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Sunday, October 19, 2014

Update on the Tesla Model S

 Cross-posted from Energy Trends Insider

Has anyone else noticed how much a Tesla Model S looks like a Jaguar XF (pictured below)? One of my neighbors drives a Tesla Model S. I was following him down the street a few weeks ago and heard his tires squeak three times in two blocks. Adequate acceleration to maneuver in traffic can enhance overall safety but too much acceleration potential can be dangerous, especially in the wrong hands. Not sure I’d want that temptation.

Tesla Model S Photo courtesy of Gareth James via Flickr

Jaguar XF Photo courtesy of Jimmy Smith via Flickr

Fast Chargers

Tesla is dead on with their promotion of fast charging stations. The ubiquitous 240 volt chargers are next to worthless simply because they take too long. A high voltage fast charger can provide a significant charge in a matter of minutes. I recently deliberately drove my Leaf beyond its range because we needed two cars to get supplies to a wedding. My plan was to stop at a charge station on the way home for a few hours to get enough charge to finish the trip. The rest of the family came home in our Prius.

I had obtained my code to use a given company’s charge station but it turned out that the station I chose was owned by a different company so I had to move to the next closest charge station, which was occupied by a Chevy Volt. So, I moved to the next closest station, also occupied by a Chevy Volt! There was a Volt at the fourth station as well but luckily, there were two chargers. However, they were owned by yet a third company. Luckily they were in a municipal parking lot so their use was free. By calling the number on the charger I was able to get the operator to unlock it for me. Don’t invest in any company providing 240 volt public charging stations.

Crash Safety

From the Tesla website: NHTSA Reaffirms Model S 5-Star Safety Rating In All Categories For Model Year 2014

That’s all well and good but a 2003 car safety study titled “An Analysis of Traffic Deaths by Vehicle Type and Model” concluded what insurance companies have known for a long time: “…sports cars, as driven, are extremely risky to their drivers…”

Personally, I never consider crash safety ratings when purchasing a car. Why? Even with new, more stringent standards in 2012, roughly 95 percent of all cars tested by the NHTSA received a four star rating or better (out of five). About 25 percent received a five star rating.  Although there are other organizations that do safety ratings, the NHTSA (National Highway Traffic Safety Administration) ratings are much less likely to contain bias. Five star ratings are inevitably used for marketing, but if you were to buy a new car that has a four star rating, the odds of being injured purely as a result of not having that fifth star are very low. All new cars today have safety features not dreamed of decades ago (three way restraints, airbags, anti-lock brakes, crush zones, safety glass and on and on).
In reality, when it comes to crashing into other cars, the overarching difference is mass; heavy cars crush lighter ones. If a three star truck hits a five star economy car, the occupants of the higher rated car are at greater risk of injury.  But that does not necessarily mean that heavier cars are safer. The vertical axis on the above chart ranks risk to the driver of the other car. The horizontal axis  debunks the myth that trucks and SUVs are necessarily safer than smaller cars. In a nutshell, driving a truck or SUV may not only put you at greater risk but the greater mass also puts other drivers at greater risk.

The Tesla is a  heavy car for its size, thanks to its batteries (roughly half-a-ton heavier than the Jaguar XF). On July 6th a Tesla (4,600 lbs) rear-ended a 2004 Corolla (2,500 lbs) at high speed, killing one adult and two children. However, largely thanks to the five star crash rating, the Tesla driver had minor injuries.

Obviously, a five star crash safety rating can only do so much. On July 5th a stolen Tesla crashed into a pole during a high-speed chase and broke in half. The batteries in the front part of the car caught on fire and the back half of the car ended up jammed in the doorway of a synagogue, I’m guessing, about 100 feet away from the front end of the car. The driver was thrown clear but is in critical condition. You can see video of the carnage here.

In response to the car fires earlier in the year, Tesla has reinforced the car’s underbelly. Although Elon Musk said that additional “…underbody shields are not needed for a high level of safety” (i.e., to reduce the risk of a Tesla being engulfed in a fiery inferno after hitting road debris) …he did it anyway. The NTSB investigation did not mandate a fix.

However, from the AP:
The U.S. government’s auto safety watchdog has closed an investigation into Tesla electric car battery fires after the company said it would install more shields beneath the cars.
To avoid the stigma associated with the word “recall” Tesla does not call this retrofit a recall (although, for the record, it is by definition a recall). This is reminiscent of when extra “non-mandatory” reinforcement was voluntarily added to the Chevy Volt after some caught fire as a result of side impact. GM called it a “customer satisfaction improvement.”

The Tesla engineers looked under their car to see where they could bolt more hardware on under the already existing quarter inch thick “ballistic grade” aluminum plate. They cobbled together a titanium plate along with a couple of  aluminum extrusions. The Tesla website has three short videos of the car running over junk (which you can bet represent the best examples out of the 152 tests they ran).
They also did a software tweak that limits how much the suspension will lower the car at highway speeds. Lowering the car at high speeds does two things: it drops the CG for better handling and less ground clearance can also improve range by reducing drag. Tesla was quick to point out that the extra weight of the fix did not meaningfully affect range but made no mention of the aerodynamic impact of higher ground clearance.

Electric cars (including Tesla) have so far proven to be far less susceptible to catching on fire than conventional cars. On the other hand, not all electric cars will necessarily be equally less susceptible. Although there are far more Leafs on the road than Teslas (due to the lower price tag) I am unaware of any of them catching on fire. The simple fact that Tesla uses quarter inch thick “ballistic grade” aluminum plate to protect its battery pack is all the evidence you need to know that Tesla was concerned about what could happen when a car hit the wrong piece of road debris.

 Drive Train Issues
 From Green Car Reports:
On Tesla’s own website forum, dozens of owners weighed in with their tales of drive unit woes. “Every car in my area has had at least one DU replaced,” noted one. “I’m on my fifth drive train at 12,000 miles,” reported another. One poor fellow was on his sixth–as far as we know, the record for drive-unit futility.
 The Gigafactory
 Tesla will eventually run out of customers who can buy $80K cars. To keep selling them, they have to get the price down. The only way for Tesla to do that is to get the battery costs down. Because their car is designed around their choice of battery cell, they are stuck with the battery they have so the only way to get prices down is with greatly expanded mass production of the battery. Aside from other concerns, the problem as I see it, is that they are going to commit themselves to mass production of a soon-to-be obsolete battery.
Unlike the Nissan Leaf, Chevy Volt, and Ford Focus Electric, which all use a larger, flat, prismatic shaped battery, the Panasonic batteries used by Tesla have been around for a long time (I wrote an article about them long before there was a Tesla). Their cylindrical shape wastes a great deal of space and their small size necessitates the use of thousands of them in a car which can lead to thousands of potential problems. Buying off-the-shelf Panasonic batteries was the best Tesla could do at the time of its development.

In Conclusion

All companies eventually fail, or get bought up. That does not mean a company was not successful. Tesla is a success. However, it is also a monopoly of sorts. It is the only electric car in its price and performance range. They can and do charge whatever it takes to cover costs. How long will Tesla survive when a car with the same performance arrives with a much lower price tag, as would be the case with a car that has cheaper, more modern batteries?

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