What the Frunk?

The front storage compartment (Frunk) of my i3 after driving a few weeks on the salt-covered winter roads of New Jersey - yuck!

First, let me begin by saying I was one of the people who really didn't mind the fact that the i3's front storage compartment (affectionately called the "frunk" by many since Tesla initially coined the term for the area under the hood of the Model S) wasn't waterproof. I never envisioned keeping anything up there that I would need to access frequently and since my Electronaut Edition i3 came with a nice storage bag that would keep whatever I put in there nice and dry, it was really a non-issue as far as I was concerned.

It looked a little better when I first got the car. Of course everything looks better new, but being exposed to all the elements means you really can't store anything up there that isn't waterproof & durable

It was so inconsequential to me at the time I didn't even list it as a minor annoyance when I did my initial likes & dislikes posts back in June. Well after living with the car for nine months now, I have some different perspectives and I think I'll soon go back and do an update on what I like and don't like about the i3. One of the things I'll add to the dislike list is the fact that the frunk area is easily penetrated by moisture, dirt, leaves and anything else that would find its way under the hood of a traditional ICE car.

Leaves can make their way into the frunk also, as found out by BMW i3 Facebook group member, Michal Cierniak

So why didn't BMW make this area waterproof? I have never gotten an official answer but my guess is because it would add weight and cost. Plus, since it is such a small compartment, they figured the vast majority of people would only use it for things like extension cords, a tool kit and the occasional use EVSE, all of which are OK to get wet once in a while. They probably also figured most people would get a bag to put those items in, and they even sell one such as the one that I have. Because I have an Electronaut Edition i3, mine was free and embroidered "Electronaut Edition." It keeps the items in the bag clean and dry, but the bag itself gets very dirty and isn't really pleasant to handle when it's covered in dust and now road salt. 

Which one would you prefer to handle?

The i3 has a lot of mechanical components up in the frunk area; they are just hidden by the removable screens on both sides of the frunk. Once you remove these snap on screens, you can see that area looks basically like a traditional ICE engine compartment, minus the engine of course. The storage compartment only occupies a small section of that area as opposed to the Model S. Since the Model S is so much larger than the i3, Tesla was able to utilize a huge portion of the area under the hood for storage, creating a large front trunk which they called the frunk and still have enough room to fit whatever mechanical parts they located up there. The i3 didn't have much space to spare since the front area of the car is so small, so the storage compartment seems like more of an afterthought than something that was a well planned design feature.

After removing the plastic frunk, and the snap-on shields on both sides of it, what you see looks very similar to a conventional gasoline or diesel powered car (minus the engine!) Photo credit: Tim Hood

If waterproofing the entire area up there just wasn't cost effective, or if it was going to add too much weight, then I do understand the reasoning, but what they should have done was provide a nice frunk cover that could snap on and provide - at the very least - a water-resistant seal. Perhaps some ingenious entrepreneur will manufacture and sell such a cover...

* If you want to use my car as the mold you know where to find me, and I'll be your first customer ;)

Guest Post: Efficiency or Range? You Can’t Have Both.

The i3 is the most efficient production car available today

Every now and then I have a reader send me an article they wrote and ask if I'd like to post it here. Usually it's not exactly what I'm looking for and politely explain why I won't be posting it and thank them for sending it nonetheless.  Occasionally I'll get something interesting though, like the post below which was sent to me by Robert Kasper. I think it's particularly timely since just last week I posted the Tesla/BMW comparison piece and I think this is an interesting follow up to it.  I hope you enjoy:                    

  Efficiency or Range?  You Can’t Have Both.

…But Advanced Technology Can Help.

By Rob Kasper

In the world of electric vehicles, whether Battery Electric Vehicles (BEVs) or Plug-in Hybrid Electric Vehicles (PHEVs), there is a clear trade off between range and efficiency.  For a given technology, efficiency suffers as range increases due to the weight of not only additional battery capacity, but the increased structure and volume to haul that capacity around.  Now that there are a significant number of plug-in vehicles being manufactured, and a recognized standard to test them, we can identify trends.  Consider Table 1 and Figure 1, a plot of efficiency (as measured in EPA MPGe) vs. range in miles for 2014 plug-in electric vehicles measured by the EPA.  They are grouped into Battery Electric Vehicles (BEVs) and Plug-in Hybrid Electric Vehicles, and further identified as either conventional or advanced technology design and construction.  Conventional technology is generally characterized by a manufacturer’s use of an existing gasoline powered platform modified for battery electric drive, steel frame construction and cladding, and standard battery technology.  Advanced technology is generally characterized by a clean sheet, purpose built EV design, extensive use of aluminum or aluminum plus Carbon Fiber Reinforced Plastic (CFRP) for weight savings, higher energy density lithium ion battery packs, with the bonus of performance equivalent to or exceeding the best of conventional technology plug-in vehicles.

Figure 1: Efficiency vs. Range

Table 1: EPA Electric Range and MPGe

Beyond the obvious observation that the price of greater range is lower efficiency within a given technology, it is important to note the significance of advancing technology.  The ground-up EV design, significantly lighter weight construction, and advanced battery technology of the BMW i3 and Tesla Model S push the blue trend line significantly up and to the right of conventional BEVs’ green trend line.  As significant is the single data point (in purple) representing the only advanced technology PHEV currently available – The BMW i3 REx.  Not only is it capable of greater efficiency and far more range than any conventional PHEV (the red trend line), it is more efficient than all but two conventional BEVs, with only slightly less range than all but the most inefficient conventional BEVs.

It is this outlier of a data point, the BMW i3 REx that might best help illustrate why a smart means of increasing the range of an EV may not necessarily be to add more battery capacity.   Battery energy is clean and well suited for powering vehicles for relatively short-range transportation but due to its weight and lengthy charge times, inefficient and inconvenient for long distances.   On the other hand, the benefits of energy density and convenience make gasoline/diesel energy better suited for longer range transportation with the trade-off being greater well to wheel emissions in many parts of the world.  In the case of the BMW i3 REx, each mile of range requires either 0.15 pounds of gasoline, or 5.7 pounds of battery capacity.  At 37 times the mass specific energy density of battery power, very little gasoline is required to extend range for a given tank size, and that tank can be replenished in minutes nearly anywhere in the well developed fossil fuel infrastructure that currently exists worldwide.  This capability requires a 265 pound increase in the weight3 of the vehicle for the REx engine and associated systems, which imposes a 6% decrease in efficiency, but once set, that efficiency does not appreciably decrease as more energy in the form of gasoline is added to increase range.  Increasing battery capacity cannot increase range as efficiently, as not only must the weight of the battery increase by 37 times the weight of gasoline per mile in the first increment, but by the weight of increased structure and volume, as well as even greater battery capacity to offset the reduction in efficiency resulting from the weight increase.  There comes a point where the sacrifice in efficiency may no longer be worth the additional range to be gained.
See figure 2:

Figure 2: EV Energy Storage (and Generation) Weight vs Range for Advanced Technology EVs

1- EPA testing protocol does not account for approximately 4 miles of range remaining after REx fuel exhaustion when publishing a 72 mile battery powered electric range before REx activation, but does account for it in the total range calculation of 150 miles:  72 electric miles + 1.9 gal x 39 mpg + 4 electric miles = 150 EPA range (76 electric + 74 gasoline).  76 miles of range is also the result of dividing the EPA measured total i3 wall to wheel consumption of 22.0 kWh by the i3 REx EPA measured consumption rate of 0.288 kWh/mile.  This value is further corroborated by the CARB BEVx designation awarded to the i3 REx which requires the electric range not only be at least 75 miles, but that it must exceed the gasoline range, neither of which would be possible without accounting for the ~4 miles of range remaining after REx fuel exhaustion.

2- The EPA’s 95 MPGe rating of the Toyota Prius Plug-In Hybrid includes 0.2 gallons of gasoline operation plus 29 kWh of electric operation per 100 miles.  Subtracting the 10 mile of gasoline operation contribution to the total (0.2 gal X 50 mpg) yields 29 kWh per 90 miles, or 32.2 kWh per 100 miles, which results in 105 MPGe for electric only operation. (MPGe = 33,705 divided by watt hours per mile.)

3- While EPA rated at 87 miles of range in its base form, purchasers of the Mercedes-Benz B-Class can choose to pay an additional $600 for the Range Package, which makes an additional 17 miles of range available.  There is no difference in total battery capacity between the two configurations, only the percentage of SOC made available to the driver.

4- The 8 BMW battery pack modules weigh 55 lbs. each, for a total of 440 lbs.  Reference page 17 of the BMW i3 Service Managers Workshop Participant Guide at http://darrenortiz.com/website_pdfs/BMWi3PG.pdf.

5- 265 lbs for the REx engine and all associated equipment is the difference in weight between the i3 BEV and i3 REx as published on BMW’s spec pages:  http://www.bmwusa.com/Standard/Content/Vehicles/2014/i3/BMWi3/Features_and_Specs/BMWi3Specifications.aspx
http://www.bmwusa.com/Standard/Content/Vehicles/2014/i3/BMWi3RangeExtender/Features_and_Specs/BMWi3RangeExtenderSpecifications.aspx.  Adding the 440 lb. battery weight makes the total energy production and storage weight at 76 mile of range 705 lbs.  This increases by 11.4 lbs. of gasoline for every 74 miles driven beyond 76.

6- Widely quoted in other sources, Car and Driver claims the Telsa Model S 85 kWh battery pack weighs 1323 lbs: http://www.caranddriver.com/reviews/2013-tesla-model-s-test-review.  This is exactly 600 kg, making it appear to be an estimate, but it is the only number we have to work with, as Tesla does not publish the spec.

7- Weight of the 60 kWh Tesla Model S battery pack is estimated from the 85 kWh figure to be 60/85 X 1323 lbs. = 934 lbs.

BMW i3 Places 2nd in European Car Of The Year Voting

Some say there are no moral victories and if you don't win, well, you just lose. I think that may apply to sports more than in other types of competitions, like say, the European Car Of The Year Award.

The BMW i3 finished 2nd to the Peugeot 308, and it was in fact by a substantial margin. However it is worthy of noting that the i3 did finish ahead of the Tesla Model S, which is largely considered the best electric car available. In fact, some automotive journalists say the Tesla Model S is flat out the best car available, electric or otherwise. So in this case, while I'm sure BMW had hoped to win the award, I think the consolation prize of finishing ahead of the Model S was definitely something they privately celebrated.

Autocar was the first to reveal the winner, getting the scoop on everybody. I'm actually here in Geneva now at the Geneva Motor Show covering it for InsideEVs and I didn't even know until I read what they posted! It seems Autocar may have in fact been surprised the i3 didn't win, and blamed the loss on the i3 and the Model S splitting the "electric vote". I'm not too sure I agree with there being an "electric vote" though, and the margin of victory was large enough to consider it a clear victory . However I really know very little about the voting process for this honor and perhaps Autocar knows something about this that I don't.  Here is what they had to say about the results:

“Peugeot wins ECOTY ahead of BMW i3 and Tesla Model S, which clearly split the electric vote. No quarrel with the 308, which is a very well sorted example of its kind, but still feel it’s an opportunity missed to pass over a revolution like the i3 in favour of something so very conventional.”

Here's how the voting went:

Peugeot 308: 307 votes
BMW i3: 223 votes
Tesla Model S: 216 votes
Citroen C4 Picasso: 182 votes
Mazda 3: 180 votes
Skoda Octavia: 172 votes
Mercedes Benz S-Class: 170 votes

So while the i3 didn't take home the trophy, it's clear the voters were impressed with what the i3 brings. To finish ahead of the Model S is pretty incredible, because the Model S is really an incredible car in its own right. So even without a win, this bodes very well for the i3. This is definitely an example of a worthwhile moral victory if I've ever seen one. Now we'll see if the people agree with the results. So far the demand has been very strong for the i3, but will that continue once the original pent up demand subsides and production ramps up to full volume? That's the three billion dollar question that BMW is praying for.

The action around the i3 on the show floor was very good, as it was basically surrounded with journalists all day. I was a little surprised by this because the i3 isn't "new" to the auto show circuit. It may be just launching for the public but journalists have had access to it at many of the past auto shows and by now I would have expected the buzz to have subsided a bit. Perhaps there was renewed interest because of the 2014 European Car Of  The Year competition.

Here are some more picture from Geneva: