Tektro hydraulic sensor (2 wire) splice to Bafang sensor (3 pin)

[robertscreek]

Hey all - question about splicing wires from brake levers and connecting to brake cutoff lines on a mid drive kit.


I have a Bafang mid drive kit and Tektro Durado hydraulic brake kit (HD-E725).

The bafang comes with 3 pin connectors for brake sensors. I have a set of magnetic sensors for hydraulic brakes that connect to the bafang.

The brake levers come with an installed brake sensor. There are bare blue and black wires coming out of the sensor (see pic).

I would like to use the installed brake sensor from the levers if possible. My idea is to snip the magnet off the end of the sensor cable and splice that to the blue/black wire on the brake lever.

Anyone dealt with this before? Snipping and splicing wires triggers warning bells for me so thought I would ask the experts. Also I know the magnetic sensor cable to the bafang is 3pin so not sure how to go about connecting these to 2 wires in the lever.

First time post. Thanks for all the great content.

 

[Dewey]

I have not done that but this thread on the Endless Sphere forum appears to answer your question https://endless-sphere.com/forums/viewtopic.php?t=104775

A German company makes 2-wire to 3-wire higo adaptors for Magura ebrake levers, you might want to ask if you buy a 2-pole male mini-b connector with pigtails if you could wire it up to their connector to make the Tektro ebrake work https://www.e-bike-technologies.de/...cables/adapters-signal/higo-a-bb-b2-s3-detail

Alternatively buy the glue on magnet ebrake sensor, I’ve done that with my Sturmey Archer drum brake lever to make an ebrake sensor that works with my BBS01 https://california-ebike.com/products/bafang-hydraulic-brake-sensors

 

[harryS]

Done it the other way around, connecting a three wire sensor to a two wire controller input. The sensor happened to be a 3 wire chip with power, ground, and signal. Controller brake input is signal/ground. Ignore power, signal-signal and ground-ground worked.

OP's case is three wire input with two wire sensor? I do that all the time with my KT controller brake input. Ignore the +5 power. Connect brakes between the other two signals. If the sensor is not a reed switch, nut a semiconductor, it might have to be reversed if it doesn't work the first time.

 

[robertscreek]

Amazing thanks all I'll post back with results.

 

[robertscreek]

Worked a treat - for me it was black to black and red (cable side) to blue (lever side)

 

[rawB]

Hello.. i spoke to Tektro Customer Service David 801-648-7237 abut this very issue..
The wiring diagram for a Bafang 3 pin connector:

https://imgur.com/VFrWhip

of the two bare wires off the bottm of the E700 series and E525 lever,
The Blue is positive, the black is negative.
You can cut a Bafang Ebrake extender cable, there will be three wires,
Then solder or Anderson connect the corresponding color wires.
Always check the Bafang wires for polarity while it is pluged into the Bafang harness,
And that will tell you which is positive and which is negative..
David from Tektro can step you thru this.. He is located in Utah.

 

[rawB]

or just take it to your ebike mechanic... They understand how to connect a 2 bare wire to a Bafang 3pin connector.

 

[harryS]

Sure they do,

 

[rawB]

Barry. i'm working on this project now. I cut the cable off my unused bafang brake lever (for cable actuated brakes).. That is the end you need to plug into the harness (for brake power cut off). I stripped the outer cable housing, and there are 3 fine wires, Red-Black'White.. it made it really simple. No guess work. I connected the wires from Etektro lever. I connected Blue (positive) bare wire to the Red on the Julet cable from the ebrake that came with the Bafang kit. I'm not electrically inclined, but this was simple. blue or red are positive and black is always negative.. Just delete white.. All is good.. May God be with you and your family.

 

[rawB]

Photo
ebay.com/itm/224926124648?hash=item345ea44a68:g:YOwAAOSwg3ViTyvc

 

[tomjasz]

black is always negative..

Oh? What if the power is blue and brown?

Like many Chinese electronics.

“The UK changed the standard wire colours in 2004: The live Red becomes Brown. The Neutral Black becomes Blue. The Earth wires continue to be Green and yellow.”

 

[rawB]

the bare wires off the Tektro HD E525 and E700 series, are blue and black according to Tektro CS...
If you're using Bafang Julet cables like the one in the photo. it will be red/black/white...
If you have other colors that these, i imagine you have a model intended for a market other than USA market.. ..
If you have a cable intended for the UK market, then use their color coding..
May God be with you my friend..

 

[tomjasz]

i imagine you have a model intended for a market other than USA market.. ..
If you have a cable intended for the UK market, then use their color coding..

It’s not at all unusual for makers to ship blue and brown to ALL markets. Making your second comment just as incorrect as your “all” declaration.

 

[rawB]

ok.. i bought my E525 directly from Tektro (USA) website located in Utah.. i used the bafang cable that came with my kit. This was my experience. good luch my friend. Sounds like you have something i've never seen before and that is something you will need to figure out. PEACE

 

[uncledustcomedy]

Barry. i'm working on this project now. I cut the cable off my unused bafang brake lever (for cable actuated brakes).. That is the end you need to plug into the harness (for brake power cut off). I stripped the outer cable housing, and there are 3 fine wires, Red-Black'White.. it made it really simple. No guess work. I connected the wires from Etektro lever. I connected Blue (positive) bare wire to the Red on the Julet cable from the ebrake that came with the Bafang kit. I'm not electrically inclined, but this was simple. blue or red are positive and black is always negative.. Just delete white.. All is good.. May God be with you and your family.

I see you have some experience with the " brake power cut off " , will an Ebike experience issues if you replace a rear brake without the " brake power cut off " cable but front brake will still be connected to cut off ? Or even disconnect both cut offs would there be any effect other than losing that feature?

 

[mclewis1]

The brake power cut out/off features are a simple safety feature but aren't always present in many DIY installations. They are a form of "belts and suspenders" approach to the risk of the motor moving your bike when you don't want or expect it to. For most folks (especially those with some experience) the concern over this risk is very small and the braking action available from just casually holding in a brake lever is usually enough to overcome any unwanted motion.

If you want the cut out feature and usually apply both front and rear brakes together when stopped (say at an intersection) then you can easily get away with just having the cut out feature on one or the other brake levers. There is only slightly more risk (and only a very very slight increase) if only one lever has the cut out.

Most cut out electronics have each brake sensor wired to the controller separately, so removing one usually doesn't affect the operation of the other. But obviously it would be good to test everything if you remove one.