Kill Switch-Brake cutoff switch

[Lectriceye]

Does anyone really know what the brake cutoff switch is doing. Please don't tell me what everybody knows: "when you pull the brake handle the a magnet opens or closes a switch (reed relay?), and cuts the power. What I want to know is this: There are 3 wires on the connector; +5 v, ground, and signal, Which 2 wires are being opened or closed to cut toff power in the controller. If nobody knows, I will waste a perfectly good sensor cable to find out, fortunately they aren't expensive. This looks like a very simple electrical circuit, I just don't know enough about controllers to figure out what is going on.

 

[AGS]

Some controllers only have a high brake input.

Some controllers only have a low brake input.

Some controllers have both high and low brake inputs, although you will only use one or the other.

High brake usually needs a 12 volt signal into the controller to cut the motor.

Low brake needs a 0v signal into the controller to cut the motor.

A 3 wire brake switch can cater for either of these two scenarios and you therefore wire the switch to suit whichever input your controller needs.

Some brake switches are magnetically operated.

Some brake switches are mechanically operated.

Some brake switches are 2 wire

Some brake switches are 3 wire.

Some people blow up the 5 volt regulator in their controller by connecting the brake switches incorrectly. Bafang BBS motors are particularly susceptible to this.

 

[Lectriceye]

Some controllers only have a high brake input.

Some controllers only have a low brake input.

Some controllers have both high and low brake inputs, although you will only use one or the other.

High brake usually needs a 12 volt signal into the controller to cut the motor.

Low brake needs a 0v signal into the controller to cut the motor.

A 3 wire brake switch can cater for either of these two scenarios and you therefore wire the switch to suit whichever input your controller needs.

Some brake switches are magnetically operated.

Some brake switches are mechanically operated.

Some brake switches are 2 wire

Some brake switches are 3 wire.

Some people blow up the 5 volt regulator in their controller by connecting the brake switches incorrectly. Bafang BBS motors are particularly susceptible to this.

Thanks for your detailed information, can you tell me the nature of the BBSHD magnetic switch, as used on a hydrolic brake sensor?

 

[AGS]

Here is a thread describing how to wire up the BBS brake cut out and more importantly how not to do it. If you get it wrong you will blow your controller.

Note from above, some brake switches are 2 wire and some are 3 wire.

The BBS has a 3 pin socket (yellow) so be careful if you have a 2 pin plug (red) from your brake switch.

Brake sensor wiring - again.

I have seen several threads her and elsewhere regarding adapting 2-pin brake sensors to 3-pin Bafang (BBSHD) connectors. I still am unclear about my specific situation. My question is really to ask owners of Tektro HD-E350 brakes what the actual switch function of the lever sensor is - normally...

endless-sphere.com

 

[Lectriceye]

Here is a thread describing how to wire up the BBS brake cut out and more importantly how not to do it. If you get it wrong you will blow your controller.

Note from above, some brake switches are 2 wire and some are 3 wire.

The BBS has a 3 pin socket (yellow) so be careful if you have a 2 pin plug (red) from your brake switch.

Brake sensor wiring - again.

I have seen several threads her and elsewhere regarding adapting 2-pin brake sensors to 3-pin Bafang (BBSHD) connectors. I still am unclear about my specific situation. My question is really to ask owners of Tektro HD-E350 brakes what the actual switch function of the lever sensor is - normally...

endless-sphere.com

Thanks again, I will check out the other thread. I think I will just cut a brake sensor cable in two at the middle (not connected to controller), and measure the voltage on the 3 wires coming from the controller when powered on, and then the resistance between the wires at the other end with and without the magnet in close proximity. This should tell me what I want to know. Thank you. What I really want to know is how to use one of the brake sensor cables to install a kill switch with an on/off button, without pulling on the brake lever. I have a hub motor and a BBS, the hub controller already has a kill switch integrated with the Throttle.

 

[docw009]

You don't have to cut any wires, if you have the little doodads that enable your multimeter to probe the connectors.

 

[AGS]

If you have a BBSHD then the kill switch can be wired across pins 4 and 8 on the brake switch socket in parallel with one of the brake switches.

So either the kill switch stops the motor or either brake switch.

 

[Lectriceye]

You don't have to cut any wires, if you have the little doodads that enable your multimeter to probe the connectors.
View attachment 358766

I don't have any doo dads, but I think I can make some, possibly buy some. And again thank you, shorting the #4 (Blue wire) to ground (Blk wire), does indeed cut the power. I use this as an extra safety to cut power to both motors when getting on and off the bike or doing something distrcting whle sitting still, incase I accidentally hit the throttle and have my bike surge when I am not expecting it.

 

[Lectriceye]

If you have a BBSHD then the kill switch can be wired across pins 4 and 8 on the brake switch socket in parallel with one of the brake switches.

So either the kill switch stops the motor or either brake switch.


View attachment 358765

One more question? do you know why Bafang included a +5 volt wire in the 3 wire configuration? seems strange to me.

 

[E-HP]

For sensors that require 5v.

https://www.amazon.com/L-faster-Hidden-Sensor-Electric-Without/dp/B0755DKC9V?th=1

 

[Lectriceye]

You don't have to cut any wires, if you have the little doodads that enable your multimeter to probe the connectors.
View attachment 358766

what are these doo dads called and where would I find them should I need them in the future?

 

[Lectriceye]

As it turns out the hub brake cut off's use a 2 wire magnetic sensor that function ike the 2 wires in the BBSHD sensor; thus I can spice in the existing left brake lever cut off sensor wires to the BBSHD controller cut off wires with the on/off kill switch. Kill 2 birds with one stone, so they say. It does simplify my cabling. I will have left side BBS LCD, throttle, power switch/power level, brake cutoff, and kill switch all on the the same side. On the right side I will have the Hub LCD, throttle, power switch/power level, brake cutoff and kill switch, nice symetry. Another benefit is using the left brake lever as a clutch for shifting, which is done on the right side.