help how to limit ebike to 15mph

[zoom]

hi am jay from the uk I have a 48v 1000w ebike and would like to limit it to 15mph for road use and full power for offroad use. because I panic when I see the cops lol. does anyone now how to do this with a switch

[Leslie]

LOL.

Gets some high gears so they at least engaged when you are going fast.  Every time you see the police pretend you are pedaling as hard as you can.

It's quite pathetic what us ev folk need to do.

Another way is to resist going fast.

Some GM controller can use a cable to set the speed in the controller.

Or you could place a series diode on the throttle out or a 4k or 5k resistor in series onto the throttle output wire, or a variable resistor is better.

I don't mind playing with the solid state carbon filmed resistors.  More practice with P and S resistors the better.

[Bikemad]

Other problem I found was the idear of having a preset potentiometer as a limmiter for when I see cops. Whith the throttle closed the voltage from the throttle signal drops below its typical 1v no throttle signal when I engage the preset potentiometer switch.. This makes the controller think there is something wrong with the throttle and gives 3 beeps. From there on the throttle stops working.

So this simple speed limiting idea is not fully functional at this point.

Fitting another preset potentiometer and diode as shown here should cure that problem:


Alan
 

[Leslie]

I don't have such problems on my controller as it doesnt have the beeps.

I used a .5 or .8 drop diode between ground and the throttle gnd to take the gap out of the throttle in the first part of twist. This could work too.

[zoom]

thanks for the fast replies. would of two these variable resistors do the job part number UH24B                     http://www.maplin.co.uk/Module.aspx?ModuleNo=2202  cheers jay

[Leslie]

Other problem I found was the idear of having a preset potentiometer as a limmiter for when I see cops. Whith the throttle closed the voltage from the throttle signal drops below its typical 1v no throttle signal when I engage the preset potentiometer switch.. This makes the controller think there is something wrong with the throttle and gives 3 beeps. From there on the throttle stops working.

So this simple speed limmiting idear is not fully functional at this point.

Fitting another preset potentiometer as shown should cure that problem:


Alan

Have you tested this out.

This is a good idea.

Linearly from a 2d view sure those values work.

I tried to simulated it as I can only guess what going on as I don't own the controller, for the throttle to always have 1v for the throttle detector and presume there is a small load over all the parts and the added load the 2 resistors in parrallel should be calculated as parallel when the switch is engaged and the restrictor resistor puts onto the output of the 1v without the restrictor switch engaged, and allowing 20ma to pass when throttle is full.  Should I allow more current to pass?

Simulation 1 is no throttle and no restriction switch.





Simulation 2 is the restriction switch engaged no throttle.





Simulation 3 is full throttle restriction switch engaged.





Simulation 4 is restriction switch disengaged full throttle.  I think I could add some more load.







Take a closer look at what I have done here.  I presume the hall creates a load over the input and output as there is a v drop when the throttle is connected.

I don't have the probe in the pics but I got that working in the sim after R150...

Work with us here because I don't put absolute faith in spice and I cn only guess what the resistance and loads are is over this circuit.

[Leslie]

Damn the throttle draw 7ma not 20ma

Back to the drawing board.

UIs hard because I need to substitute the hall with something else.

[Bikemad]

This restrictor has undergone a slight redesign, as the 5K speed adjuster resistor is too high to be left in the circuit when not restricted.
I discovered that a resistance greater than ~330 Ohms fitted in the throttle signal line will reduce the maximum speed of the motor, the 5K resistance should be ideal if wired using just two pins, which can simply be shorted across using a switch to disable restriction, as per the revised diagram shown here.

I think this revised diagram will work correctly, but I still need to test it.


Alan
 

[Leslie]

Thanks all.

I was way too tired working on this stuff to 6:40 am.  Funny when you look back at these thing to realise the mess you made.

I was looking at 22ma and then putting a decimal pint before it and more.  The last thing I did was look up the data sheet. which should of been the first thing to do.  .  Im going to try keep it close to typical 7ma to the hall.


I will try run you stuff in the sim Bikemad Im pulling my throttle off and controller to measure some load resistances and things to get it right.

This beep thing is a little harder to get around on the simulation as it seems to be all in areas that the restrictor changes engaged or not.

We need to make a reference voltage I think something that going to be rock solid no matter what we do.

[Eriknoort]

Another way to restrict is pull your brake and press the cruise button 5 times. The bike will only go half speed by pressing the cruise button, until power off and on

Erik

[Leslie]

BikeMad I tried your circuit in spice and it doesnt work but that doesn't mean it wont in real life.  I just feel we need to fill in the blanks.  a simple series resistor is one thing but to boost its output after you resist the the output is another.  Its hard to gain back what you take off ounce it is gone from the output.

This is why I think its going to be more difficult.

Between hall in and the output there is enough resistance to allow a 5v but on little load it only drops a volt, when the throttle is off the ground is closed to the output so 0v appears on the output.  When you twist the throttle you let ground off the output so you see voltage appear ion the output.

Important.

When you apply a resistor between the ground and Hall ground you decrease the effect of ground to the output not boosting the volts but giving it a higher than 0v reading at the output equalling the 1 volt required by the hall detector.  Then we place a series resistor on the output decreasing the overall voltage of the output to slow the bike.  Bypassing the output to replace the lost 1v will only reduce the load on the throttle losing the hall effect along with it.  

So I used a dpdt switch to apply some resisatnce to the hall effect from the ground.

This actually works and it should be tested before I give it a 100% assurance.


Ommit R1 because it just a dummy load to make RV3 functional in the sim.

This mod should be calibrated with wheel off the ground to set top speed first at RV2 with switch on and then calibrate 0rpm at 0 throttle at RV3.

[TRK]

[..]
I discovered that a resistance greater than ~330 Ohms fitted in the throttle signal line will reduce the maximum speed of the motor,
[..]

Interesting, I figured that would not have been much of an issue.  Here's another simple circuit suggestion using a double pole switch:

throttle out
o------------+--------o  \
             |             \      controller in
             |               o----------------o
           |   |          ||
           | 8K|<-----o
           |   |          ||
             |
             |        o  \
             |             \
             |               o-----+
             |                     |
             +--------o            |
                                 |   |
                                 | 2K|
                                 |   |
                                   |
                                   |
o----------------------------------+----------o
                    ground

[Bikemad]

Here is the latest circuit diagram which I have tested and it works fine with no problems:


The 4.7K fixed resistor has been added to ensure the hall sensor in the throttle is protected from a badly set trim resistor.

Simply adjust the voltage to 1.25V @ pin 2, which should give approx 0.75 volts on the signal wire with the speed adjusting resistor turned to the maximum restriction position.

The 0.75Volts will be high enough to prevent the controller from seeing what it thinks is a faulty throttle, but should also be slightly lower than the hall sensor output voltage to prevent any reverse current from flowing towards the hall sensor.

The 5K variable resistor is probably the ideal size as it can be adjusted to provide less speed/power than most people will require.

Alan
 

[zoom]

hi guys thanks for all the plans for the restrictor, I forgot to mention that I have a standard controller so theres no need to worry about the beeps sorry

[Leslie]

The 0.75Volts will be high enough to prevent the controller from seeing what it thinks is a faulty throttle, but should also be slightly lower than the hall sensor output voltage to prevent any reverse current from flowing towards the hall sensor.

The 5K variable resistor is probably the ideal size as it can be adjusted to provide less speed/power than most people will require.

Alan
 

\

With this circuit does the hall detector still work if the hall sensor fails in both modes?

I just seeing letting off the squeeze at the hall ground the most unobtrusive way.

Two pot resistors and 1 switch, how hard does this need to be?  No need for extra resistors diodes.

Ive been using the resistor between the ground and the hall ground for years now to take out the gap the begining of the twist when you use a speed restrictor. t  It only became nessesary to use it now because of the beeps.

When you add the resistor between ground and hall ground it has no effect on the power supply adds no load on anything and you will not see transients poping up on the other sides of components. and you get full controll over top speed and 0rpm from first pot turn to the last.  You could even set the bike to travel 2kph through a 20k pot at the speed adj and you are assured the hall detector is still going to work.

I tried the 10k resistor or the 4.7k and it draws more current from the supply.  Probably nothing to worry about.

hi guys thanks for all the plans for the restrictor, I forgot to mention that I have a standard controller so theres no need to worry about the beeps sorry

LOL we do this not just for you so don't be sorry.  I knew the answer to this by my in my second post but I like to look at others work here and at least try it out.

We ended up helping BikeMad with a new original circuit and rediscovered the old one many have been using for years.



Thanks for all the posts here, as this forum is getting very busy I don't think Bikemad is going to ne able to keep up with it all soon.
ways.

It wouldnt matter if you posted this last post at the beginning of the thread.  All would still be here working hard on this.