Use brake motor cut out as on/off switch

[leonard]

Hi everyone. I have an Urban Mover U36 which only has battery key for on/off. It's my wife's bike and she likes the choice of switching power off when on the flat, and we disarmed the throttle. I built a relay inside the battery casing (as there was room) and diverted the battery switch to the relay. I ran the relay activation wire to a handlebar switch via a small 12v rechargeable battery. This worked a treat but now I must refurbish the battery and maybe there won't be room for the relay.
Has anyone used one of the brake cut out cables as an on/off switch, or dosnt it work like that?
Any comments appreciated..

 

[Sturmey]

Yes. I have done that and it worked fine for me (like a motorbike 'kill' switch). Its important to know that although it stops the motor, the controller will still draw a small current that can run down the battery over a few days, so you still need to switch off the bike in the normal way when finished your trip/ bike not in use.

 

[leonard]

Yes. I have done that and it worked fine for me (like a motorbike 'kill' switch). Its important to know that although it stops the motor, the controller will still draw a small current that can run down the battery over a few days, so you still need to switch off the bike in the normal way when finished your trip/ bike not in use.

Brilliant thank you! I always remove battery at the end of ride anyway so that should work well. I only installed the relay on/off switch as I did not know of these forums, had no one to ask, and as it's not my bike I wanted to be absolutely certain that I had installed a 'kill' switch. Many thanks for your reply..

 

[Sturmey]

Brilliant thank you! I always remove battery at the end of ride anyway so that should work well. I only installed the relay on/off switch as I did not know of these forums, had no one to ask, and as it's not my bike I wanted to be absolutely certain that I had installed a 'kill' switch. Many thanks for your reply..

Just one further comment. The above is straightforward and works well with the common 2 wire mechanical switch type brake sensors. There is a 3 wire hall switch version that is a little more complicated and its possible to do damage if you short the 5 volts..

 

[Benjahmin]

All that needs to be done is that you slightly pull on the brake lever as you ride. Not enough to put the brake on but enough to operate the switch. It does mean holding the lever but, if it's well positioned, this isn't arduous.

 

[leonard]

Thank you Benjahmin. I feel I still require on/off switch but don't need brake cut outs as we have no throttle and only ride at comfortable off road speeds.

Sturmey, thank you for flagging a very important detail. I have yet to establish whether the U36 (of 2005) is two wire or three. If it is three, do you know a safe way of determining which wires to use please?...

 

[leonard]

I have two, 2 wire brake cut out cables, which should make it easier to do this. Thanks again for your help, I'll post again pending success...