Wireless Charging

[DJH]

The following article is from the ETA newsletter and thought it may be of interest.

'Wireless charging for electric cars and bicycles

Mayor Boris Johnson has often referred to his hopes of London becoming the ‘electric car capital of Europe’ and now plans are underway for a network of wireless charging points for electric cars and bicycles.

Four electric cars owned by Transport for London have been adapted so that they can be re0charged by parking over an electric charge pad and discussions have taken place regarding electric bicycles being offered as part of the Boris Bike scheme.

Bicycle industry website BikeBiz has revealed that electric bicycle firms are in discussion to introduce wireless charging to their e-bike ranges.

Recharging technology firm Halo IPT told the site that there had been discussions about e-bike schemes: “If you take the Boris Bikes in London – it would be very straightforward and easy to build wireless charging into the docking stations, particularly as it would only be a small air gap. It’s a relatively fast charge too.”

A spokesperson for the Environmental Transport Association (ETA) said: “Electric Boris Bikes would encourage an even greater number of novice cyclists to use the scheme and enable them to make longer trips.”

If e-Boris Bikes generated their own power

However successful London’s bike hire scheme becomes, there are inevitably times when the bikes stand in their docking stations unused…until now. A resourceful group of London cyclists who enjoy ‘spinning’ (think aerobics class on exercise bikes) have taken to placing small rollers under the rear wheels of unused Boris Bikes. The result is an impromptu, alfresco and free spinning class. But all that wasted energy could be put to use charging the bikes’ batteries if they were electric assist.'

 

[JuicyBike]

Interesting.
I know a case of a gentleman who wrapped his home in copper, inducing a decent current from a nearby electric pylon, which he used to power his home. He was prosecuted by the electric company for theft. Personally I think Boris should offer him a job.
I think this could be expensive to fully develop. But if completed would be a great boost to e-bikes. Hopefully the technology would be shared for the likes of smaller companies to adopt too.
I'd keep my mobile well away though...

 

[flecc]

It's an inefficient way of transferring current, I think rather wasteful in this conservation age. Wireless, although terminologically true, is rather misleading, it's induction current.

There have been past applications at times, even many years ago, notably a flywheel powered bus on a route in Switzerland where induction current powers the flywheel motor to spin it back up to speed at each bus stop. That takes the battery and charging inefficiencies out of the picture and also ensures bus drivers stop to pick up passengers!

 

[JuicyBike]

That flywheel method is damn good though, in conserving energy. Instead of braking the (massive) fly wheel can be driven, transferring the wasteful heat generated by traditional brakes into kinetic energy stored in the flywheel, ready to aide acceleration. Still some energy lost through the clutch, unless an "induction clutch" were used...

 

[mike killay]

Would there be a problem of these induction points attracting an unusual concentration of Radon laden dust?

 

[flecc]

That flywheel method is damn good though, in conserving energy.

Yes, when the application is right as in that bus example, it's a good source of motive power. When the latest centre-mass very high speed flywheels are used, they needn't be too heavy either, though not really suited to bikes.

 

[flecc]

Would there be a problem of these induction points attracting an unusual concentration of Radon laden dust?

I suppose the dust gathering could be turned into an advantage with brush or vacuum collection. Air pollution due to traffic has become a very serious problem in cities like London now, a problem that urgently needs addressing, and even pollution gathering clothing has been trialled recently. In that instance, the normal clothes wash disposes of the pollutants. Collection of pollutants at charge points could be part of a multi-pronged solution to the problem.

 

[Scottyf]

I've never understodd wireless / induction charging.

It was first intorduced to me on my electric toothbrush where by you put it in a dock but no metal touchs for the transfer.
Anyone have any articles how it works?

I'm intrigued by it.
Although it would be just easier cheaper and safer to use a wire

 

[flecc]

It's just the two halves of a transformer Scotty. Instead of the primary and secondary coils in very close proximity in one place, in this form of current transfer the secondary half of the transformer is in the receiving dock/vehicle etc. The switching magnetic field due to the AC current in the primary coil cuts through the adjacent secondary's coil, inducing AC current in that.

The inefficiency results from the lack of the close coupling of the primary and secondary windings that exists in a transformer.

Normally in efficient transformers the primary and secondary windings are wrapped together, but in very low current transformers where losses are not important, the two coils are sometimes just placed side by side. The low current 100 mA one below is an example with side by side coils. In induction charging, the secondary of those two coils would be in the receiving point close by:

 

[jhruk]

I've never understodd wireless / induction charging.

It was first intorduced to me on my electric toothbrush where by you put it in a dock but no metal touchs for the transfer.
Anyone have any articles how it works?

I'm intrigued by it.
Although it would be just easier cheaper and safer to use a wire

This Wikipedia entry has been updated with the London trial.

 

[Scottyf]

Thank you very much.
Always interesting to learn new things.

But as you say the additional loss is always going to be a problem. Which can be easily sorted with a hard wire or dock.

 

[JuicyBike]

Yes, when the application is right as in that bus example, it's a good source of motive power. When the latest centre-mass very high speed flywheels are used, they needn't be too heavy either, though not really suited to bikes.

Now you've got me thinking of a wheel (Flywheel) within a wheel (drive wheel) surrounding a motor that acts as an induction clutch (or brake) as well as a drive when the momentum from the flywheel is given up.

Doodling is so much more fun that VAT returns...

 

[DJH]

Doodling is so much more fun that VAT returns...[/QUOTE]

Heck you've just reminded me!!!!!!!!!!

 

[flecc]

Now you've got me thinking of a wheel (Flywheel) within a wheel (drive wheel) surrounding a motor that acts as an induction clutch (or brake) as well as a drive when the momentum from the flywheel is given up.

Trouble is that it all gets so complex. SRAM have now picked up on the idea I propounded back in July 2007, having the epicyclic in a hub motor arranged to give two motor gears, optimum hill climbing performance and optimum flat travel efficiency.

So ideally in a hub motor we'd need that arrangement, plus a braking energy recovering high speed flywheel with it's clutch and reduction gear train. Of course we'd need to provide room alongside for an adequate derailleur sprocket set and preferably provision for a hub dynamo as well.

A 135 mm dropout is starting to seem very narrow!
.

 

[JuicyBike]

Three of us were chatting about this in our white van earlier this afternoon...
The gyroscopic effects of the flywheel could make it impossible to bank into corners.
Unless the "outer" wheel became a sphere encapsulating the flywheel, left free to rotate in a vertical axis...

It's time for more doodles, starting with a 26" sphere.

Please someone tell me to get back to the VAT...

 

[flecc]

Unless the "outer" wheel became a sphere encapsulating the flywheel, left free to rotate in a vertical axis...

Please someone tell me to get back to the VAT...

VAT = Velocity of Angular Traversal

 

[Deleted member 4366]

The following article is from the ETA newsletter and thought it may be of interest.

'Wireless charging for electric cars and bicycles

Mayor Boris Johnson has often referred to his hopes of London becoming the ‘electric car capital of Europe’ and now plans are underway for a network of wireless charging points for electric cars and bicycles.

It's nice that they're trying it out. You can't beat practical experience for any newly proposed ideas. At the end of the project they'll know whether it works or not. I suspect that it won't, but I've never tried it. I should imagine that it'd be a lot more difficult for a bike than a car because the receiving coil needs to be fairly large and there isn't really any convenient place to put it. Hopefully we'll get to see how they did it.
Regarding the flywheel idea: you could use two or more counter-rotating flywheels, which would cancel out the gyroscopic effect.

 

[funkylyn]

Three of us were chatting about this in our white van earlier this afternoon...
The gyroscopic effects of the flywheel could make it impossible to bank into corners.
Unless the "outer" wheel became a sphere encapsulating the flywheel, left free to rotate in a vertical axis...

It's time for more doodles, starting with a 26" sphere.

Please someone tell me to get back to the VAT...

Bob......stop doodling........put on Snow Patrols latest album......Fallen Empires........and.....

Get Back To The VAT !!!

You know you want to..........ROFLMAO

Lynda