Msuper v3 top speed crash - wrecked shell

[Cloud]

 

4 minutes ago, KingSong69 said:

@Marty Backe As i know you get a warning/tiltbackwhen temperature is at 70 or 80 degree! 80degree is what the mosfets can max run!

160 degree is SO MUCH way off, that a shut off is acceptable as at this temperatures as other faults will have come before, your mosfets are melted anyway....

Yes but is 160 celcius or farenheit? 160 farenheit is 71 celcius which is close to their max temp. This needs to be clarified

[US69]

2 minutes ago, Cloud said:

 

Yes but is 160 celcius or farenheit? 160 farenheit is 71 celcius which is close to their max temp. This needs to be clarified

thats an argument...

did not have this on my bill :-) 

[Chriull]

7 minutes ago, KingSong69 said:

@Marty Backe As i know you get a warning/tiltbackwhen temperature is at 70 or 80 degree! 80degree is what the mosfets can max run!

160 degree is SO MUCH way off, that a shut off is acceptable as at this temperatures as other faults will have come before, your mosfets are melted anyway....

 

2 minutes ago, Cloud said:

 

Yes but is 160 celcius or farenheit? 160 farenheit is 71 celcius which is close to their max temp. This needs to be clarified

It has to be Fahrenheit (or a typing error - the 1 in front too much?) - As @KingSong69stated 160 Degrees Celcius is the terminal temperature of the semiconductor die within the MOSFET...

[Tilmann]

1 hour ago, Greg Spalding said:

<snip>

the complete shutdown of the wheel when the maximum temperature is reached is irresponsible, if that is the case

<snip>

Agreed, yet my main frustration with the whole affair is, that we are left in the dark about what really happened inside the wheel. I have to accept, that the technology under my feet has it's physical limitations. In case I over stress what it can deliver, eventually something will give up and I will hit the ground. Whether the wheel shuts down to protect it's components or happily allows me to push on until something burns up, may not be that important to me as I doubt I would be able to drive home after a high speed crash.

The big difference: if the wheels logic "decided" to shut down, it has access to telemetry data, that allow to anticipate what's coming, but it is not telling me. Especially, if our theory about the temperature build up over several minutes is correct, there would have been ample opportunity to warn the rider in an unmistakable way. The problem seems to be: once it sounds its 3rd alarm beep-beep-beep, it has no further means to deliver differentiated information acoustically. So, that uninterrupted sequence of beeps could mean: "you are faster than 37kph", "you consume >80% of available power", "something is too hot". Any single cause or all of the above at once - the alarm remains the same, I'm afraid. Yet, the consequences of ignoring it will be radically different. 

For everyday use in traffic, I can happily live by the rule to avoid 3rd alarm. For some more sporty exercises under controllable environmental conditions, I want differentiated alarms.

On the subject of heat: does anybody know for sure, which components are at risk of overheating? MOSFETs, battery, BMS, motor, CPU? And: which temperature is/are measured? With MOSFETs, is the temperature measured inside every one, or by just one external sensor on the heat sink? Are temperature values in Celsius or Fahrenheit (or a wild mix thereof)? 

 

[Cloud]

9 hours ago, zlymex said:

If the cut off speed is 50, then 
at 25 you get half the torque, 
at 30 you get 2/5 of the torque 
at 40 you get 1/5 of the torque
at 45 you get 1/10 of the torque
at 49 you get 1/50 of the torque.

At n you get 1-n/50 of the torque.

I could be fundamentally wrong, but i dont understand how this can be correct. I hope somone will straighten me out

It is my understanding that the inverse proportional speed to torque curve illustrates the maximum torque in stalling conditions ( where there is a maximum resistance applied to the motor ) and no load max speed conditions ( when due to no loading, minimum ( ideally close to zero ) torque is required to spin the wheel fast. as one lessens the resistance from the stall condition, the corresponding applied torque in turn gets smaller and the speed increases

however i dont see how this model is anywhere close to the actual riding conditions. When riding slow, the resistance is actually less because of smaller windload and the requirement to carry the same mass over at slower speed. There is less amperage requested for the motor and the resulting force ( torque) has to be smaller. When going faster, the riders weight is still the same but to go faster and also due to the increased windload, there needs to be more current( force, torque) to produce higher speed. 

Yes i understand that during acceleration, the hogher torque will be at the slower speed and once the rider has reached the desired speed the torque will go down. But at constant higher speed, i dont see how the torque is lower than at the constant lower speed. So hopefully someone can explain how the inverse proportional speed to torque curve is applicable.

[fearedbliss]

@nomad Glad you are ok and also that you were wearing a lot of protective gear. You shouldn't be going at those speeds though. Anything over 30 kph is dangerous. Even 30 kph is dangerous. I normally cruise at around 20 kph - 25 kph.

[US69]

Its not an real argument, but...

when you see what KS has done with the KS18 1200 Watt...announced with 40kmh....but lift of cut off at just max 48kmh at 100% batterie....and on THIS wheel the liftcutoff goes way way down with batterie....some faceplanted with 32 kmh...and now ks has restricted the wheel to 30kmh under 50%batterie....(mine btw only has a lift off max of 44kmh at 100%!!!)

So:

I for my side think that what gotway has delivered with the V3 is a very good job! my opinion is that riding the wheel on 45kmh is plain asking for faceplanting...my 2 cents! from my experience it is even stable for my 100+ kg at 38-39kmh down to30%....

i for my side would not try the absolute max of 45kmh....never!

yip-yeah- the marketing could be "truethfullier"...but i see it that Gotway has stated the wheel to max 45kmh(or even 40?) in the end when delivered and that just some chinese reseller announce it with 50 or more!

 

Also the temperature: when i got the V3, we still had some very very hot days here....i pushed very hard and never was able to get over 55degree celsius....and WHEN pushing really hard i DEFINITLY take a look from time to time on temperature!

we all have to beware in our minds that this is a very very young industrie with small players like Ks and Gw...and that the progress is slowly but steady!

i am happy for my part that the wheels are until now NOT regulated like with this "PLEV"....as my opinion is that these european burocratics are asking for some not deliverable characteristics like redundancy....

That would throw KS and GW out of the market and get the prices of our wheels to 3 or 4 times higher than they are

what i want to say is: sometimes i found the critics a little bit to hard....i am only in the EUC game since about 10 months...but i have seen incredible progress and the small companys are fore sure working hard to stay in the busines and deliver what we want :-)

 

so...rant over ;-)

 

 

[Tishawn Fahie]

9 hours ago, Marty Backe said:

So now I'm looking at my ACM manual and read this disturbing sentence: "Safety features: Low voltage warning tone. Automatic switch off at 45 degree side tilt angle and internal temperatures above 160 degrees"  That can't possibly be true. It actually shuts down directly? On the KingSong it beeps continuously with aggressive tilt-back.

I know that I read somewhere about a voice warning when the temperature got too high, but now I can't find where.

If the manual is correct, then maybe the temperature is what caused the shutdown.

WOW - I purchased my ACM and tossed the Manual.. Thanks for the find.. Automatic switch off..my goodness....... This sounds more like developer laziness........

[lizardmech]

37 minutes ago, Cloud said:

I could be fundamentally wrong, but i dont understand how this can be correct. I hope somone will straighten me out

It is my understanding that the inverse proportional speed to torque curve illustrates the maximum torque in stalling conditions ( where there is a maximum resistance applied to the motor ) and no load max speed conditions ( when due to no loading, minimum ( ideally close to zero ) torque is required to spin the wheel fast. as one lessens the resistance from the stall condition, the corresponding applied torque in turn gets smaller and the speed increases

however i dont see how this model is anywhere close to the actual riding conditions. When riding slow, the resistance is actually less because of smaller windload and the requirement to carry the same mass over at slower speed. There is less amperage requested for the motor and the resulting force ( torque) has to be smaller. When going faster, the riders weight is still the same but to go faster and also due to the increased windload, there needs to be more current( force, torque) to produce higher speed. 

Yes i understand that during acceleration, the hogher torque will be at the slower speed and once the rider has reached the desired speed the torque will go down. But at constant higher speed, i dont see how the torque is lower than at the constant lower speed. So hopefully someone can explain how the inverse proportional speed to torque curve is applicable.

That is theoretical maximum torque. It probably only takes something like 5% of the motors torque to stay upright once moving.

[Raptor]

I read in Russia forum . In Russia was dyno tests !  Scroll down a bit down and are find special tables of data for Msuperv3  !!  http://electrotransport.ru/ussr/index.php?topic=40242.54#topmsg

[Michael Vu]

You guys are really making this a lot more complicated than it is when it comes to us trusting these wheels. All the cut-off videos I have seen are with the last 3rd alarm sounding and everyone should know not to push any further past this alarm especially with tilt-back turned off. Gotway, kingsong, and hopefully every other decent EUC manufacturer programs their last alarm not on top speed, but on available power which does depend on speed, weight, incline, current battery life, ect.

Long story short, pay attention to the last alarm. We should only be concerned if a cutoff occurs with no alarm which I've only personally experienced with ninebot.

[Marty Backe]

1 hour ago, KingSong69 said:

@Marty Backe As i know you get a warning/tiltbackwhen temperature is at 70 or 80 degree! 80degree is what the mosfets can max run!

160 degree is SO MUCH way off, that a shut off is acceptable as at this temperatures as other faults will have come before, your mosfets are melted anyway....

I should have been clearer - they say 160 degrees Fahrenheit, which is 71 degrees Celsius.

Wouldn't it be great if Gotway was involved with community and could simply answer our operating and safety questions. I know they have a Facebook page but I rarely see them actually post anything.

[Chriull]

59 minutes ago, Cloud said:

...So hopefully someone can explain how the inverse proportional speed to torque curve is applicable.

I was just trying to get a nice graph together with Speed/torque and the different "Powers" - hopefully they'll answer your question:

I took an hypothetical wheel (1) to produce the folowing graph:

 

 

Here one sees:

- Current (max)*100

The current is direct proportional to the torque of the Wheel. In this graph there are two "cut-offs" - first the limit to 40A to protect the motherboard and second the cut-off at 52 km/h to protect whatever. If ones prolonges the diagonal current line until the x and y axis one would arrive to the speed/torque chart of a BLDC motor.

- P Motor (max)

The maximum power the motor is able to deliver with this available torque (current) at the given speed.

As contrast to this i also included the Air Drag, Friction (Rolling Resistance) to show the actually needed power to drive the wheel at a certain speed and by subtracting this from the maximal available motor power one arrives to  P Reserve - the Power Reserve for such things as balancing, riding over bumps, headwinds, etc...

This was the graph for a fully charged battery at 67.2V. The same graph for 57V:

As one sees here, at 45 km/h there is a reserve of ~1kW at 45 km/h. This is more power available than many wheels have at all, but this available power here reduces drasticaly with each km/h one goes faster. And balancing, going over bumps, small inclines, some slight headwind, etc can easily leave one without any power left, overleaning the wheel.

(1):

tire diameter: 16 inch

max motor power: 3000 W

Current Cutoff at 40A (~2800W)

Cut Off Speed: 62 km/h

no load speed at 67.2V: 65 km/h (leads to a no load speed of 55 km/h at 57V)

rolling resistance coefficient: 0,02 (motorcycle tire on tarmac)

Total weight of the wheel with rider and equipment: 100kg

For the air drag:

cw=0.78, roh=1,25, A=0,5m²=(~1,8m*0,3m)

Edit: Second Chart was wrong... is updated

 

[Tishawn Fahie]

1 minute ago, Michael Vu said:

You guys are really making this a lot more complicated than it is when it comes to us trusting these wheels. All the cut-off videos I have seen are with the last 3rd alarm sounding and everyone should know not to push any further past this alarm especially with tilt-back turned off. Gotway, kingsong, and hopefully every other decent EUC manufacturer programs their last alarm not on top speed, but on available power which does depend on speed, weight, incline, current battery life, ect.

Long story short, pay attention to the last alarm. We should only be concerned if a cutoff occurs with no alarm which I've only personally experienced with ninebot.

It's not to complicated - You purchase a wheel that's advertised to do say 50 km.... In the official Gotway app you set titltback to 45km.... Under the max speed....... And the wheel shut's off on you because it cant handle the rider's weight etc...whatever.... No tiltback to slow the rider down just cut-off..

 

Then don't advertise 50KM........ Thats all I'm saying - Nothing complicated about it. 

[OliverH]

9 hours ago, zlymex said:

Overheat is the problem associated with Gotway EUC right from the start. I first encountered the problem with my MCM2 when some 10 of us was riding uphill. Most others rode IPS EUCs and were all Ok.
I personally experienced more than ten times thermal 'shutdown' on my Msuper V2, but all in slow hill climb situation therefore no risk of faceplant. The thermal 'shutdown' of Gotway EUC is just alarm beep plus severe tilt-back wich result in immediate brake and stop. 
12 MOSFET improves little as one of my friends got 6 MOSFET ACM first and then changed to 12 MOSFET board one later. He compared the two in similar uphill situations, there is not much improvement. He added a big heatsink similar to EUC Extreme but still no help. Finally we add fans hat solve the problem forever. I'm 73kg and he is less. 

I got a heat sink from a nice guy in the north of Europe. That will drop my temperature. If you're not a heavy weight rider the MSuper2 will not have problems. We're riding hills up and down over here. I'm the only one encountered one time an overheating.

[Greg Spalding]

38 minutes ago, KingSong69 said:

Its not an real argument, but...

when you see what KS has done with the KS18 1200 Watt...announced with 40kmh....but lift of cut off at just max 48kmh at 100% batterie....and on THIS wheel the liftcutoff goes way way down with batterie....some faceplanted with 32 kmh...and now ks has restricted the wheel to 30kmh under 50%batterie....(mine btw only has a lift off max of 44kmh at 100%!!!)

So:

I for my side think that what gotway has delivered with the V3 is a very good job! my opinion is that riding the wheel on 45kmh is plain asking for faceplanting...my 2 cents! from my experience it is even stable for my 100+ kg at 38-39kmh down to30%....

i for my side would not try the absolute max of 45kmh....never!

 

I'm glad you brought this up because I don't understand why the only way King Song is dealing with their safety issues is to have the wheel cut its power significantly when the battery drops below 50%, which seems ridiculous to me.

[Cloud]

1 hour ago, Greg Spalding said:

I'm glad you brought this up because I don't understand why the only way King Song is dealing with their safety issues is to have the wheel cut its power significantly when the battery drops below 50%, which seems ridiculous to me.

Kingsong doesnt cut the wheel's power when battery is below 50%.  It simply reduces the max allowable speed by forcing the tiltback earlier. Why is this ridiculous?

[zlymex]

2 hours ago, OliverH said:

I got a heat sink from a nice guy in the north of Europe. That will drop my temperature. If you're not a heavy weight rider the MSuper2 will not have problems. We're riding hills up and down over here. I'm the only one encountered one time an overheating.

For mild or short hills, its ok, even for heavy people. However for long and steep hills, Msuper2 will overheat even for light rider.

I live in a city with many hills. We had another ride this chilly evening, a 92kg guy had two overheats riding his V3, we had to stop and wait for his EUC to cool off before we can continue.

[Greg Spalding]

1 minute ago, Cloud said:

Kingsong doesnt cut the wheel's power when battery is below 50%.  It simply reduces the max allowable speed by forcing the tiltback earlier. Why is this ridiculous?

I should not have been stated my point in that way. Obviously, safety is first.

My point is that I believe reducing the maximum allowable speed by forcing a tiltback earlier should occur when there is 25 or 30% of battery power left and not 50%.  That's all I meant.

[Cloud]

1 hour ago, Chriull said:

I was just trying to get a nice graph together with Speed/torque and the different "Powers" - hopefully they'll answer your question:

I took an hypothetical wheel (1) to produce the folowing graph:

 

 

Here one sees:

- Current (max)*100

The current is direct proportional to the torque of the Wheel. In this graph there are two "cut-offs" - first the limit to 40A to protect the motherboard and second the cut-off at 52 km/h to protect whatever. If ones prolonges the diagonal current line until the x and y axis one would arrive to the speed/torque chart of a BLDC motor.

- P Motor (max)

The maximum power the motor is able to deliver with this available torque (current) at the given speed.

As contrast to this i also included the Air Drag, Friction (Rolling Resistance) to show the actually needed power to drive the wheel at a certain speed and by subtracting this from the maximal available motor power one arrives to  P Reserve - the Power Reserve for such things as balancing, riding over bumps, headwinds, etc...

This was the graph for a fully charged battery at 67.2V. The same graph for 57V:

As one sees here, at 45 km/h there is a reserve of ~1kW at 45 km/h. This is more power available than many wheels have at all, but this available power here reduces drasticaly with each km/h one goes faster. And balancing, going over bumps, small inclines, some slight headwind, etc can easily leave one without any power left, overleaning the wheel.

(1):

tire diameter: 16 inch

max motor power: 3000 W

Current Cutoff at 40A (~2800W)

Cut Off Speed: 62 km/h

no load speed at 67.2V: 65 km/h (leads to a no load speed of 55 km/h at 57V)

rolling resistance coefficient: 0,02 (motorcycle tire on tarmac)

Total weight of the wheel with rider and equipment: 100kg

For the air drag:

cw=0.78, roh=1,25, A=0,5m²=(~1,8m*0,3m)

Edit: Second Chart was wrong... is updated

 

I understand what the graphs show, and i also understand why the power curve is what it is given the inverse proportionate torque to speed curve. What i dont understand is why at the same riders weight, torque is lower when the speed is higher. It seems to me that this scenario works when describing the varied resistance the motor with constant amperage supplied to it has to overcome. If i am supplied the same current to the motor, at zero resistance the motor will rotate at max speed and close to zero torque. At max resistance ( holding the shaft with your hand not letting it rorate) the speed will be zero and the torque will be maximum. With medium resistance ( holding the shaft with your hand but letting it slip and rotate) the torque will be in between and the speed somewhere in between. I understand how this scenario works.

what i dont understand is with riding the euc, it looks to me that there is a different scenario and the torque/ speed curve may not apply? the current demand changes per the lean. If the rider requests a deeper lean/ higher speed at same resistance ( riders weight and friction) a higner current will be provided to the motor increasing the motor's torque and increasing speed. I just dont see why the torque will go down when the current/ speed increase. Again i could be completely off with this..

[Keith]

36 minutes ago, Greg Spalding said:

I'm glad you brought this up because I don't understand why the only way King Song is dealing with their safety issues is to have the wheel cut its power significantly when the battery drops below 50%, which seems ridiculous to me.

@Greg Spalding there is some basic physic you need to understand where direct drive electric motors and lithium ion cells are concerned. When an electric motor turns it acts as a generator, producing a back EMF that opposes the applied voltage. At some RPM (the no load speed), that back EMF equals the applied voltage and the wheel generates no power/ no torque. Torque is at its highest at zero RPM and drops pretty much linearly as the RPM rises until it hits zero at the no load speed.

Lithium ion battery voltage drops significantly as the battery discharges from the 67V of a fully charged 16 cell to 48V or less under load when near empty. Internal resistance of the cells is not insignificant, increases in colder weather and tends to increase as cells discharge as well, particularly below 40% charge. Since power = volts X amps, as the voltage drops the current needs to rise to supply the same power, but that increased current results in a further voltage drop due to internal resistance. All of this lowers the no load speed which means that, at any given speed torque is also getting lower.

For example if the no load speed of a wheel is 25MPH (40kph) at 65V that, for a 16" wheel, is 525 RPM. if the voltage, under load drops to 48V then that no load speed will have dropped to 387 RPM, that's just 18MPH. Of course the safe speed will be way lower.

Kingsong are doing the right thing.

LiFePO4 batteries hold their voltage way way better at higher currents and a way lower state of charge, and, as a bonus, can't catch fire either albeit at a cost of lower charge density and much higher price. Nobody seems very happy at the battery limitations of the companies like Uniwheel and Solowheel who use those batteries.

Finally in an earlier post in this thread you talked about a wheel slowing you down if you try to go too fast - it cannot happen. The speed a wheel goes at is a byproduct of balancing, you lean forward, it applies torque to counter your leaning, that torque produces acceleration - end of story, the ONLY thing that can stop a wheel accelerating without dumping the rider on his face is the rider stopping leaning forward, all any single wheel, or single axle electric vehicle can do is have a mechanism to encourage the rider to slow down - I.e. Tilting or beeping. The electronics can only physically control speed if there are at least 2 inline wheels as on a bike. 

[Greg Spalding]

4 minutes ago, Keith said:

@Greg Spalding there is some basic physic you need to understand where direct drive electric motors and lithium ion cells are concerned. When an electric motor turns it acts as a generator, producing a back EMF that opposes the applied voltage. At some RPM (the no load speed), that back EMF equals the applied voltage and the wheel generates no power/ no torque. Torque is at its highest at zero RPM and drops pretty much linearly as the RPM rises until it hits zero at the no load speed.

Lithium ion battery voltage drops significantly as the battery discharges from the 67V of a fully charged 16 cell to 48V or less under load when near empty. Internal resistance of the cells is not insignificant, increases in colder weather and tends to increase as cells discharge as well, particularly below 40% charge. Since power = volts X amps, as the voltage drops the current needs to rise to supply the same power, but that increased current results in a further voltage drop due to internal resistance. All of this lowers the no load speed which means that, at any given speed torque is also getting lower.

For example if the no load speed of a wheel is 25MPH (40kph) at 65V that, for a 16" wheel, is 525 RPM. if the voltage, under load drops to 48V then that no load speed will have dropped to 387 RPM, that's just 18MPH. Of course the safe speed will be way lower.

Kingsong are doing the right thing.

LiFePO4 batteries hold their voltage way way better at higher currents and a way lower state of charge, and, as a bonus, can't catch fire either albeit at a cost of lower charge density and much higher price. Nobody seems very happy at the battery limitations of the companies like Uniwheel and Solowheel who use those batteries.

Finally in an earlier post in this thread you talked about a wheel slowing you down if you try to go too fast - it cannot happen. The speed a wheel goes at is a byproduct of balancing, you lean forward, it applies torque to counter your leaning, that torque produces acceleration - end of story, the ONLY thing that can stop a wheel accelerating without dumping the rider on his face is the rider stopping leaning forward, all any single wheel, or single axle electric vehicle can do is have a mechanism to encourage the rider to slow down - I.e. Tilting or beeping. The electronics can only physically control speed if there are at least 2 inline wheels as on a bike. 

Keith,

nothing is more valuable to me that an education and I am humbled and greatly appreciative of your time today in teaching me.

I understand more now and I shall strive to learn every single day about this new hobby I love

Again, it took a long time to help explain this and that means the world to me

Thank you

[Raptor]

This is the real result of this, the wheel Here you see a this wheel dyno test under load :

[Marty Backe]

36 minutes ago, zlymex said:

For mild or short hills, its ok, even for heavy people. However for long and steep hills, Msuper2 will overheat even for light rider.

I live in a city with many hills. We had another ride this chilly evening, a 92kg guy had two overheats riding his V3, we had to stop and wait for his EUC to cool off before we can continue.

That looks like some fun riding territory.

[Cloud]

10 minutes ago, Raptor said:

This is the real result of this, the wheel Here you see a this wheel dyno test under load :

Exactly - this illustrates my point above. Where do you guys see Torque decreasing with speed? Torque increases with speed during riding, as more power is demanded from the motor