I hurt myself ebiking today (fixed problem with a CA hack)

jdevo2004

100 W
Joined
Apr 13, 2014
Messages
158
I severely sprained my ankle ebiking off road today. I was testing my 3000 watt mid drive and as I was coming up to a sharp corner I slowed down using both of my brakes. My rear brake has a throttle cut off. I did not realize that I still had twist in the throttle when I let go of the brakes. 3000 watts was immediately pumped into the mid drive and the bike flew out from under me. I landed hard and now I am down for the count for at least a couple of weeks before I can hit the trails again.

Has anyone else had problems with the brake cut off acting in this way? It is all well and good if you have a cycle analyst that controls torque under full power for twist throttles, but that torque control is negated once you activate the brake cut off. If you forget to throttle all the way down before your brake cutoff disengages you will get whatever power level your twist throttle is set at all at once. This is dangerous!

I want to know if anyone has come up with a solution. What I am thinking is maybe adding a logic circuit that forces you to go to throttle zero after you have touched the brake cut off before you can throttle up again.
Or maybe a circuit that makes the cycle analyst see the throttle as zero while you have the brake cutoff engaged allowing the cycle analyst to control torque as normal if you let go of the brakes while still having twist in the throttle.

Long story short, I can not trust the cycle analyst or the motor controller to safely cut off power while I engage the brakes. I need to find a way to be able to safely let go of my brakes at any time without the chance of my bike flying out from underneath me. Can anyone help me?
 
What is your controls layout? Rear brake on left? Do you ride with two fingers over both brakes while grasping the throttle using only your forefinger and thumb?

The braking sequence should be the rear brake first using two or three fingers that are already on top of the lever while simultaneously letting your forefinger-thumb grip relax enough to allow the throttle to snap shut, then pulling on the front brake with the two fingers already on top of the lever. This stabilizes your rear a split second before you hit the front brake and gives time for the throttle to snap shut.

I like your idea of having throttle-logic disable the throttle after a brake cut-out, and not not enable until the throttle is closed.
 
Sorry to hear of your spill and Like gogo said throttle should snap off on any braking or when doing so your hand should roll throttle to off, I also ride an old beemer with half twist and reaching for brake with hand on naturally rolls throttle off, half throttle grips work great on my ebike and personally I would disengage that sensor to stop power on braking
 
jdevo2004 said:
I severely sprained my ankle ebiking off road today. ........Long story short, I can not trust the cycle analyst or the motor controller to safely cut off power while I engage the brakes. I need to find a way to be able to safely let go of my brakes at any time without the chance of my bike flying out from underneath me. Can anyone help me?

Really sorry you got hurt today... :( Getting hurt on your bike really sucks.

In my 50 years of riding peddle bicycles and motored-cycles, both street and off-road, I have been hurt many times. It is always a bad scene. Sorry you got hurt. Get well soon!!!

But (yes the lecture time.. :( )...we also have to remember our actions are the thing we must trust the most. If we are not able to safely let go of our throttle when we brake then we need to be more unconscious of what our hands are doing. I know that sounds simplistic, but when we ride two wheeled cycles we need to be incredibly conscious of what is going on. Not just with what is happening around us, but what is also happening with-in our own body. A little practice letting the throttle go while you pull your brake lever will go a long way to develop better reactions.

:D
 
Can you not disconnect the throttle cut off? I don't really understand the point of having it anyway. If you shut the throttle before you brake why do you need it?

As far as braking is concerned you are much less likely to lock a wheel (potentially losing control) if you apply the front brake first, this loads the weight into to front wheel which keeps it turning, you can then have a bit more control with the rear brake.
 
Sometimes you brake and then notices that the throttle is still engaged. Wet weather and cornering or anything crucial you lose control. its dangerous. Higher than 2000w and it is even more dangerous. This is a serious turnoff for ebiking that cruical items stops work or breaks havoc. Its in the learning curve of ebiking so most of us know this after a few months of ebiking.

Also when throttle is bad and WOTs you
Also when throttle is bad and is OFF.
Water contamination inside throttle
or wire loss, connection problem.

the solutions is a better throttle.
Buy a better one. or

YES. open it and put in mass, silicon, done.

brake cut-out. its good to have at least one brake cut-out. You can also add a button to the "start" circuit of the controller, the circuit that turns the controller on.
 
A tough spill always part of riding dirt hard. Either you RIDE and sometimes crash, or you are just cruising. Some RIDE, and are just that damn good. But I will never be in that category.

I much prefer no brake cut off on a dirt ride.

IMO, your basic problem is the brake cutoff has taught you to ride relying on it. Bet you grab brakes leaving the throttle on a lot, even if you don't realize it till you crash.


For some, the solution is to move the rear brake to the left side. Then the brake they use the most is on the other hand. Me, I use both brakes a lot, so it really doesn't matter so much.

I do have brake cutoff on one bike. On that bike I can jam the grip on the throttle, creating a crude cruise control for long distance open road street riding. Brake cutoff a good thing when riding like that.
 
Sorry to hear about your fall.

Suggestion: tune your power down to the point where it is not possible for that to happen again. Or get a controller that is capable of gradually ramping up the power, rather than suddenly. Higher end controllers like the kelly, adappto, sabvoton, etc should be able to do this. This will also help prevent accidental power wheelies, especially in a mid drive.
 
Sorry to hear you got hurt.

In current throttle mode, the CA ups the throttle when it doesn't see any response due to the ebrake. Letting off the brake gives you a jolt,even when the throttle was slightly open.

Justin may have fixed this in the current version of the firmware but I haven't had a chance to test.
 
dogman dan said:
I much prefer no brake cut off on a dirt ride.
yep- Imagine the OP had 20 Kw :shock:

A good dirt ride starts with a good bike, and one that is well tuned. That doesn't keep you from crashing once in a while, but it does make sure that when you do, it was well deserved. :wink:
 
Upon further thought, I'd consider a throttle-logic brake cut-out and throttle reset to be a training device and would not want brake cut-out for off-road.

I had a throttle break and get stuck full-on with a factory low-power ebike. Until my new throttle was installed I got into the habit of relying on the cut-out. It was actually somewhat convenient because the build was so low-powered that I rarely used partial throttle, anyway. I did have to 'retrain' myself, so I'll have to recommend that only best practices are ever used, and that means enough practice until allowing the throttle to snap shut becomes automatic.

A half throttle would be a way to still grip while allowing the throttle to snap shut.
 
givitago said:
Sorry to hear you got hurt.

In current throttle mode, the CA ups the throttle when it doesn't see any response due to the ebrake. Letting off the brake gives you a jolt,even when the throttle was slightly open.

Justin may have fixed this in the current version of the firmware but I haven't had a chance to test.

If Justin is looking into a fix for this that would be really helpful. My suggestion is just to apply the torque control under all circumstances.

I have read everyones comments and there is a lot of helpful feedback however I would like to point out a few things. First is that for downhill biking and heavy off road use, you should keep only your index finger on the brakes at all times. Because this is the case, using a half throttle is a very hard thing to do. The best setup for downhill style ebiking is a full twist throttle while using your index finger on the brakes.

I agree with everyone that you MUST learn how to lay off the throttle while braking. My issue is that there is no real way to let me know if I have done something incorrectly until it is too late. On a dirt bike you can hear that you are throttling while braking. For an ebike it is completely quiet until you let go of the brakes and suddenly you realize what you have done wrong as you lay with your face in the dirt. Ebiking should not be this unforgiving. Ebikes are getting more powerful every year, things like this brake cut off issue need to be addressed so more people do not get hurt.

Anyway, my ankle feels a lot better today. Thank you drugs. ;)
 
Glad you are feeling better. An I know what you mean by having your face in the ...well in the ground. I have had many in my lifetime.

I still remember my first bike crash. I was 5 and 1/2 years old. I had been riding my sisters bike with training wheels and had it wired before I got my first bike for Christmas.

Being a sunny Southern California Christmas day I jumped on it and rode down the long driveway, on to the side walk made a u-turn and back to the driveway. I must have made 10 laps before I got over-confident and dumped it during the u-turn. I was skinned up and bloodied at the knee, but what really made me sad was I broke the plastic silver horn on the handlebars....my bike never looked the same again....but I digress.... :roll:

Ok, how about this. Replace the e-brake on the throttle side so you can use your brake and have a better idea of when the throttle is on.
My presumption is that your right side is your rear break.
 
Sorry to hear of your injury. I hope you heal fully and quickly.

A true torque throttle controller would not do this to the same degree. It would reapply torque proportional to the throttle position, which is gentle at low throttle settings. The standard PWM controllers are quite abrupt, really they are fine at low power but at high power they have many disadvantages.

Perhaps a three speed switch to lower the power would be a good idea, or just reducing the settings of the controller until the muscle memory is fully trained. It is easy to make mistakes and having a lot of power on tap can turn a minor mistake into a more serious one.

I reduced the power settings on my controller so the front wheel won't lift off the pavement under hard acceleration. Having a lot more power available than is required has risks. I may raise the level someday, but the bike is much more comfortable and safe to ride this way. It is a real advantage of an ebike that we can tune the power, acceleration, etc. to a more comfortable level.
 
3000 watts?. good lord that's a lot of power.

At some point that much power is no longer considered an ebike, but rather an e-motorcycle. I'm glad you didn't get seriously hurt.
 
Jason27 said:
3000 watts?. good lord that's a lot of power.

At some point that much power is no longer considered an ebike, but rather an e-motorcycle. I'm glad you didn't get seriously hurt.
Lol !
Here in my hometown i see often little girls ride real horses with more than 12kw.
I started with 1.5kw ebike and now im used to 5kw which makes me get faster to travel speed than most cars get.
Hope you heal up fast to get back on your ebike to get the skills trained. :wink:
 
I thought that all the throttle cut offs just dropped the throttle until you released the brake. Mine located in the controller is the same as yours. I have a throttle that locks on as well so I have to be careful to remember once I hit the brake to unlatch the throttle before I release the brake or it will take off on me. Only done it once so far and at a stop on the road. The handlebars were ripped out of my hand when the brake was released but I was able to hit my battery switch and turn the wild thing off before it got away from me. I think once in 10-12K miles is not bad all things considered. It would be nice and much safer if the cutoff were more like cruise control on a car though.
 
givitago said:
In current throttle mode, the CA ups the throttle when it doesn't see any response due to the ebrake. Letting off the brake gives you a jolt,even when the throttle was slightly open.

This will be the case if the CA3 is 'oblivious' to the fact that the ebrakes are being pressed. So if you have the brake cutoffs going just to the motor controller without also sending the signal to the CA's ebrake input, then for sure it would see that you are pressing the throttle but not generating power so it will keep increasing the throttle output voltage in an attempt to reach your desired output current. Once you release the brakes, then suddenly wham the throttle is functional and would kick in at full power. But if you have the ebrake line going to the CA rather than only to the controller, then it will be aware of the brake cutoffs, the throttle output voltage will go down to 0V, and then when you release the ebrakes it will gradually ramp up from your minimum throttle output based on your up-ramp speed. There won't be any surge of power unless you have a very fast ramp rate and a poorly setup throttle control mode.

jdevo2004 can you clarify what exactly your configuration is, do you have a V2 or V3 CA device, and in the latter case where are your brake cutoffs wired into the system? Then it will be easier to give advice on what you can do to prevent this.
 
I'm still struggling to see the point of such a device. It just sounds downright dangerous to me. Shut throttle, apply brakes, then open throttle again when you actually want to apply power, I can't see why you would want it any other way. Am I missing something here?

If you want an emergency cut off then fit a kill switch as on a motorcycle.
 
justin_le said:
givitago said:
In current throttle mode, the CA ups the throttle when it doesn't see any response due to the ebrake. Letting off the brake gives you a jolt,even when the throttle was slightly open.

This will be the case if the CA3 is 'oblivious' to the fact that the ebrakes are being pressed. So if you have the brake cutoffs going just to the motor controller without also sending the signal to the CA's ebrake input, then for sure it would see that you are pressing the throttle but not generating power so it will keep increasing the throttle output voltage in an attempt to reach your desired output current. Once you release the brakes, then suddenly wham the throttle is functional and would kick in at full power. But if you have the ebrake line going to the CA rather than only to the controller, then it will be aware of the brake cutoffs, the throttle output voltage will go down to 0V, and then when you release the ebrakes it will gradually ramp up from your minimum throttle output based on your up-ramp speed. There won't be any surge of power unless you have a very fast ramp rate and a poorly setup throttle control mode.

jdevo2004 can you clarify what exactly your configuration is, do you have a V2 or V3 CA device, and in the latter case where are your brake cutoffs wired into the system? Then it will be easier to give advice on what you can do to prevent this.

Hi Justin. I was just out in my garage checking everything over. The brake cut off is going to the CA, not the controller. I own a CA3. I was checking the throttle out voltage to the controller. If I quickly go full throttle with my twist grip, the throttle voltage slowly goes from 1.3 volts to 3.25 volts which is normal. When I touch the brakes the throttle out voltage goes to 0 volts. When I let go of my brakes while still having the throttle at full the voltage goes from 0 to 3.25 volts instantly. What is missing is the nice controlled ramp up to 3.25 volts.
Maybe I have missed a setting on the CA?
 
Jackrabbit said:
I'm still struggling to see the point of such a device. It just sounds downright dangerous to me. Shut throttle, apply brakes, then open throttle again when you actually want to apply power, I can't see why you would want it any other way. Am I missing something here?

If you want an emergency cut off then fit a kill switch as on a motorcycle.

The motor cut off actuated by a brake switch is great and has saved me in a full throttle situation a couple of times. It cuts the motor when you brake so you don’t throttle up and brake at same time so saves damage to geared motors as well as wear and tear on other systems. It is also a safety feature that works for full throttle errors, moisture in the throttle, throttle cable binding and it stops them immediately. Once you know how it works there should be no problem just correct the original problem before releasing the brake which just saved your buns. Dirt riding with a twist throttle can be a problem when one is unable to let go of the throttle because that is the only thing keeping him on the bike or motorcycle. Nothing wrong with a kill switch either I have both.
 
by Jason27 » Mon Mar 16, 2015 12:09 am

3000 watts?. good lord that's a lot of power.

At some point that much power is no longer considered an ebike, but rather an e-motorcycle. I'm glad you didn't get seriously hurt.

I think thats a good point, which kit were you useing ? Was it the LR GNG kit ? things get realy serious with 3000w high torque and high power mid drive kits...
 
jdevo2004 said:
Hi Justin. I was just out in my garage checking everything over. The brake cut off is going to the CA, not the controller. I own a CA3. I was checking the throttle out voltage to the controller. If I quickly go full throttle with my twist grip, the throttle voltage slowly goes from 1.3 volts to 3.25 volts which is normal. When I touch the brakes the throttle out voltage goes to 0 volts. When I let go of my brakes while still having the throttle at full the voltage goes from 0 to 3.25 volts instantly. What is missing is the nice controlled ramp up to 3.25 volts.

That is strange, it should ramp up exactly the same way (based on your FastRamp V/sec setting) regardless of whether you release the ebrake with the throttle on or just suddenly twist the throttle. To doublecheck I just confirmed this with the Prelim6 and the more recent Prelim9 firmware in all the main throttle modes (pass-thru, amps, and watts). And after releasing the ebrake the output voltage would jump from 0V to 1V (the min output voltage) and then ramp up steadily to 3.6V, full throttle. It never went from 0 to full instantly.

Could you let me know what firmware version you have, and if it's the Prelim6 or later could you use the CA setup utility to save your settings to a .hex file post that here? Or just list your main throttle input and throttle output settings. The behavior that you are describing is certainly not what it's supposed to be.
 
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