Kingsong S20/S22 (Confirmed)

[Tawpie]

direct link https://www.kingsong.com/kingsongnotifications.html#images-1 for those of us that don't fb.

 

Edited April 2, 2022 by Tawpie

[Curt8892]

Compared to previous fire explanations from the manufacture this is unique to what I have ever heard. I guess they have the advantage of not having a product out in larger public consumers 

[Tawpie]

9 minutes ago, Curt8892 said:

this is unique to what I have ever heard

I can't recall a situation where an EUC manufacturer has provided this level of detail... a level that showed that they made a mistake. Hopefully it sets a standard for the others, and that they will follow!

It ain't perfect mind you, but it's light years ahead of what we're used to getting.

I judge their conclusions as plausible, and their solution reasonable given their conclusions. There's always a chance they they're only aware of or telling us part of the story and we shouldn't forget that. What they did disclose though, is definitely a smoking gun (yeah ). The investigation into why the battery got shorted is incomplete and it will be good to have that probability reduced, but to me the most important thing is reducing the chances of a catastrophic fire as a consequence of another failure in the system. In an aviation analogy, you don't want the wings to fall off because an engine exploded.

Edited April 2, 2022 by Tawpie

[5Cauac]

So now it's the S22 ?? 

[Tawpie]

3 minutes ago, 5Cauac said:

So now it's the S22 ?? 

vintage instead of us thinking it was tire size (which it wasn't)?

I think they rolled the model number so it would be painfully obvious on all the apps if the firmware was updated or not. This is a critical update, you don't want to make people dig through submenus to determine if you've got it installed.

Edited April 2, 2022 by Tawpie

[chanman]

I'm still concerned that there's no hardware changes as part of the fix. The explanation is credible, but "Instead the BMS MOS turned OFF and ON due to the firmware bug, and the time between On and OFF states were so short that it did not blow the fuse" Seems to me that the fuse should be specced to blow in this situation, since enough current was drawn to burn the batteries.

[5Cauac]

I still vote for some kind of sheathing on the the battery packs. 

Edited April 2, 2022 by 5Cauac

[Tawpie]

6 minutes ago, chanman said:

Seems to me that the fuse should be specced to blow in this situation, since enough current was drawn to burn the batteries.

The key here is the current was pulsed due to the on-off fault. If the fuse can cool back down during the off time, it might not blow before the nickel strips are red hot. For example, when you are pulsing 6 kW into a 3 kW motor heat builds up but as long as you don't hold the high current too long, the motor can dissipate the heat and not melt. Same thing applies to the fuse and the nickel strips—the strips don't cool very quickly so they can get to a higher temperature.

Edited April 2, 2022 by Tawpie

[chanman]

I understand why it wouldn't blow, but seems like it's not doing its job if it doesn't blow here, no?

[fryman]

15 minutes ago, 5Cauac said:

So now it's the S22 ?? 

Could be a PR move. All the bad social media news is on the S20.

[Tawpie]

5 minutes ago, chanman said:

but seems like it's not doing its job if it doesn't blow here, no?

The fuse the last line of defense, in case the MOSFET didn't disconnect the battery and a sustained short continued. You take a risk if you make the fuse too small... if it blows too quickly, the rider face plants and the battery pack requires replacement. That's why they have MOSFET switches as the first line of overcurrent protection. It's a non-destructive measure. Plus, it can react much faster than a melting fuse.

Edited April 2, 2022 by Tawpie

[redfoxdude]

1 minute ago, chanman said:

I understand why it wouldn't blow, but seems like it's not doing its job if it doesn't blow here, no?

With the on-off pulsing, it's probably not reaching the trip current. So they may need a fuse with a lower trip current, but maybe that would be too close to the peak operating current? I'd like to see a hardware latch circuit that prevents the on-off pulsing from even happening.

[Tasku]

13 minutes ago, fryman said:

Could be a PR move. All the bad social media news is on the S20.

To avoid any old devices sold as is. The old S20 will be converted to S22 with updates first and slapped with new stickers. The vendors have extra hassle now to deal with but generally, it is a good thing to make sure no old versions will be delivered to customers. So S22 it is.
 

 

30 minutes ago, chanman said:

I'm still concerned that there's no hardware changes as part of the fix. The explanation is credible, but "Instead the BMS MOS turned OFF and ON due to the firmware bug, and the time between On and OFF states were so short that it did not blow the fuse" Seems to me that the fuse should be specced to blow in this situation, since enough current was drawn to burn the batteries.

They (Kingsong) did state that they will also have 3rd party to do independent testing. It is understandable that technical "yargon" does not always convince customers but having external testing (professionals) is best possible outcome here. 

------------

I still consider this, what Hsiang and U-Stride said: "the condition' we drove was within "normal performance" and device response was not acceptable."
That was not word to word, but something along those lines (in podcast by blackcobra). I also would not blame the rider. There was no warnings, even experienced riders usually are aware not to torment full charged  devices to the max. 

Prolly I understood wrong but, does the system drain battery during the time when device is "OFF"? Because that could bring a lot of drained battery problems, ruining lot of devices. Just a month of inactivity could ruin batterys if there is a drain, like smart BMS is active even device is turned off, or bluetooth(commonly problem) from smart BMS keeps draining, even device turned off. Would be nice to know did the smart BMS in S20 drain batterys even offline-state (bluetooth usually drains if it is connected). Just would like to know if the fix is causing possibly wider problem in long run.

[Paul A]

 

[Paul A]

 

[Julian-NZ]

It's great to see them doing some testing but I would like to see them drop the pack onto it's corners.
Usually, the battery pack will 'hit' on each corner as it goes spinning down the road/track.
A test where they are dropping onto the corners would be a more 'real life' test.
It would also demonstrate the structural integrity of the 'box' holding the batteries.

[Elliott Reitz]

Mandella effect much?  And just like that it's an S22.

[Paradox]

"You're looking at the S22?  I heard it has great potential.  Stay away from the S20 though,  it has a lot of problems..."

[Brendan "nog3" Halliday]

The S20 is dead, long live the S22.

 

[Paul A]

S22 might be in reference to 2022.

Renamed to disassociate from disaster.

[Forwardnbak]

49 minutes ago, Brendan "nog3" Halliday said:

The S20 is dead, long live the S22.

 

Let’s go rolling I’ll film, 

you can be U-Stride 

Edited April 3, 2022 by Forwardnbak

[techyiam]

Is there going to be a new thread for the Kingsong S22, or is there going to be a title change for this thread?

[mrelwood]

41 minutes ago, techyiam said:

Is there going to be a new thread for the Kingsong S22, or is there going to be a title change for this thread?

Valid point. I added “S22” to the title, since the point of this thread is to discuss the model before mass production and the S22 still fits that criteria.

[techyiam]

One thing that we know for sure is that Kingsong never tested their design for whatever subsystems that are responsible for the prevention of the flaming inferno. I am not talking about QC testing during production. Software is digital with absolutely no variation from copy to copy. They blamed everything on software. So every KS-KS20B will have the same problem. This is what they say:

Quote

 

"After actual testing and analysis, the fault is confirmed as output overcurrent short circuit protection failure, ... "

 

https://www.kingsong.com/kingsongnotifications.html#images-2

They can no longer say that the Hsiang demo wheel is a one off since it was improperly flashed. They confirmed that their own unit exhibited the same faults.

Even if we put aside their blame on the cutout on the loss of the hall sensor signals, the short circuit protection failure at all levels due to software errors is alarming. The software in the controller board, as well as the software in the smart BMS were independent, and were all at fault. But software is digital, and hence they didn't do the necessary testing at each level, or they would have known.

These are critical subsystem functions. And yet they didn't test them (or test properly). If it wasn't for U-stride - Hsiang stress test incident to uncover these faults, ....

What else did they not test, or test properly?

Edited April 3, 2022 by techyiam

[Paul A]

KS is striving to produce a great product.

The failure has been very costly to reputation, time, trust.

Perhaps appreciate their attitude, development efforts and commitment to the long term for this very niche segment.

Scooters for the mass market might be easier and more profitable.