Veteran Sherman Failure Postmortem 

I have two hobbies. Radio controlled helicopters and EUC's. In the modeling world, we regularly fly models which can extract 7500 watts from a motor, easily 3000 continuous , and 150 amps continuous draw with spikes as high as 300 amps. The esc's used are NOT some huge and heavy package. EUC speed control design in comparison is utterly archaic and little better than what we were flying close to a decade ago. The esc in my model will automatically pull back power if current reaches threshold of safety. NOT shut down and NOT burn up. It will do the same for temp. It self monitors all of this. The wiring gauge used in these wheels to supply the motor and from batteries to control board in EUC's is laughable as well relative the what the wheel had to endure on overheat hill. The technology needed to completely avoid these kinds of failures is well established. All the wheel mfg's need to look around and get into the 21st century. Every time I ride I have to go into denial because I otherwise know what a comparative POS the speed control is between my feet and that I am forced to trust my limbs to something of quality and design that I wouldn't touch with a ten foot pole in one of my models. Want to see how to design and build an esc.......look up Kontronik/Sobek drives or YGE or Scorpion power systems You'll see why it's such a shame we are forced to ride with/on such crap comparatively speaking.

Not that this is any harder than any other wheel to repair, but it blows my mind that they have that slot to access the control board on top yet they can't make it an inch wider so that you don't have to 100% teardown the wheel to replace it..

I’m starting to like you a little more now. I like ur honesty I like you don’t have to keep ur mouth shut with a review wheel that was given to you. This board is an issues and I’m glad yiu did sugar coat it like others would like koji does. Yiu and Mickey are on point. Keep it up. You could save someone life find these flaws and making the company aware of it and make them fix it before selling them to us. Thank you. I hope you keep this up with other wheels too. If a company won’t send you a wheel to test because you will be honest. Set up a Patreon and I will donate enough money so you can speak ur mind and not have to worry about companies not wanting to send you wheels.

this man is the backbone holding the engineers together for all of the community

Yes Marty that was Interesting AF! Please find more bugs to help make next copy Better for us! Thanks again.

Lol I just watched a video of Vee doing 52mph on the Veteran Sherman. If this thing shows a tendency to fry I don’t think anybody will be riding too fast on this big boy. Excellent video.

Thanks for doing this breakdown, Marty. Would never have guessed the roll cage was two separate pieces press fit together without your video.

Yes Marty thank you for breaking it down and showing all of us the stress test of the hill and what it can do to each one of these wheels

Thanks to you and the other early testers for helping the rest of us get better wheels.

This is kinda like an AvE BOLTR ‘vigeo’ with some great insights into Veteran quality. Certainly better built than earlier GW efforts. Good on them for working with you on this! I don’t know what we would do without you Marty, very professional and much appreciated ! I’m still holding out hope that a quality company (IM?) would sign you up and design the “M B touring special edition EUC“. In the meantime there is NO doubt in the community that you’ve helped move quality forward in the industry. Great Stuff!

I love the smell of burned mosfets in the morning. Thank you for sharing Marty!

thank you Marty for sharing with the community! very informative video as always! you making me smarter everytime!🤙🏻😋

Thanks Marty, I really appreciated your honest appraisal, it's something that is really needed in the youtube EUC community. It can only help manufacturers and buyers.

thank you for doing this.. I appreciate you

Totally stupid design that you have to go so far to remove a board because its missing 4mm of clearance.

Very Interesting Marty! I really enjoyed watching the breakdown process. A great resource for us all. I’ll be interested to see if they make any changes on the board. Thanks for documenting this.

This turned into an ASMR video real quick, I love hearing you talk and take apart the motherboard

Incredible and compelling video. This may be your finest week in terms of being a test pilot, then showing what you know and teaching us how it all works (or doesn't, in this case). Thank you!

Hi, thanks for sharing! I received the 2021 model two weeks ago and whatever happened to yours, happened to mine this weekend. I actually managed to get it out as I pressed the handlebars all the way down. ✌️

as always great info from you Marty

You exhibit extraordinary patience. Veteran has to do major fixes and QC.

Hi Marty. The Veteran Sherman has grown from the fastest to the hottest thanks to you. I understand why you are protected like a RobotCop 👍

Great video. Good comments and observations from everyone too. This is a fantastic channel. Some of the other EUC channels seem a bit more like advertisements.

Snap, Crackle, Pop! Great stuff Marty 🙂

there has to be a 2nd cap somewhere in the enclosure there were two before. i dont know the wiring but it looks like that they use the caps in parrallel over the mosfet bride. The first cap has less resistance and gets used more.The heat shrink melted from both caps meaning that they got really hot before the accident because they are completly drained for long periods of time. they only use 1120µF as input buffer. For a Vesc it's recomended to use at least 2000µF. Of cause the wiring got really hot pushing the limit and melted the solder of the first cap shortend it and boom Cap takes all the mosfets with it. Just a theory of an long time vesc abuser ;)

This, of course, was another great piece of Intel sir, but I think you scrambled me eggs a bit, yeah? Reading through some of the comments posted here, I see you don't HAVE to be an Engineer to do a tear down and replacement - but it sure wouldn't hurt! Scrolling through a few of the comments is like trying to read Mandarin! I don't think I'd ever heard of MOSFETS before you said it in one of your previous vids where on a group ride one of the other guys blew his (can't recall if it was on Ol' Overheat or not though🤔) Good information to have and be able to refer back on once my Sherman pre-order is available (though HOPEFULLY they'll have settled this issue by then) Thanks for putting in the road work and opening up the class room...for us AND Veteran 🤓 "Anutha One" 👍🏽👌🏽🤙🏽🙌🏾🙏🏽

Good luck Marty you sure know your way around wheels. 😇✌

I think it's impressive that it burned like that since you are a light weight rider, Marty. Your friend kept going up without issues and he is larger than you. By the way, you should create the seal Marty Backe Firehazard Proof for the wheels you can't burn : ) Real nice job!

An informative review!

That right there don't deter me from still wanting this wheel. I won't be riding like that extreme up a hill that the wheel is not meant for, and plus with the great testing that you did. I'm sure Veteran engineers will improve it with their next line of product batch. Another great review Marty. I hope I got your name right.

The development of emerging technologies likely always involves such destructive testing. Makes me wonder how many of the first telephones, calculators, and microwave ovens self destructed before they found a design that was good enough for the average user. It will be interesting to see how mainstream these become as more people decide that personal electric vehicles are the way to go.

Super informative! Thank you for the thorough teardown. Seems a little strange that the fans are at the rear of the control board; you’d think it’d be convenient to take advantage of some passive airflow to accelerate cooling fore to aft. Seems that there’s a lack of air circulating to the control board in general being clam-shelled as it is...

Nice shop!

Putting back will be more fun.

Observations: 1. Need to separate the motor driver electronics from the controller circuitry. Yes, this may take up more space, but a separated and stacked board can still fit in the housing using stand offs 2. The motor driver electronics would need much wider and thicker traces (PCB stackup of FT4) and the mosfets spaced out to support them and a heat sink dedicated to that much power under maximum load 3. Thermal cut-off circuitry can be added to the motor driver circuitry to prevent catastrophic failure. Triacs or SCRs could be used to do this and cut power temporarily under maximum load conditions. PWM driver circuits can also do this with negative feedback loops using a microcontrolled circuit 4. Much bigger DC filter capacitors should be used to handle the larger power. These could be smaller in size but put in parallel with adequate traces to handle the power consumption and reduce the physical size 5. The PCB should be symmetrical in layout for the mosfets, capacitors and main driver components to ensure even and balanced distribution of power and thermal dissipation throughout the entire circuit. This ensures no uneven power imbalances under load because current leads voltage at initial load of the DC motor driver. Equal lengths of wire and symmetrical layout of components will help keep things balanced. That's my 2.49249795383 cents. I love the aftermath of destructive power electronics circuit testing! It's a lot of fun and a great way to learn from failure.

I actually enjoyed watching you take the Sherman apart, it's a great learning tool. Any ideas when you will be receiving the new boards?

Mine is on the way, I'm not cancelling it. The range, functional trolley handle compared to my msp, modular lights and roll cage are enough reason for me. Besides we don't have hills in abu dhabi. Very informative video. I think you can getaway without removing any cables from the board when changing tires just like msx/msp.

I was this close of saving up for this wheel myself. But after seeing this, I'll focus on getting the Inmotion V11.

Hi Marty, I wonder how many lives you just saved by exposing the weak point in that board. I'm glad you know what you're doing, because to me it looked like you were fiddling around with the inside of an a.m. radio from the 1970s, LOL.

This is very bad optics for a supposedly new EUC company to burst onto the stage with and not only that this is the most expensive EUC on earth. The design is half-baked (no pun intended) and rushed to market and if I had one on pre-order I'd definitely be cancelling. If the developers of the Sherman are truly ex-Gotway employees then Gotway themselves must be believers in karma. Maybe the fix could be as simple as a software revision that gradually limits the motor power as it nears maximum operating temperature. Maybe this functionality already exists but the upper operating limit is set too high.

I'm going to guess current=heat. Which melted the solder and let the main power leads drop onto the heatsink. Not much that could be done about that. Maybe using bolts and crimped ring terminals for connection to the PCB?

Now that's a cooked circuit board. Man!!!! I personally had my own experiences of accidentally short circuiting.........accidentally connecting wrong terminals........over voltage and the only result I had was a small burn on the board or a blown capacitor and they just would not work anymore. Those circuit boards are so damn sensitive. They need to make them much more tolerant

Ok marty. Now it would seem prudent for a fuse at the load incoming load wire to save the board and be accessible to the rider so when we are stress resting these rides there is a way to not make toast of them. I may now put one on my tesla now and keep close watch on the amps through the euc app. Thanks for the post mortem.

I was about to buy one of these than I thought what a pain in my ass just to see this lol I appreciate it

The roll bar cage looks very promising.

Great video as always, how about when changing a tire, do you have to split it in two?

Great obduction doctor :-) You said it was cool running wheel, but going uphill the Sherman ran hotter with you than the MSP with the much Heavier guy. Only time Sherman went cooler was downhill (from what i heard on the video). Could you elaborate? :-) Love teardown videos, the are allways useful and show strengths and weaknesses. On the Sherman i was really amazed that there are only 6 screws up top holding the shell together and on the bottom only the pedal hanger screws. That means all the stress from things hitting the rim cage at the bottom, will transfer to the screws at the bottom at the Pedal hangers and allready on gotway those holes shows hair line cracks on wheels. Also means you basically cant remove the roll cage and ride without it, should you want to for some reason (clearance, weight loss). How much does the roll cage weigh (now that you have it off)?

Hey Marty. I've seen much of this in one of my older, now late passion, for drone racing. Burnt boards, motors, etc. Mostly ESCs which lead many times to darkened or even burnt motor stator wires with the motor still functioning yet at reduced performance. The motor would get hotter than the others. To prove the failure of one of the ESCs, I bought a iPad oscilloscope and studied the waveforms of good motors and ESCs. I found that one of the quad's ESCs had a "dirty", and non trapizoidal image. It was fascinating to watch and study how these AC multiphase controllers and motors work. Have you thought of opening the motor to inspect the windings? Just a thought. Keep up the great work. I'm really taking in the detailed ride and wheel information you provide. Thanks! Peace from Maine...Guy

How I see it, is that if you can separate the control board from the heatsink, you won't have to split the housing. However, from a assembly perspective, the heatsink and board is pre-assembled and is slotted in first. Hence when toy try to remove it, it comes out in one block. Its a bit of an oversight.

I'm assuming there used to be a capacitor where that hole is.

have you tried to remove the fans.. and see maybe if it would allow you to slide it out under angle

What I found interesting is that you CAN take the whole wheel apart. This seems to mean that you should always be able to repair your Sherman, provided parts are available from Veteran. Do other EUCs work the same way? I was under the impression they were not as modular.

Well so much for not wanting to tinker with wheels eh? 😃 Anyways, thanks! Also, when talking about wire gauges you lost me with the whole"inches" and what not, I'm sure you meant to talk about these in metric all along but just a friendly pointer 😁

Marty, did they come back with a reason or solution on the fried board yet? And is there a V2 in the works.

BTW: The Current that is drawn from the battery.....and the current that is pushed through Mosfets/Motorwire are not the same. Actually on a situation like here, very low speed, much torque needed, the amperage might easy be way, way over 200-300amps. And the Veteran config can provide double as much amps as the actual GW’s... What is more concerning is that the Motor and firmware configuration of the sherman -even beside all the battery power available- was not able to push Marty easily up the hill. Seams they are using a very “old” version of firmware....

I'll bet the mosfets fried first, it is common for them to spew out molten guts where the leads are. If the battery is 100v that is close to arc welder voltage and currents so it then started arcing all over the mosfets leads like an electric welder, and finally the current/heat was high enough that it took out the battery wires and made that big hole in the PCB. That is the kind of thing that is normally saved by fusing the incoming battery leads... was there a fuse? Was it before the PCB, or on the PCB? Also the mosfets should be further apart on the PCB because the arc happens between the high side mosfets and the low side mosfets. If they are spaced further apart there is less chance of a full battery arc, that goes from B+ to B-. Anyway improved PCB design and improved fusing need to be done. And always beware of 100v electric battery systems because risk of arcing is much higher than a 63v or 84v vehicle.

@ElectricUnicycles, I killed my friends board by accident as I was making some changes for him and I need some components on a broken board, can you give me your dead board. I really need your help.

Strong motor!!! You know you have a well built motor when the circuit board fails first and the motor is still intact.............😁😁 So I guess the folks at Veteran need to assemble a far more resilient circuit board that can resist the current on a constant basis

I'd hate to to think people will trust that circuitry at high speed against the wind or up a hill. I wonder if the current was so high that a solder joint failed on a battery lead, causing a direct short on the board.

Surprisingly, the power electronics are not protected by something as cheap as a temperature sensor in critical areas

how did you damaged the board did you get water in it?

When are you expecting the new control board? Shipping from China?

The slowest rider burnt 🥵 out the V. Sherm lol 😂 those California hills 🥴

wow. it seems the designers don’t talk to one another. to have to take the wheel apart to replace the most likely part that is going to fail just shows no real for thought. i’m pretty sure we the riders wouldn’t mind paying more money if they would upgrade their circuit boards to a more industrial grade boards. thank you marty for your continuous work for our community.

I see what you talked about now

OMG

Talk about beta testing. This was a very informative video. :-) Only thing missing is a hardness test from Jerry Rig Everything, LOL!! :D

it it was my unit i would cut out a section of the box so i would not have to remove the wheel

It looks like the fans are an after thought, that's why the whole control assembly can't be removed. I bet they thought the heat sink was enough. The fans don't seem to be very effective from what I can tell.

I agree w/ manuelrossum's comments but don't think I can afford to support U if it comes to that.....sorry. But I have a question; if the issue was that the board could not handle the battery power does that not call into question the modded Tesla w/ the 1480 battery?

how much was a new board?

Why is the board so wet?

learn so much from these, thank you. still looks easier than changing my Nikola board.

How many miles before it fired?

It Is possible to charge of 2000 wats investor ? ( inverter )

Dang....that sucks...so, I reckon the ks s18 may be the way to roll

🤠👍

Biggest Downfall of this Wheel is too Heavy.It’s draws Heavy Current

could the board not just be screwed off of its heatsink if you needed to replace or work on it? i mean without taking the shell apart... because that seems completely ridiculous that you would need to do that.. and why do gotway/veteran refuse to put in safety precautions for the board so it wont kill itself in a spectacular manner??? fuse, firmware, whatever.. no other brands of euc would let you blow it up i cant understand this logic

I took the control off the heat sink....Then I took out the control board .

Wish you had found out what that wheel wobble was before the torture test. Might have been a clue to the failure.

There will always be a trade off of characteristics. Make the wheel better...difficult to change a pcb😃

How can you build a new device and not build the most important thing from all experience? The most important thing would be to build electronics that can withstand this performance. The second most important thing is to simply run a service. This includes the simplest expansion of a control system. To make replacing a tire very easy. What do i see here I see an ordinary Chinese product, absolutely careless in construction. And many who don't think about it and want it

You don't need the board. Just connect the red and black wires and away you go....

A simple fuse is too much to ask for in a $3500 wheel?

That is really a dumb thing.

Weak spot? Weak spot able to keep you working for hours? Not that weak then!!

First of all, that should never happen with a 3000$ unicycle to begin with. Isn't the output on this about 80 or 100 volts and about 3000 watts?? That's more than suffiencient power for hills.

You are the Sandy Munro of EUCs... You should sell your reports back to the manufacturers like he does.

It looks like water damage

A little disappointed with first version of Sherman. Very simple for my taste. It’s not bad in general, but there is no attention to detail at all.

First !

One day he'll understand that you can burn any wheel that lets you ride till the end like the gotways. One day ...

They done it by purpose so complicate to spend more money on service. Very stupid concept. King Song remain the King of unicycles