I'd venture that it's unlikely to work that way--unless they have a torque-sensing BB like the THUN/etc that outputs an analog voltage, it's highly likely to be a pulse-train output simply counting PAS revolutions. This means you'd have to take the throttle's analog voltage and convert it into a pulse train that is higher in frequency the faster you want to go (probably). Even if the BB is an analog voltage it's unlikely to be the same as a throttle voltage range (at least, the ones I've worked with so far aren't).
thank you very much for your answer .fechter wrote: ↑Nov 30, 2017 10:19 amI was trying to find a manual for that bike, but didn't have much luck. I found a view online only version but hard to know if it is the right vintage.
From the manual:
Electrical specification, motor controller
• Control function: current, voltage, temperature, speed, torque
• Power supply light: 6 V, 7 W
• Position: in motor hub
The A2B has a 'true pedal assist' function, this means
the motor engages only when the rider is pedalling. So
you can get places under your own steam yet have
the comfort of the electric motor giving you that extra
boost along the way.
The A2B is equipped with a Torque Sensor, which means
as soon as you start to pedal, you'll feel the motor kick
in to complement your pedalling – making riding an
Below is a diagram of how to remove the rear wheel. You can see the connectors along the swing arm. We need to see the pins:
A2B wheel instructions.JPG
No need to remove the wheel. Just a good look at those connectors going to it.
A cable with five ends splits, and three of them go in that direction.fechter wrote: ↑Dec 01, 2017 1:50 pmOK, that has the controller inside the motor. It looks just like the Metro connectors, so I assume the motor is the same. I think you could get a throttle from a Metro and just plug it in. But one of those might be hard to find. You could use a generic throttle and splice the wires. Let me dig around and see if I can find the wiring for Metro throttle.
The Metro has battery indicator LEDs on the throttle body. You may need to come up with a different battery indicator. There are some very inexpensive digital voltmeters you could just put across the battery wires which would be better than the LED.
What does your bike have for a battery meter?
If you follow the small 5 pin wire toward the pedals, can you see where the pedal sensor is?
Edit: here is the wiring diagram for the Metro. My guess is the motor part is exactly the same but the Switch Module is different. Anyway the wire colors are shown. The line marked EAI is the throttle signal. A standard hall effect throttle will work.
A2B Metro wiring diagram.JPG
That's what I would try. I have no idea if the wire colors are going to match the Metro though. With a voltmeter, you should be able to verify.
I do not have an ohmmeter.fechter wrote: ↑Dec 02, 2017 12:23 pmThat's what I would try. I have no idea if the wire colors are going to match the Metro though. With a voltmeter, you should be able to verify.
Throttle will need 3 wires. One is ground, which will be electrically connected to the main power black wire. Check with ohmmeter. One will be 6.5v above ground but you need to power on bike and measure. During this test, there is a chance the motor could run, so be sure to get the rear wheel off the ground or put the bike upside down. Once you determine ground and 6.5v, the remaining one will be the signal. Note: it's 6.5v on the Metro, but anything around 5v is OK.