From: Martin WINLOW > Not wanting to shoot your work down but I am reminded of (I think it was) > Lee's idea of using > an auto engaging charger connection which would be much more efficient, much > cheaper and only > marginally less practical.
It was actually Bob Rice's solution (although the idea is no doubt even older). In 1968, Bob had an EV with drive-on charging. It was a bump-stop that you drove up against. A platform between the front wheels would slide sideways to center itself between the front wheels. It had two brush contacts on the top surface, that mated with contacts on the bottom of the car. The contacts were dead until the car was present and electrical contact was established. Simple as dirt! I know that people are often fascinated by complex solutions. Advertising can often talk them into paying extraordinary prices for trivial conveniences or hypothetical benefits. Companies like them because they can make a lot of money selling them (especially if they can get laws passed to make it a "standard"). But if you actually expect them to be widely used or survive in the long run, I think we'd all be better served by working on simpler ways of doing it. GM's Magnecharger comes to mind. A good idea, expensively implemented, legislated as a standard, and now a footnote in history. On an 85 KHz high power inductive charger: As an EE, I can't see how the charger can detect a 0.1% energy loss to some unexpected device in the area. And yet, that's enough power to easily heat up unintended "receivers" and fry sensitive electronics that by chance just happen to resonate at 85 KHz. How can you reassure me that this won't happen? When I was designing safety-critical consumer electronics, we'd have someone on the team whose *job* it was to try to "break" the system. If the guy was good (and he needed to be) :-) he'd come up with things we never thought of in our wildest dreams! So... with your inductive setup, what if you *tried* to find a way to trick the electronics, and steal 5-10 watts of power from the charger without tripping the safety shutdowns? If you can do it, then Murphy will probably discover some mass-produced gadget that just happens to do it. -- A free whistle given away in millions of boxes of Captain Crunch cereal just happened to be exactly the right frequency to turn off the phone company's long-distance billing equipment, so kids could make free long-distance calls! -- Lee Hart http://www.sunrise-ev.com/controllers.htm now includes the GE EV-1 controller -- Those who say it cannot be done should not interrupt the one who is doing it. -- Chinese proverb -- Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart-at-earthlink.net _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
