Friday, August 22, 2014

BMW i3 REx vs Chevy Volt: My Take

The Challenge

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.
David averaged 4.1 miles per kWh over a 46 mile drive at highway speeds. This was driving about 15 miles in charge depleting mode and another 31 miles with the range extender running.  The display only shows an average speed of 56.7mph, but much of the trip was done at 70+ mph
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.
Getting ready to take off from Nauna's Bella Casa in Montclair

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.

People are surprised when they see the i3 next to other EVs. It is larger than I believe many people think it is.
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.
The interior of the Volt
The interior of the i3

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.  
The Volt has a larger cargo capacity, but with the rear seats folded flat, the i3's cargo space is definitely adequate for my needs.

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.

During the city driving test. I jumped out of the Volt at a red light to grab this picture.

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 on his Green Car Reports article here.


  1. Nice review, Tom! Very objective. I also read David's review, and his biases were clearly on display. Among other things, he recommended buying a Volt if your daily mileage is less than 40 miles. Huh? The correct recommendation should have been, if you drive less than 40 miles/day, buy an i3 BEV! :-)

    Also, when describing the Volt's high-speed uphill performance advantage, it would have been nice for him to explain that the Volt's ICE connects directly to the drive wheels under those conditions.

  2. I read both of your comparisons and both are very fair. Mary and I have a 2013 Volt (15350 miles since November 2013) and a BEV i3 (7300 miles since early May 2014). We've probed the limits and capabilities of these two wonderful cars in real-world driving. We've also hyper-miled well beyond the stated EPA range ratings in electric mode. I still have a 1999 Mazda Miata that I use as a reference when it comes to handling and responsiveness (also use it to gauge what Mary calls "neck-breaking", the head-snapping gawkers response when they catch a glimpse of a car they like). Anyway, on to the numbers. Range: Our daily commutes are the same except that Mary works 5 miles further than I do. I'm at 38 miles and she's at 43. We often commute together 3 times per week. We easily surpass the EPA range rating of the i3 in Eco-Pro mode and have about 11 miles of range left when we get home (BMW range estimates are very conservative it seems). If we use the Volt in Normal mode and in D (Drive instead of Low), we get 36 miles of electric range in the winter and 46-48 miles in the summer. If I hyper-mile the Volt, using a route with speeds no greater than 55, I have squeezed out 52 miles of range. Here, I totally avoid the interstate and go through urban zones. These number are with no workplace charging. Mary's ability to charge at work is variable so we can't rely on it. If she can charge her i3, we banzai our way home. Winter taxed the capabilities of our previous electric car, the BMW Active E, but with some clever adaptations on how to keep warm, we've never been stranded even if Mary wasn't able to plug in at work. The Volt gets the nod on extremely cold days. Mary wants her heat. We've yet to find out how the i3 does during winter but since ours is outfitted with the efficient heat pump option, we're looking forward to winter. Costs: the electric costs are harder to determine since we can't separate our total bill into discrete portions. I have driven the Volt 15350 miles total, 7682 in EV mode, 7668 on gas. I used 223.7 gallons of gas, at about $3.70 for premium, that comes out to $827.69. Going by useable kwH capacities for Volt and i3, it costs $1.86/day for the i3 and $1.02/day for the Volt for full charges. In our case, the operating fuel/electric costs greatly favor the i3, very different from David's conclusions. That's attributable to an individual's usage. If my Volt was driven within its 40-mile EV range, my conclusions would be closer to David's. Subjective opinions: We both prefer the i3 overall. If we were to set out on a trip within the capabilities of both (like our weekly 36 mile roundtrip Costco run), the i3 gets the nod all the time. The Volt gets the nod for longer drives were charging is optional (like the 160 miles roundtrip to Tom's restaurant). We did the same trip on the i3 but we needed to charge at Tom's and go at the reduced performance EcoPro+ mode. We did have about 12 miles of range left when arrived at Nauna's. We love the Volt's pedestrian alert horn!!! I like OnStar and the more consistent climate control system on the Volt. Mary hates the creep and headlights on the Volt. I hate the Volt's braking which feels like there are steps (blending of regen and friction brakes is horrible). The Volt understeers, meaning it likes to keep going straight when you want it to turn, a handling artifact of its heavy weight and front-wheel drive. I hate the i3's ACC stop N go cruise control while Mary loves it (cruise control uses technology to vary speed according to traffic conditions, mainly to set a safe following distance regardless of speed setting). The i3's Harman Kardon audio system is top notch but my Volt has the base system, which is not bad but lacks the clarity of the HK's. The i3 is a gawker's delight, on the road, car cruises and car shows. The Volt is a subdued handsome car but it blends with the car populace. We love both our cars. We genuinely glad that we have both. Ben and Mary P.

    1. Thanks for your detailed and informative comment! I have a 2012 Volt and my lease ends next March. Choices for replacement are the i3, Gen 2 Volt, possibly the Mercedes B-Class electric or even buying a used Volt. I'm leaning towards the Gen2 Volt but it will depend on the improvements made by GM. It is nice to have choices.

  3. I like the BMW's license plate!

  4. what do you think about the rubber air dam that crunches on speed humps with the Volt?

    1. GM offers a replacement air dam (I think at no extra charge) which is shorter and doesn't scrape as much as the stock one does.

  5. and also this issue which GM/Chevy/Holden don't want to address ... yet.

  6. This was such a piece of great information, really made my decision on which car I was going to buy for my wife so much easier. Although they are really similar there are some subtle differences that you would not know about but thanks to this blog I know am the wiser person. Thank you for sharing this with us.

    Lonnie @ Viva Chevrolet

  7. It’s funny I’ve read a lot of these comparisons and they always seem to leave the Ford C-Max energi out of the picture . I find it ironic because the Ford blows the I three the vault the Prius all of them out of the water it’s a superior vehicle in every single way imaginable especially from a driving experience it’s fast it’s agile it’s extremely reliable and efficient and it corners more like a BMW than a highbred