Using an on/off switch as a throttle with BAC-281 controller

[Esu]

Hello, I have a question, but can not post it in some another place. So, I will post this question here:
- I have a BAC-281 controller and want to use it without throttle. So, I want to replace throttle with a simple on/off switch. As I know the throttle get 5volt and send signal of about 3,5 volt for full speen or less volt for lower speed. So, my question: which resistor (how many Ohm) I need to buy to make from 5 volt A: 3,5 volt and B: 2 volt (for half speed)?

[Bikemad]

I would suggest something like this:



If you use a 4.7k trimmer variable resistor (or potentiometer) instead of R2 and connect the switch wire to the trimmer's centre connection (wiper) you can simply adjust the trimmer to obtain the required speed.

The motor usually starts at ~1.25V and maximum power is reached at ~3.25V, so ~2.25V signal voltage should produce ~half speed.

Check out this post for further information on the above circuit, or this post for an alternative method using two trimmers and a diode:



Alan