V11 Controller Board Zero'ed

[Rich Sam]

Was on a ride today and had a cutout on V11 no warning, wheel stiff and does not want to roll.  Symptoms seem consistent with frying a mosfet or two.  Went to the wheel log thinking dang did I ask for more power than the wheel could give?  No reason given on the wheel logs.  current pull low, speed relatively low, hit a hidden bump on the trail seemed to be the trigger.  Pad up folks!  Did skateboard knee slide with hands.  I'm perfectly fine.

 

[Rich Sam]

 

 

You can see the data leading up to the cutout, Green section is the few seconds leading up to controller failure, Yellow Line appears to be the last update before failure as the rest of the values [RED] do not change after that.

What can cause a mosfet to go like that?  Is there any way to prevent it?

 

[mrelwood]

On 5/3/2021 at 6:47 PM, Rich Sam said:

What can cause a mosfet to go like that?

A rock or other object locking the tire against the wheel well, motor wires routed badly to have them short, a mosfets not leaning against the heat sink properly, a rare manufacturing issue, or simply asking too much too fast from the wheel which a hidden bump can quite easily cause.

On 5/3/2021 at 6:47 PM, Rich Sam said:

  Is there any way to prevent it?

Make sure the motor cables are routed freely enough, mosfets seated properly, and learn to use a softer mode with softer knees to lengthen the current peak’s time window from a sudden bump. Or have better luck... 

[GoGeorgeGo]

That sucks man, did you open the board and confirm it was a mosfet that fried?

The only thing that jumps out to me is your current readings where all over the place for the 2-3 minutes leading to the cutout but your speeds seem fairly consistent. Swinging from 37 to -19 to 25 to -16 to 12 to -20 to 19. I don't think thats crazy by any means but perhaps that rapid reversal of currents had something to do with it. 

I know the v11 has the smaller mosfets, it was one of the design criticisms people had when the machine was announced

[Rich Sam]

2 minutes ago, GoGeorgeGo said:

That sucks man, did you open the board and confirm it was a mosfet that fried?

The only thing that jumps out to me is your current readings where all over the place for the 2-3 minutes leading to the cutout but your speeds seem fairly consistent. Swinging from 37 to -19 to 25 to -16 to 12 to -20 to 19. I don't think thats crazy by any means but perhaps that rapid reversal of currents had something to do with it. 

I know the v11 has the smaller mosfets, it was one of the design criticisms people had when the machine was announced

I will get the new board in here any day now, I will open and confirm.  I have my multimeter ready to attack.  I was in a big group ride that day and was constantly adjusting speed accordingly on a busy trail.  Sucks I cause the guy next to me to take a big spill as well.  I feel bad about that.  Plus just normal torque pumping because hey... I can

 

 

[Rich Sam]

1 hour ago, mrelwood said:

A rock or other object locking the tire against the wheel well, motor wires routed badly to have them short, a mosfets not leaning against the heat sink properly, a rare manufacturing issue, or simply asking too much too fast from the wheel which a hidden bump can quite easily cause.

Make sure the motor cables are routed freely enough, mosfets seated properly, and learn to use a softer mode with softer knees to lengthen the current peak’s time window from a sudden bump. Or have better luck... 

Interesting thought on softening the pedals, I mean it kind of makes sense because it will increase the time over demand and theoretically have a more gradual demand for power.  Good idea.

Edited May 4, 2021 by Rich Sam

[GoGeorgeGo]

25 minutes ago, Rich Sam said:

I will get the new board in here any day now, I will open and confirm.  I have my multimeter ready to attack.  I was in a big group ride that day and was constantly adjusting speed accordingly on a busy trail.  Sucks I cause the guy next to me to take a big spill as well.  I feel bad about that.  Plus just normal torque pumping because hey... I can

 

 

I would be cautious about getting to torque happy with the v11 honestly. Its just not a wheel designed to handle that kind of constant load unfortunately.  The motor wires are not a huge gauge and the mosfets are not huge, the cooling is relatively poor. 

Accelration and hard braking is the most taxing action on the components. You can hit max speed with relatively low stress to the machine but the hard accelerations and braking really spikes currents and temperatures.  Just my opinion, the v11 is meant to be a cruiser and shouldn't be cranked on unless its an emergency. 

Its one if the things that attracted me to the exn despite the relatively poor build quality, the components are noteworthy. Big motor wires, big mosfets, huge heatsink, massive 100v battery. Its much more capable of withstanding the stress of hard accelrations and hard braking. 

[Rich Sam]

1 minute ago, GoGeorgeGo said:

I would be cautious about getting to torque happy with the v11 honestly. Its just not a wheel designed to handle that kind of constant load unfortunately.  The motor wires are not a huge gauge and the mosfets are not huge, the cooling is relatively poor. 

Accelration and hard braking is the most taxing action on the components. You can hit max speed with relatively low stress to the machine but the hard accelerations and braking really spikes currents and temperatures.  Just my opinion, the v11 is meant to be a cruiser and shouldn't be cranked on unless its an emergency. 

Its one if the things that attracted me to the exn despite the relatively poor build quality, the components are noteworthy. Big motor wires, big mosfets, huge heatsink, massive 100v battery. Its much more capable of withstanding the stress of hard accelrations and hard braking. 

The failure will be in the back of my mind for sure now.  I wonder what made Inmotion cheap out on mosfets?  I'm 99 percent sure it is mosfet though I will confirm with multimeter.  the wheel is very hard to turn and feels like opposing magnets stopping it.  Tell tale sign of mosfet shortage.

[Unventor]

4 hours ago, GoGeorgeGo said:

would be cautious about getting to torque happy with the v11 honestly. Its just not a wheel designed to handle that kind of constant load unfortunately.  The motor wires are not a huge gauge and the mosfets are not huge, the cooling is relatively poor. 

Compared to what?

[GoGeorgeGo]

3 minutes ago, Unventor said:

Compared to what?

I actually compared it to the exn in the same comment if you quoted the whole thing. I understand some people may disagree with me, but all i can do is give my own opinion. 

I own a v11, i suggest to most new riders to get a v11 , i LOVE my v11. But its not without flaws, and its not perfect. And thats okay, no wheel is perfect 

[Rich Sam]

Yup two mosfets shorted on one of the 3 phases. 

Both mosfets [red circles] are shorted across all three pins.

[Rich Sam]

1 hour ago, Unventor said:

Compared to what?

 

52 minutes ago, GoGeorgeGo said:

I actually compared it to the exn in the same comment if you quoted the whole thing. I understand some people may disagree with me, but all i can do is give my own opinion. 

I own a v11, i suggest to most new riders to get a v11 , i LOVE my v11. But its not without flaws, and its not perfect. And thats okay, no wheel is perfect 

to be honest I push this wheel pretty hard.  I will probably continue to push hard, though I will wear better padding

[Rich Sam]

OK I think two mosfets are shorted, one clearly has damage.

This mosfet is clearly cracked one of the suspects

https://drive.google.com/file/d/19PniwUoN9WJJEL3eYhOKJdTnNwU6ZA6K/view?usp=sharing

 

[Rich Sam]

Swapped out the board today, huge props to Jason @ewheels for sending it so fast.

when I removed the old board, I found it odd how loose the FETs screws where to secure them.  I wonder if they were too loose...  I tightened these down tighter.  Lets see.

I'm going to call this a Mulligan, a do-over.  I will forget this ever happened.

I rode her tonight, pushed HARD.  Max speed, hills up to high temps, curb jumps, bump jumps.  Just an overall stress test of the fix.  Knock on wood... I think she is back.

[Zedling]

Did it make any sound before it cut out? For about the last week my V11 has been making an odd clicking sound when I approach 25+ MPH. I haven’t tried to record the sound yet but suspect it will be hard to hear due to the sound of wind. 

[Rich Sam]

50 minutes ago, Zedling said:

Did it make any sound before it cut out? For about the last week my V11 has been making an odd clicking sound when I approach 25+ MPH. I haven’t tried to record the sound yet but suspect it will be hard to hear due to the sound of wind. 

No warning for me.  Clicking sound sounds more mechanical in nature than electical.  Maybe bearings?  Post a vid of the sound I'm sure someone will point you in the right direction.