100V MSuper X ... check it out!

[EUCGUY]

22 minutes ago, bluewheel said:

That would be great indeed. Would you do the similar test for the 85V version please? It would be interesting to see the range differences between 1600vs 1200! Thanks! ?

84v i dont have. haha

22 minutes ago, bluewheel said:

That would be great indeed. Would you do the similar test for the 85V version please? It would be interesting to see the range differences between 1600vs 1200! Thanks! ?

or i did with my v3s+. thats 1600wh and 84v. i got 110km from it

[FULspeed]

Interesting, on that link yesterday the price was 1900$, today 2100$....

[yourtoys7]

this is very interesting machine at similar price wow. So, whats next, Tesla V2 or Tesla 100v, hmmmm...

[stephen]

5 minutes ago, Leonte Mihai said:

What I do not understand is, if the Msuper X 84V has 2000 watts of power and the 100V has the same 2000 watts of power then where is the difference in performance between the two?

I'm not an expert but i think it can give more energy out thus acheiving more torque and maybe top end speed 

[mezzanine]

2 minutes ago, Leonte Mihai said:

What I do not understand is, if the Msuper X 84V has 2000 watts of power and the 100V has the same 2000 watts of power then where is the difference in performance between the two?

While I'm probably the most electrically ignorant person here, my theory is that the 100V system won't actually prove less efficient than the 84V wheel.  It's what I love about the internet; the most ignorant people are often the loudest about their theory!    

If there's one EUC spec I try to ignore when considering new wheels, it's the motor rating.  It doesn't seem to translate directly into greater initial torque, which is the most important motor characteristic. 

The 0-15km/h speed is so much more important to me than the top end speed.  I think a lot of folks are fools for even wanting a wheel that goes faster than 45km/h, which is why I've remained hyped for the Z series despite a lot of folks becoming less interested due to it's "lack of power." 

I've read some suggest that the 100V system only really increases the top end speed.  Until I learn whether it increases the 0-15km/h speed, I'm not interested.  

[FULspeed]

Me to I'm not an expert, but if the formula:

watt / volt = ampere     give you    

2000/84 = 23,8A

and if we apply the same formula with the 100 Volt we have

2000/100 = 20A

So we have the same power with less ampere

 

But retaining the 23.8A as  possible max (?) value we have

23.8A * 100V =  2380 Watt, so about 16% more power available at the same condition...

 

 

but please, someone more experienced than me confirm if what I said is right ..

 

[meepmeepmayer]

I'm also no expert, here's my take:

• 84V is 6P battery (with 1300/1600Wh) so ~60A max. That makes a max power of 60A*84V = 5040W.
  100V is 4P battery so ~40A max. Max power: 4000W
  Because even 4000W is more than you ever need, does it matter?
• Current ~ torque, so the 84V is snappier? I don't know. 40A is very much already, so does 40A vs 60A even matter? (Short current spikes don't count here)
• Voltage ~ top speed, so the 100V definitely has a higher top speed.
• Realistically, I think the 100V will 20% better (24/20=1.2), or at least a little better in all respects. That was how it was with the 100V Monster, right? A bit more direct wheel behavior vs. less battery.

TLDR: I have no idea.

[joku]

1 hour ago, Leonte Mihai said:

What I do not understand is, if the Msuper X 84V has 2000 watts of power and the 100V has the same 2000 watts of power then where is the difference in performance between the two?

Brushless motors are driven by pulses of electricity. The average voltage of those pulses is what determines the speed. The torque/acceleration is determined by the amps. When at speed with very little requirement for torque, the amps pulled from the battery will be low. In short, you get more speed from higher volts and more torque from higher amps. In this case they've lowered the available amps to increase the voltage and give you more speed. Watts = volts * amps. 2000 watts = 84v * 23.8 or you can have 2000watts = 100v * 20amps. The rating of the motor is just what it can continuously support without overheating. Finally, I want to include that just because the total available amps if the battery pack has been reduced, doesn't necessarily mean you'll have less torque, because the wheel might never have used all the available amps in the first place

[stephen]

i think I'm confused now ???

someone tell us an idiot guide ?

[US69]

My guess:

The board they are using in the Msuper X was originally designed for the 100V Monster....

But then they wanted to use it for 84Volt version and wanted to apply the “Tesla behavior “...rock hard pedal setting...high speed acceleration 

As the first batch showed...this doesnt work out very well, (tiltback problems, pedal moving etc etc) and from a friend who visited the GW factory begin June i heard they where still fighting with the quirks of applying the Tesla firmware on this board. The official version is this quirks now with the second batch have been gone...(still the tire is scratching inside the shell, and the sidepads where going to heaven after some minutes).

As Z10 and 18L have also been released -now thats were my guessing starts- GW still wanted to top that all again and go the other way round....use the board as designed...for a 100V model. Afaik they sold that 100V 19inch version...until today....only to a handful persons(2!!! afaik)......(which i would call extensive beta/gamma testing) ......

I was even thinking of buying this 100volt version, too, and allready was in contacts with GW, but decided to first look how it does overtime...and think of instead going for the 84volt version....where i can interchange the battery packs with my Monster.

 

[mrelwood]

6 hours ago, stephen said:

i think I'm confused now ???

someone tell us an idiot guide ?

KISS: 100V version could be faster and/or have snappier acceleration, or it could be mostly just a business and/or marketing decision. No one at this forum knows until they have tested both versions. Only thing we do know for sure is that it has a smaller capacity battery. 

[Brian Morris]

if you really want to know...

"Hub motors for electric bicycles are almost universally permanent magnet machines, either brushed or brushless. Permanent magnet motors have the highest power density of any common motor type, and they are also the easiest to understand. Both brushed and brushless motors have identical performance characteristics so the discussion below applies equally to both types.

As a thought experiment, imagine hooking up a DC motor to a power supply while holding the shaft locked. As you increase the current from the supply, the torque on the motor shaft would increase as well. The relationship is linear, twice the current yields twice the torque.

Now, disconnect the supply and connect a voltmeter across the motor leads instead. With the motor stationary, you will see zero volts. But start spinning the shaft and you'll read a voltage, directly proportional to the speed that the shaft is spun. This is referred to as the back-emf voltage, and is also expressed by a simple relationship V = k2RPM. If you derive expressions for K1 and K2 from from elementary physics, it is found that they are directly related to each other because they both result from the same flux interactions between the magnets and coils. With the rotational speed is given in RPM, then K1 = K2 * 2Pi/60. If you know how the torque-current relationship, then you also know the voltage-speed relationship and vice versa.

Suppose now the motor is connected to a voltage supply, but the shaft is left to spin freely. Initially, there will be a large current flowing through the motor as given by Ohm's Law. I = V/R where R is the winding resistance in Ohms. This produces a correspondingly large torque (T=K1*I) causing the shaft to accelerate. As the shaft spins faster and faster, the back-emf voltage increases. This reduces the current through the windings because there is less available voltage to push the current, so I = V-emf / R. The motor shaft continues to accelerate until the back emf voltage is nearly equal to the supply voltage. At this point, the current has been reduced close to zero, just enough to produce a torque that overcomes the frictional forces on the motor.

The torque-speed relationship between these two extremes is a simply straight line, given by the equation w = V/k - R*T/k2. Notice that there are only two parameters needed to characterize this 1st order model of a motor, 1) the motor constant K, and 2) the winding resistance R. For a given K, the smaller the resistance R, then the less the speed drops when the motor is loaded, and hence the more powerful the machine. The motor constant K determines both how much voltage is required to make the motor spin at a certain speed, and how much torque it will output for a given current.

If you take the same motor and wind it with twice the number of turns of copper, then k will double, so the motor will require twice the voltage to reach the same speed, but it will only need 1/2 the current to output a particular torque. Notice that the power input (V*I) for a given torque and speed is the same in both cases. The power lost in the copper is the same too, since twice the number of turns means twice the length at half the wire area, so 4 times the resistance. Power loss goes as I2R, so halving the current is exactly canceled by a 4-fold increase in R. The important point here is that rewiring the motor for a different K value does _not_ change the motors fundamental performance in any way, provided that the same total amount of copper is used.

A third property that is important to characterizing a permanent magnet motor is the torque needed to simply turn the shaft. This is often called the cogging or drag torque and results from both the strong forces between the iron poles on the rotor and the magnets, and the induced eddy currents caused by the moving magnetic field. On direct drive hub motors, this torque is quite substantial, between 0.3 to 1 N-m, and it increases with the motor speed. Proper engineering and tight manufacturing tolerances can reduce this torque, but it is always a lot higher in permanent magnet motors with iron poles than any other type of machine.

The amount of power put into a PM motor is equal to the battery voltage times the current. The amount that is converted into mechanical power is equal to the back-emf voltage times the current. The conversion efficiency from electrical to mechanical energy is therefore simply the ratio of the back-emf voltage to the applied voltage.

When the motor is unloaded, it spins up to a point where the back-emf voltage is quite close to the battery voltage, and so the conversion efficiency is almost 100%. However, all of the mechanical energy produced is used to overcome this internal cogging losses, and no power is available as useful torque on the shaft. The efficiency from the perspective of output power to input power is 0%. As the motor is then loaded, the speed goes down so the electro-mechanical conversion efficiency goes down, but a significant percentage of torque produced is now available at the output shaft, so the overall motor efficiency increases. Load the motor further still, and then the losses from the cogging torque become insignificant to the I2R losses in the copper, and the efficiency starts to roll down again.

If you take two motors with the same K and R values, but different cogging torques, then the one with the lower cogging torque will exhibit higher efficiency. But this efficiency peak is only in the low power end of the graph, under heavy loadings the two graphs converge. For a respectable power density, a PM motor should typically be run at about 80% of the unloaded speed, corresponding to roughly 80% efficiency. Whether or not the motor has 95% efficiency at low powers is pretty insignificant in terms of the amount of energy it will draw on an actual trip, so it's generally not about basing motor decision on purported peak efficiency."

[esaj]

16 hours ago, mrelwood said:

KISS: 100V version could be faster and/or have snappier acceleration, or it could be mostly just a business and/or marketing decision. No one at this forum knows until they have tested both versions. Only thing we do know for sure is that it has a smaller capacity battery. 

Like Brian Morris posted above, it's down to the windings on the motor, they could use different motor for the 100V version. If it's the same, then I would think it would output more power, as the motor resistance stays the same. That would mean both faster acceleration (higher current with higher voltage) as well as higher (theoretical) top speed. More voltage with the same K-factor for motor voltage means higher (unloaded) max speed. More amps for the same K-factor of current means higher torque, but also means that the batteries are drained faster...

The total capacity of the batteries is the same, if they use the same amount of cells with the same capacity. No matter how you put them together, the total watthours is the same, consider just 6 cells of 3.7V nominal voltage and 1Ah as an example:

1S6P = 3.7V nominal voltage, 6Ah capacity  =>  3.7V * 6Ah = 22.2Wh

2S3P = 7.4V nominal voltage, 3Ah capacity => 7.4V * 3Ah = 22.2Wh

3S2P = 11.1V nominal voltage, 2Ah capacity => 11.1V * 2Ah = 22.2Wh

6S1P = 22.2V nominal voltage, 1Ah capacity => 22.2V *1Ah = 22.2Wh

EDIT: Although... the more cells you put in series (to get higher voltage), the higher the total resistance for the cell-series becomes, as the sum of the internal resistances goes up. This means more voltage drop at high amp draw, and more power lost heating the cells.

[mrelwood]

8 hours ago, esaj said:

The total capacity of the batteries is the same, if they use the same amount of cells with the same capacity. 

The 100V version is confirmed having a 1230Wh battery. It seems they couldn’t fit a 24S5P system in there. The 1600Wh 84V version has two 20S3P packs, so 120 cells total. 100V version has 24S4P, so only 96 cells.

There is some empty room at the bottom though...

[EUCGUY]

14 minutes ago, mrelwood said:

The 100V version is confirmed having a 1280Wh battery. It seems they couldn’t fit a 24S5P system in there. The 1600Wh 84V version has two 20S3P packs, so 120 cells total. 100V version has 24S4P, so only 96 cells.

There is some empty room at the bottom though...

mine says 1230wh on the label

[meepmeepmayer]

4*24 cells * 3.7V nominal per cell * 3500mAh per cell = 1243.2Wh if you want a number Some people prefer 3.6V nominal, then it's 1209.6Wh. If you use 3.65 you come pretty close to 1230.

[Chriull]

14 hours ago, esaj said:

EDIT: Although... the more cells you put in series (to get higher voltage), the higher the total resistance for the cell-series becomes, as the sum of the internal resistances goes up. This means more voltage drop at high amp draw, and more power lost heating the cells.

But the higher the voltage the less current is needed for the same output power. So with twice the voltage one has twice the internal resistance but only half the current - so the voltage drop at the internal resistance stays the same.

As power dissipation goes with the square of the current the losses at the internal resistance reduces for the same power output.  Have just seen with the excel sheet that the internal power loss stays the same for all this combinations  with for example an output power of 37W:

S	P	V Nom	3,7	V	P Out	37	W	R internal	0,03	Ohm	internal Loss
			U(V)			I(A)			R(Ohm)		W
1	6		3,7			10,00			0,01		0,50
2	3		7,4			5,00			0,02		0,50
3	2		11,1			3,33			0,05		0,50
6	1		22,2			1,67			0,18		0,50

 

 

 

[Scatcat]

It seems though that there have been some reports from Chinese customers that the 100V is less dependable. Some boards have fried when stressed. I don't have a source for this yet. Just something said when talking with a distributor that was a bit concerned.

I have no idea if this is a prevalent problem, or just something in some pre-production wheels out in the wild.

I'm considering the 84V version myself, mostly for the extra range, but also because it has been well received in the internal market of China.

Note:

Actually I have somewhat of a theory about that... please give me feedback if you think I'm on to something - or not.

It seems from the reported amperage of Gotway wheels that there is a lot of transients going on. @Marty Backe for instance has a 90A alarm set.

When I compare to my GT16 which also has a 2000W motor, the transients I get are almost never higher than 45A - which rhymes rather well with the motor max power.

My theory is that the firm-ware programmers of Gotway hasn't implemented a truly working transient control. The firmware should stop asking the batteries for more juice when they reach such levels, and that should happen fairly quickly like microsecond-quickly. There are no reasons to ask for more anyway, since the motor can't really do anything with the extra juice. The only effects you get are overheating and the risk of fried electronics.

When you up the voltage, these spikes remain, but now at a higher voltage - meaning more watts, meaning higher risk for failure.

You can compensate by going for more resilient components (To-247 and such), which alleviates the problem, but doesn't negate it.

Suppose you have a ~90A spike at ~84V, then you get a total of ~7500W in the spike. Up that to ~100V and the same spike is now ~9000W. At some point the spike is more than the board can handle.

So going up, you have to control the transients better or get more problems.

Feel free to prove me an idiot  

[EUCGUY]

1 hour ago, Scatcat said:

It seems though that there have been some reports from Chinese customers that the 100V is less dependable. Some boards have fried when stressed. I don't have a source for this yet. Just something said when talking with a distributor that was a bit concerned.

I have no idea if this is a prevalent problem, or just something in some pre-production wheels out in the wild.

I'm considering the 84V version myself, mostly for the extra range, but also because it has been well received in the internal market of China.

Note:

Actually I have somewhat of a theory about that... please give me feedback if you think I'm on to something - or not.

It seems from the reported amperage of Gotway wheels that there is a lot of transients going on. @Marty Backe for instance has a 90A alarm set.

When I compare to my GT16 which also has a 2000W motor, the transients I get are almost never higher than 45A - which rhymes rather well with the motor max power.

My theory is that the firm-ware programmers of Gotway hasn't implemented a truly working transient control. The firmware should stop asking the batteries for more juice when they reach such levels, and that should happen fairly quickly like microsecond-quickly. There are no reasons to ask for more anyway, since the motor can't really do anything with the extra juice. The only effects you get are overheating and the risk of fried electronics.

When you up the voltage, these spikes remain, but now at a higher voltage - meaning more watts, meaning higher risk for failure.

You can compensate by going for more resilient components (To-247 and such), which alleviates the problem, but doesn't negate it.

Suppose you have a ~90A spike at ~84V, then you get a total of ~7500W in the spike. Up that to ~100V and the same spike is now ~9000W. At some point the spike is more than the board can handle.

So going up, you have to control the transients better or get more problems.

Feel free to prove me an idiot  

I will do more hard stress testing with full gear on, the coming week. If the board dies, so be it, not expensive to get a new one and i have my other wheel to use. i can just pad it up so the shell doesnt take damage. Considering that the temps reported from the mosfets never got anything higher than 42c from hard riding up hills, i have a feeling that its not as bad.My plan is to overheat it 3 times in a row and then inspect. this will be going up and down a short and steep hill. if that looks fine afterward, ill do a long and steep hill.
:) yey

[EZhel]

On 7/2/2018 at 11:53 PM, Mrd777 said:

this is amazing news, but somewhat incredibly depressing since most of us are waiting for our 84v units... ouch!

Not at all - I've paid for my MSuperX order mainly because 1600 Wh and the range it should provide. 1230Wh is close to the trio of V10F, KS18L and Z10 and more torque at super high speed doesn't make much sense for me personally.

p.s. a high speed wheel with only 4 parallels in battery sounds like a guaranteed highspeed faceplant solution.

[bluewheel]

People are so concentrated on the high speeds and I still don't understand why to be honest. Falling from the wheel at thigh speeds is very dangerous and it can have life-long consequences. My understanding of EUC concept is that you should enjoy it and not target high speeds from various reasons: one - safety and two legislation. I can only envision if few accidents will happen as a result of some folks who jump on the wheel and ride irresponsibly, we will all end up suffering. Yes, I am taking about legislation, and the gray area we are still let (or tolerated) to ride today. I bet that regulators are looking for a ''one step too far'' and the chance that we will all park our EUC in the shed is nearing. My feeling is we are just a few breaking news (accidents that I am referring to) away from awaking the legislators on the high speeds an EUC could generate. And that would be it for us all.

I would only say that we should ride responsibly and don't push the boundaries . If you want speed buy a car or a motorcycle, they are already regulated and if you are caught breaking the law you won't pull anyone down with you.

Ride responsibly guys..and God bless! ?

[Marty Backe]

4 hours ago, Scatcat said:

It seems though that there have been some reports from Chinese customers that the 100V is less dependable. Some boards have fried when stressed. I don't have a source for this yet. Just something said when talking with a distributor that was a bit concerned.

I have no idea if this is a prevalent problem, or just something in some pre-production wheels out in the wild.

I'm considering the 84V version myself, mostly for the extra range, but also because it has been well received in the internal market of China.

Note:

Actually I have somewhat of a theory about that... please give me feedback if you think I'm on to something - or not.

It seems from the reported amperage of Gotway wheels that there is a lot of transients going on. @Marty Backe for instance has a 90A alarm set.

When I compare to my GT16 which also has a 2000W motor, the transients I get are almost never higher than 45A - which rhymes rather well with the motor max power.

My theory is that the firm-ware programmers of Gotway hasn't implemented a truly working transient control. The firmware should stop asking the batteries for more juice when they reach such levels, and that should happen fairly quickly like microsecond-quickly. There are no reasons to ask for more anyway, since the motor can't really do anything with the extra juice. The only effects you get are overheating and the risk of fried electronics.

When you up the voltage, these spikes remain, but now at a higher voltage - meaning more watts, meaning higher risk for failure.

You can compensate by going for more resilient components (To-247 and such), which alleviates the problem, but doesn't negate it.

Suppose you have a ~90A spike at ~84V, then you get a total of ~7500W in the spike. Up that to ~100V and the same spike is now ~9000W. At some point the spike is more than the board can handle.

So going up, you have to control the transients better or get more problems.

Feel free to prove me an idiot  

I don't have any hard facts to back this up, but I was under the impression that there was a consensus that the ampere value being reported by Gotway was not accurate because in general the values seemed too high for what was generally considered possible. It would be great to have some objective way of validating the Gotway telemetry.

So for me, I just use it as a relative indicator. I know that 90-amps is rarely achieved and when I do get the warning I'm doing something very strenuous.

[Marty Backe]

3 hours ago, EUC GUY said:

I will do more hard stress testing with full gear on, the coming week. If the board dies, so be it, not expensive to get a new one and i have my other wheel to use. i can just pad it up so the shell doesnt take damage. Considering that the temps reported from the mosfets never got anything higher than 42c from hard riding up hills, i have a feeling that its not as bad.My plan is to overheat it 3 times in a row and then inspect. this will be going up and down a short and steep hill. if that looks fine afterward, ill do a long and steep hill.
yey

Spoken like the true die-hard rider that you are 

[meepmeepmayer]

4 hours ago, Scatcat said:

It seems from the reported amperage of Gotway wheels that there is a lot of transients going on. @Marty Backe for instance has a 90A alarm set.

When I compare to my GT16 which also has a 2000W motor, the transients I get are almost never higher than 45A - which rhymes rather well with the motor max power.

Cool theory. Can't judge it, though

But you guys need to stop treating these extreme outlier app numbers like they must be the truth. 90A on 6P means 15A for a cell, which is pretty much the extreme theoretical maximum good cells will do (not sure how long). 10A maximum is probably a much, much more realistic (and healthy for the battery) number. I don't know if the cells allow for very short term (microseconds) current spikes above these maxima.

So if ever Marty gets a 90A spike warning on his Tesla e.g. which is 4P, that proves 90A (or more) most likely simply isn't true.

I strongly believe these high current spike numbers are either a mathematical or a technical artifact. They are either completely untrue or only technically true (like for half a millisecond, transients as you say), but can hardly be representative to judge what's actually going on. Can you really compute meaningful power numbers from that?

As there is no back channel from the board to the battery, the only way the board can know the batteries can't give more is when no more power comes despite demanding it. I presume the BMS takes care of limiting power output, and I don't know if it allows very short term current spikes (like maybe above 10A per cell) before settling down to a lower long-term limit, or if it's always the same limit. Anyways, not sure if "transient control" is necessary or is simply done by the fact that the battery has a power limit and the board can't help but notice that anyways. The battery, not the motor is the limiting part here.

That's how I see it, certainly I'm no expert, but can use a bit of critical thinking. Maybe these spikes are there, I wouldn't bet on it. Don't trust any numbers just because something gives them. Your GT16 comparison pretty much shows that, it's a similar enough wheel so how can be the numbers double that on GWs? Likely it's the same spike that leads to different outputs due to mathematical (half the time delta used gives you twice the number) or technical differences.

TLDR: Spike numbers are dumb, don't interpret too much into them.

[RockyTop]

On 7/4/2018 at 12:22 PM, FULspeed said:

Me to I'm not an expert, but if the formula:

watt / volt = ampere     give you    

2000/84 = 23,8A

and if we apply the same formula with the 100 Volt we have

2000/100 = 20A

So we have the same power with less ampere

 

But retaining the 23.8A as  possible max (?) value we have

23.8A * 100V =  2380 Watt, so about 16% more power available at the same condition...

 

 

but please, someone more experienced than me confirm if what I said is right ..

 

Yes , this is correct. The advantage of higher voltage is that you use less amps for the same power (wattage). So you can use smaller components. ( mofits) The disadvantage is that it needs more isolation.   More Affected  by contamination and water.  Components also need more isolation.  I work with 480 volts 60 h.p.