My 84-volt Nikola Triumphs, Tribulations, and Failures

[Unventor]

6 hours ago, eddiemoy said:

That is why there is a fuse in the KS wheels.   Even if the firmware screws up, the hardwired fuse would blow and then everything is saved.  Just need to replace the fuse, not the board or motor. Fuse blowing in the KS wheels are rare, but it does happen.  It still results in a face plant. No way around that, but just replace the fuse and if you are properly protected, can ride again.  No need to wait for replacement components to ship. BTW, with everywheel, you get spark fuses.  

I wounder what takes longer if you are doing 50kmh as people cried out for with KS16X and it blows a fuse...

A ) Picking up parts trying to find the fuse? 

B ) The recovery from a 50kmh faceplant...

C ) Getting hold of spare parts after a wheel did a 50kmh tumble... 

Or let me put this in another way I don't think it matters much. Ideal world it should never happen. But but but... 

First we aim for another continent... done. 

Then the moon....done. 

Next Marts.... in progress.... 

Once there is a new limit, humanity dictated we are to test the new limit to push it further.. 

Edited June 15, 2019 by Unventor

[Rehab1]

@Marty Backe Any idea why the block of 3 MOSFETs that sustained the most heat damage has a membrane incorporated beneath the bodies? The semi transparent  material does not appear to have any heat transference qualities. 

 

 

Edited June 15, 2019 by Rehab1

[meepmeepmayer]

10 hours ago, EU_commuter said:

@Marty BackeWhich wheels survived the Overheat Hill?  MCM5 certainly.  MSX?  How about any Kingsong wheels?  Thank you.

• MSX: didn't even get hot. Robust beyond all doubt, as seen from @EUC GUY's videos (car push test + mountain test like Marty's hill, but longer)..
• MCM5: didn't even get hot.
• 18S: juuuust made it to the top without overheating.
• 18XL: overheated shortly before the top. Runs quite hot in general.
• V10F: overheated shortly before the top.
• Z10: I forgot, but I believe it overheated.

I hope I remember correctly. Thank you again Marty for all the tests.

Edited June 15, 2019 by meepmeepmayer

[EUCGUY]

4 minutes ago, Rehab1 said:

@Marty Backe Any idea why the block of 3 MOSFETs that sustained the most heat damage have a membrane beneath them?

 

 

perhaps just the thermal mat that melted. btw, i would like to mention that the powerfull blowerfan most likely are messing with the temperature readings. If it shorted as seen here, they also got hotter, no doubt more than 50c,    

 

[meepmeepmayer]

Wow that video! What you say while knowing what is going to happen. Horror show.

"This baby is not going to overheat on overheat hill, I tell you that. Only thing that might happen, I'll blow a mosfet. I'm joking *chuckles* * theatrical gesture* Please Gotway don't burn up on me!"

And then... the disassembly. One can hear your incredulity at the details.

"Oh Gotway *exhales* will you ever learn?"

You really have to wonder what the point of the huge heatsink and huge board space was.

Let's hope this results in a better 84V board for the Nikola.

[Dzlchef]

The whole build situation is disappointing and I hope for a bigger MOSFET board release eventually, but I still love this wheel and feel confident that it will hold up under my normal riding.   I’ve seen quick spikes over 90A but nothing continuous and the temperature hasn’t varied much.  I only have 100 miles so far and have been riding it like I stole it!  

[Marty Backe]

3 hours ago, buell47 said:

 

I'm really sorry for you, but thanks for the test.
So the Nikola 84V is out of the 16X or Nikola 84V purchase decision for me!

Now the question is back again....16X or Nikola Plus 100V with bigger 247's mosfets, even if this means maybe less torque for higher speed.

But what does it look like in the Plus version? I can't imagine that it looks any different there, except for the other mosfets?
I suppose we're expecting the same design flaw there as @Seba wrote and I see it the same way, don't you?

I can only agree with that.

Unbelievable, I would have assumed that a fuse would be standard.

KS 
Gotway

The one (important) item that you are not considering is performance. Gotway has nearly always had issues with their controller designs but many of us are willing to live with the consequences because they make the highest performing wheels that you can buy. This is why I eagerly await my new control board and will continue to ride the Nikola. I'm not making excuses for Gotway, just describing reality.

Of course I understand many people would prefer the more conservative KingSong wheels. Hell, I do like riding my KS18XL knowing that at worse it'll blow a fuse.

I think under most riding conditions the Nikola will be fine, but it's important to know its limitations. If you really need a bulletproof wheel for all conditions, then go with the MSX.

[Marty Backe]

2 hours ago, Rehab1 said:

@Marty Backe Any idea why the block of 3 MOSFETs that sustained the most heat damage has a membrane incorporated beneath the bodies? The semi transparent  material does not appear to have any heat transference qualities. 

 

 

That strip of material is on all of the controller boards. I peeled it off (I think you can see me peeling it off in the video). I believe it facilitates the transfer of heat to the heatsink (instead of using thermal paste). On the three MOSFETS that got too hot, the material melted to the MOSFETs and got stuck to them.

[Marty Backe]

45 minutes ago, Dzlchef said:

The whole build situation is disappointing and I hope for a bigger MOSFET board release eventually, but I still love this wheel and feel confident that it will hold up under my normal riding.   I’ve seen quick spikes over 90A but nothing continuous and the temperature hasn’t varied much.  I only have 100 miles so far and have been riding it like I stole it!  

You heard all the 90-amp triggers? I think you'll be find as long as you monitor the current during hilly rides (Griffith Park). If you start getting a lot current spikes like in my video. Stop and give the wheel a rest.

[Marty Backe]

1 hour ago, meepmeepmayer said:

Wow that video! What you say while knowing what is going to happen. Horror show.

"This baby is not going to overheat on overheat hill, I tell you that. Only thing that might happen, I'll blow a mosfet. I'm joking *chuckles* * theatrical gesture* Please Gotway don't burn up on me!"

And then... the disassembly. One can hear your incredulity at the details.

"Oh Gotway *exhales* will you ever learn?"

You really have to wonder what the point of the huge heatsink and huge board space was.

Let's hope this results in a better 84V board for the Nikola.

Yeah, I was laughing to myself while editing the video. All the warning signs were there, preceding that actual failure.

[Rehab1]

Yes it appears that GW is using thermal pads instead of paste. Most experts state that paste is more effective than the pads as it fills in all of the microscopic pores between MOSFET and the heat sink. I hate thermal paste as it is messy to work with.

The additional downside for the thermal pads is they need to be replaced each time the MOSFETs are unscrewed from the heatsink or the heat transfer properties will be diminished.

 

 

Edited June 15, 2019 by Rehab1

[EUC Custom Power-Pads]

7 minutes ago, Marty Backe said:

The one (important) item that you are not considering is performance. Gotway has nearly always had issues with their controller designs but many of us are willing to live with the consequences because they make the highest performing wheels that you can buy. This is why I eagerly await my new control board and will continue to ride the Nikola. I'm not making excuses for Gotway, just describing reality.

Okay, I partly agree with you on that.

The engine of a racing car does not have the same service life as a road vehicle. But...if this could be achieved by installing a few fuses and a slightly larger oil cooler, which is only $10 more expensive, then it is more than stupid not to do this to save $10 production costs, even though the buyer of this race car would pay for it. 

It is even more stupid if you already know this problem, both the manufacturer and the customer, but  the manufacturer continue to save on the wrong end. There are in my eyes only 2 reasons for this nonsense:

a) Manufacturer is stupid, blind and deaf 

b) Intent! Nice additional income on spare parts sales since normally no warranty case 

 

[Marty Backe]

6 minutes ago, buell47 said:

Okay, I partly agree with you on that.

The engine of a racing car does not have the same service life as a road vehicle. But...if this could be achieved by installing a few fuses and a slightly larger oil cooler, which is only $10 more expensive, then it is more than stupid not to do this to save $10 production costs, even though the buyer of this race car would pay for it. 

It is even more stupid if you already know this problem, both the manufacturer and the customer, but  the manufacturer continue to save on the wrong end. There are in my eyes only 2 reasons for this nonsense:

a) Manufacturer is stupid, blind and deaf 

b) Intent! Nice additional income on spare parts sales since normally no warranty case 

 

I can't argue with your reasoning 

[Afeez Kay]

On 6/5/2019 at 5:41 AM, maltocs said:

Absolutely meet! I've come to the realization that no 50+lb wheel is going to be that zippy. I'm definitely in the market for a 1600Wh+ wheel that can come as close to an MCM5 as possible. If only they made the MCM5 with 800Wh swappable batteries. But so far this looks to be the closest thing. Even looks like the MCM5's big brother.

Get the Gotway Tesla.. simples 😁

[Jon Stern]

23 minutes ago, Rehab1 said:

Yes it appears that GW is using thermal pads instead of paste. Most experts state that paste is more effective than the pads as it fills in all of the microscopic pores between MOSFET and the heat sink. I hate thermal paste as it is messy to work with.

The additional downside for the thermal pads is they need to be replaced each time the MOSFETs are unscrewed from the heatsink or the heat transfer properties will be diminished.

 

 

Thermal gap pads are very effective, but only if sufficient compression force is applied. The thermal resistance quoted by the manufacturer is with a certain amount of compression.

[Marty Backe]

19 minutes ago, Afeez Kay said:

Get the Gotway Tesla.. simples 😁

He's looking for a 1600wh wheel

[eddiemoy]

3 hours ago, Rehab1 said:

@Marty Backe Any idea why the block of 3 MOSFETs that sustained the most heat damage has a membrane incorporated beneath the bodies? The semi transparent  material does not appear to have any heat transference qualities. 

 

 

I was looking at that too.  It is almost like GW tech who applied the heat spreader didn't remove the adhesive sheet completely from the thermal silicone sheet.  BAD, this would explain why those 3 blew because it wasn't make direct contact with the thermal silicone.  It was touching paper, then silicone sheet then aluminum heat spreader.

[eddiemoy]

1 hour ago, Marty Backe said:

That strip of material is on all of the controller boards. I peeled it off (I think you can see me peeling it off in the video). I believe it facilitates the transfer of heat to the heatsink (instead of using thermal paste). On the three MOSFETS that got too hot, the material melted to the MOSFETs and got stuck to them.

Marty, the thermal silicon sheets usually come with some paper adhered to hit so to keep the sticking surface clean.  from what i can tell, that is is the paper and it wasn't removed when applied.  LOL.

[Rehab1]

14 minutes ago, Jon Stern said:

Thermal gap pads are very effective, but only if sufficient compression force is applied. The thermal resistance quoted by the manufacturer is with a certain amount of compression.

Agreed but somehow I don’t envision GW techs torquing each MOSFET tab screw to the optimal tightness.

The pads are certainly a cleaner installation than the paste method.

[eddiemoy]

3 hours ago, Unventor said:

I wounder what takes longer if you are doing 50kmh as people cried out for with KS16X and it blows a fuse...

A ) Picking up parts trying to find the fuse? 

B ) The recovery from a 50kmh faceplant...

C ) Getting hold of spare parts after a wheel did a 50kmh tumble... 

Or let me put this in another way I don't think it matters much. Ideal world it should never happen. But but but... 

First we aim for another continent... done. 

Then the moon....done. 

Next Marts.... in progress.... 

Once there is a new limit, humanity dictated we are to test the new limit to push it further.. 

I really don't understand what you are asking here.  the 50km/h limit is on the 18XL too and fuse.  why does it only apply to the 16X?  Are you saying that since they put 50km/h limit on the 16X someone is going to push the limits and blow a fuse?  They push it on the 18XL without issue, why would it be an issue on the 16X?

 

[Rehab1]

5 minutes ago, eddiemoy said:

I was looking at that too.  It is almost like GW tech who applied the heat spreader didn't remove the adhesive sheet completely from the thermal silicone sheet.  BAD, this would explain why those 3 blew because it wasn't make direct contact with the thermal silicone.  It was touching paper, then silicone sheet then aluminum heat spreader.

It is interesting. @Marty Backe could you please take a close up photo of the heat sink with the thermal pad attached (I’m assuming it is still fastened)? I’m interested in seeing just how much of an indentation was created by each MOSFET tab. Thanks!

[EUC Custom Power-Pads]

14 minutes ago, eddiemoy said:

Marty, the thermal silicon sheets usually come with some paper adhered to hit so to keep the sticking surface clean.  from what i can tell, that is is the paper and it wasn't removed when applied.  LOL.

A positive surprise, actually. We can almost say that the Mosfet savings policy did not (yet) cause the failure. 

Maybe all Nikola owners should check your PCBs 

Edited June 15, 2019 by buell47

[Jon Stern]

12 minutes ago, Rehab1 said:

Agreed but somehow I don’t envision GW techs torquing each MOSFET tab screw to the optimal tightness.

That was kind of my point. Most people don't know how to use thermal pads properly. I very much doubt GW used torque control for the MOSFET screws.

[Unventor]

3 minutes ago, eddiemoy said:

I really don't understand what you are asking here.  the 50km/h limit is on the 18XL too and fuse.  why does it only apply to the 16X?  Are you saying that since they put 50km/h limit on the 16X someone is going to push the limits and blow a fuse?  They push it on the 18XL without issue, why would it be an issue on the 16X?

 

My point here is the GW vs KS doesn't really matter if you push past the limits of the wheel. Doing so will likely get you hurt. 

I just don't see any need to point finger at a fault at someone's new wheel that was in a special situation. 

I do understand things could have been designed better. But most of the EUCs we are riding have some querks. We are still in a young business.

People cry for newer, faster, stronger... But at the expense of testing. 

Now I do think it would have been nice to let some time pass before doing the GW/KS opinion wars. 

I am not special happy with GW, in fact I am happy with my KS18L. I do however see a benefits in competition between brands in the long run. 

[eddiemoy]

5 minutes ago, Unventor said:

My point here is the GW vs KS doesn't really matter if you push past the limits of the wheel. Doing so will likely get you hurt. 

I just don't see any need to point finger at a fault at someone's new wheel that was in a special situation. 

I do understand things could have been designed better. But most of the EUCs we are riding have some querks. We are still in a young business.

People cry for newer, faster, stronger... But at the expense of testing. 

Now I do think it would have been nice to let some time pass before doing the GW/KS opinion wars. 

I am not special happy with GW, in fact I am happy with my KS18L. I do however see a benefits in competition between brands in the long run. 

Don’t think I ever asked for faster/stronger.  Think they are fast enough.  I do agree competition is good. Not pointing fingers here, just trying to figure out what happened.  Don’t think folks were so critical of my comments when I was pointing out issues on the 18XL.