bother to buy one without the Rex. After owning both a Leaf and Volt, I can say that here in Texas the charging infrastructure is just not there. And the infrastructure is not growing. If anything, it is shrinking. Many stations are now broken and never repaired, or eternally in a state of ICE’d.

So.. At this point I will not likely buy another all electric vehicle, regardless of how much battery range it is, because there aren’t enough places to reliably recharge it. PHEV is definitely the way to go at this stage. I love that the i3 has fast charging AND a range extender, making it one of the most versatile EVs available.

I think a 200 mile EPA range breaks a psychological barrier for most consumers. You also have to account for lower miles in cold weather.

Thanks for the writeup, Tom.

I drove my CMax into Vermont in September, and enjoyed a free L2 boost in Middlebury. I walked around the town while charging, and grabbed some lunch. They have a dual-headed CHAdeMO/CCS charger there. I’m seeing more and more CCS chargers pop up in VT. Does your travel take you near any of them? If so, maybe you could let us know of your experience quick charging “in the wild” (i.e. truly public locations, not just BMW headquarters).

i have a chevrolet volt, which has, in my view, a minimum sized gas tank. there is a certain degree of “to each his own” when it comes to matter of opinion, but if i had to stop *every* hour for gasoline, that would get real old, real fast.

And that is one of the differences between a regular PHEV and a range extended EV.

There’s no reason an EREV couldn’t have a larger gas tank. BMW chose a small gas tank to attempt to skate past California’s EV mandates.

It seems to me that BMW chose a tiny gas tank to keep size, cost, and weight down on the i3, as evidenced by the still tiny tank used in Europe. They just made it a little tinier for California’s stupid rules.

If somebody does trips like this regularly, they could hack the ECU to use the full gas tank, instead of just the 1.9 gallons the computer limits you to in the US market. That would keep you on the road for another 15-20 minutes maybe?

It’s great that this driver is so happy with his BMW i3 REx that he’s willing to put up with stopping to fill the tank* seven times (!) in a 462 mile round trip. But somehow I think the average driver is not gonna be convinced that this isn’t a significant inconvenience. My most frequent long distance trip has been from Kansas City to western Kansas, about 350 miles one way. Along that path, there is exactly one (1) of those “service islands” that you see in this video. They’re much more common in the Eastern USA, so perhaps the driver was able to stop at one of those each of the seven times he stopped for gas? At any rate, my point is that you couldn’t count on such a very brief stop in many places. He’s cherry-picked a place where stopping for gas can be done far more quickly than usual. And aside from that… it’s a good thing the road was nice and flat on that portion of his journey. Otherwise, the very limited ability of the i3 REx to climb hills, powered by only its gasoline scooter motor (yes, not an actual automobile motor), would have… Read more »

+ 100

Typical early adopter praise. It isn’t 2 mins to refuel. You’re on a road trip, you need to find a gas station, exit, pullup, run credit card, zip code, etc.

Any Honda Civic can outperform the i3 REX on that very same road trip – in terms of speed, driving experience, passenger and cargo capacity, fuel range etc.

Same goes for those jokers that take the LEAF here and there and submit pictures of charging with L1 or L2. I’m an early adopter too but I know my BEV’s limitations.

I can cut wood with a file but why do that when I have a power saw?

Everyone knows the i3 isn’t a road warrior. It’s limitations are well-documented. The point of this article is that long-distance travel is doable without extreme inconvenience. This shows people that will use the i3 within the AER 99% of the time that they can use the i3 for the other 1% of their driving if necessary.

Sure, a Civic would be better for that 1% of driving, but its silly to buy a car that you don’t really want for just 1% of your driving. That’s why people end up buying F-150s when a Golf would be better in every way for their needs. What if they have to buy a sheet of plywood sometime in the next 5 years?! Rent a truck for an hour from Home Depot for $19.95. Similarly, drive the i3 as a great city car for 99%+ of your driving and either stop a few more times for gas on your yearly road trip, or RENT a Civic for a few days if an hour of additional driving time is that important.

Exactly my point!
Keep on cutting wood with your file. The end result is still the same.

I’ll stick with my power saw, thank you.

The engine is based on an engine used in motorcycles and scooters, but it has been modified so much that it’s not the same scooter engine.

What would you call a motor that is designed to be used in a car, and is not used in anything else but a car? I would call it a car engine.

Something got my attention here.
If filling 1.5 gallons took you 1.57 min, then the 5 minute fill up time claim by anti EV for regular 10 to 25 gallons tank are way too low.

Just saying.

you have to fill a small tank more slowly because the if you fill the tank too quickly, the nozzle will detect fumes and shut off.

Just saying… without thinking or watching the video. 😛

It took 2 minutes from leaving the highway until he was back on the highway. It was not the time it took to just pump in the gas.

Pumping in the gas for a regular tank takes about 1½ minute. So 3 minutes in total from exiting highway to entering it again should be easily doable for a normal size gas tank.

I’ve never spent as much as 5 minutes for a fill up.

Show us!
I’ll bet you’re off by many minutes.

Thanks Tom for the write-up. Interesting to hear. But wouldn’t come close to working for me. We drive from Phoenix to LA to see family many times a year. It’s 450 miles one way, and across the desert it is often 50-100 miles between where fuel is available (gas that is, forget electricity). I’m looking forward to getting the 2016 Volt soon, which will work much better for us – but thanks again for your writeup.

I timed a fill in my Forester once, although I knew that retail gas dispensers are limited by regulation to a max. of 10/gal./min. From the start of fill to auto-shutoff, I put in 13.91 gallons in 1’28”, or just under 9.5 gal./min. I normally top the tank on long trips, until the fuel is pooling in the nozzle cup and no more than can be added, which typically takes another couple of minutes.

So, while frequent fills on Tom’s very occasional inter-regional trips aren’t a problem for him, anyone who takes serious road trips isn’t going to be happy.

I think most people would accept a minimum of 2 hours of no-anxiety freeway range on the ICE, but any less is just too much hassle when you’re out west and not in some dinky New England state. California’s San Bernardino COUNTY is over twice the size of Vermont.

gra said:

“I timed a fill in my Forester once, although I knew that retail gas dispensers are limited by regulation to a max. of 10/gal./min. From the start of fill to auto-shutoff, I put in 13.91 gallons in 1’28”, or just under 9.5 gal./min.”

If we’re gonna get into the minutia of how fast a gas pump will actually pump gas (which wasn’t really the subject of this article)…

It came out in a discussion of the subject on another forum that American gas pumps actually pump gas faster than European ones; apparently regulations in Europe limit the pumps to a slower flow.

Interesting how many things are different “across the pond”.

Maybe you also made a conversion error? The british gallon is bigger than the US gallon, so the british gallon is pumped slower if you fill at the same volumic rate of the pump.

I would venture to guess stopping 7 times on a trip of 462 miles is very inconvenient in most people’s books.

A common trip I take is SF to LA (380 miles one way) and I typically make one or two gas stops. In between, I rather stop at a rest stop than a gas station. There are some gas stations that are farther than 60 miles though, so not even sure the i3 REx can make such a trip.

Wow, Tom, you just can’t get a break from these commenters! With cries like “how inconvenient!”, “typical early adopter praise”, and “just get a Volt”, people seem to be completely missing the “horses for courses” message. So you take a trip like this 2-3 times a year. And you hardly cherry-picked the route – this is the route that you would otherwise take. In the region in which you live (the Northeast), which has many towns, close together, nearly all with a gas station. What’s more – and many seem to completely miss this – is that if you had purchased a Volt instead, you would be burning gas nearly EVERY DAY (yes, even a Gen II Volt). As a result, you would be buying a lot more gas. I would wager that over the course of a year, you would visit a gas station far more times in a Volt than in your i3. And each time you’d be buying 10 gallons of gas instead of just 2! The net effect is that while your 2-3 yearly trips may be ever so slightly less convenient in an i3 than a Volt, your year as a whole is much more… Read more »

I think a 3 gallon tank would be plenty sufficient. Assuming 40 miles per gallon, that would give you 120 miles of range on gas. I realize why BMW went with the size they did, but if they could put in a 3 gallon tank that would make an enormous difference.

I generally only keep 2-3 gallons in my Volt. About once a month I’ll end up using a gallon for one reason or another, so I’ll go add a gallon back. So in practice I treat my Volt like it has a 3 gallon tank. And considering the i3 has twice the EV range of my Volt, Id probably use the Rex 3 or 4 times a year.

A 150 mile all electric and a 150 mile backup would have been great and really proven the benefit of the light-weight construction of the car. With the same el. range as the Leaf and the rest it kind of defeats the purpose quite a bit.

If they do add a 125 mile range electric car battery into the Rex that by self would have reduce the gas needed on this trip down to two gallons.

“cherry picking” really sad, and no doubt you feel that your response was unbiased. Ignore.

Tom, I know the subject has been beaten to death, but I gotta say that a 3 Imp gal tank and 8% SOC when on/at highway speeds, selectable by the user would have -eliminated- the endless press about these otherwise non-issues. I know that you mentioned that BMW was looking at the SOC, has there been any discussion of tank size? I vaguely remember hearing that there -seemed- to be room but never anything definitive (beyond CARB issues) RE reasoning on the why’s of ~2 US gal tank.
My limited logic concludes an add’l 30mi of emergency range for 8lbs weight is a good trade.

Make the battery pack a little bigger AND the gas tank a little bigger and this car would be great.

Wow, the GAS-tric bypass tank.