3 ms·

I wouldn't say it's horrible, I know roads aren't guaranteed to be smooth, if anything you could drop something to within inches to charge. Or at least don't pu

• dogma1138 10y ago
  The problem is that even 1-2 inches of distance decrease the efficiency greatly, inductive charging follows the square root law so even small changes in distance induce a large cost in efficiency which is already inefficient as it is. You can break most wireless cell phone chargers with a few sheets of paper, think what a few good inches of asphalt and a few inches of an air gap would do. Then you come to the biggest problem which is that it would require you to have coils all over the road and that would mean that a road that is pretty cheap to make now would cost millions per kilometer simply because of all the copper and charging circuitry involved. You also now add a lot of weight and cost to the cars which are now have to have large inductive coils in them to take in the charge. And lastly you take a huge risk both in term of long term health effects of driving on top of a high power inductive field and the potential safety problems, what happens when you have a guy driving his truck with a wound copper cable which is just at the right length to pick up the charge? what happens when the handlebars at on some bus are arranged just in the right way to act as act as a decent antenna for the frequency you modulating your field at? what happens when some grandma with a pacemaker decides to take a cab ride or some one is driving on the road with sensitive electronic equipment? We have barely managed to standardize wireless charging for consumer electronics and these are low power devices that need pretty much near full contact with the charge station to charge, and those still come with warnings for people with medical implants. On an anecdotal side I've seen what happens when some one with an unlucky arrangement of dental implants (bracers) comes close to an active powerful RF source (SAR RADAR) those things heat up; luckily for them some one realized what was going on before their mouth turned into a BBQ pit. An overhead/undercarriage contact charging the same way some busses and other forms of public transportation are being powered is more than fine, but again we don't necessarily need them if your car has a range of even 50 miles on a charge in most uses it would work just fine with parked charging only, anything else just adds another layer of complexity and cost to the system which is likely to only impede adoption not improve it. If electrical cars are going to rely on multi billion or trillion dollar infrastructure improvement projects they are doomed, they have to be just as independant of road conditions and detached from their supporting infrastructure as petrol cars are, and for the most part they are.
  • ge96 10y ago
    I agree with the several points you pointed out. In particular the weight problem. Since batteries don't decrease in weight while maintaining power output like Gasoline. Still if you operate a battery I don't know between 40% to 80% and you're able to keep the power output of the battery generally consistent then I guess a fixed weight isn't such a problem. Of course I am not an EE and I'm only speaking with my limited experience of operating toys. The pacemaker thing is interesting. My counter point would be to detect when it would turn on. But yeah, with the time to transfer energy and the extra complexity in the road, yes this has been nullified haha. Thanks for the details.