How to wire a push-button full throttle switch?

[Qwiksand]

Using a hall throttle, how would one go about wiring in a normally open, momentary pushbutton switch to engage full throttle? I have a variety of hand positions this would be useful in (out on the bar-ends, out on the TT bars, etc) when out cruising on long, lonely sections of trail. Any links or diagrams out there?

 

[dogman dan]

My guess would be 5v input, switch, then the signal wire. It's a guess though.

Be nice to have, use the throttle to get going, and then move your hand to a second brake lever or something that just tells the controller WOT but leaves it comfy to ride compared to a throttle. With brake cutoffs, you can do something to just jam the throttle full on, and then grab brakes when you want motor off.

 

[amberwolf]

If it doesn't work the way dogman suggests, then your controller may not accept the full 5V input as a valid throttle signal (protecting against shorts, probably), since many halls only go up to 4.something volts with a 5V supply. If that happens, then first measure your hall's signal output pin while at full throttle, and make a resistor voltage divider to give you the voltage the switch will need.

The easy way to make that divider is to use a small potentiometer, around 10K to 100K, and wire it's outer pins to +5V and ground. The center wire goes to one side of your switch, and the other side goes to the hall signal wire/throttle input wire.

Adjust the pot till it's center wire reads the same as your hall on full throttle, and now you're done.

 

[Qwiksand]

Thanks guys, I'll give it a go. I think the pot might be just the ticket for my controller, straight shorting the 5v to the signal wire did nothing.

 

[dogman dan]

Somebody chip in about this idea.

Could he have two throttles wired paralell? On on the handlebars used normal. The other locked in WOT and located anywere, would have a wire to the handlebars where a pushbutton completes the circuit. Seems like I read about that paralell method some time back for an extra left hand throttle to reduce hand fatigue.

 

[John in CR]

A proper cruise control is the way to go, but if his controller doesn't support it, then I think a momentary switch with an pot next to it is a way to go. That will give more options to adjust the speed. I disagree with the use of an on/off switch for safety reasons, but a momentary switch isn't any easier than holding a throttle. Plus I've seen some options for long distance cruising on motorcycles to make holding the throttle less of a "chore", though it's never been an issue for me. For the 6-8hr low speed non-stop ride I have planned, a cruise control will be part of the build.

John

 

[amberwolf]

Could he have two throttles wired paralell? On on the handlebars used normal. The other locked in WOT and located anywere, would have a wire to the handlebars where a pushbutton completes the circuit. Seems like I read about that paralell method some time back for an extra left hand throttle to reduce hand fatigue.

The latter method would make sense, and the former would work, but there's not really any reason to use a separate throttle that's locked to a specific value; the pot method is easier, smaller, and cheaper.


Regarding the on/off (non-momentary) switch to hold a throttle, I definitely don't recommend that approach, even if you have ebrake handles that cut off the throttle, just because you could forget it's WOT if you're sitting at a light long enough, or other similar conditions where you're holding the brake for several minutes at a time after having switched the max throttle on.

Another possibility is accidentally turning that max throttle switch on before powering up the bike, if your controller does not have a "high pedal lockout" that disables the controller until throttle is let down to zero first. That would suck, as your bike zips across the room, cieling, road, or parking lot without you....

If one *must* do this, I highly recommend getting one of those magnetically-held switches, which while not inexpensive are much safer in such a situation. The way they work is that once you engage the switch, it has a coil that must receive power just like a relay to hold the switch in the engaged position, otherwise it falls back to off. They're fairly common in aircraft cockpits, so if you have access to a salvage yard for those you might find one cheap, depending on the yard owner's thriftiness and attitude.

You would need to build an external circuit to take your pack voltage and lower it down to the coil voltage on the switch, and provide electronics to read your ebrake switch lines and disengage the switch when it detects you've braked at all. Personally, I'd also add in a current detection and possibly a speed detection so that if you have to squeeze the brakes hard to suddenly stop, then if for any reason the ebrake switches don't work the overcurrent detect (whatever threshold you like) will trip the throttle hold switch off, too.

Speed detection would just have a pulse counter that reads the wheel sensor already used for whatever speedo you have, and if it doesn't get reset often enough by the wheel pulses, it would trip the switch off, by assuming either the load is so high that WOT is a bad idea because it will burn out your motor, or that you are trying to slow down and not fully able to because the motor is on WOT.

 

[dogman dan]

Good points. I was thinking in terms of some kind of switch that has to be held down in the on position, like a doorbell perhaps. So it would be a deadman switch turning off when you aren't actually mashing it. Some of us just have old broken throttles around, that might still work in the full on position.

I just use a half twist, and ride 60 miles with no more fatique on the throttle hand than the other. Just learn how.

 

[amberwolf]

Good points. I was thinking in terms of some kind of switch that has to be held down in the on position, like a doorbell perhaps. So it would be a deadman switch turning off when you aren't actually mashing it.

Oh, I know that's what you were talking about for the switch; when I spoke of the on/off non-momentary switch I was referring to what someone else had mentioned.

Some of us just have old broken throttles around, that might still work in the full on position.

That's true enough; and for some people it may be easier to do this than to wire up something like a pot and adjust it to the right voltage.

 

[Velocipede]

I have a thumb throttle and I removed the spring inside.

I can place the throttle in any position I want and it stays there.

It may be dangerous, but I never forgot to turn it off when I want to brake.

 

[ktronik]

My one is pretty basic, you hit the button, you have WOT, you touch the brake lever its cuts out. I used it with no throttle (just the button, Mom On), for 2years, with zero probs.. you could run it in line a throttle, I would guess. Its a 5v relay & a alarm reed switch & magnet

With this you get a very basic cruze control by using the 5v relay with a feed back loop (latch link), I added a V dropper diode just in case my controller did not like the full 5v, so now it sees 4.3v on throttle signal input (as if a hall was there). Not sure if the extra load from the coil, of the relay, on the +5 throttle line,(when latched) would cause any long term probs, (unlikely) but so far not dramas...

the magnetic brake reset (which cuts the cruze control throttle button when braking)

To the left of the gear numbers is the 'GO' button



enjoy

Ktronik

 

[amberwolf]

Not sure if the extra load from the coil, of the relay, on the +5 throttle line,(when latched) would cause any long term probs, (unlikely) but so far not dramas...

I don't think there should be a problem. I'm running a 5V relay coil off the ebrake signal line on my Fusin, to trigger a brake light that runs off separate 12V battery, and I see no unusual operation or other even voltage sag on the 5V line or the ebrake signal line that wasn't there without it.

 

[Mike1]

Ktronic, you should really have a reverse biased diode across the relay coil to protect your controller againsts the back EMF when the coil is de-energized.
You may already have one but it's not shown on your diagram.

 

[Drunkskunk]

Most controllers will see +5 volts as a fault, and shut down. And my first controller would see +0 volts as a fault, and shut off as well.

A momentary switch would be fine, but you will need to drop it's voltage to the max voltage of the signal line. that 4.7V on the last controller I measured.

 

[ktronik]

Ktronic, you should really have a reverse biased diode across the relay coil to protect your controller againsts the back EMF when the coil is de-energized.
You may already have one but it's not shown on your diagram.

Should I, very good then, thank you, so reverse biased diode across the relay coil & change my Voltage dropper diode from 0.7v VD to a 0.3v VD so max voltage of the signal line is 4.7V??

thanks guys

Ktronik