simple (?) way to switch between 15mph max and deristricted

[eHomer]

I've studied a number of threads on here that have approached this topic from either motive, that's to say:

1. de-restricting a road legal 250w bike so that the motor will continue to provide power even when the wheels are going faster than 15 or so mph (ie when being pedaled faster),

and 2. adding a switched restricter to a powerful motor setup so that it's pseudo road legal by preventing it from doing more than 15 mph while switched in. (I realise it would still have a non road-legal greater than 250 watt motor, but it's part way there ).

Reading some posts on here, it would seem that method one involved disconnecting a white wire on some controllers ?

Whereas method two has had some suggestions for additional circuits with trimmer pots and switches to restrict the motor power ?

Method one seems more elegant and foolproof, (if I understand it correctly, directly knobbling the measured speed, rather than just throttling the maximum output power, which could be inconsistent on steep hills ?)

I have the X8M06-c chip in my controller, running a 1000w 48v motor at 36v (which is running nicely, thanks to the help I had from here). Is there a "restricter" pin on there that I could enable, or is that a feature not available on that chip ?

 

[amigafan2003]

I've used an RFID transponder from a car immobilser on mine - it's restricted to 250watts nominal / 16mph unless I'm within 1m of the bike.

It also stops me forgetting my house keys when I set off for work!

For obvious reasons I'm not going to post on a public forum as to how to wire it/integrate it but it's not rocket science.

 

[patpatbut]

I've used an RFID transponder from a car immobilser on mine - it's restricted to 250watts nominal / 16mph unless I'm within 1m of the bike.

It also stops me forgetting my house keys when I set off for work!

For obvious reasons I'm not going to post on a public forum as to how to wire it/integrate it but it's not rocket science.

Hi Amigafan
I am interested to know, would you mind to give me some hints?

Would you mind to pm me if you dont want to post on a public.

Many thanks
Pat

 

[Old_Dave]

Great use for RFID.. Only bit I'm stuck on is the '1 meter range' , 30cm is no problem.... But 1 meter, hmmmmmm


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[Deleted member 4366]

I have the X8M06-c chip in my controller, running a 1000w 48v motor at 36v (which is running nicely, thanks to the help I had from here). Is there a "restricter" pin on there that I could enable, or is that a feature not available on that chip ?

Have alook round the circuit board for a pad marked "XS".

 

[eHomer]

Have alook round the circuit board for a pad marked "XS".

Thanks again,

I've found the XS on the board, it's a vacant solder point. I'll try a switch between that and the adjacent earth point. Am I right in thinking that the 20k ohm resistor on cpu pin 13 then limits the pos voltage and therefore power to the motor ? I can't see how it would be able to regulate at 15 mph, would it just limit the output power ?

If so, what do you think about the idea of just linking xs to ground and replacing R87 with a variable resistor ?

 

[Old_Dave]

Should be fine, providing a stand off resistor is added in series to prevent taking the rest of that part of the circuit down to 0 if the pot is fully turned


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[Deleted member 4366]

To operate the speed limit, you connect XS to ground through a switch or jumper.

The throttle controls the speed, not the power, so the resistor just reduces the throttle voltage that the CPU sees.

20k will limit it to 12 or 15mph. If you want higher speed, you'll need a higher resistor. If you go down from 20k, your speed will go down too. You might want to put a fixed resistor in series with a variable one, with you minimum speed set by the fixed one.

 

[eHomer]

The switch sounds fine then, nice and simple, just to be able to keep it down to 15mph when necessary.

I tried the 1000w 48v motor today with the 36v battery, (after the low voltage cutoff mod suggested on here). It worked fine, giving about 25 mph max I would guess. (the damn speedo is playing up, so can't be sure at the moment). I've also fitted the digital voltmeter suggested by d8veh, and that was still reading 37 volts, with the motor stopped, after a 3 mile run at full speed, no pedaling. I guess I can only expect about 5 or 6 miles out of my 36v 10ah Lithium ion battery, when not giving any pedal assistance ?

 

[KirstinS]

Amigafan - that is possibly the coolest thing I have read on this forum

I wish I had your skills !