Inmotion V11 control board and cabling details & closeups

[mrelwood]

Opened up the V11 control board, and took a few photos.

Mosfets:

• 12 * 023N10N5, Datasheet
• 2 * HAF018 (?) (at the main power inputs), 

Cabling:

• Main battery cables are 14 AWG silicone.
• Charging goes through one pair of 18 AWG silicone.
• Motor cables (teflon etc.) didn't say, but the outer diameter is somewhere between the above two. The inner diameter is of course much bigger in a teflon cable than a silicone cable.

Photos on the control board (click for full resolution):

 

Edit Aug 27: New photos. Control board with descriptions (updated Dec 14), and the BMS:

 

Edited February 18, 2021 by mrelwood

[Marty Backe]

Interesting - there's a "watch" battery on the control board. Why?

[mrelwood]

2 hours ago, Marty Backe said:

Interesting - there's a "watch" battery on the control board. Why?

Those are commonly used for memory storage. To remember settings through battery disconnections is my guess.

[Marty Backe]

2 hours ago, mrelwood said:

Those are commonly used for memory storage. To remember settings through battery disconnections is my guess.

With Flash based memory systems? And seems odd considering the V11 control board is essentially permanently connected to a ~1500wh battery. KingSong and Gotway don't use batteries.

I wonder what the tradeoff's are when designers of these systems choose a Flash based memory system vs a Volatile memory system. 

[StuartL]

The small lithium battery is probably for a real-time clock.  Any settings will be saved in internal flash, probably on the MCU itself but maybe off-chip.  The two smaller MOSFETs are probably for a switched mode power supply to get the low voltage required for the control circuitry.  If you have a dead motherboard that doesn't respond to anything it's probably this circuit that died.

[Chriull]

4 hours ago, mrelwood said:

Those are commonly used for memory storage. To remember settings through battery disconnections is my guess.

And only really needed for real time clock.

Maybe they have some black box feature and wanted a timestamp with it?

As "normal" settings are saved with

1 hour ago, Marty Backe said:

With Flash based memory systems?

And seems odd considering the V11 control board is essentially permanently connected to a ~1500wh battery. KingSong and Gotway don't use batteries.

Could be that one can connect to the mainboard for settings even with no batteries attached?

1 hour ago, Marty Backe said:

I wonder what the tradeoff's are when designers of these systems choose a Flash based memory system vs a Volatile memory system. 

Battery has to be exchanged after many years - like on PC motherboards. But mostly these batteries have a longer lifetime as the boards are normally used...

And volatile memory has unlimited write cycles in contrast to flash memory. This could speak for some black box again - writing masses of data to this volatile memory and always keeping the last x seconds?

[Chriull]

9 hours ago, mrelwood said:

2 * HAF018 (?) (at the main power inputs

 

7 minutes ago, StuartL said:

The two smaller MOSFETs are probably for a switched mode power supply to get the low voltage required for the control circuitry.

As they are near the power supply and on the heatsink the should be to connect/disconnect the two battery packs. Afair it was stated, that the V11 has some battery control and can disable one battery pack in case of problems and drives on with just the other pack?

The switching mosfets should be some smaller ones on the PCB near the coils.

Edited August 20, 2020 by Chriull

[Lefteris]

It sometimes is easier to implement low power circuit from a round 2025 battery, than connecting to the huge battery and then regulate power..

[mrelwood]

5 hours ago, StuartL said:

If you have a dead motherboard that doesn't respond to anything it's probably this circuit that died.

There are two small green LEDs on the board, one solid(ish), one blinking. Funny thing is, when I press the power button for 20-30 seconds (complete shutdown), the LEDs do turn off. Another press and they’re back. But the device doesn’t boot, or show up in the app.

 All the power FETs measure fine, batteries are fine, and removing individual peripherals (rear light, lift switch) doesn’t help.

 When the board failed, it burned through the positive leg on both large electrolytics. But the wheel should boot even without the caps, so soldering them back didn’t help either.

 I’m of course getting a new board from Inmotion, but the wait for the shipping is going to kill me. Or make me kill someone.

[Chriull]

15 hours ago, mrelwood said:

Did they use plastic "insulation tubes" to seperate the screws from the mosfets metal plate? Or they just trust that the mosfets and screws are well aligned and will never touch?

And seems like they also used thermal pads _and_ ?thermal grease?

Ps.: Will eventually sometimes do an internet search if there maybe really exist some pads for which grease is recommended, since they are all consistently using both...

[mrelwood]

Just now, Chriull said:

Did they use plastic "insulation tubes"

Yes, the short tubes with an integrated spacer that are commonly seen in transistor attachments.

Just now, Chriull said:

And seems like they also used thermal pads _and_ ?thermal grease?

Ps.: Will eventually sometimes do an internet search if there maybe really exist some pads for which grease is recommended, since they are all consistently using both...

Yes, there is a minimal amount of thermal grease between the mosfets and the thin thermal pads.

[buffs]

36 minutes ago, mrelwood said:

 I’m of course getting a new board from Inmotion, but the wait for the shipping is going to kill me. Or make me kill someone.

is this board that failed from the wheel you recently received??

[mrelwood]

10 minutes ago, buffs said:

is this board that failed from the wheel you recently received??

Yes. While riding a 230lbs rider up an extremely steep hill on soft soil covered in wood pulp. I guess floating around on the V11 for a day got the best of my judgement and reason...

[Chriull]

1 hour ago, mrelwood said:

When the board failed, it burned through the positive leg on both large electrolytics. But the wheel should boot even without the caps, so soldering them back didn’t help either.

They most likely have an internal short circuit...

Would be great to find some sources on exactly why when and how they are overloaded and how to resolve this!

1 hour ago, mrelwood said:

 I’m of course getting a new board from Inmotion, but the wait for the shipping is going to kill me. Or make me kill someone.

Should be a good idea to replace the thermal pad! Don't know if they are "reusable". Especially if the thermal grease hardened it will have bad thermal conductivity values! Don't forget to clean the aluminium heatsink thouroughly before reassembly.

And forget the thermal grease!

Afair are here enough members with practical experience to recommend a great thermal pad!?

Or you kill your time waiting searching for good products

... or you think about using micra plates and thermal grease - this is a bit messy and more complicated but should be the best solution!

Although there should be afaik some real good thermal pads available...

And look at the 

1 hour ago, mrelwood said:

short tubes with an integrated spacer that are commonly seen in transistor attachments.

If they are already a bit "squashed" it would not hurt to replace them, too! 

[Hal Farrenkopf]

38 minutes ago, Chriull said:

They most likely have an internal short circuit...

Would be great to find some sources on exactly why when and how they are overloaded and how to resolve this!

Should be a good idea to replace the thermal pad! Don't know if they are "reusable". Especially if the thermal grease hardened it will have bad thermal conductivity values! Don't forget to clean the aluminium heatsink thouroughly before reassembly.

And forget the thermal grease!

Afair are here enough members with practical experience to recommend a great thermal pad!?

Or you kill your time waiting searching for good products

... or you think about using micra plates and thermal grease - this is a bit messy and more complicated but should be the best solution!

Although there should be afaik some real good thermal pads available...

And look at the 

If they are already a bit "squashed" it would not hurt to replace them, too! 

When I eventually get a new V11 wheel and they are still using the pad with paste, I will definitely use MICA with very thinly coated paste  to do it properly. I have done it to my V10F.

[Chriull]

4 minutes ago, Hal Farrenkopf said:

When I eventually get a new V11 wheel and they are still using the pad with paste, I will definitely use MICA with very thinly coated paste  to do it properly. I have done it to my V10F.

What i forgot to write in my post above to @mrelwood was that with micra plates one has to check first if the whole thing is designed with "no space" between the heatsink and the mosfets before switching to micra plates. As they are not flexible and cannot fill gaps like (thicker) thermal pads.

But should be designed this way? As thermal pads not squeezed together have bad thermal conductivity?

[Hal Farrenkopf]

8 minutes ago, Chriull said:

What i forgot to write in my post above to @mrelwood was that with micra plates one has to check first if the whole thing is designed with "no space" between the heatsink and the mosfets before switching to micra plates. As they are not flexible and cannot fill gaps like (thicker) thermal pads.

But should be designed this way? As thermal pads not squeezed together have bad thermal conductivity?

It is MICA and not micra. Yes, hopefully the legs of the Mosfets don't have solder right up to the body of the device so that it can be lowered a tiny bit more. At least they are all screwed down ready for just replacing the insulator. I had to drill and tap the heat sink of the V10F.  

 

[Marty Backe]

2 hours ago, mrelwood said:

Yes. While riding a 230lbs rider up an extremely steep hill on soft soil covered in wood pulp. I guess floating around on the V11 for a day got the best of my judgement and reason...

I somehow missed your original posting that documented this failure 

So we are to conclude that Inmotion is closer to Gotway than KingSong, in that under severe loads their board can self-destruct?

I'm certainly not encouraged by your failure (and mine). I think I'm going to stand by my decision to wait until 2020 is over before considering a purchase of a V11. I want to see if more V11's fail over time, and if the do, avoid this wheel.

[Marty Backe]

7 minutes ago, Hal Farrenkopf said:

It is MICA and not micra. Yes, hopefully the legs of the Mosfets don't have solder right up to the body of the device so that it can be lowered a tiny bit more. At least they are all screwed down ready for just replacing the insulator. I had to drill and tap the heat sink of the V10F.  

 

You sound like a Gotway owner   Someone who doesn't trust their new wheel and tears it apart to inspect and rebuild it to their standards.

Certainly not something I would expect to read about regards to an Inmotion owner.

Personally I would never buy a wheel where I felt that I needed to do what you are planning on doing. There are some Gotway owners that do this and I don't agree with them either.

[mrelwood]

56 minutes ago, Chriull said:

Would be great to find some sources on exactly why when and how they are overloaded and how to resolve this!

I didn't get any comments out of Inmotion yet, other than a new board is on the way to resolve the issue.

56 minutes ago, Chriull said:

Should be a good idea to replace the thermal pad!

...

... or you think about using micra plates and thermal grease - this is a bit messy and more complicated but should be the best solution!

...

If they are already a bit "squashed" it would not hurt to replace them, too! 

The spacers are pristine, they weren't tightened very much. New thermal pad is a good reminder, thanks! I won't go with MICA though, since:

7 minutes ago, Chriull said:

What i forgot to write in my post above to @mrelwood was that with micra plates one has to check first if the whole thing is designed with "no space" between the heatsink and the mosfets before switching to micra plates.

The board itself is designed to press on the Mosfets on the topside, and it has a strip of metal soldered in to function as a small heat sink at the face of the mosfet. I'd be afraid that the thin MICA plates would leave the Mosfets further away from the top sink, and that they would anyway require precise bending of the mosfet legs to a new position not to pull on the mosfet body to an angle. If my fat ash can't get the Mosfets to burn, I'd label the cooling as "sufficient" already...

[Hal Farrenkopf]

2 minutes ago, Marty Backe said:

You sound like a Gotway owner   Someone who doesn't trust their new wheel and tears it apart to inspect and rebuild it to their standards.

Certainly not something I would expect to read about regards to an Inmotion owner.

Personally I would never buy a wheel where I felt that I needed to do what you are planning on doing. There are some Gotway owners that do this and I don't agree with them either.

LOL, no, I am not a gotway owner. I went from a C+ to a V10F. Bought the V10F in May 2018 so I was an early adopter to their defects. It seems every manufacturer uses the cheap and fast pad with paste method of assembly. I'm an electrical engineer so I know how much better the mica is. Especially when there was a heat related problem.

 

[Marty Backe]

10 minutes ago, Hal Farrenkopf said:

LOL, no, I am not a gotway owner. I went from a C+ to a V10F. Bought the V10F in May 2018 so I was an early adopter to their defects. It seems every manufacturer uses the cheap and fast pad with paste method of assembly. I'm an electrical engineer so I know how much better the mica is. Especially when there was a heat related problem.

 

Oh, I know you're not a Gotway owner. I was saying that you are acting like a Gotway owner  This is surprising considering that you own Inmotion.

If you care that much about quality I doubt that you'll ever buy Gotway or Veteran 

[mrelwood]

11 minutes ago, Marty Backe said:

I somehow missed your original posting that documented this failure 

I didn't, yet, as I'm hoping to learn more about the issue. But mentioning about it on the Telegram group has of course spread pretty well already.

11 minutes ago, Marty Backe said:

So we are to conclude that Inmotion is closer to Gotway than KingSong, in that under severe loads their board can self-destruct?

Well, a friend of mine had his 18XL blow the fuses quite violently, requiring a lot of clean up to be able to use the same board with new fuses. And I fried the motor wires on the MSX, which then took the board with them. Being able to fry the V11 under extreme conditions isn't all that surprising to me now that I'm not flooded with adrenaline...

11 minutes ago, Marty Backe said:

I'm certainly not encouraged by your failure (and mine).

I see your demo V11 issue as a different one. Since the V11 software in some situations behaves differently when lying on it's side, and your pre-production board failed with no burden at all, it sounds to me that the issue was caused by a freak combination of events on a non-finished software. I was hauling my large weight up an extremely steep hill with soft soil covered in wood chips. The worst burden the wheel could ever be asked to push through, I'd imagine.

11 minutes ago, Marty Backe said:

I think I'm going to stand by my decision to wait until 2020 is over before considering a purchase of a V11.

If you can still be without the V11 suspension, that might be a good idea. Myself, I would replace the main board every freaking week to get to ride it. Every other week if I had to pay for them myself.

[Unventor]

3 minutes ago, mrelwood said:

If you can still be without the V11 suspension, that might be a good idea. Myself, I would replace the main board every freaking week to get to ride it. Every other week if I had to pay for them myself.

You need to ride in swim pants so you don't overload the wheel again. Blame it on all the gear. 

[Hal Farrenkopf]

39 minutes ago, mrelwood said:

The spacers are pristine, they weren't tightened very much. New thermal pad is a good reminder, thanks! I won't go with MICA though, since:

The board itself is designed to press on the Mosfets on the topside, and it has a strip of metal soldered in to function as a small heat sink at the face of the mosfet. I'd be afraid that the thin MICA plates would leave the Mosfets further away from the top sink, and that they would anyway require precise bending of the mosfet legs to a new position not to pull on the mosfet body to an angle. If my fat ash can't get the Mosfets to burn, I'd label the cooling as "sufficient" already...

I don't see any metal heatsink between the mosfets and the PCB. There will be a large trace on the PCB bottom for conducting Battery + and or Ground to the Mosfets. It will not be a heatsink. The legs of the Mosfets will bend sufficiently when they are tightened down with mica and paste. They are tinned copper so very flexible. 

The Mosfet should be screwed down tight with the mica to squeeze the paste really thin. The paste is designed and meant to fill only the very very small air gaps in the imperfect surfaces.

I'm in no rush to buy a V11 at this time because my V10F does me just fine where I live in Sarnia Ontario Canada where it is flat.

I'd like to see more information on your V11 failure with pictures.