Statistics service Ecodrift repair KingSong, GotWay, Inmotion (March-July 2017)

[Tomek]

13 minutes ago, EcoDrift said:

Unfortunately, you reason as a user.
With Rockwheel in general it is impossible to work as a company. First they made goods of very low quality, maybe rockwheel gt16 v2 of better quality, but having received such negative experience with them on past products, generally there is no desire to work further.

It is very difficult to work with small factories and receive competent support from them.
Buy one wheel - maybe. Building long relationships with them at the level of wholesale purchases is not an achievable task. Believe.

The law on the protection of consumer rights is one of the most stringent in Russia. And so it is very painful to work with plants with low quality like rockwheel or gotway.
Example.
A breakdown in the first 14 days is a return. (Hello got and rock) (in 2017 years I returned 2 GT16 from 5))) (In 2017 I returned 4 Msuper1600) 
Two breakdowns of the same in a year is a return. (Hello got and rock) (In 2017 years I returned 4 GT16 from 5, and after sold as used for little money)(6 Msuper 1600)

And for example - in 2017 years I returned only one KS16Sports and zero Inmotion. 

Feel the difference)

The court for the protection of consumer rights almost always stands up for the protection of the consumer, not the seller.

 

I totally understand your perspective. As a reseller I wouldn't want to deal with Rockwheel, and probably also not with with Gotway. But as a hobby-user who likes to mod wheels, it made sense for me to buy Rockwheel, and the aliexpress Rockwheel store is really, really excellent for people like me, since if something breaks they are very responsive and are fast and willing in providing spare parts (as other have reported here). That said, the chance that something will break in a Rockwheel wheel IS much higher than kigngsong or inmotion, that's the tradeoff.

[EcoDrift]

7 hours ago, Tomek said:

I totally understand your perspective. As a reseller I wouldn't want to deal with Rockwheel, and probably also not with with Gotway. But as a hobby-user who likes to mod wheels, it made sense for me to buy Rockwheel, and the aliexpress Rockwheel store is really, really excellent for people like me, since if something breaks they are very responsive and are fast and willing in providing spare parts (as other have reported here). That said, the chance that something will break in a Rockwheel wheel IS much higher than kigngsong or inmotion, that's the tradeoff.

I would understand you very well if you did not live in a civilized Europe. But how can you use all the high-quality and want rockwheel - this is very strange for me.
Now all quality brands have a good margin for maximum speed, power and battery reserve.

In 2015, yes, the rockwheel GR16 and GR12 had no alternatives. And if you want to drive fast - just him. But be kind and repair. But now, why?
I bought a Kingsong 18C (its name is "elephant" in Russia) - 40-45 km/h. 
I have been engaged in electric unicycle since 2014 and see the development of the market perfectly and understand how it was then and now.

[Tomek]

1 hour ago, EcoDrift said:

I would understand you very well if you did not live in a civilized Europe. But how can you use all the high-quality and want rockville - this is very strange for me.
Now all quality brands have a good margin for maximum speed, power and battery reserve.

In 2015, yes, the rockwheel GR16 and GR12 had no alternatives. And if you want to drive fast - just him. But be kind and repair. But now, why?
I bought a Kingsong 18C (its name is "elephant" in Russia) - 40-45 km/h. 
I have been engaged in electric unicycle since 2014 and see the development of the market perfectly and understand how it was then and now.

well, you paint a very black-white picture here. sure Rockwheel GT16 has many superficial imperfections and has statistically a higher chance of breaking, but it's still a damn good wheel!

it's performance is unmatched by other wheels in its class, and the riding experience is really amazing. all i meant is that as a reseller you'd have to respond to users having issues with superficial things that don't work as they should (ie tire rubbing shell), and ones that can have disastrous effect if not addressed (ie. waterproofing), while as a hobby user you just fix them yourself and enjoy the wheel. Of course, this doesn't apply to serious issues such as a wheel shaft breaking, or controller board malfunctioning, but those problems seem resolved with GT16 V2.

...but there's a chance that I'll be posting tomorrow a photo of all my limbs covered in plaster, which will prove me wrong .')

[EcoDrift]

2 hours ago, Tomek said:

well, you paint a very black-white picture here. sure Rockwheel GT16 has many superficial imperfections and has statistically a higher chance of breaking, but it's still a damn good wheel!

it's performance is unmatched by other wheels in its class, and the riding experience is really amazing. all i meant is that as a reseller you'd have to respond to users having issues with superficial things that don't work as they should (ie tire rubbing shell), and ones that can have disastrous effect if not addressed (ie. waterproofing), while as a hobby user you just fix them yourself and enjoy the wheel. Of course, this doesn't apply to serious issues such as a wheel shaft breaking, or controller board malfunctioning, but those problems seem resolved with GT16 V2.

...but there's a chance that I'll be posting tomorrow a photo of all my limbs covered in plaster, which will prove me wrong .')

I tell everything as it is. And it is by his honesty that he earned a great respect from all Russian riders.

My store is the largest in Russia. I managed to work with all the factories (airwheel, ips, unknown brands of unicycle and now with all the tops).
I know everything about all the wheels. This is my business - electric unicycle. I understand it perfectly. And therefore, I sincerely believe that at least Russian monocers should go for quality goods, which are not listed in my past posts.

 

And lastly - I had a goal to show the reliability of this or that brand.
To argue with owners from other countries, in which I do not sell goods - I do not have much desire.
Therefore, consider rockwheel a quality wheel - your right. I just can be happy for you. Since it has not broken down yet, like most of my customers.

[Scatcat]

31 minutes ago, EcoDrift said:

I would understand you very well if you did not live in a civilized Europe. But how can you use all the high-quality and want rockville - this is very strange for me.
Now all quality brands have a good margin for maximum speed, power and battery reserve.

In 2015, yes, the rockwheel GR16 and GR12 had no alternatives. And if you want to drive fast - just him. But be kind and repair. But now, why?
I bought a Kingsong 18C (its name is "elephant" in Russia) - 40-45 km/h. 
I have been engaged in electric unicycle since 2014 and see the development of the market perfectly and understand how it was then and now.

What @Tomek said above.

I had problems with my V1. Rockwheel actually went out of their way to help me resolve it, and even sent me some extras to compensate for the troubles. But to make a long story short I changed both motor and board, and so I had the chance to see the differences. The new board were rather obviously better made than the old one. That goes for both the design with connectors for some wiring rather than a mess of solderings, but also that the solderings were pretty flawless on the new board. The new motor had a fatter shaft, which was welcome.

The idea of using 247 MOSFETs rather than the smaller ones in for example GW-wheels is pretty good. I suspect that the reliability of six 247s is rather better than twelve 220s, as the thermal profile is about twice as good, and don't depend on balancing the power two ways.

Then the cooling in the GT16 is about as good as passive cooling in a EUC has gotten so far. Both connectors and board are close to the air-ducts and massive aluminium heat-sink. Since there is somewhere for the heat to actually dissipate, it is very efficient.

So why not a KingSong?

Actually, I may feel tempted to buy the new 18" KS when it comes out to market. If I do depends a lot on how it compares to the Ninebot Z10. But let's back away from that 18" for a while and look at the rest of the KS's.

The old 18" KS is a very quirky design. I'm sure it's one of those you come to love, but for me it doesn't tick any boxes. I also find it peculiar that they've chosen to have air-vents on top of the EUC in the latest version. Sure, they're covered by the seat, but that is not a solution AFAIC - more of a quick fix.

The old 14" KS has a rep for thin shafts, which doesn't go well with a guy like me weighing in at 200lbs. The new ones look a lot better. But if I want a small wheel, an M10 is the form-factor that makes me drool.

The 16" KS is also a good looking wheel. I've actually considered it. But I quite often go at 20-25 mph/32-40 kph, and if anything what I would want is a wheel with more power not less. I have 2000W nominal, dropping down to 1200W is a no-go. A limit of 35 kph is also a no-go.

If KS16 with 1200W and 35kph max would feel like stepping out of the Porsche and into the much more "sensible" Volkswagen, guess what going with an even less powerful Inmotion would feel like?

They're beautiful wheels, and the quality is good, but it's like they've conceptually replaced power and range with polish.

I do hope the new Ninebot is as good as it could be. And that it combines crazy and out of the box with quality and usability. That would be something.

[Hunka Hunka Burning Love]

On 10/27/2017 at 6:04 AM, EcoDrift said:

And lastly - I had a goal to show the reliability of this or that brand.
To argue with owners from other countries, in which I do not sell goods - I do not have much desire.
Therefore, consider rockwheel a quality wheel - your right. I just can be happy for you. Since it has not broken down yet, like most of my customers.

I think we all appreciate your service report and find it interesting and helpful.  I don't think anyone here is arguing with your viewpoint about Rockwheel.  Even with Gotway we've seen the headaches other dealers have had to go through especially with the MSuper V3S+ firmware fiasco.  To have to deal with a product in large numbers that is unreliable doesn't make business sense when you have angry customers returning wheels and experiencing issues.  Being a reseller is no easy job!  I think there's something lost in translation as the Rockwheel riders here are just trying to point out there are some improvements in the newer version and some good support directly from Rockwheel.

It's such a common mistake for some Chinese manufacturers to rush a product out without thoroughly testing it and end up with a flawed first version.  By the time an improved version two comes out consumer and reseller confidence is down the toilet.  Costs to ship and the time needed to repair these wheels isn't cheap in an already challenging market.  Resellers want reliable, high quality wheels that they sell and ship and out and have minimal warranty work needed.  Who wants angry customers?

I'm not sure how a company like Rockwheel can mend reseller relationships, but maybe with time they will be able to improve their quality level to bring it up to "KingSong" or "Ninebot" levels.  Sometimes tight budgets can only do so much for a smaller company.  I'm not sure if this is the correct idiom, but была не была?

[mezzanine]

5 hours ago, EcoDrift said:

I tell everything as it is. And it is by his honesty that he earned a great respect from all Russian riders.

My store is the largest in Russia. I managed to work with all the factories (airwheel, ips, unknown brands of unicycle and now with all the tops).
I know everything about all the wheels. This is my business - electric unicycle. I understand it perfectly. And therefore, I sincerely believe that at least Russian monocers should go for quality goods, which are not listed in my past posts.

 

And lastly - I had a goal to show the reliability of this or that brand.
To argue with owners from other countries, in which I do not sell goods - I do not have much desire.
Therefore, consider rockwheel a quality wheel - your right. I just can be happy for you. Since it has not broken down yet, like most of my customers.

Just wanted to say thank-you for providing this info.  It's extremely valuable and you do a service for those here that read it. 

[Zenko]

On 27/10/2017 at 2:04 PM, EcoDrift said:

I tell everything as it is. And it is by his honesty that he earned a great respect from all Russian riders.

My store is the largest in Russia. I managed to work with all the factories (airwheel, ips, unknown brands of unicycle and now with all the tops).
I know everything about all the wheels. This is my business - electric unicycle. I understand it perfectly. And therefore, I sincerely believe that at least Russian monocers should go for quality goods, which are not listed in my past posts.

 

And lastly - I had a goal to show the reliability of this or that brand.
To argue with owners from other countries, in which I do not sell goods - I do not have much desire.
Therefore, consider rockwheel a quality wheel - your right. I just can be happy for you. Since it has not broken down yet, like most of my customers.

Hello @EcoDrift, first, thanks for your review very detailed and that confirmed what I feel about the market right now. I hope you don't mind that i shared your topic for information

I also think quality prime over other aspects ! It is nice to see a reseller that as such high standards, in France we don't even have that much transparency, and this is sad.

Why do you still sell GOTWAY with the evidences you're showing ? Is it still worth despite having lots of repair services ?

Also, is not possible to reinforce security over GOTWAY wheels ? Do you check cables, motherboard, for every wheel ? I was thinking, do prevention of poor quality can be done for those wheels ?

[WaveCut]

@Zenko IMO it's popularity is pretty obvious: you want top performance - you buy gotway (and then fixing it but its another part of story)

[electricpen]

On 10/24/2017 at 1:13 AM, EcoDrift said:

My top

cheap 14 - kingsong 14b

powerful 14 - kingsong 14s 840

for light users 16 - inmotion v8

for all users 16 - kingsong 16sport

for high speed users 18 - msuper 1600, but always use defense

 

Is there a particular reason you would recommend msuper 1600 over KS-18s for the 18" group? They are close in speed and KS sport series have been more reliable in this generation. Just curious, these two are on my short list of wheels to buy...

[Marty Backe]

1 hour ago, electricpen said:

Is there a particular reason you would recommend msuper 1600 over KS-18s for the 18" group? They are close in speed and KS sport series have been more reliable in this generation. Just curious, these two are on my short list of wheels to buy...

In my opinion that KS18S is more of acquired taste (due to its tall profile) than the MSuper, but otherwise all reports indicate that it's a great wheel. I do think that the 84 volt MSuper's have more power than the KS18S for whatever that's worth. And because of their shorter profile they are a bit more agile than the KS18S.

[Jason McNeil]

There's definitely room for improvement with GW Board reliability. Except for some out-of-box quirks with the KS boards, we haven't had any failed MOSFETs on the 14D/14S/16S/18S line, the statistical tally for Gotway is around 3-5% failure rate over 1 year (on some models, it's quite a bit higher than this). 

I can't find the superb post that @esaj did a couple months ago, where he describes the comparative merits of the IRFP4368 High-duty 350A FETs on KS boards, & Gotway's approach with the 12x IRFP4110s (120A Max) that are not nearly at the same level of MTBF reliability. Would be interested to get the resident EE Wizards opinions (@esaj, @Chriull,  @Keith, sorry if I missed anyone) on if we should start a concerted lobbying effort to get GW to switch to a simpler,  6 MOSFET board (with better thermal distribution) & improved FETs like the IRFP4468, which looks like an absolute winner for a 84v Wheel.

https://www.infineon.com/dgdl/irfp4468pbf.pdf?fileId=5546d462533600a40153562c73472019

[OliverH]

Is the mosfet Problem a reliability issue, wrong parameters or just overheating?

[Hunka Hunka Burning Love]

Is this the post?

[US69]

1 hour ago, Jason McNeil said:

Except for some out-of-box quirks with the KS boards, we haven't had any failed MOSFETs on the 14D/14S/16S/18S line, the statistical tally for Gotway is around 3-5% failure rate over 1 year (on some models, it's quite a bit higher than this). 

Exactly what i know from the guys from asia and Germany! not even ONE mosfet failure on the S series!

Gotway should also switch to this 4368 Mosfet or higher...3-5% failure or even a bit higher, i would call TO high rate.

I really dont understand that..such an cheap product can make such a difference...and is just not used by Gotway :-(

 

[US69]

1 hour ago, Jason McNeil said:

Except for some out-of-box quirks with the KS boards, we haven't had any failed MOSFETs on the 14D/14S/16S/18S line, the statistical tally for Gotway is around 3-5% failure rate over 1 year (on some models, it's quite a bit higher than this). 

Exactly what i know from the guys from asia and Germany! not even ONE mosfet failure on the S series!

Gotway should also switch to this 4368 Mosfet or higher...3-5%, or even a bit higher, i would call TO high failure rate.

I really dont understand that...such an cheap product can make such a difference...and is just not used by Gotway :-(

 

[Jason McNeil]

1 hour ago, OliverH said:

Is the mosfet Problem a reliability issue, wrong parameters or just overheating?

Just speculation, but from the catastrophic MOSFET failures I've seen—with remnants FET particularised as a fine dust coating throughout the inside of the shell, it would be safe to say that something can get severely out of wack. It could be a momentary peak power, perhaps timing malfunction (with double the number of FETs, the number of switching operations is doubled I think), or maybe the combination of high core temperature with high output which is the issue here. 

41 minutes ago, Hunka Hunka Burning Love said:

Is this the post?

He had a more recent one, about  3-4 months ago.

[esaj]

4 hours ago, Jason McNeil said:

There's definitely room for improvement with GW Board reliability. Except for some out-of-box quirks with the KS boards, we haven't had any failed MOSFETs on the 14D/14S/16S/18S line, the statistical tally for Gotway is around 3-5% failure rate over 1 year (on some models, it's quite a bit higher than this). 

I can't find the superb post that @esaj did a couple months ago, where he describes the comparative merits of the IRFP4368 High-duty 350A FETs on KS boards, & Gotway's approach with the 12x IRFP4110s (120A Max) that are not nearly at the same level of MTBF reliability. Would be interested to get the resident EE Wizards opinions (@esaj, @Chriull,  @Keith, sorry if I missed anyone) on if we should start a concerted lobbying effort to get GW to switch to a simpler,  6 MOSFET board (with better thermal distribution) & improved FETs like the IRFP4468, which looks like an absolute winner for a 84v Wheel.

https://www.infineon.com/dgdl/irfp4468pbf.pdf?fileId=5546d462533600a40153562c73472019

I have no recollection which post you might refer to, but then again last few months have been more or less a blur to me     As for EE Wizards, there are actual EE's in the forums, I'm not one of them 

 

2 hours ago, Hunka Hunka Burning Love said:

Is this the post?

Funny to look back at that, I can now actually answer (at least some) of my own questions there  Also funny that I suggested using the same mosfet that the KS16S's are now using...   Not that my suggestion had anything to do with it, I probably just pulled it from some Digikey/Mouser/whatever -search looking for the lowest on-resistances with suitable voltages...

 

2 hours ago, Jason McNeil said:

Just speculation, but from the catastrophic MOSFET failures I've seen—with remnants FET particularised as a fine dust coating throughout the inside of the shell, it would be safe to say that something can get severely out of wack. It could be a momentary peak power, perhaps timing malfunction (with double the number of FETs, the number of switching operations is doubled I think), or maybe the combination of high core temperature with high output which is the issue here. 

AFAIK, no, there's no need to double the switching operations, but paralleling mosfets just by tying the gates directly together (like it was done in the broken ACM board I got from Rehab1, but there the issue was burned MCU, not the mosfets) isn't exactly a good way, one or the other can start (or stop) conducting sooner/later taking brunt of the load and there are issues with the gate voltages "ringing" (oscillating fast), which in the worst case could cause a breakdown by itself or excessive power dissipation as the mosfet "swings" from fully to partially conducting and back when it should be just fully conducting. I made a small capacitive spot-welder in the summer which shoots up to and above 1000A spike (momentary peak power is somewhere around 10kW or above, but total energy is less than 40 joules when fully discharged) through 5 paralleled mosfets for a few milliseconds, and although it's different from a motor drive (ie. they are only put into full conduction FAST and then turned off as fast as possible), it's certainly something where gate ringing could lead to (more or less) spectacular failure. I followed advice from some application note about paralleling power mosfets and did a similar set up as the Firewheel board had (separate gate resistors followed by ferrite bead paralleled with a reversed diode for faster shutdown), although Firewheel didn't even have paralleled mosfets.

 

I haven't followed up on the forums much lately, so I'm not quite sure what the situation is these days, ie. are the mosfet failures still among the most common (or the most common) mode of failure in the boards. Exploding mosfets sounds something new, usually there haven't been much (if any) outside marks, but then again, I haven't followed much on the failure topics lately. Certainly "better" mosfets couldn't hurt, at least as long as the circuitry and software driving them is done right, but just slapping lower Rds(on) -mosfets in place of the old ones probably isn't the "right way" to design it, but I'd still expect the people designing the wheel mainboards know a lot better than me what they're doing    Also they can be destroyed in a multitude of ways, too much power dissipation (overheating) is just one of the ways. A good example, I actually destroyed the mosfet on my CNC spindle motor driver a week or two back just by touching the motor with a spanner (something I've done a gazillion times before, each time I have to change the bit, which is typically at least 3 times per board, and I've used the same driver for 50+ different designs of boards, some more than one piece). Probably I had too much static electricity built up in my body and the drain-source -channel fried... when I have the time, I'll add some TVS-diodes to eat up high voltages so hopefully I don't have to deal with it again   

 

Quote

He had a more recent one, about  3-4 months ago.

Couldn't find it myself on a quick search, but it's probably floating around somewhere...