Twist Throttle Wiring

[Lectriceye]

I have a rear hub motor with a twist throttle. I haven't looked at the structure of the throttle but guessing it is a potentiometer, with ground at one end, and x volts at the other end. My assumption is that as the throttle is twisted it is adjusting the voltage on the center tap going to the controller? Does anyone have any real knowledge of how this works before I splice into the throttle cable to see what really is happening?

 

[docw009]

I believe a twist throttle is made the same, except thumb knob is replaced with a cylinder. I have a twist model. but haven;t been able to pop off the handle like I did with the thumb unit,

the metal band on the thumb piece is magnetized. It rotates around a magnetic sensor with a Hall effect transistor inside it.



Power and ground on two pins. The third pin changes from .4 volt to about 4.3 volt as the metal band passes over it.

You could also use a potentiometer, but they're not water resistant like a hermetic chip, and now there's a more complicated mechanical linkage,

 

[Lectriceye]

Got it, I appreciate the explanation. That helps a lot in my understanding. My real goal here is to find out if I can splice into the lead with the variable voltage and take both leads to two different controllers and hence front and back wheels operating together on one throttle. That would be front and back wheels. I am more interested in if I can do it, not knowing for sure if I want to do it.

 

[E-HP]

Got it, I appreciate the explanation. That helps a lot in my understanding. My real goal here is to find out if I can splice into the lead with the variable voltage and take both leads to two different controllers and hence front and back wheels operating together on one throttle. That would be front and back wheels. I am more interested in if I can do it, not knowing for sure if I want to do it.

Unless you paid $60 to $100 for it, it’s likely not a potentiometer based throttle.
This article has all you’d want to know about hall based throttles, including how to test, tune and modify them.

Guide to Hall Sensor Throttle operation, testing, and modification. - Electricbike.com Ebike Forum

***** 8-16-2018 Welcome to the Hall Sensor Throttle Thread! If there is something you'd like to add, correct, needs better explanation, or have a question about... feel free to Private Message me. Better yet, open a new thread in the "Trouble Shooting...

electricbike.com

It’s relatively straightforward using one throttle with two controllers but you’ll probably want to make adjustments to balance, or bias the front to rear contributions.

 

[amberwolf]

There are some tghrottles wiht pots (magura, domino) but most are hall.

if you want to do 2wd with a single throttle control, there are a number of threads and posts about that with more detail, especially by teklektik, but essentially "all" you have to do is connect whichever is your signal wire (usually the non-red non-black wire) to boht controllers.

if the controllers both run from the same battery, you shouldn't need to also split the ground wire (often black), andyou don't want to connect the 5v (usually red) from both controllers together (can damage the 5v regulators) so you should have all three wires on the throttle to one controller, and just hte signal to the ohter.

if you have troulbe with the second controller not corectly responding to throttle, then also run the ground from it to the throttle, but don't run the 5v.


keep in mind that if the wheels, tire sizes, motors, and controllers aren't identical, with identical settings, etc., then whihcever one is "faster" will take more of the load and do more of the work, if the throttle signal to them is identical and they respond identiclaly.

if the controlers are not idientical in response, etc., then one of them will respond first and take more of the load, etc., at least at first. if one of them has a narrower throttle response band then it will probably reach full response first and take over, then when it runs out of response if the other one has response range left then it will begin to take over.

so depends on the systems.

 

[Lectriceye]

Thank you Amberwolf. I appreciate the detail you provided which is pretty much as I surmised it might be. Given that wheel and tire sizes can be assumed to be the same, the real variable would be the controller's response and sensitivity to the voltage applied. I don't know how much of an issue that would be in real time. I presume that both wheels on separate throttles would have even variation based on the ability of the rider to manipulate the throttles. In either scenario of throttle configuration there will always be some differences in power applied to each wheel at any given moment, sometimes intentional, sometimes not. Assuming each wheel/controller operated on separate batteries, the charge level and things like sag, could also contribute to differences in power applied. Again, thanks for helping me understand the issues involved here.

 

[amberwolf]

oh, also, youc an use a regular atv / motorcycle grip throttle that pulls a cable, and get a cable oeprated throttle in either pot or hall style. i use these on my sb cruiser trike. the throttle is pulled by a metal atv thumb unit that's part of a brake lever too, (metal because the plastic stuff keeps breaking probably from desert sunrot). then a second cot is used for variable regen braking pulled by a brake lever.

 

[amberwolf]

Given that wheel and tire sizes can be assumed to be the same,

as long as you have a typical bicycle, tha'ts generally true, but some are 96ers or 69ers where one wheel is a lot different ins ize, like my crazybike2 and sb cruiser trikes. that's why i mentioned it, as you don't specifiy what you're converting.

the real variable would be the controller's response and sensitivity to the voltage applied. I don't know how much of an issue that would be in real time. I presume that both wheels on separate throttles would have even variation based on the ability of the rider to manipulate the throttles.

yes, or different response if you want that--i used separate throttles on crazybike2 for front and rear specifically for the maneuverabilyt this allowed, as well as redundancy since they were totally indpenedent except for using het same battery sourc.e it had not only different wheel sizes but also different motors and different controllers, so this made performance a lot easier to make "ideal" by using two throttles than ust one.


on the sb cruiser trike where the wheels are side by side on the back of the trike one left and one right, i use a single control source (throttle if necessary, but it's normally the pedals that send cadence to the cycle analyst which then outputs a throttle voltage to boht controllers at the same time. at the moment sbc has nearly identical motors and controllers on each side, so they respond very similarly, but i have had quite the mismatch of parts over the years, and i'd just have to learn to counter any pulling to one side by steering inputs, until it was just second nature.

In either scenario of throttle configuration there will always be some differences in power applied to each wheel at any given moment, sometimes intentional, sometimes not. Assuming each wheel/controller operated on separate batteries, the charge level and things like sag, could also contribute to differences in power applied. Again, thanks for helping me understand the issues involved here.

most situational differences, assumign otherwise identical front/rear systems, will not make much of a difference to operation. it's usually when you have significant differences between the two ends of the bike that things can require some tuning of throttle to each controller after the split point to get htem to work as needed.

sometimes it still works fine even without that, even with major differences...just that one of the systems takes more of the load does more work than the other.


some 2wd systems are actually set up that way on purpose.