The Mighty Volt wrote:AFAIK, the BMS plugs into the brake-connector of the controller.
Correct, if it's like my v2.6 BMS, it's output can be used to engage the ebrake to disable the controller.
BUUUUUUT: if you are using regen braking DO NOT DO THAT.
It won't just disable the controller, it'll drag you to a sudden unexpected stop from whatever speed you were at, instead.
Not only that, you won't even be able to pedal the bike until you turn off the controller/motor system, because it'll put all the drag it can on the motor continuing to try to brake you.
What you will want to do instead is to set up a relay or a transistor switch to the BMS output to disconnect the thin red wire from main battery power instead, so that it "turns off the ignition" of the controller instead, letting you still coast.
i have the two white wires, can I wire these into a Universal Handlebar Switch for braking??? Or do I have to use the yellow/black wires of the controller.
All the white ones do is engage or disengage regen capability. Yellow/black actually engage braking, so those need to go to your brake lever or whatever switch you are going to use to brake with.
Are there any special considerations I need to bear in mind? What happens to my battery when I regen?
It charges, assuming the BMS allows it to. That's how regen works--voltage from the motor becomes higher than that of the battery, causing current to flow into the battery and placing a mechanical load on the motor, making it slow down.
One conditions under which the BMS might not allow it to is if the battery is already fully charged, the HVC of the BMS will disable the controller, disabling regen braking, too, as soon as the regen voltage rises to or above the HVC.
I won't have a mechanical rear brake, too much effort setting it up, welding etc.
I will have a mechanical front disc brake for basic stopping needs.
Make SURE that brake can stop you completely even if the regen doesn't work at all. Regen is a complex system, requiring the motor, controller, battery, BMS, and brake switches all to work correctly over a wide voltage range. Lots of things can cause "issues" with it (but hardly ever do), and an issue at high speed where you need to stop quickly means you better have a mechanical brake that will let you do that.