INMOTION V12

[conecones]

Reporting another case of potentially faulty board QC/design. Except I was riding over a speed bump (maybe 20km/h) and wheel cut out. Could not turn on after. Face planted hard enough to break helmet and came close to breaking 3 fingers, luckily had armored jacket on at the time or probably collar bone/shoulder injury too.

Not sure how I feel about this. I was cruising at near max speed on previous rides and luckily did not encounter any potholes. After cut out, diagnostics show green across the board, so something must have fried that is preventing power to motor but board sensor doesn't know what it is. My guess is toasted non-resettable fuse? Perhaps it is not designed/specified properly. Never had issues riding over the same curb with other wheels. As a side note, and it's not a fair comparison, but I've bonked this curb going full tilt on the RS-T and can catch like 2ft of air. Have also ridden over this curb dozens of times on Nikola without issues. The V12 should be able to handle a bit of torque given its wheel size.

Please use caution and purposefully test your new V12 going up/down curbs, stairs, potholes before trusting it at higher speed. I know I'll be doing that as soon as my unit is repaired.

Edited December 20, 2021 by conecones

[Waulnut]

1 minute ago, conecones said:

Reporting another case of potentially fault board QC/design. 

May I ask if this batch 2?

[conecones]

2 minutes ago, Waulnut said:

May I ask if this batch 2?

Yes batch 2. The handle is the new version with exposed hex bolts on top. 

[Djal]

4 minutes ago, conecones said:

Yes batch 2. The handle is the new version with exposed hex bolts on top. 

Could you be more precise about that? You have a picture ?

is there other details to know which batch version ?

[Paul A]

See thread titled:

Inmotion V12 Locked wheel after Idling

 

 

 

Member  @Clark Wong is from Inmotion.

"Hello , This is Clark from Officail  Inmotion Group , please communicate with me on the email (clark@imscv.com), I will help you to solve the problem . 

Good day "

[supercurio]

3 hours ago, conecones said:

Reporting another case of potentially faulty board QC/design. Except I was riding over a speed bump (maybe 20km/h) and wheel cut out. Could not turn on after. Face planted hard enough to break helmet and came close to breaking 3 fingers, luckily had armored jacket on at the time or probably collar bone/shoulder injury too.

Not sure how I feel about this. I was cruising at near max speed on previous rides and luckily did not encounter any potholes. After cut out, diagnostics show green across the board, so something must have fried that is preventing power to motor but board sensor doesn't know what it is. My guess is toasted non-resettable fuse? Perhaps it is not designed/specified properly. Never had issues riding over the same curb with other wheels. As a side note, and it's not a fair comparison, but I've bonked this curb going full tilt on the RS-T and can catch like 2ft of air. Have also ridden over this curb dozens of times on Nikola without issues. The V12 should be able to handle a bit of torque given its wheel size.

Please use caution and purposefully test your new V12 going up/down curbs, stairs, potholes before trusting it at higher speed. I know I'll be doing that as soon as my unit is repaired.

So sorry for the destruction and harm you experienced due to this V12 failure.
It's not okay.

As pre-order customer with a unit shipping (ETA: January), I feel very concerned.

Thanks for sharing your experience.
I'll definitely stress test the hell of my unit before trusting it, fully prepared to burn a few boards until @Inmotion Global get its shit together.

[conecones]

5 hours ago, Djal said:

Could you be more precise about that? You have a picture ?

is there other details to know which batch version ?

Without opening unit or turning on screen, easiest way is by handle. If handle looks like this, then it is not batch 1. Once turned on, the other clue is board firmware shows 1.5.0, which is the most recent version, with split mode already available without needing to update.

[Flying W]

@conecones so sorry to hear of this. I've been eyeing the V12 as a commuter for wet days and a good wheel for my dad to ride when he visits (currently he rides a 16s and it's not fast enough anymore, not does it have enough battery for longer rides. He's 70yrs old and things he's 25. He will hit speed bumps on purpose at speed to jump off them.

I ride my RST daily to work and bonk speed bumps like you say. It hasn't failed me ever.....but in rare cases it could torch my apartment so there's that.

Good lesson for wearing good gear and a full face though. This could have been so much worse. I'm sure your sore, I hope you heal quickly. It would be hard for me to trust this wheel after that.

Could the 3k watt peak be a hard limit? The wattage spikes reported in EUC world on the RST are over 5k sometimes. I'm sure jumping a speed bump at 20mph gets over 3k watts. 

 

[Richardo]

8 hours ago, conecones said:

. After cut out, diagnostics show green across the board, so something must have fried that is preventing power to motor but board sensor doesn't know what it is. My guess is toasted non-resettable fuse? Perhaps it is not designed/specified properly. Never had issues riding over the same curb with other wheels. As a side note, and it's not a fair comparison, but I've bonked this curb going full tilt on the RS-T and can catch like 2ft of air. Have also ridden over this curb dozens of times on Nikola without issues. The V12 should be able to handle a bit of torque given its wheel size.

 

Does your wheel spin freely when powered off? Or does it resist spinning? That’s indicative of a shorted MOSFET, and what i have. 

[RagingGrandpa]

@conecones and/or @Richardo: when you have your old controller removed, would you please try to get an image showing the markings on one of the FETs, similar to below?

For the first-batch wheels, the FETs they installed had comically low voltage ratings, which made us wonder how it survives normal operation at all... hope Inmo updated their design.

[conecones]

Thanks guys for the kind words - I fall a lot already so this injury isn't really bugging me, but rather that I'm now without a winter commuter for who knows how long. Inmotion is tight lipped about the exact cause as expected but the solution is a new board which is still on a boat somewhere.

@Richardo @RagingGrandpaUnfortunately I sent my unit back to the retailer immediately after hoping for a quick turnaround so did not open the unit to check board. Although the symptom of resistance while pushing it is indicative of blown mosfet - it just baffles me that the diagnostics show no issues - I mean then what really is purpose of this test if a main component is faulty? I am only able to "turn on" the unit while plugged into charger and use the touch screen. However when unplugged, there is a click that can be heard when trying to power on. Similarly when plugged in and trying to do the wheel calibration (through app, where you lay unit on side and let the wheel spin up), a click is heard, calibration fails and wheel does not turn.

@Flying WThis absolutely affects how much I can trust this wheel. In the future, I am going to treat any non-torque tuned wheels gently, trying to limit any peak loads. For riding more aggressively, I will stick with Gotway's designs that uses beefy board components and tuned to allow itself to set on fire in its attempt to keep the rider from falling. I would just like a bit of warning before the battery blows up, its not too much to ask is it? 

[Paul A]

From the other thread with a similar  V12 problem:

 

Clark Wong

• Newbie
•  
• Members
• 3
• 2 posts
• Location: China
• EUC: INMOTION

•  

Posted 13 hours ago

That 's not the mainboard 's problem , we have received similar cases reported , most customers happened at a  slow speed . Replace the drive board can make the V12 working again . 

 

[supercurio]

2 hours ago, RagingGrandpa said:

@conecones and/or @Richardo: when you have your old controller removed, would you please try to get an image showing the markings on one of the FETs, similar to below?

For the first-batch wheels, the FETs they installed had comically low voltage ratings, which made us wonder how it survives normal operation at all... hope Inmo updated their design.

In case anybody was wondering like I did, these are Infineon IPP023N10N5 100V MOSFET.

On a wheel with a 100.8V battery.
With a motor which back-EMF voltage can peak at (unknown) higher V, and voltage that can rise up to (beyond 100.8) V when braking.

Seems odd indeed.

Datasheet: https://www.infineon.com/dgdl/Infineon-IPP023N10N5-DS-v02_03-EN.pdf?fileId=5546d461454603990145d5a675f86494

Edited December 21, 2021 by supercurio

[RagingGrandpa]

Yup, and it's a function of temperature... if you exceed 100.0V across the FET at room temperature, it starts exceeding 1mA of leakage current, rising hugely with every additional volt.

When the EUC is off, with no FETs driven, no harm- we don't have battery directly across any one FET.
But when the motor is active with a very full battery, it does seem that leakage could occur.

I think the FET will act with a zener behavior, dropping about 100V from the circuit and then passing the excess charge in an unlimited way.
It shouldn't be damaged instantly... just from the thermal overload that could result if nothing else limits that current.

Perhaps the design can tolerate it because:

• motor commutation is a pulsing behavior, so no one FET will suffer the leakage current continuously, and
• the FET (or at least, the silicon die inside the package) warms up quickly, so the first few moments of operation (and even the leakage current itself) may be enough dissipation to warm it up enough to raise the breakdown voltage, and
• if there is any significant (forward) motor torque being driven, resistive losses (including battery sag) reduce the apparent voltage, reducing leakage.

The part is still 'outside of spec,' but practically speaking, a small occasional current leakage might not be destructive.

And even if it seems to work most of the time, I wouldn't want to stop suddenly with a cold, full-battery V12 riding down a hill, with outside-spec parts like that.
Additional margin in the design would be nice... even Gotway uses 125V-rated FETs.

.02

 

[Paul g]

Hi, guys! I just received my V12 today, but I have some issues with it. I never had or ride an unicycle before, so I'm quite puzzled by this. As soon as I connected the app the v12 started, without me unlocking it from the screen-I’ve seen people on YouTube doing it, so it must have been unlocked from transportation mode. After that I put it on a stand and started several times the v12 just to see how it works, because obviously I have no idea, but being on the stand would start spinning until cutoff. Then realised I had to let it on the ground when on, so it doesn’t spin out of control. Then I tried to play with speed settings, and lowered the max speed to 15km/h. After that it would start shaking stronger and start pulling forward and would say: please repair! Of course, I would lift it in the air, cuz it seem to be ready to fly from my hands, and then would cut off. Is not normal to do that, isn’t it?

[supercurio]

1 hour ago, RagingGrandpa said:

Yup, and it's a function of temperature... if you exceed 100.0V across the FET at room temperature, it starts exceeding 1mA of leakage current, rising hugely with every additional volt.

When the EUC is off, with no FETs driven, no harm- we don't have battery directly across any one FET.
But when the motor is active with a very full battery, it does seem that leakage could occur.

I think the FET will act with a zener behavior, dropping about 100V from the circuit and then passing the excess charge in an unlimited way.
It shouldn't be damaged instantly... just from the thermal overload that could result if nothing else limits that current.

Perhaps the design can tolerate it because:

• motor commutation is a pulsing behavior, so no one FET will suffer the leakage current continuously, and
• the FET (or at least, the silicon die inside the package) warms up quickly, so the first few moments of operation (and even the leakage current itself) may be enough dissipation to warm it up enough to raise the breakdown voltage, and
• if there is any significant (forward) motor torque being driven, resistive losses (including battery sag) reduce the apparent voltage, reducing leakage.

The part is still 'outside of spec,' but practically speaking, a small occasional current leakage might not be destructive.

And even if it seems to work most of the time, I wouldn't want to stop suddenly with a cold, full-battery V12 riding down a hill, with outside-spec parts like that.
Additional margin in the design would be nice... even Gotway uses 125V-rated FETs.

.02

 

Thanks for the explanation @RagingGrandpa! 

It was hard to guess the impact of components seemingly "off spec" without it.

[Paradox]

2 hours ago, RagingGrandpa said:

The part is still 'outside of spec,' but practically speaking, a small occasional current leakage might not be destructive.

And even if it seems to work most of the time, I wouldn't want to stop suddenly with a cold, full-battery V12 riding down a hill, with outside-spec parts like that.

So is this a design flaw that until it can be verified corrected should make this wheel a no sale?

[RagingGrandpa]

9 minutes ago, Paradox said:

is this a design flaw

It was intentional... Inmotion thinks it's ok... they purchased the parts, built the EUCs, and sold them

The rest is community opinion.

11 minutes ago, Paradox said:

should make this wheel a no sale?

Hundreds of them have sold, and thusfar we haven't seen report of a board failure that was attributed to 'braking while full and cold,' so that's a good sign...

(Now I'm just hoping to learn if batch 2 will see a FET change; or continue with the 100V rating)

[Tawpie]

39 minutes ago, RagingGrandpa said:

It was intentional... Inmotion thinks it's ok... they purchased the parts, built the EUCs, and sold them

Which as we all know, doesn't make it a good idea... MCAS being a recent example (although that was a combo of hardware and software... the Ford Pinto is an example of a pure hardware decision, the early VW bugs an example of an inadequate hardware element that ejected you out the back windscreen when you were rear-ended)

 

39 minutes ago, RagingGrandpa said:

Hundreds of them have sold, and thusfar we haven't seen report of a board failure that was attributed to 'braking while full and cold,' so that's a good sign...

It's promising, but there have been reports of board failures under conditions that didn't seem particularly aggressive. The jury is still out but (I would certainly hope) most engineering groups would inisist on not having negative design margin at any operational condition.

Edited December 21, 2021 by Tawpie

[Petranodon]

On 12/20/2021 at 11:38 PM, conecones said:

Reporting another case of potentially faulty board QC/design. Except I was riding over a speed bump (maybe 20km/h) and wheel cut out. Could not turn on after. Face planted hard enough to break helmet and came close to breaking 3 fingers, luckily had armored jacket on at the time or probably collar bone/shoulder injury too.

Not sure how I feel about this. I was cruising at near max speed on previous rides and luckily did not encounter any potholes. After cut out, diagnostics show green across the board, so something must have fried that is preventing power to motor but board sensor doesn't know what it is. My guess is toasted non-resettable fuse? Perhaps it is not designed/specified properly. Never had issues riding over the same curb with other wheels. As a side note, and it's not a fair comparison, but I've bonked this curb going full tilt on the RS-T and can catch like 2ft of air. Have also ridden over this curb dozens of times on Nikola without issues. The V12 should be able to handle a bit of torque given its wheel size.

Please use caution and purposefully test your new V12 going up/down curbs, stairs, potholes before trusting it at higher speed. I know I'll be doing that as soon as my unit is repaired.

My friends and I experienced the same thing with our newly bought second batch V12. The only difference is that my friend's V12 cut out when he hit a speed bump as he was riding at about 15-20km/h. Whereas my V12 cut out when it was ridden at about 15-20km/h without hitting any speed bump. 

Since I bought directly from the Inmotion, I reported this case to them. So they said that they will replace the driver board of my and my friend's V12. However, it seems that they don't know the exact root cause what makes the problem happen, so that I will still not confident riding my V12 again even though the driver board will be replaced.

I don't know whether it is related to the firmware or not. But the installed firmware of our V12s is v1.5.4.

Really hoping that the Inmotion will take care of this particular problem very seriously, as I see that it happens to many riders lately, and it's a dangerous problem since it's related to sudden "cut out" without any alarm prior to it.

[Rawnei]

 

11 minutes ago, Petranodon said:

My friends and I experienced the same thing with our newly bought second batch V12. The only difference is that my friend's V12 cut out when he hit a speed bump as he was riding at about 15-20km/h. Whereas my V12 cut out when it was ridden at about 15-20km/h without hitting any speed bump. 

Since I bought directly from the Inmotion, I reported this case to them. So they said that they will replace the driver board of my and my friend's V12. However, it seems that they don't know the exact root cause what makes the problem happen, so that I will still not confident riding my V12 again even though the driver board will be replaced.

I don't know whether it is related to the firmware or not. But the installed firmware of our V12s is v1.5.4.

Really hoping that the Inmotion will take care of this particular problem very seriously, as I see that it happens to many riders lately, and it's a dangerous problem since it's related to sudden "cut out" without any alarm prior to it.

That sounds pretty alarming, did they ask you to upload any logs or such?

[Petranodon]

5 minutes ago, Rawnei said:

 

That sounds pretty alarming, did they ask you to upload any logs or such?

No, they just asked me to tell them the chronology and the video of my V12 after the accident. 

[supercurio]

I'm not too keen on crashing at 20 km/h, or any speed for that matter.
These report feel more like a pattern than a coincidence.

I won't ride my incoming V12 until the root cause is identified and fixed, and a clear testing methodology is provided by @INMOTION SCV @Clark Wong
In the meantime, I'll continue riding my Sherman which has proven its safety.

The V12 is supposed to have a "black box" where high resolution vehicle data is recorded for later analysis in case of failure.
The fact this this capability is not used and that Inmotion seem to hint they have knowledge about the cause but doesn't want to share is a red flag.

This lack of transparency could mean that the manufacturer is aware of a flaw that might require a recall of some or all the units already shipped.
A flaw that repetitively destroys boards and leads to cut-out, but are not caused by a failure of the board itself.
There are not so many components beside motor, controller, its firmware and a battery in an EUC, so it's confusing.
I hope to be proven wrong.

Edited December 22, 2021 by supercurio

[Petranodon]

36 minutes ago, supercurio said:

I'm not too keen on crashing at 20 km/h, or any speed for that matter.
These report feel more like a pattern than a coincidence.

I won't ride my incoming V12 until the root cause is identified and fixed, and a clear testing methodology is provided by @INMOTION SCV @Clark Wong
In the meantime, I'll continue riding my Sherman which has proven its safety.

The V12 is supposed to have a "black box" where high resolution vehicle data is recorded for later analysis in case of failure.
The fact this this capability is not used and that Inmotion seem to hint they have knowledge about the cause but doesn't want to share is a red flag.

This lack of transparency could mean that the manufacturer is aware of a flaw that might require a recall of some or all the units already shipped.
A flaw that repetitively destroys boards and leads to cut-out, but are not caused by a failure of the board itself.
There are not so many components beside motor, controller, its firmware and a battery in an EUC, so it's confusing.
I hope to be proven wrong.

Hopefully @INMOTION SCV @Clark Wong will give updates periodically on what they have known, the investigation plan, and the status of the investigation of the problem, so from this visibility, we riders will know what to expect and what to do. I myself think that by simply replacing the failure driver board alone will only give us false confidence and harm us over and over again if the exact root cause of the problem is not yet known. I will not ride V12 at all until it's clear first.

Edited December 22, 2021 by Petranodon

[Paul A]

What about all the V12 owners who aren't on a forum like this?

Or any EUC owner when potential failures are identified?

Are any V12 owners receiving notifications from Inmotion?