Turning pedal assist into "constant on."

I'm wondering....?

I have a generic Chinese electric bike that is pedal assist.

On the crank, in between the gears and the frame, is a little box (sensor) that's connected to the "controller." Attached to the axle is a small disk that rides a very small distance from this sensor. The disk has about 8 little pieces of metal embedded in it that each act as a "contact" when they pass by the sensor as the bike is pedaled. Working in concert this combination allows power to be applied intermittently to the wheel as it's pedaled. (Ie. Pedal assist)

But I'm wondering if I were to take the disk off..., and place a piece of metal over the sensor permanently, wouldn't this fool the sensor into remaining "on" constantly? (Or at least when power is applied by the throttle?)

I'm just curious. I'd like to do something like this if it is in fact possible. I don't see why it shouldn't work.

Anyone ever tried this before want to let me know how theirs turned out???

Thanks.

Phdintheory

Phdintheory said:

If I were to take the (magnetic)disk off and place a piece of metal over the sensor permanently, wouldn't this fool the sensor into remaining "on" constantly?

Click to expand...

No.

The sensor measures a variation in magnetic field, how often the magnetic field varies is translated in the controller into a percentage of the throttle.

You can test this right now without changing a thing. Keep the sensor and one of the magnets aligned and simply hold it there, does the motor generate any propulsion?

could you put the sensor aligned with the magnet on the spokes, the one for the speedometer?
then each wheel rotation fools it into thinking you are pedaling, right?
it won't work for the first 3 feet, so it still has a safety feature.

Matt Gruber said:

could you put the sensor aligned with the magnet on the spokes, the one for the speedometer?
then each wheel rotation fools it into thinking you are pedaling, right?
it won't work for the first 3 feet, so it still has a safety feature.

Click to expand...

It'd probably work if implemented correctly. It would likely work to some degree, but getting it to consistently put out 100% throttle would probably take some consideration in configuration. I am sure the throttle % would slowly scale up as you accelerated in a relatively smooth way.

Something to keep in mind, ebrakes wouldn't be optional for this type of setup. Obviously, there could be dire consequences if the motor continued to generate propulsion when you needed to stop. Even if your normal brakes can over come the power of your motor, stopping distances would be extended which could wind up being bad.

Maybe easier to just get a cheap chinese controller and swap it out for that, as you can get cheap ones for next to nothing.

on mine, the throttle has a spring return, so when i hit the brake, motor is shut off. the brake handle is on top; push to brake, not pull. impossible to grab brake without releasing throttle.
problem is, now i want to make a sharp turn, and there is no motor unless i pedal, despite still going 5+mph. bike is loaded with cargo, making pedaling difficult.(bags swinging)
so i find myself avoiding the brake, as it is annoying to restart.

it may be possible for you to convert the controller to throttle only like we did for the blue swede guy.

what do you imagine those metal discs are on the rotating piece? and what is the sensor? how would they work together to make an input to the controller to make it deliver power?










if you have a series of magnets passing a hall sensor, with two states, one on and one off. the hall sensor is turned on when the magnet is present and turns off when the the magnet is removed.

if the hall sensor is draining current from the circuit when active then imagine that the speed of rotation of the disc with the magnets changes the frequency that this hall sensor is switched on and off. or the length of time the hall sensor is turned on so that it can drain current off a storage capacitor when it is on. if the input to the controller monitors this voltage on the cap that the hall sensor is operating on then the speed of rotation of the disc would provide a linear input to the controller to drive the controller output.

First of all, to all who replied. THANK YOU!

I'd like to explain the reasons for my question.

The first of course is because I think it would be cool! I To be able to just sit back, relax, and let the motor take me where I want to go would be awesome. You see, I don't drive a car. At all. So I ride a bicycle everywhere. Luckily, I live in a very small town right at sea level so anywhere I need to go is going to be both close by and without a lot of hills.

I've been doing this for quite some time now and I'm in pretty good shape because of it, but even then a bike with a motor of any kind would be a huge help. Especially one that I don't have to pedal at all.

The second reason is because my eBike isn't working correctly the way it is right now. I've got a problem with my clutch not engaging correctly and for some reason I can't seem to find the parts I need to fix it. I was kind of hoping that a fix like this might have ended up being a good work-around for the repair I need. Unfortunately though, it sounds like I'm going to be out of luck.

I tried a little experiment myself earlier today since I already was already working on that area of the bike and I got the strangest results. No matter what I did, the motor ran exactly the same way. Made no sense to me at all.

It didn't take long for me to discover that the pieces of metal on the disk were magnetic so I grabbed a magnet I had and proceeded to test my hypothesis. (That application of a magnetized piece of metal in constant contact with the sensor would keep the circuit closed and thus provide constant power to the motor when the throttle was applied.) As I mentioned earlier though, this was not the case. The motor would engage regardless of the state of contact. (All it would do is turn the motor casing inside the wheel hub casing as the clutch would not engage correctly.)

Since the clutch isn't working correctly, I wasn't able to get an accurate result anyway. To be honest, at this point I don't even really know what "normal operation" is!

Anyway. So from what I've gathered so far it's a mute point anyway. That stinks.

Question: crea2k suggested a new controller... This is an option? What kind would I look for? Where would I find one?

To be honest I'd much rather just find the correct clutch/planetary gear replacement and fix the whole thing to OEM. But ... can't find the parts.

Anyway. I'm just rambling so I'll end this now. Before I go, I'd just like to say thank you again to everyone who offered their advice. I really do appreciate it.

Thanks again,
Sincerely
Phdintheory

if anybody had a clue about which motor you had they could recommend how to find the clutch since people do that all the time, but there are no pictures or any info about the motor or controller. you can look at blue swede's thread to see how to convert it to throttle if you intend to use it.

I discovered that some controllers do indeed use the PAS as a switch. These controllers are looking for the pulses from the pedal sensor. They ignore the first few and then for each one they sense, they give a fixed running time (1 to 2 secs) of the motor, which is why the motor runs on for a bit after you stop pedalling.

Rather than mess about with magnetism, you can disconnect the pedal sensor at the controller and put a switch between the signal wire (not black or red) and the ground (normally black). You cannot adjust the power from maximum unless you have an LED or LCD control panel.

Excellent reply.
Thank you. I'll check out bypassing the sensor. That sounds like a pretty good idea.

As to photo's of the motor, I thought I had included a couple. Here are a few that might help.







As for the controller, I'll have to take a pic later this evening and post them then.

Thanks again to all who have helped.

SIncerely,
Phdintheory

I have an FS20ELBIKEA works well but I'd like a throtle fitted instead of the Pedal assist.
It has a disk with magnets embedded with a sensor fitted close to it.
Only starts the motor when the pedal is turned, you can see the red light coming on on the sensor.
My question is:
If I buy a throttle kit where do I connect it to? Do I cut the sensor cable and fit a socket so the throttle plug fits in?
Thanks for you attention.

Throttle kit?

Just hook up the throttle to the throttle wires on the controller, snip the stupid p.a.s. shit and call it a day.
Get a controller from EVFitting on aliexpress they are known as Greentime. Get the sensorless one and the voltage you need.

Sorry mate, I need more and clearer instructions than that. I'm not quite a moron when it comes to electrical things but close to it.

Where is the controller located, and how do I connect?
There is a small LCD display thingo I have to set the pedal assist settings 1 to 5 and that's it as far a I can see.
There is no way to plug anything in an I'm loath to cut wires I know not what they do.
Thanks anyway

many, perhaps most, of the pas-only controllers don't have any way to hook a throttle up to them. even if you find throttle input pads on the board (usually marked "sp") to solder wires to, they often are programmed (permanently) not to respond to any throttle input.


if you aren't skilled at soldering, figuring out wiring, etc., and don't really want to get into doing that sort of thing, then it's likely to be easier to buy a new plug-and-play kit with display, controller, pas, throttle, ebrakes, etc., and simply replace everything but the battery and motor on your bike. however, this will still require figuring out wiring for your motor to the new controller, and potentially splicing wires to that, and potentially splicing wires to your battery connector from the new controller.

but you may still have to replace controller and display (and maybe pas) with a throttle-compatible unit if the one you ahve now is not.


if you are willing to open things up, you can disconnect the battery from the system, and then open up the controller box. this is usually a little hand-sized box with little ribs or grooves along the sides, and a bunch of wires coming out of one or both ends. usually silver, sometimes it's black. keep in mind there is always a risk with this sort of thing of damaging stuff in a nonrepairable way. if you're still willing to do it, then we can work out how you can do this, once you post some pics of the controller area of your actual bike.

is this your bike?
https://help.kogan.com/hc/en-us/articles/360021471714-Fortis-20-36V-10Ah-Foldable-Electric-Bike-FS20ELBIKEA-Manual

if so, the controller is probably in the box under the battery, behind the pedals.

Yes that's the bike and you are right and the controller is at the bottom has a lid secured by 4 screws.
I'm quite willing to muck about with it and can get help from an electronics tech.
Taking off the cover tomorrow and taking pictures to post.

Would you know if that 36 volt hub motor is a brush type? Plenty of controllers available at reasonable prices but they say "Waterproof Brush speed controller"

Opened up box on the bike and there is an aluminium box with dozens of wires and plugs. loos like an ordinary controller.
Has one free socket with 3 wires.
The model number is BN 1054-101-36 serial? is 2019072300022.
Tried to google it but couldn't find any reference.

Any ideas w to bypass the sensor and use a throttle?
Thanks

marcus25 said:

Would you know if that 36 volt hub motor is a brush type? Plenty of controllers available at reasonable prices but they say "Waterproof Brush speed controller"

Click to expand...

Ad says it has a 250W brushless motor.

https: //www. kogan.com/au/buy/fortis-20-36v-10ah-foldable-electric-bike/

marcus25 said:

Any ideas w to bypass the sensor and use a throttle?

Click to expand...

Maybe, if you are able to post a picture of the controller and label, and another of the wires and connectors exiting the controller (and close up of the 3 wire connector you mentioned)? Otherwise, no.

Posted the model number on the box, looks like any other controler on the net aluminum box with fins.
The spare socket is an inline flat socket with 3 wires. short of opening up the control box there is not much to see.
All the wires are going back to brakes sensor, LCD display etc.

marcus25 said:

Posted the model number on the box, looks like any other controler on the net aluminum box with fins.
The spare socket is an inline flat socket with 3 wires. short of opening up the control box there is not much to see.
All the wires are going back to brakes sensor, LCD display etc.

Click to expand...

Oh OK. Hope you figure it out.

Thanks for the reply think I let it be the way it is. Works OK for the price. $490 AUD.
Just thought it would be cool not to have to pedal.
It actually might be a lot simpler to supply electrical pulses directly into the sensor instead of the rotating magnets?
Have to think.

Makes sense. If it ain't broke, don't fix it. Most controllers, even the crappy ones, will have the information on the label to let you know if it's capable of throttle, so if it only has a model number, then you're probably out of luck.

Actually there is something more on it.
"Speed set 1-4 2vdual"
and "Boost 1-3"
Current 15