Tesla is preparing to deliver its first Model S electric sedans to customers next month, but in the spirit of full disclosure, has outlined why it anticipates its 300-mile version will be rated by the EPA for 265 miles.
The Model S’ drawn-out unveiling has ingrained three specific driving ranges related to battery size – 160, 230, and 300 miles – but the EPA will have its own stamp of approval. An official blog bylined by CEO Elon Musk and CTO JB Straubel dives right into the matter, presumably foreseeing questions and concerns about the 35-mile disparity with the farthest-traveling selection.
The difference between 265 and 300 miles extracted from the Model S’ substantial 85-kilowatt-hour lithium-ion battery comes down to the EPA’s testing methodology. The stated 300-mile range with the highest-capacity battery was always Tesla’s target. From one perspective, it has actually exceeded the mark, claiming 320 miles under the EPA’s old 2-cycle fuel economy evaluation. It’s when the EPA’s updated 5-cycle test enters frame that “265 miles” rears its head. For comparison, the 245-mile-rated Roadster and Roadster 2.5 endured the elder cycle while the Nissan Leaf has a 73-mile range under the 5-cycle assessment.
Going from the 2- to 5-cycle test can drastically impact vehicle ratings. The simpler 2-cycle had an approximate weighting of 55-percent city and 45-percent highway use; the more comprehensive 5-cycle is more representative of 43-percent city and 57-percent highway driving. The certifications are run on dynamometers, and the specifics are as follows:
1) Federal Test Procedure: 2-cycle, 5-cycle
2) Highway Fuel Economy Driving Schedule: 2-cycle, 5-cycle
3) Cold Federal Test Procedure (run at ambient 20 vs. 75 degrees Fahrenheit in standard FTP): 5-cycle
4) SC03 (air conditioning test at ambient 95 degrees F): 5-cycle
5) US06 (aggressive acceleration test, up to 80 mph): 5-cycle
Exactly how much the 85-kW-hr battery’s claimed range figures matters will likely be determined as Model S driving impressions roll in from customers and media outlets.
Tesla hasn’t disclosed its anticipated EPA ranges for the 160- and 230-mile batteries, but a 12-percent loss like the 300-mile option would peg them at a predicted 141 and 203 miles under the EPA 5-cycle, respectively. The 160- and 230-mile estimates from the respective 40- and 60-kW-hr packs can be achieved from a steady 55-mph cruise, per Tesla spokesperson KC Simon.
Interestingly, the blog gives insight into the Model S’ range and electricity consumption behavior with graphs. These graphs often have little bearing on the real world since Main Street USA is not a laboratory with fixed inputs. Nevertheless, considering the less expensive Model S is considerably heavier, it’s reassuring to see the family-friendly electric four-door head and shoulders above the Roadster from an efficiency standpoint.
The Model S costs from $57,400 (160-mile battery) to $105,400 (Signature Performance model with 300-mile battery) depending on battery size and trim, excluding the highly touted $7500 federal tax credit that gets applied to your income tax return. Depending on your state of domicile, there may be additional state and local tax credits or rebates as well.
By Benson Kong