I was stuck with the rusty old acetylene B tank that they had exchanged for my new one and then refused to exchange again, because they said it had been abused. I was able to get them to take it for safe disposal by buying another new tank from them. I'm sure they pulled the same stunt with the same tank on other suckers, saying it was the last tank left when I was desperate. Needless to say, I changed my vendor.
We can expect the same sort of game to be played with a battery exchange system for electric cars.
A few years ago at CES, Fulton Innovations demonstrated a wireless charging mat for a Tesla Roadster. The efficiency was remarkably close to that of a wired plug-in charger, even with a distance of several inches between the mat and the pickup coil mounted on the underside of the vehicle.
But for all the reasons others have mentioned, and more, it is completely impractical to embed charging mats in the roads and attempt to wirelessly charge EVs that are in motion. Safety issues alone would demand that the vehicle be stationary and well aligned with the coil in the charging mat for a long enough period of time to allow for foreign (metal) object detection and a negotiated, controlled power transfer session. That is not likely to happen if the vehicle is zooming past the primary coil at 45 mph or more.
Given that the US has over 4 million miles of public roads and over 600,000 bridges with one in ten being structurally deficient with an estimated $78 billion repair bill, the notion of now electrifying this aging infrastructure with inductive charging seems a bit unrealistic.
However inductive charging mats for parking areas such as your garage are sure to dominate the charging infrastructure a few years down the road. Nissan is delaying its Infiniti branded EV until the technology is more mature as it wants to launch its EV for the Infiniti line with inductive charging.
BTW, Tesla has stated it hopes to bring to market a DC fast charger with a 5 minute charging time! Just imagine the strain a whole bunch of these 1 MW chargers would have on the distribution grid. If they are successful then road electrification would be clearly be unneeded.
EmbeddedSteve718 raises a couple good points. I think we need to understand what the objectives of the road safety tests. Roll over hazard, side impact are primarily related to the mechanical design of the vehicle. The lowest the center of gavity, the safer the vehicle. It has always been the objective of any car makers. Unfortunately, due to the inherent nature of gasoline engine, the center of gavity can go so far. The H-type engine designed by Subaru has improved the center of gavity and yet, it can't beat the heaviest component - battery pack - being put in the almost lowest point of a Tesla Model-S.
Going back to EmbeddedSteve718's points, I believe there are a couple more tests that shall be included to rate the safety of an electric vehicle. I am sure the industry will continue evolve and I still believe electric vehicle is our future of transportation.
You might want to find safe disposal of that rusty acetylene tank. They can be spectacular when they fail. The interior of the tank is filled with adsorbant (a clay, IIRC) to stabilize it, cracks and free space accumulating pressurized acetylene will spontaneously explode.
If it is completely discharged by now then maybe not such a worry.
Low temperature fuel cells do not deliver power. They can store the energy, but for a given weight and cost only a trickle of power. They also tend to need very pure fuels to avoid poisoning the expensive electrodes.
A low temp fuel cell might eventually make sense for trickle recharge, if the trickle can get into the kW range for reasonable weight and cost.
Blog Doing Math in FPGAs Tom Burke 23 comments For a recent project, I explored doing "real" (that is, non-integer) math on a Spartan 3 FPGA. FPGAs, by their nature, do integer math. That is, there's no floating-point ...