IDEA: Recharge as you travel

JennyB

JennyB

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Jan 25, 2008
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Northern Ireland
A hundred years ago some electric cars carried a kit to allow them to take current from overhead tram. I'm wondering if an updated version is technically feasible - some sort of power source laid at road level that ordinary traffic can safely drive over. Obviously a permanently live rail with a bare-metal contact would be impractical - think of all the electrocuted roadkill. Would an inductive coil be able to efficiently transfer power from a buried cable?
 
Closed systems seem to be favored.

http://abclocal.go.com/wtvg/story?section=news/local&id=6259830
6259901_600x338.jpg


http://www.wired.com/autopia/2009/01/rail-meets-the/
tritrack2.jpg


I imagine an open system has the vulnerability of being tapped anywhere along the charging route by freeloaders.
 
I've seen some stuff like that for electric busses, some kind of deal I don't understand where the bus parks on a coil in the pavement, and charges while parked at the stop for a few seconds. Something sorta like a magnet stirrer I guess? I could see a bunch of EV's all competing to park there a few minuites and steal the power. I guess that could be set up to have a RF signal to only let power flow to the busses easy enough.

It would be bitchin though, if there was an EV lane on the freeway that let you charge as you drive, and debit you by identifying the chip on your car. Imagine what that infrastructure would cost though! ouch. Lots of parking spaces that allow charging may be more practical.
 
Dogman is right: the capital cost of these schemes would be impractically collosal, however for urban bus use this ultracapacitor bus seems a good idea:
http://endless-sphere.com/forums/viewtopic.php?f=1&t=8521&p=129648&hilit=chinese+bus#p129420
Edit: Sorry, that link has gone dead. Searching for a replacement...
Here it is:
http://www.youtube.com/watch?v=hPXIjRB9mIU
 
But then you Americans probably think buses are a nasty socialist plot to deprive you of your liberty (like the NHS) :wink:
 
paultrafalgar said:
Dogman is right: the capital cost of these schemes would be impractically collosal, however for urban bus use this ultracapacitor bus seems a good idea:
http://endless-sphere.com/forums/viewtopic.php?f=1&t=8521&p=129648&hilit=chinese+bus#p129420
Edit: Sorry, that link has gone dead. Searching for a replacement...
Here it is:
http://www.youtube.com/watch?v=hPXIjRB9mIU
Click to expand...

The Danish RUF scheme (Tyler's second post) seems well thought out, and possibly the least expensive way to make a guideway system. From the website, though there doesn't seem to have been much progress in the last ten years. :(
 
paultrafalgar said:
But then you Americans probably think buses are a nasty socialist plot to deprive you of your liberty (like the NHS) :wink:
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Are you trying to imply that they aren't???????? I don't understand. :lol:
 
paultrafalgar said:
But then you Americans probably think buses are a nasty socialist plot to deprive you of your liberty (like the NHS) :wink:
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No, they're disease carrying mobile boxes to ensure the fastest spread of pandemics possible as well as a socialist plot to deprive you of your liberty to travel freely. I'd rather ride my e-bike in the rain than ride a bus. On the other hand, I have no problem with canceling everyone's right to drive a car and force them on buses as long as e-bikes are ok. Imagine how nice the riding would be with only buses to contend with.

Sharing the road with cars isn't so bad though, since I've realized that peak traffic times are the best time to ride where I live. Traffic goes so slow that it's a non-issue, just obstacles to dodge. It took a while for me to make the change, after years of resisting using my car other than late at night or between 10am and noon due to my hatred of traffic. Now I laugh hysterically inside as I pass the barely moving cagers, who are moving too slow to hit me even if they tried. I went from absolutely HATING TRAFFIC to loving it over the past year, as long as I'm not sitting in a car or bus stuck in it.

John
 
paultrafalgar said:
But then you Americans probably think buses are a nasty socialist plot to deprive you of your liberty (like the NHS) :wink:
Click to expand...
Actually busses were a nasty capitalist plot:

"The Great American streetcar scandal (also known as the General Motors streetcar conspiracy and the National City Lines conspiracy) is a conspiracy in which streetcar systems throughout the United States were dismantled and replaced with buses in the mid-20th century as a result of illegal actions by a number of prominent companies, acting through National City Lines (NCL), Pacific City Lines (on the West Coast, starting in 1938), and American City Lines (in large cities, starting in 1943).

On April 9, 1947, nine corporations and seven individuals (constituting officers and directors of certain of the corporate defendants) were indicted in the Federal District Court of Southern California on two counts under the U.S. Sherman Antitrust Act. The charges, in summary, were conspiracy to acquire control of a number of transit companies to form a transportation monopoly, and conspiring to monopolize sales of buses and supplies to companies owned by the City Lines.[11].
The proceedings were against Firestone, Standard Oil of California, Phillips, General Motors, Federal Engineering, and Mack (the suppliers), and their subsidiary companies: National City Lines, Pacific City Lines, and American City Lines (the City Lines)."

http://en.wikipedia.org/wiki/Great_American_streetcar_scandal
 
Actually, public transportation is one of the biggest screws I've ever seen. In all cities in the US, public transit does not pay for itself, so it comes out of taxpayer pockets, only New York's subway is able to pay for more than half of itself. So its expensive. But, I've never had a problem with riding the buss or train to work, since I can get stuff done, check my email, etc while on my way to work which is really nice. As for "disease boxes", they're just people who are probably too pour to own a car and often not in shape to ride a bike, they aren't lepers though they do smell like it sometimes. I'm all for having smaller safer vehicles on the road, but bikes in traffic are dangerous, half the time they don't obey traffic laws and when I'm driving they always make me nervous, I've seen them race me on my e-bike and go right into traffic without signaling at all.
 
A good bus or train system is great, such as I saw in London. Ours sucks, ebike travel time for my bike is 45 minuites to work, by bus, it's an hour and a half, and the bus goes by once an hour. Miss it, and you get to wait one hour, making the time to get to work 2 1/2 hours. for fifteen miles? Nobody rides is because it's usefull only to the unemployed, nobody with a job has 3 hours to spare in their day.
 
paultrafalgar said:
But then you Americans probably think buses are a nasty socialist plot to deprive you of your liberty (like the NHS) :wink:
Click to expand...
"Liberty"? What is this thing you call "liberty"? We Americans aren't familiar with that term.
 
GMs EV-1 used an induction paddle, so there was no metal prongs contacting. You'd put a plastic covered paddle into a sealed slot, and magnetic pulsing in the paddle caused a pulsing in the cars charging system. Regardless of any drawbacks or inefficiencies, it guaranteed no electrocutions, even when wet.

It could be done in parking places for EVs. It could easily be configured to require a card swipe and a PIN to ensure the costs were properly charged (like Dogman said)
 
Public Transit does pay for itself, it just can't pay for all the leaches in public employ that attach their overinflated salaries and pensions to it.
 
John in CR said:
paultrafalgar said:
But then you Americans probably think buses are a nasty socialist plot to deprive you of your liberty (like the NHS) :wink:
Click to expand...

No, they're disease carrying mobile boxes to ensure the fastest spread of pandemics possible as well as a socialist plot to deprive you of your liberty to travel freely. I'd rather ride my e-bike in the rain than ride a bus.

John
Click to expand...

Hey John, rain in CR is not he same stuff as rain in NY or London in January !! :lol: :lol: ( or even Sydney in August ! :shock:)
A good PT system is a godsend , for those that have that luxury...some of us dont have that option though.
 
dogman said:
the bus parks on a coil in the pavement, and charges while parked at the stop for a few seconds. ... I could see a bunch of EV's all competing to park there a few minuites and steal the power. ... if there was an EV lane on the freeway that let you charge as you drive, and debit you by identifying the chip on your car. Imagine what that infrastructure would cost though! ouch. Lots of parking spaces that allow charging may be more practical.
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As I understand, if the "coil" in the pavement is a cable going about 20 kcps and the receiver coil in the EV is tuned to this frequency, and if the coils can be close, the power transfer is efficient, or at least comparatively so. Conductix calls it IPT, inductive power transfer (there are other companies using different terms), and they have a system commercially available. I don't see the infrastructure being prohibitively expensive. Indeed, I'm convinced this is the future.
 
lol at the perpetuation of the stereotypes here.....the idea of anyone being suspicious of public transport as some kind of conspiracy....here in Chicago is considered a very good PT system by US standards and it sucks eggs. Don't mistake bureaucratic nonsense and a bad implementation for a bad idea though, public transport works great when it's done great.

I didn't watch the video but is this the super capacitor idea - where the bus charges caps quickly at bus stops - just enough to get to the next stop? China is doing this....

I really like Shai Agassi's "Better Place" concept, where the batteries are charging while you travel - just not on the vehicle. You don't own the batteries, you rent them....when you get low on juice you pull into a station and swap out your spent batteries for some charged ones.
 
Contactless power transfer has been around for many years. I first saw it in an application where they had to connect and disconnect power cables underwater, so they used a magnetic coupler instead of contact pins inside the connector.

There is also the familiar electric toothbrush, with a contactless charger.

A number of companies are working on wireless power transfer, where there is an appreciable air gap between the two parts. Applciations range from power tools up to electric vehicles. To get any reasonable power transfer across the gap, you need to make the two coils resonant. AFAIUI, the higher power systems all require some sort of communications between the transmitter and receiver. This is to do things like not turn on the power until the receiving device is in place, set up and tune the coils, but it could also be used to administer the process and charge the appropriate account.

There are some issues, such as the intensity of the em fields generated. One of the questions being asked currently, is what technical standards and licencing should be applied. There is one school of thought that says they generate high frequency energy and send it to an antenna, so they are radio transmitters and should be regulated as such. At the moment in Europe, they have to fit into the provisions for low frequency inductive systems, but it is under discussion.

Nick
 
The Magne Charge system employed high-frequency induction to deliver high power at an efficiency of 86% (6.6 kW power delivery from a 7.68 kW power draw).
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That's not terrible but I think you'd need more than 1 "power line" per lane since it wouldn't quite be a continuous 6.6kw. If you had 3 you'd get about 26.5HP which seems like it'd be pretty good. Now lets add that up...

If you use one 6.6kw charger per foot then you need 247,505,279 to stretch the length of the Interstate. Multiply by 3 so you have a little more power (19.8kw) and you'd need 742,515,839 chargers. Double that so you can wire a lane in the opposite direction.

I found a Magne Charge on ebay for $200...so for *just* $297,006,335,600 you can buy the chargers you'd need. Then add on what it would cost to integrate them into the road, etc. Ouch.

Just for fun. :wink:
 
Buses are too damn slow. Slower than a car, often times slower than an eBike..

I rode one for 3 years as an adult before i had a car. What a miserable experience. Where i lived, i was, 90% of the time,the only person that wasn't mentally / physically handicapped, a drunk, a weirdo, or ultra poor. And the availability was crap too, it ran twice a day to my destination... :|

So the bus wasn't really appealing unless you were forced into it.

OK, now living in Portland, we have a great public transport system that nobody really digs on. Most folk riding it are pretty straight. Lots of people replacing cars with the electric light rail because it is fast, decently priced, and runs very often.

I don't hear anyone complaining where i live about how public transport is some kind of commie plot. The light rail is jam packed during rush hour and you are lucky if you can get on.
 
I was able to attend the public session at the Plug-In 2011 conference here in Raleigh, NC last week. A pair of companies had inductive charging stations that they were showing off. One had actively deployed some stations on an Italian bus line, with 25 buses powered by their system. When the bus comes to a stop, it lowers the receiver to the pavement. They have to keep the air-gap small to maximize the area efficiency of the coupling. Even with lowering the plate to the surface of the pavement, there is still a layer of pavement and protective layers of the receiver plate that add up to several cm of air gap. Despite the limitations, they get a 60 kW power transfer rate at each stop.

One other vendor was advertising their system as a convenience add-on to your garage. The idea was that you could just drive into your garage and the transmitter plate would be raised to your car from underneath to complete the magnetic circuit. I don't think this system has a chance in the market considering how easy it is to use the SAE connector.

A key provision of both systems was that they get the transmitter and receiver very close together to minimize the air-gap and maximize the power transfer for a given surface area. I don't think it is practical for embedded general roadway use at anything other than stoplights.
 
I don't think it is practical for embedded general roadway use at anything other than stoplights.
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Even there it's not very practical. How many car-lengths back would be wired? How long do you really sit at a light or stop sign? How do you get close enough to the charger without getting out of your vehicle? How do you deal with the people that would sit there to get a charge while traffic backs up?

Oh, looks like there is/was a 50kw Magne Charge!...
qkpaddle.jpg

So if you sat at the light for 1 minute, it coupled/decoupled automagically, and your vehicle could take that 50kw, you'd get about 0.83kwh. If you average 277wh/mi that would move you 3 miles. Not bad...if all the intersections in your city were wired you'd likely never have to manually recharge.

IMO, EVs don't need help in the cities, they need help on the Interstate.
 
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