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Modding trottle signal
- Thread starter Tunk
- Start date
You can try it and see if it works. A hall throttle will (in theory) provide a signal from 1-4v on the output. Reducing the input voltage with a variable resistor (or, preferably, a voltage divider, since there isn't much current going to the throttle) should work fine, though you'll have to measure current flow if you want to just use an inline resistor.
No - can't possibly work.
You are reducing the hall operating voltage. As soon as the supply voltage gets around 4V (depending on the particular hall) it will simply stop working. This is like dimming your television picture by dialing the tv mains power down to 25VAC.
Ideally, your controller can be reprogrammed, but if that is not possible, then:
You can do this by instead hooking a pot across the throttle output and Gnd - then use the pot wiper as the input to your controller. This will make a variable voltage divider on the throttle output to supply a fixed percentage of that signal voltage to the controller. The exact pot value is a bit of a crap shoot and will depend on the hall output current rating, pull-down resistor inside the controller, etc. A 5K pot will keep the hall current draw under 1ma and should work okay. No promises...
You are reducing the hall operating voltage. As soon as the supply voltage gets around 4V (depending on the particular hall) it will simply stop working. This is like dimming your television picture by dialing the tv mains power down to 25VAC.
Ideally, your controller can be reprogrammed, but if that is not possible, then:
You can do this by instead hooking a pot across the throttle output and Gnd - then use the pot wiper as the input to your controller. This will make a variable voltage divider on the throttle output to supply a fixed percentage of that signal voltage to the controller. The exact pot value is a bit of a crap shoot and will depend on the hall output current rating, pull-down resistor inside the controller, etc. A 5K pot will keep the hall current draw under 1ma and should work okay. No promises...
So if I understand the trottle in low possision gives 4 V and with full aprox 0 V.
Can I then take a switch and a variable resistor/pot wired in serial, then parallell to the red and green wire on trottle.
(I also have working pas on 4 the bike with speed limit 25kmh KT36ZWS controller)
Can I then take a switch and a variable resistor/pot wired in serial, then parallell to the red and green wire on trottle.
(I also have working pas on 4 the bike with speed limit 25kmh KT36ZWS controller)
Drunkskunk
100 GW
the throttle signal works from 1 volt to 4 volts, with 4 being full speed. For the controller to boot up without throwing an error code on the throttle, it needs full 5 volts to the Hall, and 1 volt from the idle throttle. To lock in a lower speed, you need a way to keep that 1 volt output, but drop the 4 volt signal down to what ever ends up being 6kph for your motor. That can't be done very well with just a simple circuit.
The best way would be to use a Cycle analyst and comparable controller to program a hard limit of 6kph. that would limit the speed but not the power. You could also limit the power if you chose, but that's a separate setting. The down side is the cost. >$200
the easy alternative is a mechanical lock. A pin or block inside the throttle that keeps it from turning any further than what amounts to 6kph. If you open most throttles up, they have a plastic tab that runs in a groove and hits a stop when the throttle reaches full. Putting in a pin or something, or even filling that grove with epoxy will limit it's travel. That would limit the speed by limiting the power, so you might end up with a very weak motor when trying to climb a him. The up side is the cost. >$1 in glue or scrap.
A third alternative is to use an Arduino to intercept the throttle signal. Using a speed sensor as an input, the Arduino could be programmed to cut the throttle back if the speed sensor passed 6kph. That would allow full power but limit the speed. Its also the hardest of the three. Cost should be well under $50 depending on the design.
The best way would be to use a Cycle analyst and comparable controller to program a hard limit of 6kph. that would limit the speed but not the power. You could also limit the power if you chose, but that's a separate setting. The down side is the cost. >$200
the easy alternative is a mechanical lock. A pin or block inside the throttle that keeps it from turning any further than what amounts to 6kph. If you open most throttles up, they have a plastic tab that runs in a groove and hits a stop when the throttle reaches full. Putting in a pin or something, or even filling that grove with epoxy will limit it's travel. That would limit the speed by limiting the power, so you might end up with a very weak motor when trying to climb a him. The up side is the cost. >$1 in glue or scrap.
A third alternative is to use an Arduino to intercept the throttle signal. Using a speed sensor as an input, the Arduino could be programmed to cut the throttle back if the speed sensor passed 6kph. That would allow full power but limit the speed. Its also the hardest of the three. Cost should be well under $50 depending on the design.
teklektik said:
That's fair. I wasn't sure how much slack they had in their voltage range. I've seen some that will work as low as 3.5v, which should give you a peak output of around 2-2.5v depending on the magnets, but that's going to be particularly sensor dependent, and working the output side is a better idea.
dnmun
1 PW
the hall sensor current from the throttle input is so low that your idea would not work. you would have to use at least 50kR or more to get significant voltage drop.
if you wanna go slow then just don't use a high voltage battery and use a high torque motor with low final speed.
if you wanna go slow then just don't use a high voltage battery and use a high torque motor with low final speed.
Few controllers monitor the throttle supply current and in the recommendation above the throttle remains connected so the normal throttle current is drawn. (FWIW - I run Lyen controllers all the time without the throttle +5V connected (CAV3)). I know of no controller that has a 'minimum voltage fault' - because it's harmless. The controller may not apply power if powered up with a throttle voltage above 1V but less than 4V (prevents runaways), but would work normally with the divider. The usual controller 'input fault' arises only when the throttle input signal exceeds 4+V because this is an indication of a broken throttle Gnd and a resulting runaway WOT condition.Drunkskunk said:
So - controller faults should not be an issue.
That said - the divider solution is in the vein of what the OP asked for - but not a good approach.
It would give very poor performance on the getaway, etc. as would a throttle stop or any scheme that limited the throttle input voltage to a fixed (low) value.
Ok, Thanks for good reply.
So far I have disconnect/cut the green wire, made it go through some switches so I can turn it off and the trottle will not work when pedaling on public roads.
Next controller will be with 6kmh wires and the all the other stuff that needed for get the most out of the ebike , as a street legal.
Thanks again.
So far I have disconnect/cut the green wire, made it go through some switches so I can turn it off and the trottle will not work when pedaling on public roads.
Next controller will be with 6kmh wires and the all the other stuff that needed for get the most out of the ebike , as a street legal.
Thanks again.
