Ebike brake lever with power cut off

[DiggyGun]

One of our ebikes has Wuxing power cut off brake levers. Unfortunately the distance from the lever to handle is a bit too far for my wife to use safely/ comfortably. It has no lever adjustment.

Can you get ebike power cut off levers that can be adjusted for brake pull or are there ones with a smaller lever pull distance?

 

[PC2017]

You can get brake sensors and fit standard bike brakes, however the sensors can be expensive on ebay, and you will need to match the connectors to that of your wuxing brakes. I can not remember them been that much of a reach maybe you got a faulty batch, contact the supplier. You should also be able to remove the brakes and the add standard brakes the kit should work without them albeit the motor will not cut off when you brake.

 

[Deleted member 33385]

That does look way too large a reach - the furthest point of the brake lever to the handle on mine (Bafang BBS01b) is 6.5 cm. Have they attached the wrong handle to the wrong brake case at the factory?

 

[vfr400]

If you're any good at wiring and soldering you can use hidden wire brake sensors (HWBS) that go on the cables, then use any levers you want, or you can use a reed switch and magnet on the brake cable. There are all sorts of solutions depending on your DIY skills.

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[DiggyGun]

You can get brake sensors and fit standard bike brakes, however the sensors can be expensive on ebay, and you will need to match the connectors to that of your wuxing brakes. I can not remember them been that much of a reach maybe you got a faulty batch, contact the supplier. You should also be able to remove the brakes and the add standard brakes the kit should work without them albeit the motor will not cut off when you brake.

The bike is a Cyclotricity Sahara 16” frame.
You mention about adding standard brakes with no power cut off. Why is a power cut off needed when there is no throttle.

The motor is a hub type fitted to the front wheel, does it only work when you are pedalling.

 

[sjpt]

You mention about adding standard brakes with no power cut off. Why is a power cut off needed when there is no throttle.

Two reasons. There is always a lag between stopping pedalling and motor cutting out; a cadence sensor needs time to make sure you really have stopped. If you are in an emergency situation you don't want the motor pulling you forward when you slam on the brakes.

Conversely, if you are in a very slow maneuver (eg through safety railings) you don't want the motor suddenly to kick in half way through because you did just enough pedal turn for the sensors to register.

p.s. They are not needed with torque sensor ebikes, the above arguments do not apply to those.

 

[DiggyGun]

Two reasons. There is always a lag between stopping pedalling and motor cutting out; a cadence sensor needs time to make sure you really have stopped. If you are in an emergency situation you don't want the motor pulling you forward when you slam on the brakes.

Conversely, if you are in a very slow maneuver (eg through safety railings) you don't want the motor suddenly to kick in half way through because you did just enough pedal turn for the sensors to register.

Thanks for explains that.
Next question is. If we fit standard brakes with a lever adjuster, how do you fix the HWBS to the lever body. Is there a recommended pairing of a standard brake lever and a HWBS. I’ve checked the Wuxing cable and it appears to be two wires, so is a case of splicing the wires from the HWBS to the existing cable

 

[sjpt]

There are two parts to the sensors. A magnet that is fixed to the moving handle part of the brake lever and the sensor itself which is fixed to the body of the lever and includes the electric cable. Generally fixed by strong glue. We fixed the magnet by electrical tape to make sure we could adjust it if needed. We never needed to adjust it, but the sticky tape is still working well nearly 3 years later.

It's just a two wire connection, on/off switch. You'll probably find you can just unplug the existing lever cable from the controller or display (whichever it is plugged into) and plug the sensor kit cable in instead. If there are any problems such as different connectors, insufficient cable lengths or the sensor hard-wired in then you could cut and splice the new and old.

If you are a bit handier you can disassemble your current brake levers and extract the relevant parts.

 

[vfr400]

Thanks for explains that.
Next question is. If we fit standard brakes with a lever adjuster, how do you fix the HWBS to the lever body. Is there a recommended pairing of a standard brake lever and a HWBS. I’ve checked the Wuxing cable and it appears to be two wires, so is a case of splicing the wires from the HWBS to the existing cable

The HWBS threads over the inner cable, like it's part of the outer. it's 50mm long, so you cut off 50mm of the outer cable to compensate, or get a new inner cable. They're directional, so you have to fit them at the correct end of the cable, or you can cut the outer wherever you want and install it there. They're designed so that the outer cable fits in one end and the peg on the other goes into the cable stop, so if you fit mid cable, you need to install an end-stop adapter.

The wiring is straight-forward. They have three wires. Make sure that you know which wire does what. There are more than one colour set, but the silvery coloured HWBSs are normally red 5v, yellow ground and blue signal. One side of your present two wire connector is 5v (striped or any colour), which is the signal wire, and the other side is ground (black). You connect those black to yellow and signal to blue. The 5v red wire has to be spliced into any of your 5v wires, which are, the motor hall sensor red, the pedal sensor red (sometimes brown) or the throttle red if you have one.

Note that the 5v in your present signal wire is not a real 5v. That's what you see with a meter, but it can't power anything. It's just a signal 5v, which gets pulled down to ground by the switch

You only need one brake sensor. If you want 2, you can connect them in parallel to the same connections.

 

[TooManyBikes]

I posted this on the CyclingUK forum but you can get Wuxing ebike levers with a longer lever and a less steep angle. These might do? https://torquetech.co.uk/products/wuxing-47pdd-electric-bike-e-bike-mechanical-brake-lever-pair-cutout?variant=10154903109679