Why don't EUC's have internal brakes?

[UniVehje]

3 hours ago, mike_bike_kite said:

How do we actually know the limit of the braking available to us? Can the wheel easily tell us what percentage of the available braking has been used? and what happens if we try to use more? When braking hard it's the motor acting against the rotating wheel that's providing the braking. We see plenty of riders overpowering their motors when accelerating and then face planting. Is the limit for deceleration somehow much stronger than the limit of acceleration?

Breaking on an EUC is really just reversing. Same rules as for acceleration. The limit is not motor power on modern wheels but rather rider’s ability. That’s why people add power pads. We know the limit has been reached by buttplanting as opposed to faceplanting when accelerating. 

[mike_bike_kite]

15 minutes ago, UniVehje said:

Breaking on an EUC is really just reversing. Same rules as for acceleration. The limit is not motor power on modern wheels but rather rider’s ability. That’s why people add power pads. We know the limit has been reached by buttplanting as opposed to faceplanting when accelerating. 

I've seen plenty of face plants on modern wheels but not one butt plant. Does that mean people aren't breaking as much as is currently possible? Can we tell how close to the edge our own braking is?

 

 

[UniVehje]

28 minutes ago, mike_bike_kite said:

I've seen plenty of face plants on modern wheels but not one butt plant. Does that mean people aren't breaking as much as is currently possible? Can we tell how close to the edge our own braking is?

 

 

Yes, it must be more about gripping the wheel and skill. Also when accelerating the rider is moving towards area of less torque as it decreases with more rpm. I don’t really know what the limits of the motor and board are when it tries to slow down. Basically it turns into a generator before starting to reverse. There must be some limit but I do think we can do more with wheel geometry and other things before we reach the motor limits. Remember that the wheel is balancing you while breaking. It cannot just decelerate as fast as possible. Its only job is to keep the balance. You and your leaning angle are the limit. When you lean back more than the wheel can decelerate you have reached the limit. 

[meepmeepmayer]

28 minutes ago, mike_bike_kite said:

I've seen plenty of face plants on modern wheels but not one butt plant. Does that mean people aren't breaking as much as is currently possible? Can we tell how close to the edge our own braking is?

I'm pretty sure it's nearly impossible to overpower any half-decent motor (1000W and above?) when braking before simply losing tire traction. Electric motors have maximum torque at standstill, so the more you brake, the more braking power you have. That's the difference to a faceplant where you run out of torque as the speed increases.

So I would say if the tire slips and you butt plant, that's the braking limit, and it isn't limited by the motor, but by the tire friction on the ground you're on. Which one can intuit quite well without slipping (think braking on asphalt vs. gravel/sand, you'll automatically be more careful on the latter).

No data on this, just my intuition on the topic.

[Mark Wilson]

Here's a video of FANTOMAS bringing an EUC from 52 to 2 kmph. He also seemed to overpower the wheel and fall off the back at 0:13. Edit: I was wrong.

 

Edited August 18, 2020 by Mark Wilson

[meepmeepmayer]

23 minutes ago, Mark Wilson said:

Here's a video of FANTOMAS bringing an EUC from 52 to 2 kmph. He also seemed to overpower the wheel and fall off the back at 0:13.

Doesn't look like he overpowered the wheel. The pedals stay level. He just loses balance because he doesn't have enough leverage to lean the wheel with his body in this extreme position.

So looks like staying on the wheel/ergonomics/leg leverage might be the limit to braking, not even the tire slipping.

[Mark Wilson]

39 minutes ago, meepmeepmayer said:

Doesn't look like he overpowered the wheel. The pedals stay level. He just loses balance because he doesn't have enough leverage to lean the wheel with his body in this extreme position.

So looks like staying on the wheel/ergonomics/leg leverage might be the limit to braking, not even the tire slipping.

You're right. I wasn't thinking.

[mike_bike_kite]

It looks like there'd be a real benefit in the wheel automatically tilting back a little during extreme braking. In the video the pedals are perfectly flat which makes it difficult to lean back so far.

[UniVehje]

5 hours ago, mike_bike_kite said:

It looks like there'd be a real benefit in the wheel automatically tilting back a little during extreme braking. In the video the pedals are perfectly flat which makes it difficult to lean back so far.

Z10 has “breaking assist” feature that does just that. It’s just very difficult to do it well and in a manner that doesn’t make the rider panic when emergency breaking. It shouldn’t feel like the wheel is giving out. I’ve never tested that feature. But many riders are using soft modes to help especially in breaking. The hard and flat pedals are more difficult to lean back. 
I believe this kind if breaking assist feature will be seen more in the future wheels. But for now adding pads and using softer mode are the best ways to shorter breaking distance. (And practice)

Edited August 19, 2020 by UniVehje

[RockyTop]

We are limited by the size of the MOSFETs and a place to dump the energy. The batteries can’t handle it all. This is why we would need resistors. The limit then would be the motor. It is hard to say how much of the motor we are using. I would guess less than half. Continuous duty cycle would come into play. However you should be able to brake faster than you can accelerate. Acceleration is limited by the batteries. When we always have some one that is going to push harder, we are going to need warnings. Brake beeps. “That enough for now!!!!!! “ “ Ride like a sane person for a few minutes please!!!” 

As the EUC develops, new advancements come into play. Suspension was a dream that was never going to happen. Now people are push harder with bigger wheels. We have not had the need or skill for more powerful brakes until now. If this is perceived as a weakness than some company will finally address it as they did the suspension. When they have asked in the past no one was screaming better brakes. The truth is most people that complain about the brakes don’t know how to stop properly. If the wheel is not stuttering or cutting out while braking it is not the wheel, it is the riders skill that is lacking. 
 

New braking system. - 

Adding braking resistors would require a secondary system. Braking on the resistors alone would be easier but you would lose regen and creat large amounts of heat. Splitting the power, redirecting the power after a set limit might make more sense. It is very doable. The resistors are not heavy and would not take up much space but they would get very hot and need space away from the CPU. A very simple system would be an adjustable parallel system. Stronger brakes less regen. More regen less brakes. I would hope for a smarter system that just used the resistors above a set amperage. 

[Zopper]

52 minutes ago, RockyTop said:

However you should be able to brake faster than you can accelerate. 

While it would be nice in some cases, in practice we are usually not limited in braking power even with current tech with a reasonably powerful wheels. I could easily overbrake a V5, but I never managed to do it on a V10, even downhill. My abilities and my mind do not let me lean that much back while staying in control. And I intentionally try some training emergency brake here and there.

[RockyTop]

1 hour ago, Zopper said:

While it would be nice in some cases, in practice we are usually not limited in braking power even with current tech with a reasonably powerful wheels. I could easily overbrake a V5, but I never managed to do it on a V10, even downhill. My abilities and my mind do not let me lean that much back while staying in control. And I intentionally try some training emergency brake here and there.

I think that might be because your feet are both facing forward. If you turn one of your feet backwards facing the other way you will get better braking. .......... Just kidding.
On the KingSong XL I can move one foot back so that the center of my foot is on the back edge of the pedal during hard braking. The wheel shutters and I back off.  They can stop quickly and I believe that they can be over powered. ( I have always backed off not wanting to wreck) For reference I weight 220pound. I haven’t been able to do the same on the MSX. Harder pedals, bigger MOSFETs?  As stated before the KS has softer pedals that help you overpower them.

Edit: the foot on the back edge of the pedal Is a strange feeling. It takes commitment. you can’t slide off because your foot is wrapped around the back side of the pedal. You are either going to stop, over power the wheel or fall off the back. 

Edited August 19, 2020 by RockyTop

[mike_bike_kite]

25 minutes ago, RockyTop said:

I haven’t been able to do the same on the MSX. Harder pedals, bigger MOSFETs?  As stated before the KS has softer pedals that help you overpower them.

So which one stops quicker, the KS or the MSX? If the KS actually allows you to use all the available braking then it sounds like it should stop quicker all things being equal.

[RockyTop]

2 minutes ago, mike_bike_kite said:

So which one stops quicker, the KS or the MSX? If the KS actually allows you to use all the available braking then it sounds like it should stop quicker all things being equal.

Good  question, Giant sigh!! The KS helps you lean back and lets you use the limited resources that you have. The MSX does not lean back and help you use IMHO a greater amount of resources. I have watched many people compete against each other with this in mind. From what I can tell, the average person does better with the KS. Add skill and the MSX wins. We are not finished yet. Add even more skill and for some reason the KS begins winning again. If you check the stats, 1st place usually goes to KS followed by  5 GW then evens out with equal KS and GW. The key is force verses finesse. A truly skilled finesse rider can out do a forceful GW rider. 
Force = Bullish, make it happen by all out force. ( me, that’s why I favor GW at 220 pounds) 

Finess = gracefully working with the timing and movements of the wheel. (Wins in motocross too) 

[GothamMike]

What about center of Gravity?