pendix crank motors

Electrically assisted bikes, trikes, etc.
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[XAP]Bob
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Re: pendix crank motors

Postby [XAP]Bob » 12 Nov 2017, 9:11am

My very brief test of the steps system on an ice trike showed no discernible lag between pushing and getting kicked up the rear. But there is a lag on my throttle controlled motor ;)
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reohn2
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Re: pendix crank motors

Postby reohn2 » 12 Nov 2017, 6:25pm

I can't say we've noticed any lag of the power coming on when we start pedalling.
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willcee
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Re: pendix crank motors

Postby willcee » 15 Nov 2017, 6:24pm

http://ebiketips.road.cc/content/review ... ystem-622..
sent this by one of the UK stockists.. in my view i would leave it until i could either try one myself or read a bloody practical roadtest.. will

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willcee
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Re: pendix crank motors

Postby willcee » 15 Nov 2017, 6:25pm

sent this by one of the UK stockists.. in my view i would leave it until i could either try one myself or read a bloody practical roadtest.. disillusioned somewhat ...will

http://ebiketips.road.cc/content/review ... system-622
link won't paste in full but if you look for reviews at the headers and pendix its there..

kwackers
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Re: pendix crank motors

Postby kwackers » 15 Nov 2017, 8:53pm

reohn2 wrote:I can't say we've noticed any lag of the power coming on when we start pedalling.

Do you have a torque sensor or is it simply a "the pedals are rotating" sensor?

The mid drive unit I'm using has a "the pedals are rotating" sensor. It also looks at the cadence to work out the amount of assist.
There's definitely some lag there, I'd say about a tenth of a turn before the motor kicks in and when you stop pedalling probably less than half a second before it drops out again.
(Apparently the standard setup is ball ox and looking online there are some setups that are much better but I haven't tried them yet.)

It's interesting that in the review willcee posted the lack of lag seems to be a major bugbear, if one isn't a smooth pedaller then the drive is choppy - i.e. it multiplies up the torque at any given point.
Should be easy to fix in software but only by introducing some lag...

I'm somewhat less sure now of my original thought that torque sensors are the answer. Seems things aren't quite that simple...

reohn2
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Re: pendix crank motors

Postby reohn2 » 15 Nov 2017, 11:11pm

kwackers wrote:
reohn2 wrote:I can't say we've noticed any lag of the power coming on when we start pedalling.

Do you have a torque sensor or is it simply a "the pedals are rotating" sensor?

The mid drive unit I'm using has a "the pedals are rotating" sensor. It also looks at the cadence to work out the amount of assist.
There's definitely some lag there, I'd say about a tenth of a turn before the motor kicks in and when you stop pedalling probably less than half a second before it drops out again.
(Apparently the standard setup is ball ox and looking online there are some setups that are much better but I haven't tried them yet.)

It's interesting that in the review willcee posted the lack of lag seems to be a major bugbear, if one isn't a smooth pedaller then the drive is choppy - i.e. it multiplies up the torque at any given point.
Should be easy to fix in software but only by introducing some lag...

I'm somewhat less sure now of my original thought that torque sensors are the answer. Seems things aren't quite that simple...

It's a PAS(Pedal Assisted Sensor)mounted on the rear crank axle,power kicks in instantly when we begin to pedal,and stops when we stop.
The only time I've noticed any kind of interruption or lag in motor power is when we change down under pressure ie; on a climb,there seems to be a slligghtt stoppage in power output from the motor for a fraction of a second.We've not noticed any other power interruption or lag in power.
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kwackers
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Location: Warrington

Re: pendix crank motors

Postby kwackers » 16 Nov 2017, 9:06am

reohn2 wrote:It's a PAS(Pedal Assisted Sensor)mounted on the rear crank axle,power kicks in instantly when we begin to pedal,and stops when we stop.
The only time I've noticed any kind of interruption or lag in motor power is when we change down under pressure ie; on a climb,there seems to be a slligghtt stoppage in power output from the motor for a fraction of a second.We've not noticed any other power interruption or lag in power.

I'm probably being oversensitive.
Without a torque sensor there has to be some movement of the pedals and from a standstill the motor has to feed in power to avoid snatch.
The engineer in me wants to fiddle though...

Interesting you get a power dip when you change down, I'm guessing that's something to do with the sudden increase in cadence.

reohn2
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Re: pendix crank motors

Postby reohn2 » 16 Nov 2017, 9:46am

kwackers wrote:
reohn2 wrote:It's a PAS(Pedal Assisted Sensor)mounted on the rear crank axle,power kicks in instantly when we begin to pedal,and stops when we stop.
The only time I've noticed any kind of interruption or lag in motor power is when we change down under pressure ie; on a climb,there seems to be a slligghtt stoppage in power output from the motor for a fraction of a second.We've not noticed any other power interruption or lag in power.

I'm probably being oversensitive.
Without a torque sensor there has to be some movement of the pedals and from a standstill the motor has to feed in power to avoid snatch.
The engineer in me wants to fiddle though...

I don't think the motor has enough power in it to offer any discernable snatch either two up or when ridden solo,it's definitely off or on but we/I have only ridden from a standing start on No2 of 5 power settings.

Interesting you get a power dip when you change down, I'm guessing that's something to do with the sudden increase in cadence.

Yes it surprised me a bit though it's only momentary.
Thinking about it,it shouldn't switch off as cadence of any variance powers the motor,with the bike hung up in the workshop the slliigghhtteesstt turn of the pedals and the motor powers up,changing up or down chainrings or on the cassette doesn't make any difference the motor doesn't hesitate,so I can only think its some thing to do with load.
It's a bit of a puzzle that one :| .
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I cycle therefore I am.