could anybody answer the questionning of the presence of a 'induction' charging system, that would operate automaticalle when park at home or other pre-designed spots?
i very much support this option as a 'must'

rfreund | 30. September 2011

These systems take AC mains, rectify, convert to high frequency AC at a high voltage and convey that applied power to the primary of the induction system. The secondary output is then rectified yet again, and the regulated to the necessary pack voltage so that normal charging can be accomplished.

Double AC-DC conversions cost - in terms of power losses (6-8% typically, depending on ...).

In the past GM EV-1, Toyota RAV4EV and Nissan HyperMini used 'smallish' paddles to act as separable transformer halves. This paddle encased a 2 turn primary which was to be placed into an expensive ferrite 'C' shapped receiving assembly. The secondary had 2 turns wound on that ferrite.

To place an induction scheme under the car so that the driver simply drives over it to charge has additional difficulties (which could be solved for additional $$$ or course). The alignment of the two transformer halves is pretty critical. The additional power electronics is also expensive.

AC Proplusion experimented with this on a 1993 Saturn under contract with the SCAQMD. The project was abandoned, ultimately.

'Copper-to-copper' is more efficient, simpler and lighter weight.

Albert Einstein said "Everything should be made as simple as possible, but no simpler."

Volker.Berlin | 30. September 2011

There are a couple of interesting comments on induction charging in these threads:

Brian H | 30. September 2011

As I mentioned elsewhere, Fully Charged has a video of a prototype Rolls-EV with inductive charging.

Episode 20, beginning about 4:30 in ...

Roelof Reineman | 13. Oktober 2011

Yes there are losses associated with inductive charging. Most systems currently on the market can achieve a transfer efficiency well over 90-95% in the parked situation. In the end those losses is what people will accept given the convenience, it will be a 'Park and Forget' option, not having to worry if your car will get charged.

The alignment is less critical from what I have gathered so far, though truth be told, perfect alignment allows for better efficiency. Another study I read investigated larger coils in your parking space and a smaller one on the vehicle; this will make perfect alignment less of an issue.

At the current state of the technology and scale of things being produced, a unit that would fit under your car that taps into the powertrain of your car, would cost somewhere in the range of €1000-2000. The pad on the ground would add a similar figure.

However, I think the most interesting thing about this technology is not the parking solutions that everybody is betting on now, but the option to charge vehicles while they drive. Another study on this topic I read that has resulted in a patent describes a vehicle driving at 100 km/hr, having a gap (road to vehicle) of 20cm and an efficiency of 90%! Imagine roads, or sections of road to be fitted with this!

Here in the Netherlands we aim to organize an inductive powered race, the Inductrophy next year in 2012. Check out for details. For questions feel free to contact me through my Linked In or Twitter: @my_hev

Kind regards,

Volker.Berlin | 14. Oktober 2011

Yes, yes, yes! That's what I've been saying all along! :-) It is relatively distant future, given the dimension of the project even after all technical obstacles have been solved. But once we have charging built into the trunk road system, EVs have "unlimited" range. Not like those old fossil ICE stinkers that have to fill up every few hundred miles...

As a result, batteries would really only be needed to get around town, which means that they could be much smaller and lighter...

Some promising research has been done at the Technical University Braunschweig (Germany): (German language)

In Korea, an actual system has been installed in 1:1 scale that works under real-life conditions in some amusement park, in cooperation with the Korea Advanced Institute of Science and Technology: (German language)

I seem to remember that in some other city, a similar system has been installed in the public, at bus stops. Public transportation buses run on their regular route and get a short charge at every stop. Unfortunately, I cannot remember the city, or the source of this information.

Great food for some visionary dreaming...

NielsChr | 14. Oktober 2011

for a reference, the Rolly EV is equipped with a wireless charge system from this compagny

They seam to plan or are ready to produce pad for aftermarket to be fittet in ANY (read tesla :) ) EV

Now we only need som prices from this site, and ultimatly that Tesla would ship this as a standard option already implemented in the car.

Volker.Berlin | 15. Oktober 2011

Green Car Reports: Electric Race Cars To Get On-Track Inductive Charging

"Inductive charging through the road [...] could soon be reality for electric race cars, thanks to HaloIPT in partnership wth Drayson Racing Technologies."

Volker.Berlin | 15. Oktober 2011

autobloggreen: How gas cars use more electricity to go 100 miles than EVs do

"Let's go over that again. If we simply count the electricity used to make the gasoline that gets burned in a normal vehicle, you need more juice than you do to move an EV the same distance. Of course, then you need to factor in the actual gasoline used (and the resulting CO2 emissions). Plus, don't forget, it takes a bunch of water to refine gasoline. Put this all together and you've got on hell of an energy efficiency argument in favor of plug-in vehicles."

Volker.Berlin | 15. Oktober 2011

(Sorry, the last link was supposed to go into this thread.)