Begode Extreme cutout at 30+mph Chooch

[onewheelkoregro]

https://youtu.be/yJttCtLd9JI?si=rRdZ0kRL474gvi2P

[woke rider]

Chooch's guardian angel was definitely called into action on that one. When I watched the crash it looked like he would have broken his ankle for sure, but he's young, so he's tougher. That crash makes me question riding for sure.

[GothamMike]

Begode, nuff said.

[dycus]

In the US, the federal guideline for the road line length is 10ft. Usually 30ft apart, but sometimes 20ft.

If we count from the start of the video, Chooch travels past 6 line+space areas in 3.20 seconds before the wheel starts to dip. If the line+space is 40ft, that's 75 feet per second, 51mph. Most likely it's less, assuming 30ft per section, that's 56fps, 38mph.

Since he is speeding up, if I take the speed from just the last 3 line+space sections (still assuming 30ft), 62fps, 42mph.

Pretty quick to be going on a 16" class wheel at 50% battery that you believe to have a problem by draining so fast!

[corn]

4 hours ago, dycus said:

In the US, the federal guideline for the road line length is 10ft. Usually 30ft apart, but sometimes 20ft.

If we count from the start of the video, Chooch travels past 6 line+space areas in 3.20 seconds before the wheel starts to dip. If the line+space is 40ft, that's 75 feet per second, 51mph. Most likely it's less, assuming 30ft per section, that's 56fps, 38mph.

Since he is speeding up, if I take the speed from just the last 3 line+space sections (still assuming 30ft), 62fps, 42mph.

Pretty quick to be going on a 16" class wheel at 50% battery that you believe to have a problem by draining so fast!

We'll find out when/if he posts the ride logs. 

But the extreme has a smart BMS and it's reasonable to expect that it should alert the user of a battery issue if there is one. 

[trailless]

6 hours ago, dycus said:

In the US, the federal guideline for the road line length is 10ft. Usually 30ft apart, but sometimes 20ft.

If we count from the start of the video, Chooch travels past 6 line+space areas in 3.20 seconds before the wheel starts to dip. If the line+space is 40ft, that's 75 feet per second, 51mph. Most likely it's less, assuming 30ft per section, that's 56fps, 38mph.

Since he is speeding up, if I take the speed from just the last 3 line+space sections (still assuming 30ft), 62fps, 42mph.

Pretty quick to be going on a 16" class wheel at 50% battery that you believe to have a problem by draining so fast!

Nice calculations. Also he was going uphill. 

[eezo]

16 hours ago, dycus said:

In the US, the federal guideline for the road line length is 10ft. Usually 30ft apart, but sometimes 20ft.

If we count from the start of the video, Chooch travels past 6 line+space areas in 3.20 seconds before the wheel starts to dip. If the line+space is 40ft, that's 75 feet per second, 51mph. Most likely it's less, assuming 30ft per section, that's 56fps, 38mph.

Since he is speeding up, if I take the speed from just the last 3 line+space sections (still assuming 30ft), 62fps, 42mph.

Pretty quick to be going on a 16" class wheel at 50% battery that you believe to have a problem by draining so fast!

Isn't the point of Smart BMS and PWM-based tilt/alerts to make it such that the rider isn't having to be continually aware of their battery level, incline, acceleration, etc? The wheel, which should be aware of the ongoing state of its electronics, is supposed to alert the rider and prevent this from happening. If the rider ignores the device feedback, that's on the rider. But the wheel is supposed to detect the operating conditions and warn the user in time to make changes, and it doesn't seem like that happened here.

I get what you're saying, that the circumstances make it seem ripe for a cutout. But what's the point of a Smart BMS if it's not smart enough to alert the rider to a potential problem state prior to just dumping them at 35mph+?

Edited August 30, 2023 by eezo

[Planemo]

8 hours ago, eezo said:

But what's the point of a Smart BMS if it's not smart enough to alert the rider to a potential problem state prior to just dumping them at 35mph+?

A smart BMS can't see into the future. It can only relay the battery voltage to the mobo at any given time, same as any other non-smart BMS.

Remember that a Smart BMS' primary benefit is in monitoring and protecting cells, it's not any better at 'warning' the rider. The mobo PWM alarm system does that based on the voltage at any given time.

So given that no system can see into the future, a good example would be someone riding a wheel at 89% PWM with the alarm set to 90% PWM and thinking everything is wonderful. Then hits a dip/bump in the road and pushes the wheel to 100%+ PWM in an instant. No warning. Although it's possible the rider may hear a single beep just as their body is being launched off the wheel.

This is why we set PWM alarms with a reasonable buffer to allow for the 'unknowns'. What's reasonable? Thats on the rider. For me it's 80% max. The Sherman was shipped with 70% and tbh I am thinking of going back to that figure.

I apologise if you know all this, I just wanted to make it clear that the spec of the BMS makes no odds to the warnings from the wheel.

[eezo]

7 hours ago, Planemo said:

A smart BMS can't see into the future. It can only relay the battery voltage to the mobo at any given time, same as any other non-smart BMS.

Remember that a Smart BMS' primary benefit is in monitoring and protecting cells, it's not any better at 'warning' the rider. The mobo PWM alarm system does that based on the voltage at any given time.

So given that no system can see into the future, a good example would be someone riding a wheel at 89% PWM with the alarm set to 90% PWM and thinking everything is wonderful. Then hits a dip/bump in the road and pushes the wheel to 100%+ PWM in an instant. No warning. Although it's possible the rider may hear a single beep just as their body is being launched off the wheel.

This is why we set PWM alarms with a reasonable buffer to allow for the 'unknowns'. What's reasonable? Thats on the rider. For me it's 80% max. The Sherman was shipped with 70% and tbh I am thinking of going back to that figure.

I apologise if you know all this, I just wanted to make it clear that the spec of the BMS makes no odds to the warnings from the wheel.

All good, more information is never a bad thing. The role of the proper BMS would be in ensuring that the wheel is properly detecting and managing the cells so that the PWM-based alerting would reliably function. In this particular case, after reading more about the background after my comment, someone riding at 50% battery at very high speeds with a 90% alarm is asking for trouble.

[Chriull]

1 hour ago, eezo said:

All good, more information is never a bad thing. The role of the proper BMS would be in ensuring that the wheel is properly detecting and managing the cells so that the PWM-based alerting would reliably function.

PWM based tiltback does not need any BMS information.

PWM% is the output of the balancing algorithm - "how much the throttle between battery is opened".

The lower the battery, the faster the throttle is opened to reach balance.

And the faster 100% is reached and one overleans...

So battery/cell state is automatically/implicitly regarded.

1 hour ago, eezo said:

In this particular case, after reading more about the background after my comment, someone riding at 50% battery at very high speeds with a 90% alarm is asking for trouble.

Indeed!

Edited August 31, 2023 by Chriull

[Glock43x]

it's stupid to road in the road if there's a vehicle behind you.  bad things can happen. imagine rolling down the road and the car behind you couldn't brake in time and ran you over or rolling into oncoming traffic.

[Rawnei]

18 hours ago, eezo said:

someone riding at 50% battery at very high speeds with a 90% alarm is asking for trouble.

Where did you get 90% confirmed? If firmware allows you to set 90% that's a problem in itself IMO, 80% should be max roof for this setting.

[Planemo]

19 hours ago, eezo said:

 someone riding at 50% battery at very high speeds with a 90% alarm is asking for trouble.

Battery % shouldnt make any difference if the alarm works correctly because its based on voltage so its all relative. I accept that a pack at 50% will sag a lot quicker than one at 100% but the PWM alarm should reduce at the same rate. To go one better you could even build in a logarithm so the mobo monitors the 'rate' of % decline and advances the alarm. Sort of looking into the future if you like.

28 minutes ago, Rawnei said:

 If firmware allows you to set 90% that's a problem in itself IMO, 80% should be max roof for this setting.

Whilst I agree with you in principle I think I would have to disagree on this one, if only for the racers who are certainly skilled enough to ride on the edge of 90%, if not more. Maybe a compromise would be to restrict access to FW that allows more than 80%. Kind of like a 'homologation' FW that can only come from the manufacturers directly to the racers.

[Rawnei]

1 hour ago, Planemo said:

Whilst I agree with you in principle I think I would have to disagree on this one, if only for the racers who are certainly skilled enough to ride on the edge of 90%, if not more. Maybe a compromise would be to restrict access to FW that allows more than 80%. Kind of like a 'homologation' FW that can only come from the manufacturers directly to the racers.

I disagree, in a race you're giving all you got to win, if the alarm sounds at 90% it's way to late disaster waiting to happen, the only scenario I can see that 90% make sense is someone riding on a straight stretch of road with phone in hand trying to max the speed making a video to brag about it.

[eezo]

4 hours ago, Rawnei said:

Where did you get 90% confirmed? If firmware allows you to set 90% that's a problem in itself IMO, 80% should be max roof for this setting.

It's not confirmed, but I read somewhere that his friend said he was riding at 90%.

4 hours ago, Planemo said:

Battery % shouldnt make any difference if the alarm works correctly because its based on voltage so its all relative. I accept that a pack at 50% will sag a lot quicker than one at 100% but the PWM alarm should reduce at the same rate. To go one better you could even build in a logarithm so the mobo monitors the 'rate' of % decline and advances the alarm. Sort of looking into the future if you like.

PWM percentage is relative, but isn't voltage sag absolute? So a theoretical 5v drop at 100% battery will have a larger safety percentage than a 5v drop at 50% battery. Higher remaining voltage means more margin to withstand an absolute value sag in voltage.

Agreed though that more robust calculations around a dynamic safety percentage would be great. All of this data is accessible to the wheel.

[Freeforester]

Just a thought that occurred: I’m guessing too, so please bear this in mind, but does anyone know where the final assembly of this Extreme was done? Specifically, did the batteries and motor arrive in the US by separate consignment?     My reasons for asking are simply to try to evaluate WHO did the assembly, and how thoroughly was the voltage checked - for all we know, the assembly of the wheel (if made outwith the factory) may have been done by someone perhaps not as au fait with the whole process as might have been desired; we see a lot of “rush-release” of wheels to reviewers who are obliged to fix the batteries (which have arrived separately) to the wheel chassis and mobo, etc, and I have concerns that this may possibly be a place where errors can occur. I still recall er, Chooch’s attempt to reconnect the phase wires of a wheel, and the result was instant and salutary in its ‘fail’ quotient!     Im absolutely not suggesting that Chooch may have had any part in this aspect WRT the crashed wheel, but I would very much like to know by what means he came to be riding it, more or less before it has been put out on general release? 
 

Apologies in advance if I seem to be barking up the wrong tree or missing some important information here, I’m just trying to understand how all this incident began. TIA for any response with regard to this aspect.

[Rawnei]

50 minutes ago, Freeforester said:

Just a thought that occurred: I’m guessing too, so please bear this in mind, but does anyone know where the final assembly of this Extreme was done? Specifically, did the batteries and motor arrive in the US by separate consignment?     My reasons for asking are simply to try to evaluate WHO did the assembly, and how thoroughly was the voltage checked - for all we know, the assembly of the wheel (if made outwith the factory) may have been done by someone perhaps not as au fait with the whole process as might have been desired; we see a lot of “rush-release” of wheels to reviewers who are obliged to fix the batteries (which have arrived separately) to the wheel chassis and mobo, etc, and I have concerns that this may possibly be a place where errors can occur. I still recall er, Chooch’s attempt to reconnect the phase wires of a wheel, and the result was instant and salutary in its ‘fail’ quotient!     Im absolutely not suggesting that Chooch may have had any part in this aspect WRT the crashed wheel, but I would very much like to know by what means he came to be riding it, more or less before it has been put out on general release? 
 

Apologies in advance if I seem to be barking up the wrong tree or missing some important information here, I’m just trying to understand how all this incident began. TIA for any response with regard to this aspect.

It has a "smart BMS" if BMS didn't see pack not connected it's not particularly smart and that would also be a problem, pretty unlikely though, more likely the firmware alarm function is not working as intended, same thing happened in Ride One review.

Edited September 1, 2023 by Rawnei

[Yook]

On 9/1/2023 at 1:38 AM, Chriull said:

PWM% is the output of the balancing algorithm - "how much the throttle between battery is opened"...

Thanks, your insights have really helped me understand how the balancing algorithm works and how it inherently takes into account the state of the battery.

It's interesting to note that PWM% in the EUC context essentially serves as request for "motor torque." This reminds me of how compensating for pack SoC (State of Charge) is implemented in other controllers like Betaflight and VESC. 

[Rawnei]

Another one, same behaviour, beep and drop, so has happened at least 3 times now, definitely something wrong with firmware.

https://www.facebook.com/groups/ElectricUnicycle/permalink/6547136835384224/

Edited September 3, 2023 by Rawnei

[MetricUSA]

I stopped following cooch after he claimed how great s20 was... The Worst Suspension Wheel Ever Made... 

[Freeforester]

1 hour ago, MetricUSA said:

I stopped following cooch after he claimed how great s20 was... The Worst Suspension Wheel Ever Made... 

….Until Beg..  another company started to try to make them…

[alcatraz]

On 9/6/2023 at 7:12 PM, MetricUSA said:

I stopped following cooch after he claimed how great s20 was... The Worst Suspension Wheel Ever Made... 

Careful! People are only allowed to shit on Begode nowadays. 

[GothamMike]

EUC manufacturers need to tone down their algorithms. The obsession with being 3% faster is appealing, to some, but is not healthy if there are too many cut outs. 

[Jason McNeil]

There's a new firmware update in the works... Implemented 3 levels of top-level alarms, for the one that can't be disable from the App, this will replicate the behaviour that Veteran are using on their FW.
70kph for the initial tone, 75kph for the 2nd level, 80kph for the top level/danger alarm—these numbers are provisional & will vary by the model.
 

 

Edited September 12, 2023 by Jason McNeil

[onewheelkoregro]

I knew there was a reason why I don't really ride my wheel the way I usually do when I get to about 50% battery. I really never let my wheel drop below 50% because coming from an automotive background I understand the lower the voltage in the battery means less power for everything else. But I guess some people think technology is some kind of infallible magic and when people don't understand the limitations of a machine they usually push past them with dire consequences. I really wouldn't expect someone like Chooch to realize this though. Entertaining as his video's might be, he is just an above average rider.