Thursday, 7 August 2014

Tesla Roadster Targets 400 Miles Range With A Battery Pack Upgrade

CleanTechnica.com: The Tesla Roadster was the first model of Tesla Motors. It helped to pave the way for the success to the next model, the Tesla Model S. The Roadster was more than impressive specifications, it was a statement about how electric cars can be appealing, powerful, and functional.

Tesla Roadster – Deskinned. Image Credit: Jurvetson on Flickr
Built from 2008 until 2011, they were and are able to cover 245 miles in a single charge thanks to a 53 kWh battery pack. A real milestone in that time that still no other brand can beat. The Tesla Roadster was adopted by wealthy environmentalist as an evidence of change; electric mobility was finally true.
Many of the 2,500 Lotus Elise converted to electric by Tesla Motors are still on the road and some have already covered over 100,000 miles keeping the 85% of the battery capacity, well exceeding the 36,000 miles or 3-years warranty.
Earlier this year, Elon Musk, CEO of Tesla Motors, announced a surprise would be coming for Tesla Roadster owners. He recently made public that Tesla will offer a battery pack update for the sportive two-seater. A battery replacement with a new design, a state-of-the-art chemistry, and improved performance.
6 years after the design of the original battery packs for the Tesla Roadster, the battery cells chemistry and the battery pack components have evolved considerably. For instance, the cells used in the first model were Panasonic 18650, working at 3.7 V and with 2,100 mAh of electric charge. Currently, Tesla is using in the Model S the same type of cylindrical cells but with 3,100 mAh at 3.6V.
These numbers translate into a huge difference in energy density (the amount of energy stored per mass), being 117 Wh/kg for the Roadster battery pack and 240 Wh/kg for the luxury liftback accumulator.
In an interview to Auto Express, Mr. Musk estimated that the “new generation battery pack should have a range of about 400 miles, which will allow you to drive from LA to San Francisco non-stop.”
Roughly, calculations tell us that, in order to be able to cover 400 miles in a single charge, the new battery pack should have about 85 kWh, like its top performance brother, the Tesla Models 85. In that case, the new battery pack would be slightly heavier than the original battery pack (1,200 lb for the Model S 85 battery pack and 992 lb for the Roadster), but this is just an approximation until official specifications are given.
The announcement can be considered as a recognition to the pioneers that trusted the company at its beginnings, but also as an alternative for those vehicles that soon will need a replacement. The new battery pack might be the best option for Tesla Motors, which will benefit from a better price by using the same battery cells as for the Model S. However, it has to be taken into account that the design of a new battery pack is not a trivial task — it is not “Plug & Play.” The new design implies an investment of time and money. Therefore, it should be considered as a deference from Tesla Motors to its customers.
The price of the replacement was not unveiled yet. To replace the original battery pack was $40,000 dollar, and considering that a 85 kWh battery pack for the Model S costs around $45,000, it could be expected to be a similar price.
Whatever the amount is, the result is priceless. The limited Tesla Roadster is almost a collector’s item, and thanks to the new battery pack it will become the highest-range electric car on the road. Moreover, it is expected that, together with the upgrade, the Tesla Roadster could get access to the Supercharger network. But this is, for the moment, just a rumour. Does anyone want to bet?
Overall, it is interesting to point out another interesting fact of battery-powered electric vehicles: the battery packs can be upgraded as new developments emerge. This allows extension of the service life of the vehicles and they become cheaper, safer, and extended-range cars, making the purchase of this technology profitable in the long term.