100V MSuper X ... check it out!

[mrelwood]

1 hour ago, bluewheel said:

People are so concentrated on the high speeds and I still don't understand why to be honest.

I agree with your post, but even disregarding the obvious speed thrill some of us are addicted to, it is a lot safer to ride at 35km/h with a wheel that can go 50km/h than 35km/h. I have found myself pushing at the verge of tilt-back (~34km/h) more and more on my 16S. A few times when accelerating back to travel speed after easing up for bumps I think I have even been closing up on the limits of the wheel. Even if my travel speed wouldn’t increase much at all, I like the idea of not having to concentrate on it nearly as much with the Msuper X that should arrive on tuesday.

But some people ride at just 20km/h (13mph). It seems impossible for the other end of riders to understand the other. I’m currently a 35km/h guy, and while I don’t get a lot what I yearn from riding at 20km/h, I don’t get the 50km/h riders either. Must be some gear they’re prepared to slide with.

And speed is an easy spec to ask and tell. (And to sell by.) Same with cars. ”Yours go 200km/h?! Ooooohhh...” We don’t drive even close to their limits either.

[US69]

From my experience the Amps shown in wheellog for Gotways are at LEAST 2 times to high....more realistic even 3 times to high....

[esaj]

3 hours ago, meepmeepmayer said:

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.

The cells can give out a huge number of amps, the amperages reported by the manufacturers are (maybe somewhat conservative) ratings for maximum continuous (like 10A) and shorter while (20A) output currents. Above these the cell may overheat and catch fire or explode, but if you short circuit a cell over a small resistance, the amperage will be HUGE. The protections on the cells (like the CID, "current interruption device") should trigger and cut the current, but they aren't always acting fast enough or even working. Still, you can get a hundred or more amps out from a single cell for a brief period, probably at least tens of amps for a longer while, but it can also go up in flames pretty quick. Sometimes they just heat up, maybe make some smoke, other times...

Video description: "Charging at 30 amps and then short it"

 

Quote

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?

Very short-term transients can be really high just inside the circuits with caps discharging, I used 10 x 47000uF / 160 milliohm each caps in parallel for a spot-welder that goes way above 1000A for a short period (~1 millisecond), and that's in a controlled fashion with 5 x mosfets in parallel with "proper" gate driving (large current drivers, ferrites, fast turn-off -diodes, parallel TVS's to kill of transient voltage spikes from weld cable inductance)  to start / stop the discharge. But still, the Gotway amps measurements likely is way off.

 

Quote

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.

The overcurrent protection in BMS only disconnects the output, it does not limit it really (so more like "on or off"). The mosfets in the BMS board cannot limit the current, they would overheat and burn, only either "allow it or disallow it", not much in between. Usually the BMS datasheet has times for how long it takes for it to react, so for a short while (micro- or milliseconds) it can allow as much current as the cells just can give.

Some random BMS datasheet, over current protection delay time is 5-20ms, short circuit protection delay is 200-500µs. Also note that this is for 4S (and any number in parallel) BMS, with working current of 100A and over current protection triggering at 300A +- 20A. The short circuit current is expected to be higher.

 

 

[RockyTop]

Esaj knows his stuff.  I started working with VVVF (veritable voltage veritable frequency) in the early 90’s. When you start a motor the amps jump up 2-5 times the rates running amps until the moter reaches a balanced emf. The amperage that we use never actually balances. So we are just constantly jabbing it with starting amps to control the speed. We can measure the amps but it is never considered continuous amps. This is how we can seemingly overload  without Damaging the components.

I however yield to Esaj’s Superior knowledge.

[esaj]

31 minutes ago, RockyTop said:

Esaj knows his stuff.  I started working with VVVF (veritable voltage veritable frequency) in the early 90’s. When you start a motor the amps jump up 2-5 times the rates running amps until the moter reaches a balanced emf. The amperage that we use never actually balances. So we are just constantly jabbing it with starting amps to control the speed. We can measure the amps but it is never considered continuous amps. This is how we can seemingly overload  without Damaging the components.

I however yield to Esaj’s Superior knowledge.

Thanks for the trust, but I'm just a hobbyist in electronics, and my word definitely shouldn't be taken as any sort of "gospel"... there are actual EE's (electronics engineers) in the forums who likely know far better than I do. 

[RockyTop]

10 minutes ago, esaj said:

Thanks for the trust, but I'm just a hobbyist in electronics, and my word definitely shouldn't be taken as any sort of "gospel"... there are actual EE's (electronics engineers) in the forums who likely know far better than I do. 

I am sure the first electric unicycle came from the mind of a hobbyists ..........that might have also of been an engineer.  

[Vikas]

10 hours ago, esaj said:

Thanks for the trust, but I'm just a hobbyist in electronics, and my word definitely shouldn't be taken as any sort of "gospel"... there are actual EE's (electronics engineers) in the forums who likely know far better than I do. 

With utmost respect I have seen the walls of calculus. Esaj and his hobbyist knowledge go much MUCH deeper than Mariana's trench. A compendium of wisdom without question and without equal. Nufffsaid.?

[Scatcat]

Just a note on 18650 max amps.

There is no "boolean" hard limit on any 18650 without a protection circuit. Even a cell rated at 10A can put out 40A or more for a very short period of time, and cells rated at 20A CDR can actually put out as much as 80A for half a second or so without taking permanent damage.

The effect of "pulse power", that is discharging well over the CDR limit of course taxes the cells and shortens the life span. It heats them up pretty fast, faster the higher you go. To put it in a practical context, as I'm a vaper in love with my mech mods: My typical coil is 0.2Ω and I use two of those in parallel. That means I use my single 18650 with a resistor of 0.1Ω, which means a theoretical max amp draw of 42A.

There are no cells on the market that can give that kind of juice continuously, the ones I use are rated ~20-25A CDR. I mostly use Samsung INR20R or Sony VTC5A, both of them with INR chemistry. Samsung are the only ones who've dared to actually publish figures for how long high pulses can be sustained, and those figures go up to 100A (less than half a second at that power ).

In reality, with voltage drop, the true figure for my amps should be somewhere around ~35-38A. I can stress the cell for up to 6-7 seconds at that amperage without any undue risks, as long as I allow some cooling down in between. I can even do it twice or three times if I allow the cell to cool down afterwards.

It DOES affect battery longevity, and I can't hope to use a cell for more than a year or so before noticing a serious degradation of capacity. When my 2500mAh goes down to 1500-1800mAh it is time to retire the cell.

The Sanyos and Pioneers we use in our EUCs are a bit more volatile than the Samsungs and Sonys I use for vaping. They have a higher capacity but lower CDR. Mostly they should not be pushed beyond 10A draw continuously, but can peak at much higher powers. When my GT16 transients at 45A, that is from four parallel packs, meaning each cell is required to give ~11-12A. That number are well within the bounds of what the cells can take for such short transients. You could actually double the number for very short periods of time, and those transients are seldom longer than fractions of a second. Sure, it will affect the lifespan of the packs, but not that badly.

So seen just from the battery perspective, 90A from 4p would stress the cells, but not dangerously so. The number is probably wrong anyway as @Marty Backe and @esaj both say above.

Still and all, my speculation was that Gotway could do a lot more to handle those transients in a way that are safer for the board.

[FreeRide]

On 7/6/2018 at 3:08 AM, Chriull said:

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

 

 

 

The last column seems all wrong. Power loss is I^2R, and the R for 6S would be 0.1 not 0.18.  So i think you will find you need to reverse again, back to your original statement. 

[Chriull]

6 hours ago, FreeRide said:

The last column seems all wrong. Power loss is I^2R, and the R for 6S would be 0.1 not 0.18.  So i think you will find you need to reverse again, back to your original statement. 

R for 6S is 6*0,03 Ohm = 0,18 Ohm, for 6P it is 0,03 Ohm/6=0,005 Ohm (the ohmic values were rounded with one digit too less ;( ). So 10 A*10 A * 0,05 Ohm = 0,5 W and 1,67 A*1,67 A* 0,18 Ohm = 0,5W....

... the table is not well formated and a bit too much rounding... but everythings right?

ps.: With the assumption of 30 milli Ohm internal resistance per cell. Is imo somewhere near what i read in some datasheets of cells used in EUCs

[FreeRide]

8 hours ago, Chriull said:

R for 6S is 6*0,03 Ohm = 0,18 Ohm, for 6P it is 0,03 Ohm/6=0,005 Ohm (the ohmic values were rounded with one digit too less ;( ). So 10 A*10 A * 0,05 Ohm = 0,5 W and 1,67 A*1,67 A* 0,18 Ohm = 0,5W....

... the table is not well formated and a bit too much rounding... but everythings right?

ps.: With the assumption of 30 milli Ohm internal resistance per cell. Is imo somewhere near what i read in some datasheets of cells used in EUCs

OK you are correct, when I correct the table for rounding which is significant in row 1, and I use the correct resistance in row 4 as you had stated I see calculations working out as per your revised statement that internal power loss of the battery is the same.  So if appropriate cabling is used (scaled to adjust for increase current, and practical) then the internal cable losses would not be an issue either.  The motor winding though would have to be of suitable gauge also which could create a heavier motor depending on specifications.

[Cloud]

On ‎7‎/‎6‎/‎2018 at 2:04 PM, esaj said:

Thanks for the trust, but I'm just a hobbyist in electronics, and my word definitely shouldn't be taken as any sort of "gospel"... there are actual EE's (electronics engineers) in the forums who likely know far better than I do. 

lol @esaj, You have been saying you are a hobbyist for at least 3-4 years now. I got news for you buddy, 3-4 years hobbyists are called experts ( also known as gospel writers )! lol

[Slartibartfast]

As discussed in this thread I just ordered what I thought was an 84v MSuper X but was surprised to discover when it arrived it in fact only has a 60v motor. I'd done a reasonable amount research before ordering and had not come across any mention a 60v option and thought the 1600Wh capacity was the critical thing, so was sure to order a 1600Wh 2nd gen wheel.

Is this 60v option new, and should I be concerned about it? I really wanted the 84v version and was a bit shocked that this 60v version even existed, let alone that I had ordered it.

[Marty Backe]

50 minutes ago, Slartibartfast said:

As discussed in this thread I just ordered what I thought was an 84v MSuper X but was surprised to discover when it arrived it in fact only has a 60v motor. I'd done a reasonable amount research before ordering and had not come across any mention a 60v option and thought the 1600Wh capacity was the critical thing, so was sure to order a 1600Wh 2nd gen wheel.

Is this 60v option new, and should I be concerned about it? I really wanted the 84v version and was a bit shocked that this 60v version even existed, let alone that I had ordered it.

Every Gotway wheel made in the last few years has 60-volts marked on the motor. 67-volt wheels, 84-volts wheels, and 100-volt wheels. Don't worry about it, you have an 84-volt wheel.

[Slartibartfast]

9 minutes ago, Marty Backe said:

Every Gotway wheel made in the last few years has 60-volts marked on the motor. 67-volt wheels, 84-volts wheels, and 100-volt wheels. Don't worry about it, you have an 84-volt wheel.

Arr, fantastic!
Is there any way to verify this on my wheel in particular?

It's just that now that I look at the sellers listing more closely it actually states that it has a 60v motor. I was willing to just dismiss the marking when I first saw it but given the fact that the seller actually lists it's stats as 60v I'd like to be able to verify that despite the marking and the stat listing it is really 84v.

[Marty Backe]

19 minutes ago, Slartibartfast said:

Arr, fantastic!
Is there any way to verify this on my wheel in particular?

It's just that now that I look at the sellers listing more closely it actually states that it has a 60v motor. I was willing to just dismiss the marking when I first saw it but given the fact that the seller actually lists it's stats as 60v I'd like to be able to verify that despite the marking and the stat listing it is really 84v.

There is no such thing as a 60-volt Gotway wheel.

But if you insist on going down this path:

• Does your charger say that it outputs 84-volts? Measure if you still think it's an intricate fraud.
• Does the charge port on the wheel have 4-pins? 67-volt wheels have 3-pins and 100-volt wheels have 5-pins

Please understand that we get this question constantly from new riders unfamiliar with the EUC scene.

And you will probably come back later and say the app reports 67-volts. The apps were never updated to report the proper voltage.

[Slartibartfast]

4 minutes ago, Marty Backe said:

There is no such thing as a 60-volt Gotway wheel.

But if you insist on going down this path:

• Does your charger say that it outputs 84-volts? Measure if you still think it's an intricate fraud.
• Does the charge port on the wheel have 4-pins? 67-volt wheels have 3-pins and 100-volt wheels have 5-pins

Please understand that we get this question constantly from new riders unfamiliar with the EUC scene.

And you will probably come back later and say the app reports 67-volts. The apps were never updated to report the proper voltage.

Cool, thanks.

Charger output does say 84v, and it does indeed have 4 pins.

It was more that Green Fashion themselves actually listed the wheel as only being 60v that un-nerved me. I just would've thought they would know better.

I'll sleep easy now, thank you.

[meepmeepmayer]

60V is some safety limit in the U.S. and Green and Fashion just lie about the voltage for that reason. That's 99% what happened.

Something to know about the EUC business: Everybody lies. The manufacturers lie. The sellers lie. Even @Jason McNeil has numerous errors or questionable numbers in his comparison charts (though surely not intentionally). This is compounded by the fact that you can't really state some numbers as clearly as one might think (e.g. top speed and range may depend on rider weight). Don't believe any official specs or spec sheet you find anywhere.

Some examples:

msuper X official top speed is 20km/h because that's the max allowed in China. Says Gotway. Same for the Ninebot One Z. Says Ninebot. Which is obviously BS.

The upcoming IPS S5 is  67.2V wheel. But if you magically use a battery cell's nominal voltage instead of the max voltage, the voltage comes out to under 60V, as which it is stated. Plain lie.

All Gotway wheels report their voltage as 67.2 via Bluetooth. So the app does not have to consider what wheel it actually is. Lie.

How many sellers actually put the "Lithium Ion battery warning thing" sticker on their boxes for delivery, as required? Wanna check your box?

Everybody lies (for various reasons). Believe nothing that didn't come from a real world test or what people here on the forum can confirm

@Marty Backe Your reply is almost poetic

[esaj]

The motors may very well be 60V "nominal", the thing about motor voltages and powers is that they're not an exact and absolute value. 60V motor can take higher voltage, assuming the windings have thick enough coating that it won't strike-through between the windings (even there it isn't that cut-and-dry, because the inductance of the winding can cause voltage spikes that are higher than the battery voltage), and a 1000W nominal motor might withstand much, much higher power without the lacquering/windings melting. Of course there are some upper limits for both, and if the lacquering on the windings burns away due to the windings running too hot, the motor will short circuit and stop dead under you, same for short-circuit caused by a high voltage strike-through. I recall reading somewhere that people have been able to run 1kW nominal motors at several kilowatts continuously without issues, and even the 1-2kW wheels have peak powers several kilowatts above the nominal values. In that sense, 60V or 72V or 84V, or "1000W" or "2000W" motor doesn't mean that much, the main thing is that the motor can take it without breaking and that the controller can supply (or sink during regenerative braking) enough power without breaking.

[meepmeepmayer]

Funny, Jason said the standard nominal numbers are way above what these EUC motors can actually take indefinitely (they'd overheat). But I guess it depends on the details, cooling, whatnot.

My point was, the official 60V of the Gotway motors have nothing to do with the 60V stated by Green and Fashion other than that may have been the perfect excuse for their lie

But you strengthen the fact that some numbers can't be stated as exactly as one might think.

[esaj]

37 minutes ago, meepmeepmayer said:

Funny, Jason said the standard nominal numbers are way above what these EUC motors can actually take indefinitely (they'd overheat). But I guess it depends on the details, cooling, whatnot.

My point was, the official 60V of the Gotway motors have nothing to do with the 60V stated by Green and Fashion other than that may have been the perfect excuse for their lie

But you strengthen the fact that some numbers can't be stated as exactly as one might think.

Sure, it could go the other way too, manufacturer overstating the "nominal" values, but then we'd have motors burning if they couldn't go above 60V and were driven with higher voltages in 20S wheels. In the "60V" motor-case, I think (but don't know for sure of course) that whoever makes the motors (IPS, or KS or Gotway or whatever don't build their own motors, they buy them from companies specialized in electric motors, like DAAO for example: http://www.daaomotor.com/html/Motor/  DAAO is a good example, because at least earlier, their catalog contained motors with IPS-logos in their sides   and I know for a fact that Firewheel motors were made by DAAO as they had the manufacturer stamps). The motor manufacturer has defined the nominal continuous voltage and wattage the motor is meant to be used at, and if I were a motor manufacturer, I would use conservative values, so when a customer comes complaining that the motor I sold them can't handle 80V (or some can, others can't, because it's right at the limit and there's variance from one motor to the next), I'd point out that they're meant for 60V nominal voltages and not to be run constantly at higher voltages .

[Slartibartfast]

Interesting. I take it the voltage is more related to the batteries than it is the motors. As in, I take if there is not really any difference between a 60v motor and a 100v motor, the real difference is in the batteries that power the motor rather than the motor itself. Obviously you wouldn't want to over power a motor and burn it out but assuming the motor is "tough enough"(tm) it will handle most any voltage, yeah?

[bluewheel]

 

Gotway MSuper X 2019:

https://www.espritroue.fr/topic/6455-msx-2019-120v-3200wh/