Interview

I had originally planned to interview Peter Arnold at the Chewonki Foundation. He is the Sustainability Coordinator and is involved with hydrogen energy including fuel-cells. I made my questions and had been trying to reach him for a week until I found out that he was away until March 28th.

So for a back up plan, I decided to ask questions of the engineering experts working at Tesla Motors. Roy Harvie, an electronic technologist, took the time to answer my questions and gave me additional sources for my questions.

Q-I would think wide tires on the Tesla Roadster would help with lateral acceleration, but have you calculated the efficiency/range loss vs. using narrower tires?
A-Tesla has special tires designed to have lower rolling resistance but still be wide enough to be “sporty”, after all it is a sports car.

Q-How much do the Roadster batteries weigh?
A-The battery pack weighs almost 1000 lbs.

Q-What is the lifespan of the batteries?
A-The batteries are designed to maintain performance for at least 160,000 miles.

Q-Can the batteries be recycled?
A-Recycling the batteries has already been arranged. The batteries are made from lithium-oxide. They are made with strict environmental controls in Japan and do not contain common battery toxins like lead, mercury, cadmium, chromium and other chemicals. The batteries will be recycled by the company Kinsbursky Brothers/Toxco. Only the modules in the battery need to be recycled. The modules are ground up in a big grinding machine into 2'' pieces. The lithium-oxide and metal are then recycled and sold.

Q-I live in Maine and was wondering about the loss of battery power and range between freezing and -10 or -20 degrees F?
A-There would be some loss in range due to cold weather, mostly due to the requirement to heat the car and not because of efficiency loss in the battery itself. The battery has a built in heating/cooling system. The Roadster has the advantage of not needing to wait for an engine to warm up but can immediately get to work on the windshield using our electrically powered PTC heating system. We passed the defrost test with flying colors.

Q-How does the Tesla Roadster handle in the snow?
A-The Roadster has been extensively tested at the Continental Proving Ground in Arvidsjaur, Sweden. The anti-lock break system and traction control system were tested in extreme cold temperatures on a frozen lake. The anti-lock breaks have been adjusted so that they do not slip when they recharge the batteries during breaking since this process could cause the car to slide out of control. The traction control system is important because electric cars create so much torque at low speeds.

Q-If Tesla makes a car all-wheel drive, how much efficiency/range might be lost?
A-A 4-wheel drive version should actually be more efficient. Most of the braking energy is consumed by the front wheels, so the energy recovered can be higher in a front wheel drive electric vehicle. Tesla is rear only drive primarily to keep the cost down as a second motor and controller for the front would raise the price and also increase the weight slightly.

Q-Has Tesla tested the safety of these cars to passengers and first responders after they have been damaged in accidents, and how great is the risk of electrocution?
A-Tesla spent most of the first few years on battery safety, It is the only large battery pack certified for air travel in the world. The Federal Motor Vehicle Safety Standards are slightly different for electric vehicles in that they cover spillage of electrolyte and avoidance of electric shock rather than the spillage of fuel as in a conventional gasoline powered vehicle. We have therefore incorporated numerous safety systems into the battery box to prevent such dangers. The most significant of these systems opens the primary contactors during a crash event and thus completely isolates the high voltage system from the rest of the vehicle. This system when combined with the physical protection of the enclosure, results in an electrically safe vehicle.

Q Which do you think are more promising, electric cars or fuel cell cars?
A Years ago the car makers spent a lot of time and money trying to create a viable battery system for cars. They failed. Eventually they turned their interest to fuel cells. The Oil companies encouraged this trend because they know that they will run out of oil and fuel cells have the advantage that they could keep their customers coming to the pumps to buy hydrogen. Tens of billions of dollars have been spent on fuel cell research, many more times than batteries. The last thing the oil companies want is to see customers charging their cars at home. Mean while battery research continued and great advances have been made. It’s all about size weight and energy density, how far can you travel on a tank of hydrogen vs a battery pack? Which costs more? Battery break throughs are happening almost daily now and is leaving the fuel cell camp in the dust. There is no question that batteries are much more efficient, about 95% vs 50% for fuel cells. Charge time for batteries can be about the same as fueling time for hydrogen. In a few more years even die-hard fuel cell advocates will give up completely.

Q Will fuel cell cars be cost competitive with electric cars?
A No.

Q Do you think it will be more difficult to make hydrogen stations or battery swapping/charging stations?
A Who cares? Both are losers. Battery swapping is a bad idea, why swap when you can charge just as quickly?

Q Will this be a deciding factor in which car will be more broadly used?
A When a low cost battery can take a car 800 miles on a charge, the whole world will go electric. When you can charge over night and drive all day there will be no more need for gas or diesel vehicles.

Q Are you aware of any other possible fuels such as bio-diesel which be competitive with electric or fuel cell cars?
A No.

Q How long do you estimate that it will take the United States to transition into using only alternative energy cars?
A 10 years. I know most people talk about 20 to 40, but I think it will happen much faster. As soon as point 4 (800 miles a charge) is reached, no one will buy anything else.