One ebrake to tail light and controller( No CA)

[nickceouk]

I need to operate my ebike taillight with the same 2 wire (NO) ebrake that is wired to the controller Baserunner.
The taillight is powered with battery voltage and individual switch with turnlights which is great for a headless setup like mine.

The problem is that I need to operate both the taillight stop light when the lever is pressed and the motor braking.
The taillight has a harness and two of the connectors are for the 2 brakes. I checked the voltage against ground and it was 40V.
On the controller side the voltage is 0.85V which also gets pulled to Gnd when pressed.

I can alternate to connect the lever to either control the motor(grounding the 0.85V) or the taillight (grounding the 40V) but can not get it to do both.
I should mention that because of how things need to be set for this controller the ebrake is returning signal to the same line that the throttle does ( Baserunner headless, dictated this arrangement) when wired to stop the motor.

Any clues?

 

[AGS]

You could consider using the front brake for cutting the motor and the rear brake for operating the tail light. This is what I have done to keep it simple.

 

[glennb]

I need to operate my ebike taillight with the same 2 wire (NO) ebrake that is wired to the controller Baserunner.

It’s doable. To avoid additional wiring to the brake lever, you could:

A) as suggested, use a single lever switch for each function

B) leave the wiring alone and implement a sensor to detect deceleration (which in turn triggers the brake lights)

C) Use lever switches to activate a DPST 40V coil relay

D) implement other even more convoluted methods

However, the real need is only …

… to operate both the taillight stop light when the lever is pressed and the motor braking.

And that’s simpler to achieve.

All you need is two wires, a magnet, a reed switch, and some glue.

Or a prebuilt kit (commonly sold for adding after-market brake switching on hydraulic levers).

 

[nickceouk]

I need to operate my ebike taillight with the same 2 wire (NO) ebrake that is wired to the controller Baserunner.
The taillight is powered with battery voltage and individual switch with turnlights which is great for a headless setup like mine.

The problem is that I need to operate both the taillight stop light when the lever is pressed and the motor braking.
The taillight has a harness and two of the connectors are for the 2 brakes. I checked the voltage against ground and it was 40V.
On the controller side the voltage is 0.85V which also gets pulled to Gnd when pressed.

I can alternate to connect the lever to either control the motor(grounding the 0.85V) or the taillight (grounding the 40V) but can not get it to do both.

I should mention that because of how things need to be set for this controller the ebrake is returning signal to the same line that the throttle does ( Baserunner headless, dictated this arrangement) when wired to stop the motor.

Any clues?

You could consider using the front brake for cutting the motor and the rear brake for operating the tail light. This is what I have done to keep it simple.

What I think will happen is I will need to press both levers same time all the time to imitate the desired result and eventually just press the one that cuts the motor ignoring the tail light. At that point I will have to ask myself why did I even connect the taillight if not used and connect that to also cut the motor.
I will also feel that I have managed to get something working but can't take proper advantage of the hardware I have which really sucks.

 

[nickceouk]

It’s doable. To avoid additional wiring to the brake lever, you could:

A) as suggested, use a single lever switch for each function

B) leave the wiring alone and implement a sensor to detect deceleration (which in turn triggers the brake lights)

C) Use lever switches to activate a DPST 40V coil relay

D) implement other even more convoluted methods

However, the real need is only …

And that’s simpler to achieve.

All you need is two wires, a magnet, a reed switch, and some glue.

Or a prebuilt kit (commonly sold for adding after-market brake switching on hydraulic levers).

I have seen those ebrake kits with magnets and this definitely ticks most of my requirements and overall feels like the best solution for me.

Thank you, I really appreciate it!

 

[glennb]

Glad to be of assistance.

Check whether the contacts are NO or NC on those things.

Measure the light’s current draw.

Check the reed switch current handling. Little reed switches are typically 100mA. 1000mA reed switches are actually rather large, so the pre-made kits won’t be using these. You might need >100mA, and want some overhead to play with. 300mA would definitely be preferable to 100mA.

Pre made kits should’ve accounted for this, but the magnet strength, magnet location, and switch orientation to the magnetic field, are all critical to when the switches engage and release.

You can play around with it yourself when you have some in your hands to do so. Or just muck around with a speedometer, cadence sensor, or cupboard door light, in the meantime.

They’ll actually engage and release at different points in your lever throw. And if you bodge the locations and orientations might engage at the start of the lever throw, and disengage towards the end of the lever throw (with lever approaching handlebar). They behave unusually with 45 degree orientations.

You might not want the switch to engage until partially into the lever throw, to avoid following vehicles getting flashed when you’re only gently pulling on the lever in preparation of real braking.

With your ear in close proximity you’ll be able to hear the switching. But that’s subject to background noise, and a visual indicator, such as multimeter resistance value, is preferable for setting them up.

They’re fiddly to get right if you’re a perfectionist. It’s far less critical for brake lights, but for activating regen on my scooter I’m very particular about the degree of lever throw I want it to engage at.

Cable ties and tape and such are your friend for trial positioning. Having a range of magnet strengths and shapes and sizes on hand can open up a greater range of positioning options (in order to be able to hide the assembly, and/or neaten the wiring).

But, it’s only for a brake light, and you’re going with a pre-made kit with installation instructions, so you can likely disregard all the above except for the remarks concerning NO/NC contacts and current handling.

 

[amberwolf]

You can wire up a relay easily enough. Use two very small 5v-coil relays, they can be SPST NO, but DPST or DPDT works too (it has both NO and NC); I use some out of a dead UPS (power backup) on SB Cruiser; these are almost always DPDT (sometimes SPDT) with 5v coils.

Two SPST NO relays isolates everything, but one relay is enough if they are DPDT or DPDT NO and saves some coil current.

Assuming your ebrake switches on the levers are wired in parallel, and are momentary NO SPST (two wire), you'll connect one of their wires to controller ground, and the ohter to one side of the coil of both relays.

The ohter side of the coils is wired to controller 5v. (if the controller has 12v available, you can use that instead and use 12v-coil relays) When the lever is pulled, it provides current thru the coil and engages the relay.

You also need a diode wired "backwards" (arrow toward positive) across the coil, to absorb the tiny voltage spike that happens when the coil power is turned off, to protect the controller.

Common of one relay goes to ebrake signal input of the controller (or cycle analyst, in my case). NO contact of same relay goes to controller ground.

Common of other relay goes to brake light input. NO contact of same relay goes to whatever activates that light (voltage, or ground).

See my variable-regen brake lever thread for some pics of what I use (it has three relays because it *also* switches the throttle signal from the thumb throttle to the brake throttle, which you don't need) for my ebrake to the CA isolated from my 12v brake light system.