New Inmotion V10 / V10F

[MBIKER_SURFER]

Hm - that doesn't look too steep. And your velocity wasn't too fast - or is it different than it looks on the video?

[Icewheel]

6 minutes ago, MBIKER_SURFER said:

Hm - that doesn't look too steep. And your velocity wasn't too fast - or is it different than it looks on the video?

It wasn't. I was on my V5F+ and as you can see he's not going that much faster than me considering the much larger motor.

[Rehab1]

My feeble attempt to lighten up this topic. 

 

[Demargon]

26 minutes ago, Rehab1 said:

My feeble attempt to lighten up this topic. ...

Maybe I can help

 

[Harold Farrenkopf]

1 hour ago, Demargon said:

Maybe I can help

 

Is that the wheel that exploded?

[quixfz]

my v10f died an hour ago...  it was only 8 days old. 127xxx serial. was soo happy with it

video

was driving up a steep offroad trail, and suddenly it stuttered for 1-2 tenths of a second and then completely stopped. i could continue running and stayed on my feet. since it was steep and difficult i was driving quite slow, less then 10kmh. i was used to get overload warnings on steeper parts, so i wasn't too concerned the v10f couldn't handle it, i was expecting to warn me if it's too much. but not in this case... when i walked back to it, it was turned off. after turning it back on, whenever it had to turn the motors, it was stuttering. when it's balanced and not moving it looks completely ok, but when leaning it stutters violently. to me (not too much unicycle experience, but brushless motors knowledge) this looks like a burned mosfet.

will contact the shop (onewheel.be) later and see how quickly something can be done...

BTW: the wheel had only very short and light rain on the first day. absolutely no water contact since then (in case someone would suspect this to be the problem)

Edited September 15, 2018 by quixfz

[Demargon]

33 minutes ago, quixfz said:

to me (not too much unicycle experience, but brushless motors knowledge) this looks like a burned mosfet. 

Is the first time I see that fail. Probably you are right with the mosfet, can you connect it with the app? maybe the diagnose give you a clue

[quixfz]

https://youtu.be/im_gaEfxXd0

reports 100% ok

[Demargon]

6 minutes ago, quixfz said:

reports 100% ok

Its painful see that. Probably you have more knowledge about electrics than I. Hope you can solve it with the guaranty in a sort time.

[beast@tanagra]

On 9/13/2018 at 7:51 PM, maltocs said:

I got my wheel back yesterday, took it out of the box today. From the day they received the FedEx pkg 9/4 it took them 5 business day to ship it out again 9/11, not bad. The ONLY communication I got from InMotion was the UPS Quantum delivery tracking notification. No thank you card in my box!

I haven't had a chance to test it yet because it was received with NO PADS ATTACHED. The sticky film from the original pads probably should be removed to ensure maximum adhesion from the new enclosed pads. I need to find a scraper and some adhesive remover. I can look at this TWO ways: GLASS HALF EMPTY - "WTF, at least put the pads back on so I can ride it right out of the box like it should be," or GLASS HALF FULL - "after I scrape the sticky crap off this wheel, I'm going to put velcro adhesive on my BRAND NEW pads in so I can easily take apart this wheel in the future if need be.  

This was my exact experience. Mine was tested the same day, even. It certainly seems strange to stick the customer with the gooey mess from the old pads.

Total turnaround time for me was about 10 days. No issues with my returned wheel, but I've never ridden in any of the scenarios causing people trouble.

The virtues of this model are easier to appreciate after some time away from it -- in particular, the awesome headlight, the pep at medium speeds, and the graceful high-pedal center-of-gravity feeling while turning and carving.

[Harold Farrenkopf]

43 minutes ago, beast@tanagra said:

This was my exact experience. Mine was tested the same day, even. It certainly seems strange to stick the customer with the gooey mess from the old pads.

Total turnaround time for me was about 10 days. No issues with my returned wheel, but I've never ridden in any of the scenarios causing people trouble.

The virtues of this model are easier to appreciate after some time away from it -- in particular, the awesome headlight, the pep at medium speeds, and the graceful high-pedal center-of-gravity feeling while turning and carving.

Maybe they have no fingers left rubbing that stuff off. 

[novazeus]

12 hours ago, Marty Backe said:

I believe he already did. So sheeesh - don't wake him 

ha ha!

danke.

[novazeus]

On 8/21/2018 at 11:07 PM, Marty Backe said:

I have no idea what the Inmotion manuals look like, but maybe they are better than the 90-percent Chinese / 10% kind-of-English manuals produced by Gotway.

They are really covering their bases, so they probably want to add a warning sticker / page  to the manual that advises you how to operate the wheel around water.

So send the manual in. I'll be curious to see if I'm right.

no ur wrong.

[quixfz]

On 9/15/2018 at 7:05 PM, quixfz said:

my v10f died an hour ago... this looks like a burned mosfet...will contact the shop (onewheel.be) later and see how quickly something can be done...

i've contacted them and they will send a new mainboard in 2 weeks max. and the factory would like the see photos of the damage, which i've sent.

the middle two mosfets and their driver (IRF IRS2186) is burned.  i've checked the partnumbers, and like i thought previously (v8 pcb with better parts), these are top-quality parts. the 6 mosfets are 100V, continous 120A rated infineon IPP023N10N5 with 2.3 mohm rdson! these aren't cheap

another very nice thing is that the mainboard has two main cpu's (2x stm32f103), separating the important from the less important stuff. one for driving the mosfets with the gyro/accel (is a mpu6050) doing the main business. and another one with the bluetooth module and leds etc doing housekeeping stuff. a single stm32f103 could easily do both, but they choose to spend the money and make it more safe.

as far as i can judge, the design is good, as are the components.

Edited September 17, 2018 by quixfz

[WaveCut]

On 9/15/2018 at 8:05 PM, quixfz said:

this looks like a burned mosfet

i would guess hall sensor failure

[quixfz]

20 minutes ago, WaveCut said:

i would guess hall sensor failure

hmm, hall sensor failure would lead to wrong commutations, that would stutter/shake the wheel, but should not burn anything (especially not with all the current sensors)... the wheel is in a "steady state" after powering on and having it level without moving, without a working hall sensor this wouldn't be possible.

i have made some closeups and could potentialy narrow down the problem: https://imgur.com/a/BdRpH6o

the middle terminal of one of the mosfets is completly burned free. my theory is that this was a bad/weak solder joint (higher resistance), and it that it burned at high currents, which lead to destroying the driver too.

edit/PS: some of the other surviving terminals could also use some more solder and heat while soldering to spread it more across the solderpad.

Edited September 17, 2018 by quixfz

[Glitched]

43 minutes ago, quixfz said:

hmm, hall sensor failure would lead to wrong commutations, that would stutter/shake the wheel, but should not burn anything (especially not with all the current sensors)... the wheel is in a "steady state" after powering on and having it level without moving, without a working hall sensor this wouldn't be possible.

i have made some closeups and could potentialy narrow down the problem: https://imgur.com/a/BdRpH6o

the middle terminal of one of the mosfets is completly burned free. my theory is that this was a bad/weak solder joint (higher resistance), and it that it burned at high currents, which lead to destroying the driver too.

edit/PS: some of the other surviving terminals could also use some more solder and heat while soldering to spread it more across the solderpad.

I think you're the one that can put this overload issue to bed with your engineering/circuit board prowess. Maybe once you get another board, you'll be able to easily see if the cooling 'bottleneck' is from an inadequate mainboard and/or the cooling system.

PS I don't know how expensive this is in the context of a business or relative to their competition, but the mosfets are about $5.50 each and the gyro $1.75 (US).

Edited September 17, 2018 by Glitched

[FreeRide]

On 9/12/2018 at 11:33 AM, Rehab1 said:

Yah! My modified V10F arrived from Inmotion a few minutes ago!  Looking at the enclosed placard it looks like they went to extremes to waterproof this baby. 

Just glad it’s back home and was cared for by a group of trained professionals. Such a quick turn around time! Thanks Inmotion USA! 

Don't believe it for a second. 

[Animation-Imp]

4 hours ago, quixfz said:

i've contacted them and they will send a new mainboard in 2 weeks max. and the factory would like the see photos of the damage, which i've sent.

the middle two mosfets and their driver (IRF IRS2186) is burned.  i've checked the partnumbers, and like i thought previously (v8 pcb with better parts), these are top-quality parts. the 6 mosfets are 100V, continous 120A rated infineon IPP023N10N5 with 2.3 mohm rdson! these aren't cheap

another very nice thing is that the mainboard has two main cpu's (2x stm32f103), separating the important from the less important stuff. one for driving the mosfets with the gyro/accel (is a mpu6050) doing the main business. and another one with the bluetooth module and leds etc doing housekeeping stuff. a single stm32f103 could easily do both, but they choose to spend the money and make it more safe.

as far as i can judge, the design is good, as are the components.

I bought my V8 in the same store in Belgium, could you keep us posted on how they handle this issue?

[Nils]

9 hours ago, FreeRide said:

Don't believe it for a second. 

If you're referring to @Rehab1's submerged picture above then you're right, that was a joke. A slightly dangerous one in my opinion, but then I guess @Rehab1's faith in his fellow humans exceed mine

[Fastmike]

11 hours ago, Glitched said:

I think you're the one that can put this overload issue to bed with your engineering/circuit board prowess. Maybe once you get another board, you'll be able to easily see if the cooling 'bottleneck' is from an inadequate mainboard and/or the cooling system.

PS I don't know how expensive this is in the context of a business or relative to their competition, but the mosfets are about $5.50 each and the gyro $1.75 (US).

Like it! And the Mosfet, are still TO220 which were fine for the V8 motor bubt will never be able to cope and dissipate the heat generated by the 2000W motor. Only reason why they are forced to be conservative! but still overheat...

[The Fat Unicyclist]

20 minutes ago, Nils said:

If you're referring to @Rehab1's submerged picture above then you're right, that was a joke. A slightly dangerous one in my opinion, but then I guess @Rehab1's faith in his fellow humans exceed mine

Those that have been around long enough may recall that this wouldn't be the first wheel that @Rehab1 tried submerging.   

The question now is whether he is prepared to put his wheel where his Photoshop is and do this for real, again?   

Though the insurance company may question how a second truck got backed into the lake...   

[quixfz]

5 hours ago, Fastmike said:

Like it! And the Mosfet, are still TO220 which were fine for the V8 motor bubt will never be able to cope and dissipate the heat generated by the 2000W motor. Only reason why they are forced to be conservative! but still overheat...

The TO220 package is absolutely adequate (additionally to being a top quality expensive new part). they are among the packages with the lowest thermal resistances (junction to package).

i've calculated that the mosfets are switching around 24Amps max (2000W/84V). With an rdson of 2.3mOhms, the mosfets are, at full power, producing 1.3 watts of heat (R*I^2). for the commutation sequence, there are at most 2 phases turned on at any moment, 1.5 on average (https://m.eet.com/media/1111369/brushfig1.gif). that's 3 mosfets on average (2 mosfets per phase). so that's 3.9W of heat produced in the mosfets. there are additional losses from switching at partial loads (which we're at most of the time), but they aren't orders of magnitude larger then that (and the resistive loses are lower in this case).

the heatsink is big enough for that. and there's also a fan.

another point is that the mosfets are rated for 175 degreesC (higher then the standard 150). the higher the temperature, the better the heat-transfer heatsink to air. this isn't a cpu that shouldn't be run hotter then 70-80C. mosfets easily handle 100degC and more

you guys should see the tiny size of rc-plane/drones brussless motor controllers that do the same 30A with much smaller heatsinks, much cheaper mosfets and often much less airflow.

the design is absolutely okay in this case. i'd say they are extra cautious in the firmware for a few possible reasons:

• people are hurt when something fails
• no temperature sensor directly on the mosfets or on the heatsink next to the mosfets (the only negative thing i can say about the design). so no knowledge when it really overheats
• potential problems with water...
• bad soldering (like in my case)
• mosfets are not bolted down (still well pressed down with the pcb), so there are more variances in pressure and temperatures
• maybe compensating for some other problems on the pcb (for example not working temperature/current sensors, etc...)

PS: just rechecked my photos. there IS a sensor on the heatsink between two of the mosfets!

Edited September 18, 2018 by quixfz

[Chriull]

30 minutes ago, quixfz said:

...i've calculated that the mosfets are switching around 24Amps max (2000W/84V). 

The motor driver with the coils work as DC DC Converter - on the motor is a voltage proportional to speed + coil_resistance times motor current (plus some "transients" from the inductance for the not "static" case...)

So at low speeds the motor currents switched by the mosfets can get "dramatically" higher.

Quote

 

• no temperature sensor directly on the mosfets or on the heatsink next to the mosfets (the only negative thing i can say about the design). so no knowledge when it really overheats

It was reported by inmotion USA that the V10/V10F measures the heatsink temperature for the overheat warning - they just don't show it in the app. But i have no idea were this sensor is located in detail...

Quote

• mosfets are not bolted down (still well pressed down with the pcb), so there are more variances in pressure and temperatures

They are not mechanically fixed to the heatsink?!

Edited September 18, 2018 by Chriull

[Fastmike]

25 minutes ago, quixfz said:

The TO220 package is absolutely adequate (additionally to being a top quality expensive new part). they are among the packages with the lowest thermal resistances (junction to package).

i've calculated that the mosfets are switching around 24Amps max (2000W/84V). With an rdson of 2.3mOhms, the mosfets are, at full power, producing 1.3 watts of heat (R*I^2). for the commutation sequence, there are at most 2 phases turned on at any moment, 1.5 on average (https://m.eet.com/media/1111369/brushfig1.gif). that's 3 mosfets on average (2 mosfets per phase). so that's 3.9W of heat produced in the mosfets. there are additional losses from switching at partial loads (which we're at most of the time), but they aren't orders of magnitude larger then that (and the resistive loses are lower in this case).

the heatsink is big enough for that. and there's also a fan.

another point is that the mosfets are rated for 175 degreesC (higher then the standard 150). the higher the temperature, the better the heat-transfer heatsink to air. this isn't a cpu that shouldn't be run hotter then 70-80C. mosfets easily handle 100degC and more

you guys should see the tiny size of rc-plane/drones brussless motor controllers that do the same 30A with much smaller heatsinks, much cheaper mosfets and often much less airflow.

the design is absolutely okay in this case. i'd say they are extra cautious in the firmware for a few possible reasons:

• people are hurt when something fails
• no temperature sensor directly on the mosfets or on the heatsink next to the mosfets (the only negative thing i can say about the design). so no knowledge when it really overheats
• potential problems with water...
• bad soldering (like in my case)
• mosfets are not bolted down (still well pressed down with the pcb), so there are more variances in pressure and temperatures
• maybe compensating for some other problems on the pcb (for example not working temperature/current sensors, etc...)

PS: just rechecked my photos. there IS a sensor on the heatsink between two of the mosfets!

TO242 used by competitors on 1000W+ motors can dissipate twice as much heat compared to TO220. So there is a good reason on why they all moved to those mosfet after facing the same overheat issues that IM is facing today... except that was almost 2 years ago...

So yesterday technology tomorrow is the credo here...   :-)