An alternative to thumb or twist throttles

[Russell]

the TRIGGER throttle.

To me a full twist throttle is at home on a motorcycle where the rider is stationary and usually in an upright or even laid back position but they don't seem to be the best solution on an ebike which someone is actually pedaling and may even be getting out of the saddle from time to time. The full twist throttle that came with my kit is hard plastic and I know it would be a real pain holding it in position for any length of time. I ordered a left hand thumb throttle but then I noticed many active vehicles where the rider may be getting jostled such as ATV's and jet skis often have trigger throttles. Of course those are cable actuated but I did find a trigger throttle used on an electric scooter to try.

The trigger throttle I puchased is advertised as a "5K" model so I knew it might not work perfectly since my stock throttle is a hall effect model. I measured the voltages of the stock throttle at rest and at full throttle as well as the supply voltage, they were: 0.83V, 4.07V and 4.75V, respectively. When the new trigger throttle arrived I found it actually used a 10K potentiometer so it didn't work properly out of the box.

Here's what I did to make it work;

First I opened it up and adjusted the pot (small gear) so that the resistance between the green wire (signal) and the black wire (GND) varied between 0 and 3.3K ohms by rotating the gear a bit and reinstalling the cover. Stock it ranged between 1K and 4.5K and the red wire to green wire (edit: corrected from "red wire to black wire") varied from 9K to 5.5K.


View attachment 2


Next I added a 470 ohm and 100 ohm resistor as shown below:

UPDATE May 5, 2009: the motor reached full power before the throttle was at the end of its travel, which is ok but I wanted to use the full sweep of the throttle to get finer control over the speed when I swapped out a Bafang motor for a more powerful 9C model. To do this I changed the 100 ohm resistor to 220 ohm and the 470 ohm to 1K-ohm. This change resulted in response a bit sooner when the throttle was first pulled and more progressive action throughout the arc of the lever. One problem however was that my thick grips prevented the lever from reaching its full travel so I had to swap the grips for thinner ones, but it is close even with them.





It works quite well now with instant response as soon as I pull the lever. Here it is mounted on my bike:





The throttle is angled just forward of vertical. It's nice since now I can just grab the lever and hold on pretty much like I usually do when riding a non-powered bike. The downside is the throttle is larger than I expected so I'm going to use a downtube shifter to control the front derailleur. Since many folks don't use their lower gears once they motorize their bikes they could just as well eliminate the front shifter and derailleur.

I purchased the throttle here;

http://www.extremescooters.biz/throttleleverbladezpart70171.aspx (EDIT: no longer available)

10/21/2009 Try here? http://www.justformotorsports.com/p...ADEZ-Lever-Throttle-Assy-For-Electric-Scooter

-R

 

[etard]

I agree that the throttles found on the market have much to be desired. originally my WE came with a thumb throttle but it would cutout before I pushedit all the way in, so I would have to hold it in a certain position to go full speed. Then I got a magura full twist which is better quality, but didn't feel right (even though I have had all sorts of motorcycles). I like the trigger idea, let me know how it is for you.

 

[recumbent]

I like your trigger idea on the left side, i also removerd my front derailer rapidfire and just screwed the adjuster directly on the front derailer to the center gear.

However the half twist throttles work very well because your still holding onto the handlebar on the end and work the throttle with finger and thumb rolling sorta, feels relaxing and intuitive. Took me only couple days to get used to a left hand throttle.

 

[Russell]

Recumbent,

In your situation with the handlebars up high and in a reclined seating position, not unlike a chopper motorcycle, the half twist throttle is a good choice and I could even see using a full twist. My bike is a regular flat-bar hybrid type on which the handlebars are about an inch below seat level and I ride leaning forward. In this case twisting a throttle is not a natural movement. It's also not great when riding out of the saddle. For me I think the trigger throttle is the best choice with the thumb throttle the next best followed by the half-twist.

One reason I chose to put the throttle on the left side is because it precludes the possibility of applying the front brake and power to the front motor at the same time. Since I have a low power motor (250W Bafang) which I plan to use mainly once up to cruise speed I also considered simply rigging up an on/off switch feeding the throttle signal through a resistor voltage divider to obtain max power when activated. For safety I would have probably needed to use E-brake levers or use a “dead man” switch of some type which I held down or depressed. I bought another little two-wire trigger “throttle” which is simply a switch to implement this however it was too low quality to use. I also wondered if engaging full throttle immediately might be damaging even if done at speed. So far the “5K” trigger is the best solution I’ve come up with for my bike and riding style.


-R

 

[frank9755]

My setup is:
- thumb throttle with the spring removed
- brake cut-outs
- an additional off switch (wired into the brake cut-outs).

It works very well - much easier on the wrist and enables much finer speed control than a normal throttle.

There is the risk of forgetting and releasing the brakes without either zeroing the throttle or flicking the switch but, having done it once, I've remembered every time since then!

 

[Russell]

Frank,

I was thinking about something along those lines as well. I took apart my full twist throttle (which I planned to cut down to a half-twist) and removed the spring but then there was no resistance whatsoever. I could see how it would work better with a thumb throttle however.

I also thought about simply using a 5K linear potentiometer through a handlebar mounted switch and perhaps e-brakes. The pot (a few bucks from RadioShack) idea works fine but there is of course no response right away until moved up to 2.08 K-ohms and full throttle was achieved at 4.34 K-ohms. That could be solved with a couple additional resistors as I did with the trigger throttle but it wouldn't really be necessary. One reason I didn't go that route was I had already cut off all unnecessary wires coming out of my controller, the e-brake signal being one of them I guess. I say I guess because the wires were not identified and my kit didn't include e-brake levers so I don't really know. Also if I would forget just once to turn off the switch like in a panic situation it could be a real problem. Running the pot throttle signal through a handlebar mounted momentary switch could work too.

Not having any throttle is what I'd really like but I didn’t want to shell out the big bucks for a Bionx system to get that. I also wanted a simpler, open system and a front motor. I am considering the Ezee kit for my next ebike and trying out their “Pot Box” with pedal sensor system. It appears to be basically just a potentiometer in a little handlebar mounted box that is enabled by the signal from the rotating magnets and crank mounted sensor. Another option would be to get a Crystalyte controller with their cruise control box though I’m not sure it would work with my present motor.

All stuff to play with in the future!


-R

 

[wanders]

Russel:

This is first-rate work! IMO, it actually solves two problems:

1) How to effectively add throttle control to a MTB that already has a twist-grip shift and a brake lever. I prefer the twist shifter, myself. And your point about normal bike posture is exactly correct and (unless you live at wide-open throttle) this should be easier for motor control.

2) How to add regenerative braking control in a similarly unobtrusive manner.

So I'm going to use two of these, RH for go, LH for stop.

Thanks for the resistor-divider circuit as well.

Willie

 

[TPA]

Is this throttle originally intended for use with brushed motors?

 

[Russell]

Is this throttle originally intended for use with brushed motors?

Probably, though it has no bearing on the throttle used. Most throttles on ebikes are hall type however this one has a potentiometer in it, and not the usual 0-5Kohm pot usually found in throttles. No matter it works quite well with my brushless kit when modified as described above.

There is a question of long-term reliability for a resistive type throttle such as this one compared to a hall type. I've been on a couple dozen rides and logged 600 miles in the last two and a half months and it has performed very well so far.

-R

 

[TPA]

Russell:

I now have one of these throttles, but I have some questions.

I have an e-crazyman BRUSHED controller that has red black and blue throttle inputs, the throttle has as you know red black and green leads, which gives 6 possible arrangements. 4 do nothing, the other 2 cause the motor to come on WOT without using the throttle, in fact pulling the throttle lever causes the motor to slow down (opposite what it should do).

the working combos are

red black
black red
blue green

and

red green
black red
blue black

in both cases the throttle red wire is not needed and works the same if you unplug it.

also...My battery reads 33v going in to the controller and the motor leads coming out of the controller read 11v at WOT (brushed motor runs slow).

The throttle reads 900 to 5K ohms between green and black throttle wires when actuated


Any thoughts? Do I need to do your resistor mod?

 

[Russell]

Russell:

I now have one of these throttles, but I have some questions.

I have an e-crazyman BRUSHED controller that has red black and blue throttle inputs, the throttle has as you know red black and green leads, which gives 6 possible arrangements. 4 do nothing, the other 2 cause the motor to come on WOT without using the throttle, in fact pulling the throttle lever causes the motor to slow down (opposite what it should do).

the working combos are

red black
black red
blue green

and

red green
black red
blue black

in both cases the throttle red wire is not needed and works the same if you unplug it.

also...My battery reads 33v going in to the controller and the motor leads coming out of the controller read 11v at WOT (brushed motor runs slow).

The throttle reads 900 to 5K ohms between green and black throttle wires when actuated


Any thoughts? Do I need to do your resistor mod?

If you look at my drawing above you will notice my controller has the same color wires as yours. Red and black are pretty much universally going to be V+ and GND which leaves blue as the throttle signal from your controller. It's a good thing the throttle is a potentiometer because if it was a hall-effect throttle you probably would have blown it up trying all of those combinations.

If your throttle measures ~9K to 5K-ohms between the RED and GREEN leads (or 10K-ohms between RED and BLACK) then yes you will need to reset the pot and add the resistors as I described. If the throttle were a true 5K pot, that is if it measured 5K-ohms between RED and BLACK it would not be necessary except to eliminate the initial dead spot.

-R

 

[TPA]

Got it working Russell, you are a genious! There was one deviation from your instructions though, the resistance on the throttle reads 0 to 890 ohms instead of 0 to 3.3k ohms like yours between throttle black and green.

one more concern:

I only have some old crappy nimh batteries to test with and they sag badly.

On the battery side of the controller, the resting voltage is about 34V and they sag to about 31.5V at no load WOT.

On the motor side of the controller the resting voltage is about 34V which sags immediately to about 11V as soon as the motor starts turning.

Will the batteries cause this? Good batteries fix it? Or is it the throttle resistance thing I mentioned above?

 

[Russell]

Got it working Russell, you are a genious! There was one deviation from your instructions though, the resistance on the throttle reads 0 to 890 ohms instead of 0 to 3.3k ohms like yours between throttle black and green.

one more concern:

I only have some old crappy nimh batteries to test with and they sag badly.

On the battery side of the controller, the resting voltage is about 34V and they sag to about 31.5V at no load WOT.

On the motor side of the controller the resting voltage is about 34V which sags immediately to about 11V as soon as the motor starts turning.

Will the batteries cause this? Good batteries fix it? Or is it the throttle resistance thing I mentioned above?

You said in your prior post;

"The throttle reads 900 to 5K ohms between green and black throttle wires when actuated"

If you reset the pot so it started from zero then it should read 0 to 4K-ohms now. The important thing however is that the motor starts soon after you start squeezing the throttle and that it reaches full speed when fully actuated.

My LiMn battery voltage drops about 0.2V at no-load because the controller is drawing less than 1A. I would guess a brushed motor draws more current but 2.5V of sag with no load on the motor does sound like quite a bit.

I couldn't tell you what the voltage on the output of a brushed motor controller should be but 11V (2-wire DC right???) certainly doesn't sound correct.

-R

 

[rguy56]

God, how I've wrestled with that same problem. I've even thought of using a simple on off switch, except that it would not work at all on some gravel trails on my commute.

Honestly, 90% of the time my throttle is on or off.

Bob

 

[TPA]

If you reset the pot so it started from zero then it should read 0 to 4K-ohms now. -R

You are correct, I was checking the wrong thing, it is 0 to 3.75k ohms, so it is correct. I have 3 slas on loan, and when I get them back I will do more testing.

You've been a big help Rus!

 

[Russell]

Update:

My motor reached full power before the throttle was at the end of its travel, which is ok but I wanted to use the full sweep of the throttle to get finer control over the speed after I swapped out a Bafang motor for a more powerful 9C model. To do this I changed the 100 ohm resistor to 220 ohm and the 470 ohm to 1K-ohm. This change resulted in response a bit sooner when the throttle was first pulled and more progressive action throughout the arc of the lever. One problem however was that my thick grips prevented the throttle lever from reaching full travel which wasn't a problem before but now the motor only got to 90% of its full speed. I swapped the thick grips for thinner ones which allowed for full travel of the throttle lever...but just barely.

The throttle supply on my latest controller is 4.95V instead of 4.75V with the throttle voltage spec'd on the rating plate at 1.1-4.2V. The latest resistor combination I use results in a range of (0.220K/1.220K x 4.95V) 0.9V to (3.5K/4.5K x 4.95V) 3.85V. The 3.85V is a bit low but as I said the motor does reach full speed. I rode the bike with this new configuration and found it was easier to control the speed of the Nine Continent motor, especially at small throttle openings, which is what I wanted. The resistor values I specify are by no means cut in stone, you can of course customize them to suit your needs.



-R

 

[callagga]

Russell,

How much better do you think this throttle is than a 1/2 twist mounted on the left hand side (i.e. allows me to do the up/down gears on the right side whilst adjusting throttle on the left, albeit the throttle has to twist away from me rather than towards me)?

Don't you accidentally hit the throttle when slamming on the back brake hard?

Cheers

 

[Russell]

Russell,

How much better do you think this throttle is than a 1/2 twist mounted on the left hand side (i.e. allows me to do the up/down gears on the right side whilst adjusting throttle on the left, albeit the throttle has to twist away from me rather than towards me)?

Don't you accidentally hit the throttle when slamming on the back brake hard?

Cheers

I can't say how a left side half twist compares since I've never used one. On a bicycle I'll take pulling a trigger over twisting my wrist any day of the week.

My left brake lever is connected to my front wheel which works out well since I can never hit the throttle to the front wheel motor at the same time I apply the front brake. The way I have the throttle and brake lever arranged I have never hit the throttle while braking, by accident or otherwise. When taking off from a full stop I have reached for the brake a few times instead of the throttle, which of course gets me nowhere.

I'm quite surprised someone hasn't supplied a kit with a trigger throttle like this one; the solid feel, the spring action, and the ability to precisely control the power puts it far ahead of the cheap plastic throttles supplied with most motor kits. I like the throttle so much I ordered another one (now at a higher price) for a work in progress even though I already have a full twist and two thumb throttles lying around. With the recent resistor change I made I now have better low speed control over the 9C motor and hence better efficiency. I imagine the pot won't last nearly as long as hall-effect devices but there's no reason they couldn't make something like this with the solid state devices.

-R

 

[Patriot]

This is the same throttle I am considering as well. I already have a 1kohm resistor inline with the signal lead going to the controller, so hopefully I wouldn't have to do very much.

I found the same throttle at http://www.electricvehiclesusa.com/product_p/th-bz31686.htm

They say theirs is already 0-5k, so I would assume no manipulation is needed.

$25 seems like a good investment to stop the wrist pain from using a thumbie at a weird angle. The thumbie is turning out NOT to be as egronomic as I had hoped.

 

[Russell]

This is the same throttle I am considering as well. I already have a 1kohm resistor inline with the signal lead going to the controller, so hopefully I wouldn't have to do very much.

I found the same throttle at http://www.electricvehiclesusa.com/prod ... z31686.htm

They say theirs is already 0-5k, so I would assume no manipulation is needed.

$25 seems like a good investment to stop the wrist pain from using a thumbie at a weird angle. The thumbie is turning out NOT to be as egronomic as I had hoped.

Yeah they said mine was a 0-5K also but the pot actually measures 10K-ohms between the red and black leads which is why I had to modify it as I did.


-R

 

[Patriot]

Ah. Got it. I'll make sure I check mine if I decide to get one.

 

[ekline309]

in your diagram you show that the red wire from the throttle is not used, but in a corresponding goldenmotor thread you say all three wires are connected.

 

[Russell]

in your diagram you show that the red wire from the throttle is not used, but in a corresponding goldenmotor thread you say all three wires are connected.

The RED wire from the throttle is NOT used however I said there were still THREE connections from the modified throttle to the controller throttle input connector. What I did was cut the throttle cable, solder in the resistors and tape it all up (see photo). The connector from the throttle uses three pins; one is from the 1K resistor (originally 470 ohm), which I designate the "Red" pin, one is from the green wire, which is designated "GR/Blu", and one is from the 220 ohm resistor (originally 100 ohm) which I designate the "Black" pin.



Hope that clears things up.

-R

 

[callagga]

Hi Russell,

So is this correct to say (plus some questions)

* All throttles work on the concept of providing a variable voltages back to the controller, therefore all one needs to do is mimic this behaviour when working out resister values?

* I have a Crystalyte throttle for an eZee kit (http://ebikes.ca/store/store_ezee.php) so irrespective of how the current throttle works your approach should be ok for the eZee kit?

* If you put no resistors in at all and the voltage sent back is say 0V - Supply Voltage, could this damage the controller do you think? In other words how sensitive do you think controllers would be to getting things wrong here (e.g. resister values)? (I would get there shouldn't be an issue)

* You don't talk about current (A) in your thread - are there any current limits that a controller would be sensitive to? Like you could get the same voltages buy buying a potentiometer & resisters that were 1/10 of the value, or 10x the values no? You would still get the same ratios however the currently flowing would change. Did you measure the current flow on your original bike, or just assume that if scooter throttles come in this 3.3kOhm range this is normal and work from here?


thanks again

 

[callagga]

PS. Justin at ebikes.ca already gave me some info re the eZee kit:

Anything you do to generate a 1V - 4V intput signal on the throttle line will work fine. But be aware that with the eZee controllers, a voltage greater than about 4.5V is considered a fault condition (as happens if the gnd pin of the throttle is disconnected) and will result in no output power and a flash error code on the controller.

Might be useful for others too I thought...