King Song S22 motor stator slippage issue: more severe than expected

[gon2fast]

42 minutes ago, oolong said:

Did you do the test from @supercurio to check for motor slippage?

Do we really need to keep doing the test now that the resellers and KS are in agreement that there is an issue? I can feel slippage in my S22 under moderate acceleration so I am I am just  putting around until my motor arrives in however long it takes the boat to get here.  

[pedroMDK]

I haven't done a full test or anything like that. I did a free spin test out of the box, cutout at 43ish. Top speed so far has actually been about 33mph per euc.world. I'm not pushing it and I'm only 140lbs. Softest shock setting (both pre/rebound) and medium ride mode. Pedals are still stock facing w/ grizzla large pads. Just crossed 110 miles this afternoon. I'm completely geared up and taking it easy, fingers crossed. Jason will probably send new motors out anyway.

[pedroMDK]

Forgot to mention, it does have a wobble at about 25 mph, I think the tire got a little deformed while sitting for the last 5 months in customs. I'll deflate, massage, repeat a few times and hope it goes away.

[oolong]

8 minutes ago, gon2fast said:

Do we really need to keep doing the test now that the resellers and KS are in agreement that there is an issue? I can feel slippage in my S22 under moderate acceleration so I am I am just  putting around until my motor arrives in however long it takes the boat to get here.  

I was just curious as to whether the previous poster had tested his or not since he was doing drops and stairs.  I agree that repeated testing will just lead to a catastrophic failure sooner rather than later.

[oolong]

4 minutes ago, pedroMDK said:

I haven't done a full test or anything like that. I did a free spin test out of the box, cutout at 43ish. Top speed so far has actually been about 33mph per euc.world. I'm not pushing it and I'm only 140lbs. Softest shock setting (both pre/rebound) and medium ride mode. Pedals are still stock facing w/ grizzla large pads. Just crossed 110 miles this afternoon. I'm completely geared up and taking it easy, fingers crossed. Jason will probably send new motors out anyway.

Jason told me they are on a boat and will take about 6 weeks for a new motor to get to me.  Although in a previous email he said a couple of weeks...  Maybe he's just trying to be more conservative with the timing.

[chanman]

5 minutes ago, oolong said:

Jason told me they are on a boat and will take about 6 weeks for a new motor to get to me.  Although in a previous email he said a couple of weeks...  Maybe he's just trying to be more conservative with the timing.

As I understand there's two shipments of motors, one coming in sooner via air that will be put in new wheels so those wheels can be sent out, and a second on a boat for the remainder of the wheels and for sending out to customers that have wheels already but want replacement motors. 

[supercurio]

Progress update:

King Song has been working hard at validating stress tests and shared some videos today of very tough tests with their employees demonstrating high fitness and stamina 💪😅.

Confirming what we learned with eWheels, here's the description of the tougher spin test:

Note: Expect a majority of S22 with a motor manufactured before July to fail during this test.
Confirmed by KS engineers: good motors and mainboard are unharmed.

Provisional description: 

• hard mode, below 80% battery
• turn on the wheel
• adopt a wide and stable foot stance, lift the wheel with a wide secure grip between the handle and suspension
• angle the wheel forward or backwards, until the motor reaches maximum rotation speed
• change the wheel so the motor suddenly changes rotation direction
• repeat up to 10 times, and take a break. It is physically demanding.
• if you hear a really bad sound coming from the motor, you can stop here: the motor is defective (in this revised test: "clunk" sounds are acceptable)
  At the next rotation change after a really bad sound: the motor might slip one more time, short circuiting and unnecessarily kill the board instantly.

King Song thinks that the clunk sound, the one I was focusing on earlier are okay and a side effect of the direction change due to the electro magnets pulling hard on them magnets at that point.
It is consistent with previous observations as Voltride tested this specifically, observing no slippage after a test where the clunk sounds were present. However, myEWhee's tests on July+ motors produced no clunks which seems contradictory, therefore that needs more testing.

In the King Song latest tests of good motors, clunks could indeed be heard at the time of rotation changes despite the whole system surviving the tougher max rpm spin test.

Landing test

King Song engineers also implemented the suggested landing test, by lifting and spinning the wheel repetitively and suddenly dropping it to the ground for several minutes long.
After this test, they opened the motor to check if the stator slipped and with new motors, confirmed that it wasn't the case.

Stress testing stand / support frame

Since executing the tougher, full rpm spin test requires solid physical fitness and strength, I suggested the design of a frame to hold the S22 during an automated version of it instead. Here are some basic characteristics:

• the S22 slots in the frame at a decided angle, which should likely be different from vertical or kick-stand angles.
• the frame has a wide base in order to keep the system balanced during rotation changes
• the automated, tough spin test is implemented in firmware and can only be started by scanning a QR code printed on the frame inside the KingSong mobile app
• this frame could be sent to customers to complete who need it to complete the test, and it would be cheaper than sending wheels back and forth
• this frame would also be used to run the same test in factory, in order to catch bad board and motors, including re-occurrence of the stator slippage.

Since the V12 MOSFET crisis, I think a minutes-long version of this test should become part of the standard test suite of any EUC before reaching customers.

 

Also, KS engineers confirmed that these tests are harmless for good board and motors.

Edited September 12, 2022 by supercurio

[gon2fast]

4 minutes ago, chanman said:

one coming in sooner via air that will be put in new wheels so those wheels can be sent out, and a second on a boat for the remainder of the wheels and for sending out to customers that have wheels already but want replacement motors.

Yeah, I was bummed to hear that those with S22s in hand got routed to the end of the line. Pretty sure that it was not Jason's decision, but I understand that he has to get those wheels sitting in storage out of the door before he loses more business. You have to have patience with this hobby...

[oolong]

50 minutes ago, gon2fast said:

You have to have patience with this hobby...

Which is kind of the opposite sentiment for people who pre-ordered wheels and wanted them shipped immediately...  Technically those who waited have more patience.  A lot of people who wanted their wheels shipped early are probably in a rush to use it before the winter.

[supercurio]

1 hour ago, gon2fast said:

Do we really need to keep doing the test now that the resellers and KS are in agreement that there is an issue? I can feel slippage in my S22 under moderate acceleration so I am I am just  putting around until my motor arrives in however long it takes the boat to get here.  

So depending on how hard to accelerate and especially if you shifted your pedals forward like some do, what you think is moderate might be really hard 😁 and a classic pedal dip / overpower condition.

Simple question tho: does the wheel beep before / during / after, or is it at very low speed (where the stall detection throttling can interfere sometimes)

1 hour ago, pedroMDK said:

I haven't done a full test or anything like that. I did a free spin test out of the box, cutout at 43ish. Top speed so far has actually been about 33mph per euc.world. I'm not pushing it and I'm only 140lbs. Softest shock setting (both pre/rebound) and medium ride mode. Pedals are still stock facing w/ grizzla large pads. Just crossed 110 miles this afternoon. I'm completely geared up and taking it easy, fingers crossed. Jason will probably send new motors out anyway.

Hi @pedroMDK and welcome here!

The free spin test you describe purpose is to confirm the max speed at a given battery voltage. It is sometimes used to see if the tire has wobbles as well, but it is not a stress test in any way.
Great idea to always gear up 👏 and also listen for any abnormal sounds on the S22.

[gon2fast]

17 minutes ago, oolong said:

A lot of people who wanted their wheels shipped early are probably in a rush to use it before the winter.

I feel confident with my ability to work on EUCs so I saw no reason for my wheel to sit in Compton (especially since I paid the balance off a month ago). We also did not know if the eWheels motors were going to be compromised, I surely went in fingers crossed LOL. Oh well, it is what it is.  

BTW - is anybody else's charger fan noisy as all hell after 3 or 4 uses? 

Edited September 12, 2022 by gon2fast

[gon2fast]

Just now, supercurio said:

So depending on how hard to accelerate and especially if you shifted your pedals forward like some do, what you think is moderate might be really hard 😁 and a classic pedal dip / overpower condition.

Simple question tho: does the wheel beep before / during / after, or is it at very low speed (where the stall detection throttling can interfere sometimes)

Pedals are in the default position. I say moderate because it does not produce dipping. It is a quick stomp on the toes, like if you needed to accelerate past something at higher speeds, but I just tap it for a second to see how the motor reacts.

I had some dipping on the first day, but have not experienced it anymore after doing two calibrations.

The second day I rode the wheel I did hear single beeps while in motion which I found odd. Nothing came of it and it has not returned. 

[supercurio]

@gon2fast I see.

From current elements, I would expect a slippage that's a stator slippage to be accompanied with some noticeable abnormal sound coming form the motor.
I could be wrong however: still lacking data on this specifically.

[Elliott Reitz]

FWIW, my working S20 Motor produced late 2021 is working nicely now (with S22 Controller/Batteries).  It clunks sometimes but that goes away a ride or two later (I've shared clunking videos).  I did a spin-stress-test on it once (passed, and not worth doing any more as long as its ridable). 

On my 12.5 mile round trip commute I reach 37 to 40 mph max while averaging about 24 mph.  It has a plush 350 lbs spring.  I cut/removed most of my fender and the part remaining needs improvement as a wire-guide.  When I get another S22 (eWheels order) I could be persuaded to sell my MSX 100V with 2000 miles and 3 years on it for what I paid for it!  It saved my summer from being S18 speed limited!  

  Summer 2022 commuting miles:

• S18: 300 (June)
• MSX100V: 500 (July, Aug)
• S20/S22:  300 (Aug, Sept) (s22 bat/controller.  the s20 motor/chassis also had another 200 miles in the spring before the fire and firmware brickings)

Edited September 12, 2022 by Elliott Reitz

[supercurio]

The first customer to run and share the tougher full-rpm S22 spin test, thanks Curtis! for allowing to re-share (source)

Context

Quote

Did not want to do this but so many remarks about people having issues with their wheel.
My board blow after my first week on my first trail ride so I was very nervous about this test.

And his motor is from 220505

The test passed!
It also highlights how physically demanding the execution is. The gyroscopic effect of the high rotation speed makes the movement particularly hard to control.

 

Edited September 12, 2022 by supercurio

[Jamroxorz]

11 minutes ago, supercurio said:

The first customer to run and share the tougher full-rpm S22 spin test, thanks Curtis! for allowing to re-share (source)

Context

And his motor is from 220505

The test passed!
It also highlights how physically demanding the execution is. The gyroscopic effect of the high rotation speed makes the movement particularly hard to control.

 

No clunks from rotation change at all on this wheel.

[supercurio]

REV Rides just started to send this video to their customers, suggesting and demonstrating how to run the (tougher) spin test.
Note: this is an "unlisted" video so please take the context and re-sharing in consideration. Obviously don't contact REV Rides support about your S22 bought elsewhere 😆

Once again: very happy that distributors are informing their customers 👏

 

[supercurio]

9 minutes ago, Jamroxorz said:

No clunks from rotation change at all on this wheel.

Only a couple, at 0:27 and 0:41

[oolong]

3 hours ago, gon2fast said:

I feel confident with my ability to work on EUCs so I saw no reason for my wheel to sit in Compton (especially since I paid the balance off a month ago). We also did not know if the eWheels motors were going to be compromised, I surely went in fingers crossed LOL. Oh well, it is what it is.  

BTW - is anybody else's charger fan noisy as all hell after 3 or 4 uses? 

I'm in the same boat.  I can ride most of the winter and I don't think I'll have any problems swapping out the motor.  Took a risk, but I didn't realize that by getting it early I would be put in the back of the line for getting a replacement motor......  That kind of sucks and I don't know why KS wouldn't offer to airship new motors directly to people.

My fan seems noisy after one use.  Might be able to swap it out for a higher quality fan with the same air flow rate.

[supercurio]

43 minutes ago, oolong said:

I'm in the same boat.  I can ride most of the winter and I don't think I'll have any problems swapping out the motor.  Took a risk, but I didn't realize that by getting it early I would be put in the back of the line for getting a replacement motor......

Thanks @oolong for explaining your reasoning. Before that I didn't understand why anyone would take a bet on getting S22 shipped directly before the dealer would do its own QC - knowing the risks with S22 motors defects added to a bunch of other ones, resulting in an overall failure rate of 20% as found by some distributors.

High risk strategy on a high risk first batch.

43 minutes ago, oolong said:

That kind of sucks and I don't know why KS wouldn't offer to airship new motors directly to people.

That one is simple, I can answer since I asked the same thing:

The costs for airshipping a motor from China is unreasonably high due to its weight. So high that according to King Song and distributors, it becomes financially entirely impractical for King Song to send hundreds of replacement motors to customers all around the world. They might send a few here and there to customers who don't have dealers who can support them or special circumstances, but that's about it.

IMO, if there's some kind of recall or at least replacement of a significant percentage of S22 motors, it'll be with units sent by train or sea.
Initially, some dealers will aim at replacing all motors that failed the updated stress test and might leave it at that. Others will try to replace them all instead of relying on a stress test - like eWheels decided.

The situation is bad enough that in the industry, the discussion can circle around how to stay afloat and survive these problematic launches of products with fatal flaws.

Edited September 13, 2022 by supercurio

[oolong]

26 minutes ago, supercurio said:

Thanks @oolong for explaining your reasoning. Before that I didn't understand why anyone would take a bet on getting S22 shipped directly before the dealer would do its own QC - knowing the risks with S22 motors defects added to a bunch of other ones, resulting in an overall failure rate of 20% as found by some distributors.

With the existing slider issue, replacing tires, springs, and other mods, replacing a motor doesn't seem like a big deal.  It also doesn't seem like eWheels is doing any better testing on this issue than what you've already demonstrated.

I think knowing about the issue puts people in a much better position now.  Before people were riding there S22s normally, stress testing them, taking them off road, pushing them to their limits, etc. without regard for the potential for motor slippage.  So I think the failure rate will end up dropping as a result of people knowing what to look out for, at least for the people who pay attention to forums.
 

27 minutes ago, supercurio said:

The costs for airshipping a motor from China is unreasonably high due to its weight. So high that according to King Song and distributors, it becomes financially entirely impractical for King Song to send hundreds of replacement motors to customers all around the world. They might send a few here and there to customers who don't have dealers who can support them or special circumstances, but that's about it.

IMO, if there's some kind of recall or at least replacement of a significant percentage of S22 motors, it'll be with units sent by train or sea.
Initially, some dealers will aim at replacing all motors that failed the updated stress test and might leave it at that. Others will try to replace them all instead of relying on a stress test - like eWheels decided.

The situation is bad enough that in the industry, the discussion can circle around how to stay afloat and survive these problematic launches of products with fatal flaws.

I figured it was an issue of cost, but it sounds like they are just pushing costs and labor on to dealers.  If they were more concerned about safety over making a buck you would think they would want to get these motors out as soon as possible.   Instead it sounds like they are just waiting until a customers complain or get injured.

At the very least they could have offered to airship it for people who are willing to pay some kind of fee to do so.  I'm sure a lot of people who "pre-order" would be willing to do just that.  I just got an item that is not that much lighter than a motor delivered to me last week air-shipped from China and it only took 3 days.   

However by not offering that option and not being public about, it just sounds like they are making the calculation that it is cheaper for people to potentially get injured than to do a formal motor recall.  Being quiet about a major issue like this is not something that I would have ever expected from King Song, especially when the issue is arguably not even their fault. 

It seems like all companies forgo their principles of safety/quality and start acting like Gotway when it comes to money.

[5Cauac]

@supercurio I just had a thought. Could the sudden change in pedal angle be an indicator of the stator starting to slip? It would be in a different position thus misaligned with the hall sensors resulting in a slight pedal shift in either the forward or backward position?? Could be useful info if so.

[oolong]

4 minutes ago, 5Cauac said:

@supercurio I just had a thought. Could the sudden change in pedal angle be an indicator of the stator starting to slip? It would be in a different position thus misaligned with the hall sensors resulting in a slight pedal shift in either the forward or backward position?? Could be useful info if so.

I wouldn't think so since the balance position would be based off the gyroscope and not the motor.

[oolong]

BTW I think riding with the stock pads or even no pads might be a good way to keep from accidentally over torqueing the motor until it is replaced.  

[Jamroxorz]

Opened my motor after the board fried. It appears fine. No pulled wires. I wonder what skipping sensation is during braking.