Ninebot One Z8 Open-β Tester's FAQ (link)

[mezzanine]

7 hours ago, US69 said:

@Niaraeth thanks for your honest answers...

Actually the quoting from "Turbocharge" goes with my exspectations...

 

 

 

Early returns suggest you were right to be skeptical.  I really expected the early reviews to rave about the improvement in safety from the wide/tubeless tire design.  The disappointment in the power is one thing; I knew there was cause to be concerned with that characteristic.  It's the lack of positive response to the tire design that I didn't see coming. 

From now on, I'm not getting excited for any new wheel that doesn't excite you, @US69- it looks like your prediction was correct.  

[Adel]

Thanks @Niaraeth for posting and sharing your experience with the Beta program.

[Dmitry Buzmakov]

@Niaraeth, I have a couple questions that maybe you could answer and/or be able to pass it to the 9bot Lead Tech guy

1.Will be E+ pedals used in final product? If so, what was the reason for dropping nice stylish pedals that we saw on earlier prototypes?

2. What is recommended tire pressure, what is your current level? Have you tried different pressure levels? It is interesting how tire pressure may affect rider's experience in the case of such unusual design.

3. How many parallels does the battery pack have? Is it possible to remove the battery without full casing dismantle?

4. What about speed limitations on different markets? Will the max speed be permanently capped on some wheels depending on market/seller or users will have the right to unlock full potential?

5. And finally. We was all waiting for this launch and the release date was delayed several times. It'd be interesting to get some insights on what actually has been improved or added vs the first prototypes we saw a year ago)

[Hunka Hunka Burning Love]

I have a few burning questions - why did Ninebot stick with the lower voltage specification when others have been at 67.2 and 84V and higher for the longest time?  Are there some specific countries that they have to cater to that demand a sub 60V specification?  I just don't get it.  No other wheel manufacturer seems to make wheels with lower voltages so why does this limit exist?  If anything it seems like there is a drive towards 100V as limits are being explored.  Is it due to some safety issue?

I think Ninebot made the S1/S2/A1 with the smaller battery packs to try to get them allowed on airplanes, but it seems like airlines forbid these wheels no matter what so that effort was pretty futile.  Is it some requirement to be able to pass a certain certification that Ninebot wheels are required to be below 60V?  UL / CE standards maybe?  Or do they feel that there is no need to break the 60V barrier as they can achieve adequate performance as is?

Too bad they don't have a sub-60V version for the sub-60V market, but also have a "grey" market or modifiable 84V -100V powerhouse version that can outperform the competition.  I wonder what the Ninebot wide tire motor is capable of.   Say if the specifications were known, and imagine programming a Tesla control board to mate with the Ninebot engine... what would the possibilities be?    Too bad there's no open source control board with working software...

[Rehab1]

 

On 5/17/2018 at 5:49 AM, Niaraeth said:

Hi guys,

I got into Beta-testing, Z8. 

 Here's my Report/FAQ, on the official Ninebot bbs. (due to contract I can only link it)

 [EN] Z8 Open-β Testing Report - FAQ

Thank you for your realistic, unchaperoned  viewpoints. A portion of this statement really concerns me:

3.   ........if you are not used to the weight you'll get pendle/sway motion at 30km/h+, which can be VERY dangerous.

I’m assuming ‘pendle sway’ = w ?bble = loss ~of ~control ?= faceplant = hospital? ?‍♂️

 

 

[mezzanine]

42 minutes ago, Hunka Hunka Burning Love said:

I have a few burning questions - why did Ninebot stick with the lower voltage specification when others have been at 67.2 and 84V and higher for the longest time?  Are there some specific countries that they have to cater to that demand a sub 60V specification?  I just don't get it.  No other wheel manufacturer seems to make wheels with lower voltages so why does this limit exist?  If anything it seems like there is a drive towards 100V as limits are being explored.  Is it due to some safety issue?

I think Ninebot made the S1/S2/A1 with the smaller battery packs to try to get them allowed on airplanes, but it seems like airlines forbid these wheels no matter what so that effort was pretty futile.  Is it some requirement to be able to pass a certain certification that Ninebot wheels are required to be below 60V?  UL / CE standards maybe?  Or do they feel that there is no need to break the 60V barrier as they can achieve adequate performance as is?

Too bad they don't have a sub-60V version for the sub-60V market, but also have a "grey" market or modifiable 84V -100V powerhouse version that can outperform the competition.  I wonder what the Ninebot wide tire motor is capable of.   Say if the specifications were known, and imagine programming a Tesla control board to mate with the Ninebot engine... what would the possibilities be?    Too bad there's no open source control board with working software...

I'm sure they're trying to appeal to a larger market by going with the lower voltage.  I'm guessing there is some regulation that they're trying to stay within.  

If I'm being optimistic, I'd guess that they'll have to adapt to market demand and do a revised version with higher power output somewhere down the road.  I've never been as concerned as many with the power concerns because of that belief.  Realistically, though, I really wonder whether the average EUC buyer will care in the same way we do on this forum.  It's going to be very interesting to see.  

[Niaraeth]

8 hours ago, EUCMania said:

Hi @Niaraeth What is the fact and your opinion about these items:

1. It is only nimble at slow speed, the agility is really not that good above 10-12 mph, to me personally it is to a level that I feel unacceptable. Some testers report that with enough practice it would turn well. Well, I don’t think so, I don’t think it will ever be as nimble as a V10 or a Msuper 3 no matter how much practice you put into improve it.
2. Power output is disappointing, acceleration is slow, braking is not that good too. This is an Off Road wheel by design, but it fail to climb a slope when a same rider can get up with easy on a Ninebot S2.
3. The tire, it slips on painted lines on the road, slips on wet, and it is hard. You think a 18 inch fat tire will bring superb comfort? Well, no.. nowhere near the comfort of GW 18 or the new V10. But again it does perform great on gravel and grass.

Since you can talk to the lead designers, I have a few hypothesizes about the reasons: 

About the slow braking: During the braking,  the control board does not charge one of the two battery packs, see the video of the Taiwan tester. This will make dumping the energy into battery twice as hard. The bug comes from that the algorithm is for Z6 who has only one pack. 

Another solution for the slow braking and acceleration: Choose a lighter weight tire. The tire used now may be too stiff, some testers complained. Check those fat tire bikes, their tires are pretty soft and light.

The complaint of side slips on tilted roads and wet surface is a serious complaint. It must be addressed before releasing to the market. 

Here's a fact for everyone:

The One Z has a build-in turning support system, that will assist you while turning.

It WILL take some time to get used to that, since it's not present in other wheels, thus taming the wheel takes a bit longer.

AND if you really don't want the system to kick in, ride backwards (Yup, you heard it right).

1. That System is the key for the nimbleness. And as for high speed, just pretend it's a GW Monster and you'll have no problem turning it, it's the same weight after all.

You have to know that most testers are not wearing protective gears (it's China =-=) so they don't to go high speed or turn that hard.

2. The Acceleration and breaking distance have been greatly improved by recent hardware patches, there's also an option to have a tilt-back feedback while breaking. (can be turned off for advanced users) Personally I think the acceleration and breaking feels quite good now.

3. It's a hard tire, and ROUND. Combined with the turning assist, it will slide slightly if you are on blind-walk (those tile for blind person?). As for wet, I was going up-down road slopes during rain but no slides occurred. As I have heard from other testers, Higher tire-pressure allows less slide.

In my personal opinion, I think testing on aqua-planing to prove that the tire is unstable is really mean

6 hours ago, Confusius15 said:

@Niaraeth, 350km in 2 weeks, so around 25 km a day. Do you feel like your Z8 can really reach 80 km as announced ?

Z8 can reach to 80km if you go like constant 15-20, I don't have a lot of free time (family, work) so that's not a lot. Other people have over 800km over the two weeks.

For me, I hate it when the speed-limit kick in, and that's about ~30km. So I rarely go anywhere further than 15km.

My ride-style is pretty while, breaking down to 10 then push up to 42 again etc. You get the picture.

The Longest trip I did at one time was 51km, leaving 10% battery. (Speed-limit then was 25.0)

2 hours ago, Dmitry Buzmakov said:

@Niaraeth, I have a couple questions that maybe you could answer and/or be able to pass it to the 9bot Lead Tech guy

1.Will be E+ pedals used in final product? If so, what was the reason for dropping nice stylish pedals that we saw on earlier prototypes?

2. What is recommended tire pressure, what is your current level? Have you tried different pressure levels? It is interesting how tire pressure may affect rider's experience in the case of such unusual design.

3. How many parallels does the battery pack have? Is it possible to remove the battery without full casing dismantle?

4. What about speed limitations on different markets? Will the max speed be permanently capped on some wheels depending on market/seller or users will have the right to unlock full potential?

5. And finally. We was all waiting for this launch and the release date was delayed several times. It'd be interesting to get some insights on what actually has been improved or added vs the first prototypes we saw a year ago)

Yup, all good questions, I'll forward them. 

1 hour ago, Hunka Hunka Burning Love said:

I have a few burning questions - why did Ninebot stick with the lower voltage specification when others have been at 67.2 and 84V and higher for the longest time?  Are there some specific countries that they have to cater to that demand a sub 60V specification?  I just don't get it.  No other wheel manufacturer seems to make wheels with lower voltages so why does this limit exist?  If anything it seems like there is a drive towards 100V as limits are being explored.  Is it due to some safety issue?

I think Ninebot made the S1/S2/A1 with the smaller battery packs to try to get them allowed on airplanes, but it seems like airlines forbid these wheels no matter what so that effort was pretty futile.  Is it some requirement to be able to pass a certain certification that Ninebot wheels are required to be below 60V?  UL / CE standards maybe?  Or do they feel that there is no need to break the 60V barrier as they can achieve adequate performance as is?

Too bad they don't have a sub-60V version for the sub-60V market, but also have a "grey" market or modifiable 84V -100V powerhouse version that can outperform the competition.  I wonder what the Ninebot wide tire motor is capable of.   Say if the specifications were known, and imagine programming a Tesla control board to mate with the Ninebot engine... what would the possibilities be?    Too bad there's no open source control board with working software...

I'll ask him. 

As for Chinese Airlines, we are actually allowed to take them on board if the battery is removed.

1 hour ago, Rehab1 said:

 

Thank you for your realistic, unchaperoned  viewpoints. A portion of this statement really concerns me:

3.   ........if you are not used to the weight you'll get pendle/sway motion at 30km/h+, which can be VERY dangerous.

I’m assuming ‘pendle sway’ = w ?bble = loss ~of ~control ?= faceplant = hospital? ?‍♂️

 

 

Yup, wobble, almost all "new" users to oneZ in the beta-test have experienced it. It's just lack of muscle to control the beast. Some get it at 20+, some at 30+ some at 40.

(People with experience with heavy/high-speed wheels were less affected)

Meanwhile, ALL of them have gotten over it

It took me one-afternoon / four riding sessions to get to top-speed without wobble.

 

@US69Somehow I got the noob mute again after 3 posts yesterday, how long does this state last...?

 

[Adel]

@Niaraeth one of the beta user reviews claimed that the Z has engine cutoff safety feature like the V10f so that when you lift it by the handle when it's on, the wheel doesn't turn. Is that true?

[Niaraeth]

3 minutes ago, Adel said:

@Niaraeth one of the beta user reviews claimed that the Z has engine cutoff feature like the V10f so that when you lift it by the handle when it's on, the wheel doesn't turn. Is that true?

Yup. I wrote that in my FAQ, too, though  

More about that: since Inmotion is holding the patent of pull-lifting, the OneZ has a pressure-based lifting-detection system inside the bottom half of the handle. 

!!For all users: There's a testing calibration for the pressure sensor for the first time, but only when the wheel has reached 4km/h, so  if you get the wheel, ride it a bit before lifting it.!!

[EUCMania]

1 hour ago, Niaraeth said:

Yup. I wrote that in my FAQ, too, though  

More about that: since Inmotion is holding the patent of pull-lifting, the OneZ has a pressure-based lifting-detection system inside the bottom half of the handle. 

!!For all users: There's a testing calibration for the pressure sensor for the first time, but only when the wheel has reached 4km/h, so  if you get the wheel, ride it a bit before lifting it.!!

We will love it if you can produce a video showing the hill climbing. You can install an angle measurement app on your smart phone to measure the incline angle. That will show the true power of the wheel.

Also, the reason for I plan to buy One Z is the shock absorbing ability of the wide tire under lower pressure. Please compare the rider comfort when going over a tree root road crack, comparing 1z vs GW MSuper. Please ask the Ninebot designer to use tires that can absorb more shocks. This is the best reason I want to buy 1Z, because I was bounced off a few times and got hurt by road cracks due to tree roots.    

[Niaraeth]

5 hours ago, Dmitry Buzmakov said:

@Niaraeth, I have a couple questions that maybe you could answer and/or be able to pass it to the 9bot Lead Tech guy

1.Will be E+ pedals used in final product? If so, what was the reason for dropping nice stylish pedals that we saw on earlier prototypes?

2. What is recommended tire pressure, what is your current level? Have you tried different pressure levels? It is interesting how tire pressure may affect rider's experience in the case of such unusual design.

3. How many parallels does the battery pack have? Is it possible to remove the battery without full casing dismantle?

4. What about speed limitations on different markets? Will the max speed be permanently capped on some wheels depending on market/seller or users will have the right to unlock full potential?

5. And finally. We was all waiting for this launch and the release date was delayed several times. It'd be interesting to get some insights on what actually has been improved or added vs the first prototypes we saw a year ago)

I updated my FAQ on the ninebot bbs, please take a look.

I just got feedback from the Lead Tech:

1. E+ pedals are final... unfortunately. But they come with sand-papers for better grip.

2. 25-32 is recommended, higher for less drift. I didn't measure mine, can't tell...

3. Don't know about parallels, but he stated that it's easy to change the battery.

4. No regulations so far, in the tech division.

5. The Trolley changed, the Mud-guard changed, THE TIRE BECAME BROADER, and the Max RPM was raised. 

4 hours ago, Hunka Hunka Burning Love said:

I have a few burning questions - why did Ninebot stick with the lower voltage specification when others have been at 67.2 and 84V and higher for the longest time?  Are there some specific countries that they have to cater to that demand a sub 60V specification?  I just don't get it.  No other wheel manufacturer seems to make wheels with lower voltages so why does this limit exist?  If anything it seems like there is a drive towards 100V as limits are being explored.  Is it due to some safety issue?

I think Ninebot made the S1/S2/A1 with the smaller battery packs to try to get them allowed on airplanes, but it seems like airlines forbid these wheels no matter what so that effort was pretty futile.  Is it some requirement to be able to pass a certain certification that Ninebot wheels are required to be below 60V?  UL / CE standards maybe?  Or do they feel that there is no need to break the 60V barrier as they can achieve adequate performance as is?

Too bad they don't have a sub-60V version for the sub-60V market, but also have a "grey" market or modifiable 84V -100V powerhouse version that can outperform the competition.  I wonder what the Ninebot wide tire motor is capable of.   Say if the specifications were known, and imagine programming a Tesla control board to mate with the Ninebot engine... what would the possibilities be?    Too bad there's no open source control board with working software...

The 60V is for safety regulations by the government, so he says, if ninebot wishes to be sold in China via standard shipping.

33 minutes ago, EUCMania said:

We will love it if you can produce a video showing the hill climbing. You can install an angle measurement app on your smart phone to measure the incline angle. That will show the true power of the wheel.

Also, the reason for I plan to buy One Z is the shock absorbing ability of the wide tire under lower pressure. Please compare the rider comfort when going over a tree root road crack, comparing 1z vs GW MSuper. Please ask the Ninebot designer to use tires that can absorb more shocks. This is the best reason I want to buy 1Z, because I was bounced off a few times and got hurt by road cracks due to tree roots.    

I wish I could xD

I'm bit of a sole rider, so I'll try to ask other testers to make some videos.

As for the shock absorb ability of the wheel, IT'S AWESOME!

Bumps will still make you jump tho, that's no helping in it, but Cracks, you get over them like nothing with this wheel.

As I don't have a GW, I'll ask other ppl try to compare it next time  

[Hunka Hunka Burning Love]

Thank you for fielding our questions, Naireath.  I still don't quite understand about the 60V upper limit.  How do the competitors all sell and ship their wheels in China then?  By courier?  Are you saying that because China Post won't ship EUCs with voltages over 60V, that is the main reason Ninebot has kept it low?  That is very interesting.  Maybe people only will pay for standard shipping or something?

Regarding the steering assist, does the wheel basically detect the bank angle and increase the speed a little?  That would make sense as there is a tendency to slow down a bit in curves unless you body lean it a fair bit through the turn, but there is always that fear of pedal scrape.  Leaning back would counter this.

[EUCMania]

14 hours ago, Hunka Hunka Burning Love said:

Thank you for fielding our questions, Naireath.  I still don't quite understand about the 60V upper limit.  How do the competitors all sell and ship their wheels in China then?  By courier?  Are you saying that because China Post won't ship EUCs with voltages over 60V, that is the main reason Ninebot has kept it low?  That is very interesting.  Maybe people only will pay for standard shipping or something?

Regarding the steering assist, does the wheel basically detect the bank angle and increase the speed a little?  That would make sense as there is a tendency to slow down a bit in curves unless you body lean it a fair bit through the turn, but there is always that fear of pedal scrape.  Leaning back would counter this.

I guess that as you turn, it senses the angle, and it tilts up a little to compensate the pedal dipping

[Mono]

21 hours ago, Hunka Hunka Burning Love said:

I have a few burning questions - why did Ninebot stick with the lower voltage specification when others have been at 67.2 and 84V and higher for the longest time?

My hunch would be that this is because higher voltages do not give any decisive technical advantage, apart from the publicity buzz. The additional wire weight is probably rather insignificant overall.

[Chriull]

36 minutes ago, Mono said:

My hunch would be that this is because higher voltages do not give any decisive technical advantage, apart from the publicity buzz. The additional wire weight is probably rather insignificant overall.

Power dissipation goes with the square of the current. With higher battery voltages the current can get lower and by this power dissipation for the mosfets and wirings/connectors much lower...

[mezzanine]

50 minutes ago, Mono said:

My hunch would be that this is because higher voltages do not give any decisive technical advantage, apart from the publicity buzz. The additional wire weight is probably rather insignificant overall.

I'm skeptical about the motor-rating differences, too.  It's something Jason has mentioned in the past; that we should take the advertised wattage ratings with a giant grain of salt.  

I'm not suggesting there are no technical advantages to higher rated motors or voltages, just that it's not as clear to me that they're inherently advantageous in the way people interpret them to be.  

[Mono]

46 minutes ago, Chriull said:

Power dissipation goes with the square of the current.

I guess that is true all else being equal, which is not a very reasonable assumption to make for two systems designed to operate under two different base voltages. The "problem" remains that the e-motor engineer Justin Lemire-Elmore owning Grin Technologies tells us very elaborately that voltage has essentially nothing to do with e-motor performance. Is he wrong? 

https://youtu.be/IxB2j-egWcQ?t=5m33s

[Scatcat]

29 minutes ago, Mono said:

I guess that is true all else being equal, which is not a very reasonable assumption to make for two systems designed to operate under two different base voltages. The "problem" remains that the e-motor engineer Justin Lemire-Elmore owning Grin Technologies tells us very elaborately that voltage has essentially nothing to do with e-motor performance. Is he wrong? 

https://youtu.be/IxB2j-egWcQ?t=5m33s

Well yes and no.

He's not wrong in the respect that you in principle can build two motors/control boards with a difference in operating voltage in the order of ten, but the exact same power. It depends on factors like how many turns of coil you have and thickness of the wires for the motor, and the wiring and specs of the parts on the board.

What he didn't speak about, and what I find a bit suspect in this reasoning, is that lower voltage comes with a serious disadvantage. You have to move a lot more current to get the same effect, which means you absolutely need to lessen the resistance at all stages in the circuit. The alternative being a massive power loss and heat problem.

It is by no means certain all 200V motors would be better for a EUC than all 60V motors, it "depends" (to be equivocal). But in general the risk of melting wires and other heat problems should be less with higher voltage.

Look at the Tesla cars, they operate at 400V, and there sure as hell are reasons for that. Part of it is rotational speed and the need to overcome induction voltage in the coils. Part of it is the sheer amount of power used, and the absurd currents that would mean at lower voltages. But part of it is efficiency, where higher voltages create less problems.

As we expect more out of our EUCs: higher cut-off speeds, more torque, more responsiveness, higher nominal and peak powers, I think going up in voltage rather than down is kind of natural. If I would guess, I'd say I expect the EUCs in a few years will span between 84 and 126V or so - 20-30 cells in each serie. Hopefully the cells will be able to take a "continuous" load of 20A or so, leading to peak effects in the order of 6-10kW. This would give enough headroom for true raw power going uphill, accelerating and braking. Of course that means the engine heat problem must be handled too, which in turn leads to wiring for higher voltages to avoid resistance induced heat loss...

So the NBZ10 might do OK with <60V, but I think it is a bad compromise made for all the wrong reasons.

[eddiemoy]

23 hours ago, mezzanine said:

I'm sure they're trying to appeal to a larger market by going with the lower voltage.  I'm guessing there is some regulation that they're trying to stay within.  

If I'm being optimistic, I'd guess that they'll have to adapt to market demand and do a revised version with higher power output somewhere down the road.  I've never been as concerned as many with the power concerns because of that belief.  Realistically, though, I really wonder whether the average EUC buyer will care in the same way we do on this forum.  It's going to be very interesting to see.  

I think it has to do with how they are fitting in the batteries into the hub of the unit as part of the design to keep it small.  they probably can't fit in the required cells to make the higher voltage.

[Niaraeth]

Yesterday was the 19th May Ninebot Club Beijing - Canal-Park Event, if you guys have the app you can check out more pics on the app (choose Chin. Area for more)

About 40 ppl participated, amongst them 7 Beta One Z testers. You guys can guess which one is me in the pic.

I got to test the Z10, it really feels a bit more powerful than the Z8. i.e. faster/lighter in acceleration.

As a Wheel, it feels like a GW Tesla+GW Monster combined. (Tesla-like acceleration/nimbleness + Monster-like stability) PERSONAL OPINION!

As for slopes, there was only a small bridge with slope of about 15 degrees, and we could climb it with less than 3km/h. After all, it was an all-ninebot-model event so there wasn't a lot of extreme situations.

[Turbocharged]

8 hours ago, Niaraeth said:

 

As a Wheel, it feels like a GW Tesla+GW Monster combined. (Tesla-like acceleration/nimbleness + Monster-like stability) PERSONAL OPINION!

I am also in this photo, anyway, I and Niaraeth might just have to agree to disagree here, because I think Tesla is much quicker in acceleration especially the launch from idle,  and is much more agile at higer speed. Anyway, the Z6 does feel like having a bit more torque when climbing compared to Z10.

I uploaded a video for this event to a Chinese media site, I have just moved it to YouTube. The video is made for the participants so it probably is quite boring for you. Anyway there is a short part of close up shot of Z in action if you fast forward to 1:22. and since I didn't intend to upload this to YouTube, I didn't pay close attention to what BGM to use, I don't know if it will trigger any copyright problems and be taken down or muted soon... 

 

[Mono]

On 5/20/2018 at 2:12 AM, Scatcat said:

What he didn't speak about, and what I find a bit suspect in this reasoning, is that lower voltage comes with a serious disadvantage. You have to move a lot more current to get the same effect, which means you absolutely need to lessen the resistance at all stages in the circuit.

"a lot" means twice the current on a 40V system compared to an 80V system. Sure, you need to lessen resistance where it matters, but that isn't really rocket science. I am absolutely positive that Justin has heard about this problem and the solutions, even if he hadn't been talking about it ?, though I actually hear him talking about it in this very vid at around 7:20.

[Chriull]

8 hours ago, Mono said:

"a lot" means twice the current on a 40V system compared to an 80V system. Sure, you need to lessen resistance where it matters, but that isn't really rocket science. I am absolutely positive that Justin has heard about this problem and the solutions, even if he hadn't been talking about it ?, though I actually hear him talking about it in this very vid at around 7:20.

(Disclaimer - i just watched the video from the starting point of the link ~minute 5 to minute 15)

There he's speaking of powers of 1000W. That with 12V system leads to ~100A and with 36V around 30A. So for this "setup" 36V is common, because normal("household") wiring is sufficient. (Also this ~100A would be about the upper "medium peak" limit for actual used single mosfets...)

A bit later he talks about motor "capabilities" - that this direct driven hub motor goes with 1000W at 500 rpm forever without overheating, but with 200W at walking speed it will smoke after 10 minutes. And this bike had a ~54V system. (25A of max continous battery current, 1000 to 1200W)

(Thats from the motor driver working as step down converter - the lower the speed the lower the transformed battery voltage gets and the higher the motor current gets.)

Also with high speeds one has "active" cooling by the air drag. Imo the cooling situation on an e-bike should be much better than with an EUC. Everything is in open air instead of a more or less closed compartment!

So adding this together - with the ~54V and battery current of 25A the 1000W sytem will work fine with normal/"household" wiring and fries the motor/(electronics) at low speeds...

From what i remember from the opened EUC motor pictures each motor wire is split up to ?3-5? copper wires inside the motor. The wires inside the motor have better cooling, so the weak point first to fail in EUCs is not the motor going up in smoke but the wires going to the motor (or the mosfets)

That's about what one has seen with the EUC's - they normally fry(overheat) when going "slowly" uphill. After the cabling/connectors/mosfet probs of the GWs they went from 64V to 84V _and_ increased the wire diameter and it seems they quite solved the problem... For their newest wheel they go up to 100V.

The 84V MSuper V3s was tested from @EcoDrift on the rig for ~4,6kW of peak power...

Technically one could increase wire diameters and mosfet capabilities to go with powerful "low" voltage EUCs, but still the power dissipation happens in an almost closed compartment and is resistance times the squared motor current. So lowering the "square root of" the current is much more "sane" than lowering the resistance. Especially as the first goes quite without any additional measures and the second increases ?weight? and some complexity (handling paralleled mosfets design)

I'm looking forward to the first comparisons of a Z and an actual 84V wheel going up longer inclines. As you said, it's not rocket sience and they could have implemented better cooling design and "high current handling", but imo they have taken the hard way with their "low" voltage decission.

So i'd bet on the Z to overheat first, but i'm open to be positively surprised!

[Scatcat]

51 minutes ago, Chriull said:

(Disclaimer - i just watched the video from the starting point of the link ~minute 5 to minute 15)

There he's speaking of powers of 1000W. That with 12V system leads to ~100A and with 36V around 30A. So for this "setup" 36V is common, because normal("household") wiring is sufficient. (Also this ~100A would be about the upper "medium peak" limit for actual used single mosfets...)

A bit later he talks about motor "capabilities" - that this direct driven hub motor goes with 1000W at 500 rpm forever without overheating, but with 200W at walking speed it will smoke after 10 minutes. And this bike had a ~54V system. (25A of max continous battery current, 1000 to 1200W)

(Thats from the motor driver working as step down converter - the lower the speed the lower the transformed battery voltage gets and the higher the motor current gets.)

Also with high speeds one has "active" cooling by the air drag. Imo the cooling situation on an e-bike should be much better than with an EUC. Everything is in open air instead of a more or less closed compartment!

So adding this together - with the ~54V and battery current of 25A the 1000W sytem will work fine with normal/"household" wiring and fries the motor/(electronics) at low speeds...

From what i remember from the opened EUC motor pictures each motor wire is split up to ?3-5? copper wires inside the motor. The wires inside the motor have better cooling, so the weak point first to fail in EUCs is not the motor going up in smoke but the wires going to the motor (or the mosfets)

That's about what one has seen with the EUC's - they normally fry(overheat) when going "slowly" uphill. After the cabling/connectors/mosfet probs of the GWs they went from 64V to 84V _and_ increased the wire diameter and it seems they quite solved the problem... For their newest wheel they go up to 100V.

The 84V MSuper V3s was tested from @EcoDrift on the rig for ~4,6kW of peak power...

Technically one could increase wire diameters and mosfet capabilities to go with powerful "low" voltage EUCs, but still the power dissipation happens in an almost closed compartment and is resistance times the squared motor current. So lowering the "square root of" the current is much more "sane" than lowering the resistance. Especially as the first goes quite without any additional measures and the second increases ?weight? and some complexity (handling paralleled mosfets design)

I'm looking forward to the first comparisons of a Z and an actual 84V wheel going up longer inclines. As you said, it's not rocket sience and they could have implemented better cooling design and "high current handling", but imo they have taken the hard way with their "low" voltage decission.

So i'd bet on the Z to overheat first, but i'm open to be positively surprised!

Yes, it is easy to forget that the voltage we discuss from the batteries is not the same as the voltage actually used by the motor. At lower speeds the voltage is down and the current is up. While this is perfectly OK for the batteries, at that end it's the same, it is not so for the wiring and the MOSFETs.

As @Chriull rightly notes, the typical overheating scenario is going slow and going uphill, as the power requirements are high and the voltage low in those situations. You get absurd current levels demanding a couple of kilowatts from the system when the voltage is maybe a fourth of the speced battery voltage. Suddenly you demand maybe a hundred amps at twenty volts, and the resistance from the circuits, connectors, wires and motor becomes a very acute thing, with extreme heat generation as a consequence.

At those currents, even the best insulation may start to melt, and you would get a nice burn mark if you touched a wire.

[Duf]

On 5/18/2018 at 7:56 PM, Hunka Hunka Burning Love said:

I have a few burning questions - why did Ninebot stick with the lower voltage specification when others have been at 67.2 and 84V and higher for the longest time?  Are there some specific countries that they have to cater to that demand a sub 60V specification?  I just don't get it.  No other wheel manufacturer seems to make wheels with lower voltages so why does this limit exist?  If anything it seems like there is a drive towards 100V as limits are being explored.  Is it due to some safety issue?

I think Ninebot made the S1/S2/A1 with the smaller battery packs to try to get them allowed on airplanes, but it seems like airlines forbid these wheels no matter what so that effort was pretty futile.  Is it some requirement to be able to pass a certain certification that Ninebot wheels are required to be below 60V?  UL / CE standards maybe?  Or do they feel that there is no need to break the 60V barrier as they can achieve adequate performance as is?

Too bad they don't have a sub-60V version for the sub-60V market, but also have a "grey" market or modifiable 84V -100V powerhouse version that can outperform the competition.  I wonder what the Ninebot wide tire motor is capable of.   Say if the specifications were known, and imagine programming a Tesla control board to mate with the Ninebot engine... what would the possibilities be?    Too bad there's no open source control board with working software...

Isn't this all about CE certification?