BMW i3 REx Versus Chevy Volt – Real-World Comparison Test
Last week I was contacted by High Gear Media Senior Editor John Voelcker and asked if I had interest in doing a head to head comparison piece between my i3 REx and a Chevy Volt. Green Car Reports contributor David Noland (who happens to own a Volt and a Model S) wanted to pit the Volt against an i3 REx and asked John to reach out to me and find out if I was up for it.
I liked the idea of swapping cars and driving side by side for a few hours and that met David’s needs as well. David wanted to do an efficiency test and measure the miles per kWh’s used driving 15 to 20 miles in a city environment, and then do the same thing at highway speeds of 65 to 75mph. Going in, David expected the i3 to be more efficient in the city driving test, but the Volt to be more efficient on the highway test where weight plays a lesser role and aerodynamics are more important. The i3 is tall, has a large front area and is a bit boxy compared to the Volt. This creates a much higher CdA which will lower the i3’s efficiency at high speeds. Having driven my i3 for a while now, I knew it would be more efficient in the city cycle, but I figured it would probably tie the Volt on the highway leg of the test. My i3’s life time efficiency so far is 4.5 miles per kWh and I do at least 50% of my driving at highway speeds.
Editor’s Note: This post appears on Tom’s “The Electric BMW i3” blog. Check it out here.
David was also very interested to find out how the range extender performed. In my opinion, the i3’s range extender is largely misunderstood. Even months after the launch, few people really understand how it works, what it can and cannot do. It has been called everything from a “limp mode” to an “emergency use only” option, and quite honestly BMW hasn’t done itself any favors by not fully explaining how it works and how to use it properly. I promised David he could drive it as he wished, and even purposefully overwhelm the REx by driving fast enough to use more energy than the range extender could produce, should he desire to do so. At one point he even asked if I minded if he did just that, but due to the other traffic we couldn’t really sustain a speed much over 70mph for long and we were not going up and long, steep inclines so the REx was able to put out enough power to maintain the SOC between about 4% and 6%. In short, we couldn’t overwhelm it without driving in a an unsafe manner.
There aren’t many long climbs in my area and I’ve driven with the range extender on quite a bit. I haven’t found any condition where it isn’t perfectly capable of allowing me to drive as long as I needed to, including hundreds of miles if I really wanted. However I know the REx has its limits, unlike the Volt. I have heard stories of people not being able to maintain highway speeds as the car drops to 45 mph suddenly. That’s a problem that BMW needs to address. I think they need to make a better effort to communicate to the customers what the limits are, and I also believe the customer needs to be cognizant of the limits and keep an eye on the SOC under high speed driving up long inclines. It’s not a do-all-under-any-condition vehicle. The range extender has limits but I definitely believe that for the vast majority of people it will do just about anything they need. Also, since the i3’s electric range is double that of the Volt, the range extender will be used much less, so it’s reasonable to understand why it is less robust.
On the Road
I felt very comfortable behind the wheel of the Volt as I’ve driven many of them and have always liked the driving experience that they offer. However, this was the first time I’ve driven a Volt since getting my i3 REx three months and about 6,500 miles ago. The two cars definitely feel very different. The much heavier Volt absorbs road irregularities better and is quieter at high speeds, where the boxy i3 has noticeable wind noise. The i3 is much quicker, especially at higher speeds and has better braking and handling. The i3’s steering is more direct and sensitive and the Volt’s brakes seemed a little spongy or squishy compared to what I’m used to in the i3. The i3 is clearly more of a performance car, while the Volt offers a more supple, softer ride. The regenerative braking on the i3 is much stronger than the Volt’s, even in Sport mode and low driving gear. I’m sure I would adjust to it if I had a Volt for awhile, but I just couldn’t get myself to stop for traffic lights without needing to depress the friction brake pedal every time. I almost never use the friction brake pedal on my i3 unless it’s an emergency situation where I need to slow down unexpectedly. I really love this on the i3, and haven’t found any other EV to have a regen system that matches it. It’s definitely one thing that BMW got right. I know the Volt blends regen with friction braking so I suspect most of the time I depressed the brake pedal I wasn’t even using the friction brakes, but I’ve really grown fond of the one-pedal driving of my i3 that anything else now seems sub-standard.
I found both cars comparable in seating comfort and room, with the Volt having a larger cargo area. Because the e-drive motor and range extender are under the deck behind the rear seats, the i3’s cargo deck is higher, which cuts down on the cargo space, but it also doesn’t have a tailgate lip so you can slide objects in and out without having to pick them up over the lip to remove them as is the case with the Volt, which my bad back appreciates. Personally I like the uncluttered, modern interior look of the i3 better, and the large center display probably is the nicest I’ve seen in any car besides the Model S. However the exterior styling of the i3 is definitely unconventional and I’m sure many people will say they like the look of the Volt better, but styling is subjective so I’m not really going to get too caught up appearance here. One thing I really do like in my i3 is how the absence of a center transmission tunnel (battery tunnel on the Volt) provides a much more open, spacious feel in the cockpit. In fact, this makes it quite easy to slide across from the drivers seat and exit from the passengers door if you want to.
David really wanted to focus on the efficiency of the cars so we did roughly 15 miles of city driving, followed by 15 miles of highway driving at 60 -70 mph. There were a few occasions we got up to 75 or so to pass other vehicles but for the most part we drove in the middle lane and averaged a little under 70mph. In the city cycle the i3 averaged a 5 miles per kWh used compared to the Volts 4.5. The Volt did better than I expected in this part of the test though, which I am happy to report. On the highway test the i3 delivered 4 miles per kWh used and the Volt averaged 3.5 mi/kWh. David and I were both surprised that the i3 actually had a larger advantage on highway driving than it did in city driving, but was 14% on the highway. I suspect if we drove faster, and averaged over 70 mph, the Volt would have caught the i3 in efficiency. The test also isn’t perfectly controlled, since David and I aren’t the exact same drivers. However, we are both very experienced electric vehicle drivers, and understand perfectly well how to maximize efficiency with the use of regenerative braking and limiting jack-rabbit style take offs. We drove with the climate controls set to 72 degrees and the windows closed.
Having had quite a bit of previous experience driving Volts, there were really no surprises for me. I have always liked the Volt, and nothing from this experience has changed that. It’s a very capable extended range electric car that offers a good ride, decent performance and nice styling. It is a better choice for long range driving (over 200 miles) and definitely if you live in a mountainous area. I can’t even count how many people I’ve recommended the Volt to; and many have stopped back to my restaurant weeks or months later to show me that they took my advice. With a starting price of $34,999 it’s a really a great deal. The i3 REx on the other hand starts at $46,125 which is $11,000 more. Yes, you do get a more nicely optioned vehicle but it’s very hard to ignore the $11,000 difference. If price is a big consideration then it’s hard not to pocket the eleven grand and take home a Volt.
However buying a car isn’t always a rational decision, and there are indeed emotions involved. If that weren’t the case we’d all be driving $15,000 Honda Fits. There are a lot of reasons why the i3 REx is a better EV for me than the Volt. First off, I drive about 33,000 per year, and the 38 mile AER of the Volt would mean I’d be driving on gas about as much as I drove on electric. The i3 REx will allow me to drive on electric over 90% of the time. For me to increase that 100% I’d need to jump up to Model S-type range because the times I have needed the REx were usually 150 to 200 driving mile days and there are no other current production electric vehicles capable of doing that without using a robust DCQC network which doesn’t yet exist in the Northast. Another consideration is the 3.3kW onboard charger that the Volt has. I’d find it very hard to buy any EV that was limited to 3.3kW charging. My i3 can actually charge faster from zero to full an a level 2 EVSE than a Volt can, yet it has twice the electric range. GM absolutely needs to upgrade the onboard charger to a minimum of 6.6kW for the next generation Volt in my opinion.
I’ve read many comments on various online forums regarding the size of the i3’s gas tank and I can say I categorically disagree with the notion that the car needs a larger gas tank. In fact, I’d be fine with a smaller one. If you think you need a bigger gas tank on the i3, then what you really need is a Volt because you’re buying it for a use that it’s not really intended for. The i3 REx is fine for driving in range extender mode for short distances, and I think it’s really a great car for trips up to 150 miles or so, but if you really need to frequently drive more than that, it just may not be the best fit. If you need to go further once a month or so, then sure that shouldn’t be a problem as long as you don’t mind the 2-3 minute stop to refill the tiny tank, but frequent long distance driving just isn’t the car’s best use.
I also put a big emphasis on the driving experience and the i3 is really a blast to drive. The Volt is fun in its own right, and it is certainly no slouch by any means, but the i3 is noticeably faster and has a much more direct steering feel. I also love the fact that the i3 is all carbon fiber reinforced plastic and aluminum, the open cockpit and simple dashboard with the large center display. It was indeed the better choice for me, but honestly, I would be very happy driving a Volt also, especially if I drove less than the 90 miles a day that I do now. I don’t think you can lose with either of these extended range EVs. Just pick the one that fits your budget, needs and desires and you’ll be happy with whichever you choose.
*You can read David’s thoughts in his Green Car Reports article here.