Wisper: could the '1 revolution rule' be changed?

[allen-uk]

On Wispers, you have to turn the pedals through 1 revolution (360º) before the motor kicks in.

Why?

And would it be feasible in engineering terms to modify my Wisper 905 so that the motor kicks in as the pedals BEGIN to turn.

Are there any hub motored-bikes where the power comes through as you push the pedals?


A

 

[Mussels]

On Wispers, you have to turn the pedals through 1 revolution (360º) before the motor kicks in.

Why?

And would it be feasible in engineering terms to modify my Wisper 905 so that the motor kicks in as the pedals BEGIN to turn.

Are there any hub motored-bikes where the power comes through as you push the pedals?


A

The power cuts in on my 906 before a revolution is done, is yours last years model?

 

[MAB]

The power cuts in on my 906 before a revolution is done

Likewise, half a revolution to be precise!

Regards,

Mike.

 

[onmebike]

I'm not familiar with the Wisper, but if using a magnetic disc on crank, fitting a disc with 1 or 2 more magnets may do the trick.

 

[allen-uk]

Definitely 2010 - from Powabikes a month ago, and 6 weeks ago still on the high seas from China.

But you've now worried me. I shall be going out now (to retry the pedals!). I might be some time.


A

 

[allen-uk]

Ahem.

Can I rephrase my question?

=====
On Wispers, you have to turn the pedals through 1/2 a revolution (180º) before the motor kicks in.

Why?

And would it be feasible in engineering terms to modify my Wisper 905 so that the motor kicks in as the pedals BEGIN to turn.

Are there any hub motored-bikes where the power comes through as you push the pedals?


A
-----
(Put it down to old age and dopeyness).

 

[Vikki]

You may notice that if you pedal backwards the motor doesn't start at all. This is because the magnets are not evenly spaced and this asymetrical spacing allows the controller to know which way the crank is rotating. It takes 3 magnets passing under the sensor to determine the timings between each magnet to determine the direction.

If the motor started on the first pulse it saw from the sensor, that could be dangerous. If you are waiting at lights, brakes not pulled in, then just rocking the pedals would cause the motor to start.

My old PowaByke Euro 6 wouldn't start until it was up to 2 mph. A safety feature. That 2 mph equated to 2 turns of the crank. It also would start regardless of which direction the crank moved in.

Hope that helps .

Vikki.

 

[Straylight]

I suppose an instant start could be achieved with a torque sensor, and it would be safe as there is virtually no torque involved when back-pedaling. This would make the whole thing more complicated though. I personally prefer to have the bike in low pedelec mode, then use the throttle to apply power as required, and find this means that I can have instant motor assistance if I want, as well as being able to gently ramp in the motor to save the useless waste of energy when setting off from a standing start.

 

[overlander]

I really do not think an instant start would be a wise idea. There would be many a time when you move the pedals by accident or like previously said rocking etc. I think half a turn sounds reasonable possibly 1/4 turn at the min.

 

[allen-uk]

Points taken about the possible hazards. Maybe the 1/4 turn would be feasible.

I ask not because I should have bought a Kalkhoff (talking of which, why doesn't the 'hazard principle' apply to them?), but because I often need electric assistance when I start from stationary, and I COULD achieve it with the pedals, but the 1/2 turn can make the process a bit wobbly.

A

 

[eddieo]

I really do not think an instant start would be a wise idea. There would be many a time when you move the pedals by accident or like previously said rocking etc. I think half a turn sounds reasonable possibly 1/4 turn at the min.

Me neither, I feel there is nothing wrong with system "as is"

just use the throttle.........

 

[garrence]

I'd have thought a half-width twist throttle would offer better control.

If you didn't want to hold it open, then perhaps a push button to start the motor and microswitches on the brake levers to stop it? Maybe with a dial for speed.

 

[Vikki]

I ask not because I should have bought a Kalkhoff (talking of which, why doesn't the 'hazard principle' apply to them?)

Because they work on a completely different principle. Because they use your input as a measure to multiply, the motor has to respond instantly by giving that multiple of your input power.

Best regards.

Vikki.

 

[CeeGee]

I personally prefer to have the bike in low pedelec mode, then use the throttle to apply power as required, and find this means that I can have instant motor assistance if I want, as well as being able to gently ramp in the motor to save the useless waste of energy when setting off from a standing start.

That's the way to do it.
Other "solutions" involve added parts, with added things to go wrong and, of course, added cost.

Colin

 

[Wisper Bikes]

Hi Allen

The reason the half turn is needed before the motor starts is for two reasons, firstly is saves a massive amount of power and gives you better range in stop start journeys and secondly is for safety reasons so the bike does not scoot off as soon as you put pressure on the pedals.

Our USA spec bikes with full throttle capability can of course access power from stand still.

All the best

David

 

[Wisper Bikes]

I personally prefer to have the bike in low pedelec mode, then use the throttle to apply power as required, and find this means that I can have instant motor assistance if I want, as well as being able to gently ramp in the motor to save the useless waste of energy when setting off from a standing start.

Thanks SL, this is exactly why the throttle is there, far better to choose your own level of assistance than let a torque sensor do it for you, a torque sensor cannot calculate a riders level of fitness, hence the reason we have steered clear. The throttle assist is more simple and can be adjusted by the rider as often as is necessary and becomes second nature.

All the best

David

 

[dan]

My old PowaByke Euro 6 wouldn't start until it was up to 2 mph. A safety feature. That 2 mph equated to 2 turns of the crank.

Vikki.

Not designed as a safety feature, it was designed to reduce the drain on the battery. The most energy is drained from the battery when going from standstill, by only engaging the power when the bike reached 3.3 kph it incresed the range. When it was realised that some people would find that difficult to do a simple device was developed to bypass this feature. I think they are still available from Powabyke.

 

[allen-uk]

Just trying to pin down the odd logic in some of these points.

Why don't the Kalkhoffs represent a safety hazard? I KNOW they operate on a different principle, but the SAME safety principle is involved, i.e. scooting off from stationery by applying pedal pressure.

Why don't the Americans have safety problems when they 'access power from standstill'?

I do know that using power to move away from standstill is a big drain on the battery - it's just that only having ONE leg, the main reason why I chose Wisper over Kalkhoff was precisely so that I COULD get power from standstill - obviously, I knew that was only on the throttle, but since riding it for a month or so questions do occur to me, like 'why?'

Allen.

 

[flecc]

Why don't the Kalkhoffs represent a safety hazard? I KNOW they operate on a different principle, but the SAME safety principle is involved, i.e. scooting off from stationery by applying pedal pressure.

Two reasons. The Panasonic unit has the best torque sensor of all e-bikes, very precise in it's operation, so the rider's degree of pressure on the pedal dictates the power of the take off. Secondly, the power signalled from that pedal thrust only operates for that one downthrust. A hub motor bike once taking off tends to continue in the same manner and overrun somewhat after pedalling stops. Having punched a hole in a panel door with a bike after touching the pedal with it switched on, I know only to well how true this is.

Why don't the Americans have safety problems when they 'access power from standstill'?

E-bikes tend to be leisure vehicles for playing around on in the USA, much of the time in far more space than we have, or off road. Their e-bikes are often high powered and used more in motorcycle fashion.
.

 

[Wisper Bikes]

Just trying to pin down the odd logic in some of these points.

Why don't the Kalkhoffs represent a safety hazard? I KNOW they operate on a different principle, but the SAME safety principle is involved, i.e. scooting off from stationery by applying pedal pressure.

Why don't the Americans have safety problems when they 'access power from standstill'?

I do know that using power to move away from standstill is a big drain on the battery - it's just that only having ONE leg, the main reason why I chose Wisper over Kalkhoff was precisely so that I COULD get power from standstill - obviously, I knew that was only on the throttle, but since riding it for a month or so questions do occur to me, like 'why?'

Allen.

Flecc's points are as always spot on. With the Panasonic unit as soon as you stop putting pressure on the pedals the power stops so would be completely useless for someone with one leg. However the safety feature is exactly that, as soon as you stop pedalling the motor cuts. Most speed sensor pedelec motors do not cut after the pedals stop turning until the bike has traveled for at least 2M this gives us the nice smooth power delivery we all love. 2M is the figure used in the new EN regulations when considering whether a pedelec needs brake cut outs or not. If a pedelec can travel under power for more than 2M after the cyclist stops pedalling the brakes must have a cut of installed.

As Flecc says, in the US they are far less fussy about the finer points and virtually anything goes!

All the best

David