BMW i3 REx: One year review

This is a guest post by Tom Moloughney. Tom is a leading voice when it comes to electric vehicles. Alongside consulting work with major carmakers, including BMW, he is a director at Plug In America. More of his work can be found on his blog.

Well that went by fast. After waiting patiently for years for BMW to bring the “Megacity” car, their first production electric vehicle to market, my first year of ownership really flew by quickly. On May 21st of last year I was the first i3 REx delivery in the US. My one year review is about a month late, but that has only given me some more time to gather my thoughts about it.

About a month into ownership last year, I authored two posts dedicated to my initial likes and dislikes. Many of those initial thoughts still hold true, but I’ve also had some changes of opinion as well as discovering new annoyances and new attributes which I appreciate.


One of the few pictures I have of my car in its real color: Laurel Grey. I wrapped it red the first week I had it.

Overall I’m very happy with my i3 and there isn’t another car I’d prefer to have. It really suits my needs while offering the perfect balance of performance, utility, comfort and efficiency that I desire. I managed to pile up a little over 25,000 miles by my first year anniversary (I’m up to about 27k now) with 23,700 miles on battery alone and 1,300 miles with the REx engine running. That equates to about 95% all electric miles. I’m sure some will question whether I needed the range extender option at all since I only used it for about 5% of my driving and that’s a valid question. I guess I didn’t really need it, but I definitely don’t regret spending the additional $3,850 for it and I’ll explain why.


The REx performed perfectly on my 462 mile road trip from New Jersey to Vermont. Going there and back I drove a total of 111 miles on battery and 351 on the REx, needing a little under 10 gallons of gas for the trip. I’ll gladly replace gassing up on long trips with a couple 30 minute quick charge stops once the infrastructure matures, but for now the REx is my best option for the occasional long trip.

First and foremost, the range extender allowed me to take the car every day without even thinking twice about whether I had enough range or whether or not I would have the opportunity to plug in during the day. Back when I did my initial likes and dislikes, the first thing I pointed out was that I think BMW missed an opportunity to separate themselves a bit from the pack of “80 mile EVs” out there. The 81 mile EPA range rating for the BEV i3 was just a little too low for me so I went for the REx. As it turns out, there weren’t too many days which I needed the REx, but having it there allowed me to take the car on days I may not have because I wasn’t sure how far I might need to drive that day. So in reality, the range extender allowed me to drive more electric miles than if I didn’t have it. I’d say I probably only needed the REx about two or three times a month on average, and even then it was usually for less than twenty miles. There were a couple long road trips which accounted for the majority of miles, and a few times I needed it for 30 to 50 additional miles. When I first got the car I took it to get wrapped and the shop was about 130 miles from my house. The drive back was nearly all on the range extender. I took a couple 150 to 200 mile round trips, my wife took the car on a business trip to Pennsylvania and I also made a 462 mile round trip to Vermont. It’s true I could have managed without the REx, but having it there increased the utility of the vehicle immensely and if I had it to do all over, I would definitely get the REx again. However, if BMW had optioned it with a 28-29kWh battery pack (33% larger), I would definitely choose that over the REx.


The car is holding up well and there are no squeaks or rattles to report. My interior still looks brand new, even with heavy use and high mileage for one year. I’m pointing that out because I have heard a few i3 owners report their leather seats showed premature wear, and even a couple people say the eucalyptus wood dash panels developing cracks (which BMW replaced under warranty). I have nothing negative or unusual to report on this though. Since I wrapped the car shortly after getting it, I can’t really comment on how the exterior painted surfaces are fairing. Since this is the first BMW with all plastic body panels, and since BMW developed an entirely new way of painting the panels which uses 70 percent less water and 50 percent less energy than painting systems employed for their steel body panels, I think it’s fair to wonder how well the painted panels will hold up over time. I have had a few people ask me how the wrap is doing and I can say that after a year of driving in New Jersey (including a harsh winter with a lot of snow and ice) the wrap is beginning to show signs of wear and even peeling on some of the corners. You really have to be looking at it hard to find the problem spots, but small issues are surfacing which I’m sure will only get worse. I really only intended to keep it wrapped for a year or so, so I’m not concerned. I figured this would happen after about a year. Just keep this in mind if you are planning to do a vehicle wrap.


Over the year I had a couple of maintenance issues which needed service. The good thing was my dealer, JMK BMW, has i3s in their loaner fleet so I was able to drive an i3 even when my car was in for service, which amounted to a total of 14 days. The first issue was one that all the early i3’s had, a blown onboard charger, or as BMW calls it, a KLE (Komfortladeelektronik or Comfort Charging Electronics in English). One good thing about the way BMW engineered the onboard charging is that there are two 3.7kW on board chargers, one in the main EME (Electrical Machine Electronics) and the other, the KLE, is installed separately from the EME. So if you do have a KLE failure, you can still charge the car, albeit at half speed. I can’t give BMW a pass on this issue though. They had five years of field testing with the MINI-E and ActiveE, and to come out of the gate with a faulty on board charger is inexcusable in my opinion. To their credit, they quickly resolved the issue by re-engineering the KLE, and installing it in the existing i3 fleet. I’ve had the new KLE in my car for 10 months now, and it’s been working fine. There was another issue that all i3’s with the range extender had, which was a faulty fuel pressure sensor. Almost immediately after the i3 launched, REx owners were getting a Check Engine light, even if they never fired up the REx. It turned out a fuel pressure sensor was getting corroded by the gasoline used in the US. Evidently the mixture is different from the gas used in Europe where the i3 had launched 6 months earlier without this issue, and the additives in the US gas were creating havoc with the sensor. Again BMW quickly made a new fuel pressure sensor, this one actually has gold plated connectors to resist corrosion.

I also had a flaky voltage regulator for the battery heating element which was occasionally sending an error message. I don’t think BMW was sure if the sensor was bad or if the regulator was bad so they just replaced both. That required removing my entire pack to replace the regulator. I was surprised that this major service was accomplished by my dealer in less than two days. The only other issues I had were flat tires; four of them to be exact. It’s difficult for me to really assess blame on this, since flat tires are usually the fault of the driver for running over debris or adverse road conditions, but four flats in one year is a little troublesome. Could it be related to the rubber compound Bridgestone used to make these unique tires, or related to how tall and thin they are? The two main problems I have with this are the fact that since the i3 doesn’t have a spare, you are left stranded unless the mobility kit (an air compressor and tire sealant) can temporarily seal the hole and allow you to drive home or to a repair shop. Secondly, the tall thin tires are unique to the i3, so they aren’t always in stock at the dealer. One time I had to wait four days for the dealer to get one.


With no spare tire onboard, a flat means you’re getting towed.

Three of the four flats I had were caused by sidewall bubbles, which happen when the inner liner of the tire is damaged. Sidewall bubbles typically happen when you hit a pothole, curb or road debris. In all three cases when I had this happen, I hit a good sized pothole and immediately figured I’d have a problem. Pulling over once it was safe confirmed what I had expected. The other flat I had was caused by a large metal screw. In that case I was actually only a couple blocks from a BMW dealer who actually had the tire in stock and I was able to wait there and drive off about an hour later. A few years back I had a Porsche Boxster with low profile Pirelli tires and had sidewall bubble issues with that car also, so I know this is something that is common with low profile tires. The difference was the car had a spare tire and the Pirellis were available everywhere. If I could go back in time I probably wouldn’t have gotten the $1,300 optional 20″ sport wheels and I certainly would have paid the $1,000 for the tire and wheel insurance. I definitely like the look of the 20″ wheels, but they are lower profile than the 19″ stock wheels, and that makes them more susceptible to bubbling.


91 miles on a charge is my personal best to date

As for the range, in warm weather (over 65 degrees) I can usually beat the EPA rated range of 72 miles per charge. In fact, I average about 78 miles per charge in these favorable conditions. The cold weather takes its toll and the worst range I ever got was 48 miles on a full charge before the REx turned on. This happened back in January when the temperature was below zero with ice covered roads and I didn’t precondition the cabin or battery. I actually wanted to see just how bad the range could be in those conditions. However most of the winter when temperatures were under 30 degrees I averaged about 58 to 60 miles per charge. The furthest I ever drove before the REx kicked in was 91 miles, which I did shortly after taking delivery.