From tzero to Model S; How AC Propulsion was a catalyst for Tesla Motors

Popular Mechanics* recently took on the fascinating 120-year history of the electric car. It's remarkable to witness the rise, fall, and (now) rise again of electric cars. Needless to say, much of the latest "rise" is related to the breakthrough work of Tesla Motors (NASDAQ: TSLA). But, in order to better understand the catalyst driving Tesla Motors forward it's best to rewind back to the 1990s. We've already discussed GM's EV1 as an important inspiration that sparked Tesla CEO Elon Musk to take the electric vehicle further. But, the real catalyst behind Tesla's rise was a daring, young under-appreciated company that developed a small, electrified fiberglass kit car.

Who was that company? Popular Mechanics (PM) explains: "Alan Cocconi founded AC Propulsion in San Dimas, California, in 1992. He provided GM with much of the electric-related genius that made the Impact concept and subsequent EV1 work properly, including contributions to its inverter. In 1997, AC Propulsion revealed the tzero [see below], with 150 kW (200 horsepower) and lead-acid batteries (Johnson Controls Optima Yellow Tops). The body and chassis were basically the pre-existing Piontech Sportech fiberglass kit car. Lithium-ion cells were just becoming available (thanks in large part to consumer electronics and investment from both governments and industry into basic battery research in this era), and eventual Tesla Motors co-founder Martin Eberhard commissioned a tzero using these instead."  

Wait... what was that bit about Tesla Motors? PM explains: "When Cocconi and partner Tom Gage resisted putting the [tzero] car into production, Eberhard and Marc Tarpenning incorporated Tesla Motors in 2003. Borrowing the lithium-ion tzero as a demonstrator, they pitched Silicon Valley venture capitalists on their idea... one potential investor approached was Elon Musk, who first tried to get AC Propulsion to go into production of tzeros, just as Eberhard had. Instead, Gage and AC Propulsion opted to do electric conversions on the Scion xB (they called it the eBox) and pursue contract work, like helping electrify the Mini. So Musk wound up pouring his money into Tesla Motors... The rest is becoming electric-car history, but just remember that you can draw a line from EV1 to Tesla—and that the line goes through San Dimas."

Fast forward about 15 years after the founding of AC Propulsion, and PM documents that: "Tesla Motors entered production in 2008 with the Roadster, the first generation of which could be fairly described as an AC Propulsion tzero with the kit-car bits replaced by one-grade-above-kit-car Lotus Elise components. Later models (like the 2011 Roadster 2.5 shown here) use proprietary drivetrain technology developed at Tesla, but the first run depended on licensed AC Propulsion power system and reductive charging systems. First to put lithium-ion batteries in a production car and the first to demonstrate a 200-mile driving range (although not if you drove it as hard as you might an Elise), the Roadster used three-phase, four-pole AC induction motors. These gradually got stronger as the production run continued through 2012."

Next up: PM proclaims that Tesla Motors' sedan, the Tesla Model S, is now, "making history happen [since it was] introduced in 2012, it made our 10 Best Cars lists for 2015 and 2016. It's both a large luxury car and a performance car with an available, aptly named 'Ludicrous Mode.' At 4600 to 5000 pounds packed with 70 to 90 kWh of lithium-ion cells, the Tesla Model S [seen above] is its own kind of moonshot... It has 20 years of battery and electronics development beyond EV1 to draw upon with its latest products... It's a 'halo car' for the entire class, and credit goes to Elon Musk for making it happen."


*Source: Popular Mechanics