Wireless battery charging for e-Bikes

[mark sutton]

I've been speaking with a chap in Switzerland who has begun the process of developing a wireless charge system for e-Bikes. Looks like it could be a sensible enough bet for the future of electric hire fleets: https://cyclingindustry.news/wireless-charging-for-electric-bikes-on-the-horizon/

 

[Danidl]

Why? The entire geometry of bikes works against it.. these wireless tech are usually transformers with an air gap between the driving coil and the receiving coil. The bigger the area and the shorter the gap , the better. In a mobile phone, the gap for my Samsung is a couple of Millimetres , an automobile would have the wheel radius as a gap , but the floor area of the car could be used . Bikes have bigger wheels, no floor area, and the weight of the receiving coil is dead weight.... Plugging a cable into a socket, is not an onerous task. Even in the arrangement as shown, the paddle sticking out of the side of the front fork is another obstacle, additional weight, and a wind gatherer... There is a reason why bikes use spokes in wheels. Cycle in blustery conditions with side winds etc...

There might be more sense in including the mains adaptor charger in the bike and using a lightweight power cord, as it is only 1 amp ...

 

[flecc]

The Swiss have long had an obsession with induction charging and power transfer, not sure why. The earliest I remember many years ago was a flywheel propelled bus, which at bus stops had induced power driving the flywheel back up to speed to drive the bus to the next stop.

As Danidl has posted, bike shape is very unsuited to induction charging.
.

 

[Woosh]

Why?

because connectors are the weak points, liable to be corroded, vandalised etc.

 

[Fordulike]

because connectors are the weak points, liable to be corroded, vandalised etc.

I don't usually disagree with any of your comments, but I think you're over-dramatising an issue that doesn't really exist.

 

[danielrlee]

Another reason wireless charging is a bad idea is that it's horribly inefficient. Even a well designed induction charging solution is an order of magnitude more inefficient than wired charging and that's forgetting many of the issues raised above.

 

[anotherkiwi]

Another reason wireless charging is a bad idea is that it's horribly inefficient. Even a well designed induction charging solution is an order of magnitude more inefficient than wired charging and that's forgetting many of the issues raised above.

Yes but when it is your only option it is a life saver - my 2013 Google nexus 7 tablet has a faulty USB charging interface and can only be charged by induction now. So it is a bad idea which has some uses.

 

[rower]

It sounds good to me, this could help with bikes in which batteries are more firmly secured e.g. inside the frame or even wheels. Clearly the most sensible application would be in shared ebike schemes where a client can just stick the bike inside its cradle instead of faffing around with cables.

 

[flecc]

Clearly the most sensible application would be in shared ebike schemes where a client can just stick the bike inside its cradle instead of faffing around with cables.

No need for cables and plugs, so why have the terrible induction inefficiency wastage when contact pads on the bike and in the cradle work perfectly ok? It is after all only charging current which pads easily handle.
.

 

[Deleted member 4366]

I can't see it working. Effectively, you'd need an on-board charger and induction coil, which will add weight. induction charging is great for flat things like phones and tablets, but would be a nightmare on an ebike. You'd be better off putting a dynamo in the front wheel and charge it by pedalling.

 

[MikelBikel]

I didn't know there were so many self-docking, self-charging and in some cases self-emptying robo-vacuums and robo-lawnmowers! Electric bike makers had better wake up? Hehe
Mikel

 

[Woosh]

I don't usually disagree with any of your comments, but I think you're over-dramatising an issue that doesn't really exist.

have you seen how people dock their rented Boris bikes?

Why wireless charging is the future:

http://batteryuniversity.com/learn/article/charging_without_wires

 

[Gubbins]

There has been talk of electrifying roads.. charge while you drive...
So to be of any practically use the current transfer would need to be high . Iwouldnt want to be inbetween the transmitter and receiver.. it might make my hair curl.. If I had any that is..

 

[Woosh]

it might make my hair curl.. If I had any that is..

TV transmitters are much more powerful than an e-bike charger.
there are also plenty of non-radiative wireless charging designs.
google up resonnant inductive coupling transfers.

 

[Gubbins]

I read that Apple is working on a room charger..
Not sure I want to be exposed to hair curling technology..
Unless it makes mine grow back.

 

[Woosh]

e-bike chargers use a small transformer to transfer the energy from the mains to the battery. When you look closely, what you do here is simply to replace that small transformer by a bigger one. The rest of the design differs little. Also, a little shielding can go a long way, like the mesh on the door of your microwave oven.

 

[Gubbins]

e-bike chargers use a small transformer to transfer the energy from the mains to the battery. When you look closely, what you do here is simply to replace that small transformer by a bigger one. The rest of the design differs little. Also, a little shielding can go a long way, like the mesh on the door of your microwave oven.

So what are you saying? To avoid exposure to a room charger that is transmitting some sort of radiation 24/7 i will need to wear mesh suit?

 

[Woosh]

So what are you saying? To avoid exposure to a room charger that is transmitting some sort of radiation 24/7 i will need to wear mesh suit?

you don't wear a mesh suit when you use your microwave oven because the mesh on the door stops 99.999% of the radiation. The body absorbs very little radiation below the microwave frequencies. E-bike chargers run between 10kHz to 100kHz, they don't even have mesh shields.
Nothing to worry about.

 

[Gubbins]

you don't wear a mesh suit when you use your microwave oven because the mesh on the door stops 99.999% of the radiation. The body absorbs very little radiation below the microwave frequencies. E-bike chargers run between 10kHz to 100kHz, they don't even have mesh shields.
Nothing to worry about.

Sorry, at cross purposes.. of was discussing wireless charging..

 

[Woosh]

Sorry, at cross purposes.. of was discussing wireless charging..

wireless charging is not different compared to your current e-bike charger.
The basic design is the same, except for the transformer that separates the battery side from the mains.