Bafang and Ezee brake sensor wiring (SOLVED)

[Andyvanman]

Hello

I'm a newbie to both electric bikes and this forum, but am rapidly getting to appreciate both!

I just put an Ezee high torque front wheel on a cargo bike (taking the kids to kindy etc.), but I've got Shimano hydraulic brakes on it.

In anticipation of installing the Ezee gear, I got a pair of Bafang BBS reed switch brake sensors (these here), which like the standard Ezee levers are open when the brakes are off, and have the same plugs on them.

Turns out that a high torque wheel on a very heavy bike with very good brakes doesn't really need brake cut-outs at all, but I thought seeing as how I already had them.........

However when I tried the Bafang sensors on my bike, the system started up incorrectly (some sort of error?), and the front wheel turns slowly regardless of whether the brake sensor is open or closed.

So I naively thought that both systems would just be using the open to closed circuit across 2 pins to sense brake activation, but that's obviously not the case.

Anyone know what the difference is between the 2 wiring systems please?

Cheers

 

[joss]

I don't know about the differences between the systems but the part you linked to (the Bafang part) is a 'hall effect' sensor which uses 3 wires. one wire for +VDC one for Ground and the other is the sense wire. The hall effect sensor detects the presence of a magnet which needs to be positioned on the brake lever.

 

[Andyvanman]

Thanks for your reply joss.

When I did a continuity test of both the 3 wire stock Ezee brake levers with sensors, and the 3 wire Bafang sensors, I got an open circuit across 2 pins when the brake lever was off, and when the magnet was next to the Bafang sensor, and a closed circuit when the brake lever was pulled, and when the magnet was moved away from the Bafang sensor.

I've never played with Hall sensors before, but is that how you would expect them to behave without any voltage across them?

It made me think that despite having 3 wires, they were both just 2 wire switches, the Bafang one being a reed switch.

If not, then that is what my problem might be....

Hmm, need to do a bit more investigating.

 

[joss]

Here is a link to a typical hall effect sensor

http://www.allegromicro.com/~/media/Files/Datasheets/A1301-2-Datasheet.ashx?la=en

The top of page 4 of the pdf describes how the voltage on the output pin changes from about half of the supply voltage (when there is no magnet present) up to the supply voltage (Vcc) when a magnet is present.

Hope this helps!

 

[Andyvanman]

Yup, that helps.

Just need to cut the wires on the Bafang sensors now and figure out which way round they need to go to match the Ezee wiring.

Cheers

 

[Andyvanman]

Just incase anyone else is trying to mate Bafang sensors to an Ezee system.....

Cut the wire on the Bafang sesnor and rejoin:

Plug side blue to sensor side black
Plug side red to sensor side blue and;
Plug side black to sensor side red.

Works just like a bought one.