help how to limit ebike to 15mph

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thanks again for all the info but you have lost me with all the info and diagrams. sorry for been a pain but can someone tell me which diagram I should use or draw me a simple wiring diagram for my standard controller, I am not very good with electrics but I can understand very simple diagrams cheers jay

[Leslie]

Here yar,

The first one will allow you to make your controller responsive to the touch with the second resistor and will fix the beep error for those using the newer controller.

The second will work fine on the average controller but you may notice some gap in the first part of the twist.

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thanks that makes it easy to do will try it this weekend cheers jay

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just tried out the speed restrictor works perfect thanks guys

[Leslie]

This has been tested on a GM controller but without the switch and works perfect on any controller.

There could be an issue if the DPDT reeds don't snap in time together and a voltage peaks over 4v.  Usually a decent toggle or rocker switch with a nice click are pretty fast and to have any discernable latency between both reeds is highly unlikely.

So do I buy a GM magic controller just to test this?  Maybe someone would try it out for us.  If my design does work with the switch it should have a better range of adjustment and the throttle failure safeguards should not be bypassed..  You could use a 50k or 100k series resistor pot to get the bike to go 2kph have full sweep of the twist and still have throttle failure detector still functional..

The worst case senario when switched, is zero throttle and beeps or full throttle for 1000th of a second followed by normal feel and operation of the throttle with speed limitation. Or the ground reed gets stuck on while the other get stuck off vice versa.  These things do happen but so do pots fail and controllers burn out and astroids hit the earth too.   Nothing is ever certain.

As with Allans design if the throttle fails it could go into full limited speed and not stop. 

And the throttle could come off in your hand and your brake could fall off dragging on the ground.  Your wheel could fall off and land in the lake and just when you thought it couldnt get any worse that asteroid flies out from space and hits your bike and turns it into a flaming ball.

The design is only as good as the quailty parts you use and the way you out it together.  The rest is luck.

Both designs need further testing before I would give a certain on the safety.  I believe the circuit I put forward without the DPDT switch is the safest and has been tested..

[Bikemad]

To save any confusion, I've drawn a schematic diagram of my circuit showing how the components should be connected:


I have shown an adjustable Potentiometer instead of another trim pot so that you can easily adjust the maximum speed whilst riding and set it exactly where you want it.
This could be replaced with a second trim pot if required, or if a two way switch is used, it could even be used in addition to it.
This would give you the option of switching between a pre-set legal maximum speed setting and a user adjustable maximum speed which could be adjusted anywhere between "snail mode" and unrestricted.

I especially like the idea of being able to easily reduce the maximum speed whilst riding, as it would be handy for matching my dog's speed which usually decreases as the walk/ride goes on!

It can also be used to give non ebike riders a chance of keeping up with you!

A two way switch could also be used to switch between two pre-set trim pots, which would be required if you use two different voltage battery packs.



This circuit has been tested on my Magic Pie and works fine, but I see no reason why it shouldn't also work with the separate cruise controllers which are based on a similar design.

Alan