Tag Archives: Tesla Roadster

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Detroit, “Get Off Your Butt”

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Arnold Schwarzenegger is an avid proponent of green technology. California has made massive strides to make itself the green tech capital of the world. He loves his Tesla Roadster so much that he gave Tesla huge incentives to manufacture their future sedan, the Model S, in San Jose.

Now, about this bailout.  With all the resources available to the Big 3, they still could not produce a viable electric car after GM destroyed the EV1. The Chevy Volt has about a quarter of the range the EV1 was capable of in the mid 90’s. And now they expect us to bail them out so that they can continue to produce gas guzzling vehicles that nobody wants? They expect us to bail them out after we had to get a second job just to pay for gas because no domestic cars could get decent gas mileage?  They expect us to bail them out after they continue to outsource jobs?

As of this hour, tonight, the fate of Detroit is in the hands of President Bush. The GOP does not want to bail them out, so I am curious to see what Bush will do. Mitt Romney suggests a managed bankruptcy. In a managed bankruptcy, “the federal government would propel newly competitive and viable automakers, rather than seal their fate with a bailout check.” I think this is the best course of action. This way, these new companies could reorganize and build cars for the 21st century.  Maybe we could see an electric car company spinoff, based on the Chevy Volt and Chrysler ENVI programs.

Yes, if the Big 3 do go under, hundreds of thousands of US jobs will be lost, and several companies that manufacture for the Big 3 will go under.  But $25 billion is probably just going to slightly delay the inevitable collapse of these helpless companies if they do not make a significant change of direction. If we bail out the Big 3, and they continue to be obstinate, and refuse to appease consumer demands, and continue to fail and embarrass America,  I would rather they just “drop dead”.

Tesla Roadster

What is the Tesla Roadster 1.5, exactly?

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The second generation of Tesla Roadster will look exactly the same, but sport a new “Powertrain 1.5”.  This powertrain is an improved motor, inverter and gearbox designed to replace their previous two-speed transmission that had many durability, efficiency and cost challenges.  The faulty 2-speed transmission effectively forced Tesla to sell its Roadster locked into second gear, dramatically hampering acceleration. The one speed transmission “improves motor torque by a bit more than 30% beyond what was already great and the ¼ mile time for the car is now in the 12.9 second range. The top speed of the vehicle remains over 120 mph,” according to Tesla CTO JB Straubel.

According to Tesla’s site, Powertrain 1.5 makes the following improvements:

  • An improved inverter (PEM) to deliver higher motor current
  • An improved motor to handle higher current and torque
  • A new single-speed gearbox
  • A new motor to gearbox coupler and an improved motor cable
  • Upgraded vehicle firmware
  • NO changes to the battery pack

Tesla Roadster Inside

PEM-green, Battery-blue, Electric Motor-under the PEM

The Power Electronics Module (PEM) basically acts as an amplifier and guide that converts and regulates the power from the battery to the motor. When you put the pedal to the floor you tell the PEM to give the motor some juice. By using newer IGBTs (Insulated Gate Bipolar Transistors) that convert and regulate power from the battery, they have been able to boost the PEM output current by about 33% from 640A rms to 850A rms with the same number of IGBTs.  Fancy talk for using recent advances in electronic technology to make a more efficient PEM and a more powerful Roadster.

The motor has been improved by changing the casting in order to link with the new transmission. The motor terminal lugs have been changed, as well as the cable from the motor to the PEM to improve efficiency and reduce temperature rise.

The heart of the Powertrain 1.5 improvement is in the gearbox. CTO JB Straubel explains it best in his blog:

The new gearbox is the most significant change from powertrain 1.0 to 1.5. We have significantly reduced the complexity of this gearbox by getting rid of the need for shifting or speed matching between two gear sets. There is only one set of gears that is always engaged with a ratio of (8.2752:1). There are no clutches and we have also done away with the need for an electric oil pump and instead integrated a very efficient gear-driven oil pump into the gearbox. All of these simplifications have saved a great deal of mass and the new gearbox is approximately 45kg instead of 53kg for the old two-speed design.

This mass savings is even more impressive when you consider that we have designed this transmission to have a long life at a much higher input torque (400 Nm) and higher speed (14,000 rpm).

The engineering design of this new gearbox has been finished for over a month and we are now running prototypes through their paces on dynamometers. We built two initial gearboxes with machined aluminum housings so we could gain some early test results before finalizing the cast housing tooling and machining fixtures.

One of the most exciting features of this new gearbox (from an EV perspective) that we have been able to validate on the first prototypes is that it has extremely low spinning drag (less than 0.1 Nm of dry drag torque.) This is less than any other gearbox we have tested with the only possible exception being the EV1 gearbox. This low drag contributes to the 1.5 powertrain having a slightly improved range figure.

The two pictures below show some of the gears and shafts. On the left is the input shaft assembly…spinning up to 14,000 rpm bearing selection is very important. The spline on the right connects to the motor coupling. The picture on the right is the intermediate shaft assembly. Notice the transmission locking “gear” in the center that engages with a stationary pawl when the car is parked.

All these changes will dramatically improve performance without effecting the range or power draw from the battery.  Tesla has learned a lot from its inaugural launch, hopefully with this more efficient powertrain they will ramp up production.

Sources: [MotorAuthority, Tesla Motors]

Model S, Tesla Motors, Tesla Roadster

Extraordinary Recession Affects Tesla Motors

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Newly appointed CEO of Tesla Motors, Elon Musk, created a new post, Extraordinary Times Require Focus, in his blog today.

He announces Tesla is going to “consolidate operations”, which means “lay off” a few people. This was expected since every car company is getting hit by the economic crisis, even electric car startups. He also had some discouraging news on the Model S:

Tesla is absolutely committed to development of our next generation vehicle, to be unveiled early next year. However, we are going to reduce activity on detailed production engineering, tooling and commitments to suppliers until our Department of Energy loan guarantee becomes effective.

This will delay in start of production of the Model S by roughly six months to mid-2011.

Elon Musk is a very competent businessman, as exemplified by his Paypal success and his SpaceX gig. He also seems to have a genuine passion for electric cars, as he has spent about twice as much money as he expected in the project. So I don’t think a few bad quarters will end the ride.

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On Alan Cocconi

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Alan Cocconi

If you follow electric cars you need to be familiar with Alan Cocconi.  As you can plainly see from the picture above, he’s kind of a badass.  He is predominantly responsible for the technology found in the GM EV1; which was ahead of its time, or technology today is behind the times depending on how you look at it.    In his garage he fabricated what was basically a 100,000 watt stereo amplifier that would allow the EV1 to travel 90 miles on a charge, go 0-60 in 7.9 seconds, and have an ungoverned top speed of 123 mph on the test track.   And this was before Lithium-Ion batteries were viable; the EV1 started out with plain old Lead-Acid batteries.  To this day, first generation EV1’s would still be completely cutting edge and capable electric cars.  The EV1 was only leased, but estimated retail was $30,000- $40,000. This lease agreement allowed GM to take them back to be subsequently crushed, but we got the movie, Who Killed the Electric Car?, out of the whole ordeal.

Anyways, so what happened to Alan? Well he’s still in the electric car business.  Unfortunately he has not been contracted to work on major project to the extent he did at GM.  But the company he founded in 1992, AC Propulsion, is a major player in the electric car market today.  The first AC Propulsion Tzero was built in 1996. Like the EV1, the Tzero had a range of about 90 miles, but could rocket from 0-60 in 4 seconds, making it the first electric supercar. By 2003, a second generation Tzero was born, packing lightweight Lithium-Ion batteries instead of Lead-Acid. This gave the Tzero an ev range of a whopping 300 miles. If that wasn’t enough, a trailer mounted generator could be attached to the back to extend the range even further. Seen here:

Tzero and trailer

Well the Tzero never made it to production, unfortunately.  Out of the Tzero, and the potential of the Lithium Ion battery, came the concept for the eBox.  Basically, AC Propulsion converts customer-owned Scion xBs by removing the internal combustion engine and related components and installing the AC Propulsion electric drive system and battery. You can do this now, but you have to provide the $15K Scion and another $55K for them to convert it. Undoubtedly, if AC Propulsion operated on a larger scale, this could be done for less than half that. Tom Hanks was pretty enthused about this one:

But the real legacy of AC Propulsion and Alan Cocconi stems from that 100,000 watt amp. The AC Propulsion drivetrain that Cocconi developed has evolved, and is now used in the Venturi Fetish, Wrightspeed X1, and the Tesla Roadster. All of which are on the cutting edge of electric vehicle technology and have inspired others to design future concepts.

Fisker Karma

On the Fisker Karma

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Fisker Karma

As much as I love the Fisker/Tesla slap fight going on right now, I don’t care to talk about it. Hopefully, this will be the start of a long, healthy competition between the two companies, not just a sue fest. And with Fisker optimistically anticipating production of about 15,000 Karmas a year at $80,000, we could have a battle on our hands. Tesla only expects to produce 2,000 Roadsters a year with its higher price tag of $100,000. However, the Fisker Karma will not have quite the performance, 0-60 in 6 seconds, compared to the Roadster’s 3.9. Interestingly, the Karma will have two driving modes, “Stealth Drive” and “Sport Drive”. The former will provide “relaxed and efficient driving” while the latter will unleash the cars power according to the company site .