Tesla

Tesla on battery recycling

One of the enduring issues related to battery-powered cars is what becomes of those massive batteries when they reach end of life? As one of the first companies to utllize large-scale lithium ion batteries, Tesla is addressing this problem even before they start series production. In the latest entry on the company blog, Kurt Kelly talks about the battery recycling plan including a description of the pack's construction. The 6,831 individual cells are spread among 11 modules, each of which can be individually replaced if their capacity to hold a charge drops too low. Once modules or packs are declared no longer useful, Tesla has a recycling plan set up with KBI/Toxco. Tesla will ship expended modules to Toxco for dismantling and reuse, recycling. Kelly gives a full rundown of the process.

Busting some myths, Tesla VP debunks electric Elise meme

One of the most common beliefs about the Tesla Roadster is that it's an electric Lotus Elise. The reality is that the Roadster is a descendant of the Elise but, as Darryl Siry so forcefully documents on the Tesla blog, it's a very different car. The Tesla used the Elise as a starting point because it's one of the lightest and best-handling sports cars in the world. The chassis of the Elise is made up of bonded aluminum extrusions and the basic design makes it relatively easy to modify for different applications. For an electric car with a nearly 1,000lb battery pack, minimizing the rest of the mass of the car was critical. By the time the electric powertrain and battey were added, few of the mechanical bits of the Elise were left. When I visited Tesla in January to drive the car they told me that about 15 percent of the Elise components were carried over with the rest being modified or all-new (mostly the latter). According to Darryl the number is actually be seven percent by part count. Regardless of the actual number, the fact is that this is a very different car although it does retain some of the character of the Elise, only a lot quieter. In spite of some "luxury" upgrades, this is still a pretty bare bones and hardcore sports car. Other than the Elise/Exige, you won't find a much more direct driving experience in a full bodied road legal car anywhere. It's not an electric Elise, but the heritage is there and nothing to be ashamed of.

Tesla engineer talks about developing EV traction control

There have been a veritable flurry of posts on the Tesla blog in the last few days, one of which was written by software engineer Drew Baglino. Drew was tasked last year with revamping the traction control system for the Roadster after they made a change from an analog to a digital controller for the motor control. Drew describes the development process he went through over the next several months developing a control algorithm to provide wheel spin up control as well as the equivalent of engine drag torque control (EDTC). The Roadster traction control is all done in the motor control, with no brake intervention.After developing a first cut of the software, he quickly learned that developing a slip control system goes way beyond the basic theoretical controls. Controls for closed environments like a test track with fixed maneuvers are pretty straightforward. The problem is when you start throwing in transient maneuvers and surface transitions. All of a sudden the problem becomes much more complex as Drew found when other people started driving his traction control on the road. I can definitely sympathize with Drew on this project after working as a controls and software engineer on abs/tcs and stability control systems for 17 years before quitting a few months ago. Head over to the Tesla Blog to read all about Drew's big adventure and don't forget to check out the videos after the jump.

Martin Eberhard goes solar, getting ready to plug in his new car

Deposed Tesla Motors founder Martin Eberhard only has a few more weeks to wait for delivery of his new Roadster. Series production is scheduled to start on March 17 and first car off the line that day is destined for the Eberhard family garage. In preparation for his new ride, Martin has been making some changes around the house including the installation of a solar array on the roof so that the Roadster doesn't add any load to the grid. The 5.2kW setup has been operating since November and Eberhard estimates that about two-thirds of its output will go toward energizing the Roadster. In the latest post on the Founders Blog, Martin runs through some of the ways you could calculate payback on the system. Based on just the savings from replacing grid power with solar the system pays back in twenty years. Looking at the gas that won't be used by the Roadster, the payback drops to nine and a half years. The biggest cost of the system actually turned out to be all the work involved in integrating it into the house's electrical system. Based on his personal experience, Martin proposes that new homes that are built should made solar ready so that retrofits could be a lot cheaper and easier.