Do I need brake sensors?

[AndyBike]

I can just picture the throttle jamming on full and being propelled through a junction and under a double decker bus.

 

[jimriley]

I can't recall whether mine broke on full power or not, whatever, I have brake cut off switches that would have saved the day at the junction.

 

[MikelBikel]

Another rare feature of *some* ebikes ebrakes is having the rear light act as a brake light while stopping in traffic. If controller has that capability. Useful?
Or have a "kill" button next to brake, just in case

 

[guerney]

Another rare feature of *some* ebikes ebrakes is having the rear light act as a brake light while stopping in traffic. If controller has that capability. Useful?

This can be fitted if not? Looks puny and small.

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[Downward]

I’ve lost the magnets on the yose power brake sensors.
Looking on amazon but no idea what size I need.

 

[Nealh]

5 or 6 mm dia by 2mm should do the job, one can always stack them as well if too weak.

 

[Az.]

My question is do I need connect brake sensors.
Is this kit will work without brake sensor connected?

I have Yosepower kit and ordered brake sensors as well. Didn't bother to install them though. Still have sensors unpacked somewhere. Kit will work without them.

Woosh made me think though. I might install sensors after all. Still don't think sensors are necessary, but they should help a bit in jammed throttle scenario.

 

[PC2017]

jammed throttle scenario.

I use mine as a clutch.

 

[Bonzo Banana]

Well at least some of the throttles are very cheap and dont enspire you that they would be long term reliable.

I can imagine the fun as you try to switch off the ebike as your speeding across a busy junction since the bike took off whilst you were waiting at the lights.

Most ebikes in the world have throttles its by far the most common control method and in China ebikes are dirt cheap averaging only around $200 to buy. I've watched couriers on youtube delivering for thousands of miles on throttle based ebikes and not once do I remember them reporting any issues with the throttle. A huge number of e-mopeds, e-scooters, e-motorbikes are throttle based and manufactured in China and again I've never actually heard of any problems although I'm sure there has been some. In contrast I've heard of many people having sporadic issues with cadence sensors where sometimes they work and sometimes they don't and they can have intermittant connection issues which means they don't function consistently or safely. It's easy to see why as most cadence sensors are fairly basic. I would of thought this was a far greater issue in the real world by numbers especially as they are exposed to dirt, moisture, physical damage, rain etc. The sometimes random and intermittent way they can operate meaning unexpected assistance surely would mean a greater need for brake sensors especially as some simple ebike controllers give full power instantly with a cadence sensor. Looking at hall sensors used in throttles they get an extremely easy life compared to hall sensors in hub motors and are contained within an enclosure. It feels to me the reliability of throttles is far superior to cadence sensors especially as there are so many more failure points with cadence sensors which also have a hall sensor I believe.

However all that said I would still use brake sensors on an ebike with a throttle I just don't see why they are less important with a cadence sensor if anything I would say they were more important with a cadence sensor due to greater unreliability. Also the strain gauge in torque sensors can be unreliable but it maybe when they fail it gives a automatic low reading which would stop assistance.

 

[Az.]

I use mine as a clutch.

Throttle as a clutch? Interesting... Can you elaborate please?

 

[Cadence]

As mentioned in post #13, my throttle developed a fault on Monday while riding. It wouldn't fully shut off without pulling it back with a finger. When I fitted the kit I wasn't going to bother with brake sensors as I have cable brakes with Shimano combined brake lever/shifters, and it's nigh-on impossible to fit sensors to them. I did, however see a mod on Youtube that an Australian guy had made using a magnetic sensor sold for hydraulic or cable brakes and decided to "refine" it.
It involves fitting a sensor on the rear brake cable near the rear cable stop on the top tube:-

The magnet is attached to a small piece of aluminum with a screw and nut. That is attached to an electrical terminal block threaded onto the brake cable. The terminal block screws allow for fine adjustment of the magnet along the cable relative to the sensor. It is contained in a piece of half-round D-LIne electrical trunking and the snap-shut cover stops it from getting knocked or wet:-

I did have to buy an extension lead for the sensor (cheap on ebay) and this runs down the seat tube and up the bottom of the down tube (contained in another piece of half-round trunking along with the 4-in-1 main cable).
If anyone wants to try this, I would just add that I don't think it would work on a steel frame due to the proximity of the magnet.

I fitted this as I thought it would be useful when wanting to change gears but not use the motor. A partial squeeze of the brake lever cuts out the motor before the brake is applied.
I didn't think I would need it due to a jammed throttle though!
I would just add that Yose have been very helpful and a replacement throttle is on its way.

 

[StuartsProjects]

There are brake sensors that will detect the movement of the brake cable inner directly. The inner just runs through the sensor, its not actually attached. Easy to fit.

 

[Bonzo Banana]

As mentioned in post #13, my throttle developed a fault on Monday while riding. It wouldn't fully shut off without pulling it back with a finger. When I fitted the kit I wasn't going to bother with brake sensors as I have cable brakes with Shimano combined brake lever/shifters, and it's nigh-on impossible to fit sensors to them. I did, however see a mod on Youtube that an Australian guy had made using a magnetic sensor sold for hydraulic or cable brakes and decided to "refine" it.
It involves fitting a sensor on the rear brake cable near the rear cable stop on the top tube:-
View attachment 51758
The magnet is attached to a small piece of aluminum with a screw and nut. That is attached to an electrical terminal block threaded onto the brake cable. The terminal block screws allow for fine adjustment of the magnet along the cable relative to the sensor. It is contained in a piece of half-round D-LIne electrical trunking and the snap-shut cover stops it from getting knocked or wet:-
View attachment 51759
I did have to buy an extension lead for the sensor (cheap on ebay) and this runs down the seat tube and up the bottom of the down tube (contained in another piece of half-round trunking along with the 4-in-1 main cable).
If anyone wants to try this, I would just add that I don't think it would work on a steel frame due to the proximity of the magnet.

I fitted this as I thought it would be useful when wanting to change gears but not use the motor. A partial squeeze of the brake lever cuts out the motor before the brake is applied.
I didn't think I would need it due to a jammed throttle though!
I would just add that Yose have been very helpful and a replacement throttle is on its way.

It doesn't sound like the hall sensor has failed in the throttle if its still operating to a point although you have to move the control slightly differently to switch off. Maybe inside the magnetised bar has moved from where it should be so the readings are not correct. It may be an easy repair and you could improve it perhaps with silicone sealant after repairing it to improve it over the standard model. Alternatively the hall sensor may have gone out of spec for some reason or the controller has a fault that means its not handling the throttle input correctly. I really don't think this is a common issue though.

 

[lenny]

Another rare feature of *some* ebikes ebrakes is having the rear light act as a brake light while stopping in traffic. If controller has that capability. Useful?
Or have a "kill" button next to brake, just in case

 

[Cadence]

It doesn't sound like the hall sensor has failed in the throttle if its still operating to a point although you have to move the control slightly differently to switch off. Maybe inside the magnetised bar has moved from where it should be so the readings are not correct. It may be an easy repair and you could improve it perhaps with silicone sealant after repairing it to improve it over the standard model. Alternatively the hall sensor may have gone out of spec for some reason or the controller has a fault that means its not handling the throttle input correctly. I really don't think this is a common issue though.

It's definitely the return spring inside not functioning propery. When the replacement arrives I might take a look inside, but more likely it will end up in the bin.

 

[lenny]

There are brake sensors that will detect the movement of the barke cable inner directly. The inner just runs through the sensor, its not actually attached. Easy to fit.


View attachment 51760

Pardon our interruption...

 

[afzal]

... In contrast I've heard of many people having sporadic issues with cadence sensors where sometimes they work and sometimes they don't and they can have intermittant connection issues which means they don't function consistently or safely. It's easy to see why as most cadence sensors are fairly basic. I would of thought this was a far greater issue in the real world by numbers especially as they are exposed to dirt, moisture, physical damage, rain etc. The sometimes random and intermittent way they can operate meaning unexpected assistance surely would mean a greater need for brake sensors especially as some simple ebike controllers give full power instantly with a cadence sensor. Looking at hall sensors used in throttles they get an extremely easy life compared to hall sensors in hub motors and are contained within an enclosure. It feels to me the reliability of throttles is far superior to cadence sensors especially as there are so many more failure points with cadence sensors which also have a hall sensor I believe.

However all that said I would still use brake sensors on an ebike with a throttle I just don't see why they are less important with a cadence sensor if anything I would say they were more important with a cadence sensor due to greater unreliability. Also the strain gauge in torque sensors can be unreliable but it maybe when they fail it gives a automatic low reading which would stop assistance.

Cadence sensors would be more prone to failure as compared to throttle. But a cadence sensor failure would not be catastrophic as in the case of open/jammed throttle. Cadence sensor provide a train of pulses under normal operation, the controller observing the continuous pulses (rather square wave) from sensor understands the pedal is rotating. In case of sensor failure, signal line would be held low or high - controller misunderstands this situation as pedal stop & motor assist would be stopped, no sudden accelerations would happen. And I can't think of a cadence sensor failure condition where it can provide a continuous train of pulses in the absence of pedal rotation.

 

[Woosh]

Throttle takes priority over the cadence sensor, so it is possible to use throttling to control

Cadence sensors would be more prone to failure as compared to throttle.

both are relatively fragile because they are exposed to the elements.
The most exposed is the magnet disc in an ordinary cadence sensor. Chains fall onto them, resulting in breakages. For that reason, a left side pedal sensor is much better.
The throttle is still preferable to a torque sensor. You get the same instant response without effort and simpler to replace.

 

[PC2017]

Edit just to clarify it's brake sensor as a clutch...

Throttle as a clutch? Interesting... Can you elaborate please?

Mostly changing to low gear before traffic lights, junctions etc, going to high gear for speed imo does not require a clutch.

Engage brake, enough to activate sensor & deactivate motor but not enough to engage brake pads (the way I have set mine up is extra sensitive) then change gear whilst pedalling to more of a "set off" friendly gear. I believe it should, at lower speed save strain/wear on the drive train. I have not done any research, however, and others with more mid drive knowledge may chime in, some bafang systems have a "gear sensor" on the gear cable that deactivates the motor between gear shifts, whether this sensor is both ways ie high & low I have never asked the question but assume it is.

I find putting thousands of mile per year on an ebike can take it's toll on wear & tear items, chain etc. It's not the cost per se, that I have an issue with it's only having dexterity in the warmer months to fix issues. I couldn't, but may have too, trust others to do a sound job when serving my bike but I fear I will find the odd bit not done to my/ebike kit safety standard.

Also, having sensitive brake sensors allows for good pedestrian management, if for example, you are on PAS 1(assuming KT system for custom settings) traveling at slow speeds around or near people (heading towards a bike rack etc) , having a brake cut off allows for low gear pedalling with disengaged motor for brief periods.

 

[PC2017]

not handling the throttle input correctly

I had a throttle magnet interfere with brake magnet before but not the other way round.