My Sherman Trials, Tribulations, and Triumphs

[Paradox]

3 hours ago, Marty Backe said:

Overheat Hill Stress Test Results

 

 

I am sorry for your rough day.  The information you bring to the community is priceless.  Your video was amazing from the start.  This was eye opening.

[FreeRide]

1 hour ago, Ben Kim said:

I suspect you missed the part where I stated possibly other loads on the circuit. At home, there is very little reason to charge at such speeds, it’s use case is on long distance rides where charge speed will dictate how much distance you’ll get on a given day, where you have absolutely no clue how much load is on the circuit before you draw another 1000W from it (100.xV * 10A)

Explain where you came up with this 90VDC figure? 

PS: stock YZpower charger is rated for 450W. 

90VDC was a good guess based on max voltage someone said they charged to (not full 100.8V), typical tolerances for amperage ratings at max voltage, and typical wattage range for consumer chargers that don't break the bank.  I got lucky at nailing 900W on the nose giving some operating margins.

I didn't miss your comment about circuits having some existing loads, maybe it's different for apartments, but in my experience a typical outlet in a home is very rarely loaded to 900W so I figure easily enough left to supply 900W to the wheel if needed.  Just don't operate it on the same circuit as your refrigerator or electric kettle. I agree if you are using public outlets it will vary a lot in something like a cafe, but be less of an issue in some other areas.

[Esbu]

1 hour ago, FreeRide said:

 I think we heard the capacitor can roll out onto the floor when you removed the controller cover.

Marty's video - One of the wires from the battery packs should be red. The capacitor was thermally stressed more than the other due to the design of the circuit and therefore was probably burned and loosened.

 

Edited July 14, 2020 by Esbu

[RayBanMonster]

Epic watch... epic information.

No data" left off the table" with that stress test  Marty, taking that wheel down must have been a P.I.T.A.

Many thanks for that...  Leaperkim ( V.Sherman manufacturers) must, & Im sure will respond with a board revision.  Still utterly thank full for this wheel though.

Edited July 14, 2020 by RayBanMonster

[Chriull]

4 hours ago, Marty Backe said:

Overheat Hill Stress Test Results

...

Wow - great video again! Hope you recovered well from the exhaustion!

Seems the capacitors are the new "weakest link" after stronger mosfets and thicker motor wires were used...

As in the beginning some first motherboard versions of KS16B had capaciror legs melting...

And some nice pictures shortly of missing capacitors in https://forum.electricunicycle.org/topic/18494-warning-gotway-nikola-100v-1800wh-battery-fire/?do=findComment&comment=315432

Or @Planemo reporting an ?msx? with a blown capacitor in https://forum.electricunicycle.org/topic/18815-capacitors-on-motherboardsany-tech-gurus/

Could be we see soon some metal film capacitors in parallel to the electrolytic capacitors. They can take much more peak/ripple current. This was at least a hint in an electronics forum from one who seemed experienced...

[Patton250]

You killed it!!!! Lol

[Marty Backe]

4 hours ago, Esbu said:

Marty's video - One of the wires from the battery packs should be red. The capacitor was thermally stressed more than the other due to the design of the circuit and therefore was probably burned and loosened.

 

When I disconnect the batteries, both battery cables (4-wires) fell out of the wheel. That whole corner of the board is destroyed (crumbly). I'm beginning to think that there was so much current flowing from the batteries in the board that the solder in that area started re-flowing.

I still need to get the board out of the wheel, but am wondering if the MOSFET's were actually part of the failure.

Edited July 14, 2020 by Marty Backe

[Heyzeus]

An EUC hanging from a cherry picker bucket, that's got to be a first.

Love it

 

Edit: I have to say I think it's really cool that they gave you permission to tinker with their loaner wheel and break it/stress test it and didn't have you sign some sort of NDA or censor you first.

Edited July 14, 2020 by Heyzeus

[Marty Backe]

41 minutes ago, Heyzeus said:

An EUC hanging from a cherry picker bucket, that's got to be a first.

Love it

 

Edit: I have to say I think it's really cool that they gave you permission to tinker with their loaner wheel and break it/stress test it and didn't have you sign some sort of NDA or censor you first.

Yeah, EWheels is great.

[Marty Backe]

Roll Cage Secondary Uses

I recently discovered that the roll cage makes for an excellent attachment point for lifting with a crane. Flexibility is king 

Photo (and crane) courtesy of @Jrkline "Wheel Whisperer" 

[Mr A.A]

On 7/11/2020 at 12:22 PM, Marty Backe said:

Previously I had experienced some downhill rides where I needed to brake, and to be honest, it wasn't the greatest feeling. But the Sherman allows you, via the LCD panel, to change the tilt of the pedals forwards or backwards 1 to 5 degrees, in 1-degree increments. Takes literally about 15-seconds.

So at the top of one of these steep hills, I reached down and tilted the pedals 2-degrees forward.

Can the same technique be used in reverse ? (tilting the pedals 2 degrees backward) to making hill climbs easier. So that you don't have to lean forward too much. 

It's real inspiring to see the openness towards documenting and disclosing the flaws, so that they can make it better.

And it was a "Tribulation" for Marty, as from the title of the thread itself. Looking forward for being triumphant.

Can't imagine walking down, with all the protective gear and the wheel, in that temperature.

 

Edited July 14, 2020 by Mr A.A
Spelling

[Marty Backe]

3 minutes ago, Mr A.A said:

Can the same technique be used in reverse (tilting thew pedals 2 degrees backward) to making hill climbs easier. ? So that you don't have to lean forward too much. 

It's real inspiring to see the openness towards documenting and disclosing the flaws, so that they can make it better.

And it was a "Tribulation" for Marty, as from the title of the thread itself. Looking forward for being triumphant.

Can't imagine walking down, with all the protective gear and the wheel, in that temperature.

 

I've tried tilting the pedals back for hill climbing, but for someone reason it feels more awkward and uncomfortable. I prefer to depend on the powerpads.

[Planemo]

6 hours ago, Chriull said:

Or @Planemo reporting an ?msx? with a blown capacitor in https://forum.electricunicycle.org/topic/18815-capacitors-on-motherboardsany-tech-gurus/

Could be we see soon some metal film capacitors in parallel to the electrolytic capacitors. They can take much more peak/ripple current. This was at least a hint in an electronics forum from one who seemed experienced...

The GW capacitors (and other wheels if similar caps are used) for sure will become an increasing problem for high mileage and/or old wheels. I will be starting a new thread on it when I have a little more info. But yes, this is an issue which will need to become as much of a 'maintenance check' as others things such as tyre checks etc. A rider has already gone down with some rather nasty injuries because of it, and I sadly say there will be more.

[MrRobot]

Marty do you have any speed bumps in your area you can test the roll cage clearance on? This is my main concern... Don't do a ton of curb hopping but there are a lot of speed bumps here. 

[travsformation]

41 minutes ago, MrRobot said:

Marty do you have any speed bumps in your area you can test the roll cage clearance on? This is my main concern... Don't do a ton of curb hopping but there are a lot of speed bumps here. 

That kind of test is prone to injury. I think Marty's already put himself on the line enough for the community, I reckon that test should be left for someone else 

[travsformation]

14 hours ago, Marty Backe said:

Overheat Hill Stress Test Results

Nice job, you accomplished what the NYC crew failed at! And they think they're the badass ones!  

A big thanks for doing this for the community! Especially in this very unique scenario where face-planting was far less of a concern than the exhaustion of having to lug the wheel back home!

This image is absolutely EPIC and is going to go down in EUC history! 

I'm also wondering if the birds of prey circling around you at the base of the hill were yet another ominous sign of what was to come... 😂

On a serious note...aside from the board blowing (I'm just going to say board because it seems unclear whether the MOSFETS were the sole culprits, or maybe the soldering), that motor noise and vibration prior to the cut-off was a bit unnerving...

Edited July 14, 2020 by travsformation

[winterwheel]

1 hour ago, travsformation said:

Nice job, you accomplished what the NYC crew failed at! And they think they're the badass ones!  

No pussy flat-landing...

Seriously though, this was a super disappointing result for some of us on the heavier side.

[travsformation]

Just now, winterwheel said:

No pussy flat-landing...

Seriously though, this was a super disappointing result for some of us on the heavier side.

And for those of us who were hoping it would be capable of serious off-roading as well as cruising. But with Marty's testing and Jason's determination to get Veteran to make this wheel "Overheat-hill Certified", we might just get what we're after, even if it's a little further down the road...

[winterwheel]

18 minutes ago, travsformation said:

And for those of us who were hoping it would be capable of serious off-roading as well as cruising. But with Marty's testing and Jason's determination to get Veteran to make this wheel "Overheat-hill Certified", we might just get what we're after, even if it's a little further down the road...

Here's hoping! Batteries can move 5000 lb Cybertrucks around, seems like it should be possible to get them working for us.

[Patton250]

I can’t figure you guys out. Someone takes a product, the first of its kind mind you, kind of a prototype, the first run and does to it what it was never designed to do and it fails and you guys are devastated? Gezzzz

 

I had to add to this. You know very well veteran and Jason will get this fixed so let me ask you this. So let’s say they get it fixed and Marty takes the thing up overheat hill and it passes. But then he goes up overheat Hill for a second time immediately after the first trip and it fries that time. Are you guys going to be devastated then as well? My point is 99.999% of you guys will never put any wheel never mind this wheel under that kind of stress condition. Rant over.

Edited July 14, 2020 by Patton250

[Shield]

Issues from a brand new wheel from a brand new company shouldn't be a shock to anyone. It's how they handle these hurtles that will determine their value and from what I can see they are on top of it, so no worries from me. To be honest I expected a lot more problems than what has been reported and I knew there could be going into this purchase.

[Planemo]

1 hour ago, Patton250 said:

My point is 99.999% of you guys will never put any wheel never mind this wheel under that kind of stress condition. Rant over.

Well said. However, to counteract that, I think people were under the assumption that the highest power wheel ever made would make it up overheat hill, given other far lesser spec wheels have.

Further, the fact that the Sherman is a bit heavier shouldn't make any difference (as has been suggested) IMO, given an extra 10kg or so isn't a huge amount relative to the weight differences between humans.

The Sherman has a monster spec in all departments, so I would have expected it to make it up the hill. The board should be a factor of X more robust than other wheels in direct relation to the power it can produce (and maintain), taking into account the torque requirements for the diameter of the wheel. I totally accept that other wheels have also failed overheat hill but they were never touted as the most powerful wheel on the planet either.

I am sure that Veteran will sort it, they will want to, in order to maintain the stature

[.....]

Oh man, fail on overheat hill? Hate to see this for sure! Hey Marty, is that axle socket similar in size to ANY  O2 sensor sockets? Cutting the ribs was a good idea, but vibration is a bitch. Even with almost no pressure, I could see how that wire would become worn again.  Too bad they didnt make a simple tab in the case to hold those down properly.  Damn damn! It really is TOO bad they dont do user firmware ability. I really do hope Jason forces them to handle this, BEFORE mine ships.. Too funny, simple ride with Marty breaks what NYC couldnt. How's that for the truth about how a typical rider can give these wheels a workout. I foresee many many 3d printed frame sliders installed. Why not put that big ole boy Jeff on the hill for a REAL test. I'd think his body type is more fitting for the average usa rider. Jeff seems awesome, I'd love to share a hearty beer with that fellow! Thank you BOTH for doing the work that these companies SHOULD be doing themselves, BEFORE release. Maybe bring a fire extinguisher in the future... lotsa dry grass up there! I think you are overdoing it with that helmet, I know you say atgatt, but...

Edited July 14, 2020 by ShanesPlanet

[winterwheel]

4 hours ago, Patton250 said:

I can’t figure you guys out. Someone takes a product, the first of its kind mind you, kind of a prototype, the first run and does to it what it was never designed to do and it fails and you guys are devastated? Gezzzz

 

I had to add to this. You know very well veteran and Jason will get this fixed so let me ask you this. So let’s say they get it fixed and Marty takes the thing up overheat hill and it passes. But then he goes up overheat Hill for a second time immediately after the first trip and it fries that time. Are you guys going to be devastated then as well? My point is 99.999% of you guys will never put any wheel never mind this wheel under that kind of stress condition. Rant over.

I live in (or at least near) mountain country, I'd like to be able tour them on a wheel, but my riding weight is 80 pounds more than Mr. Backe.

So yes, I continue to be very disappointed.

I express this disappointment publicly because I'd like it to be known that what is for him an extreme use case leading to failure feels like an everyday use case for me, if I draw an equivalence between a shallower slope but a heavier rider. 

I'm hoping that veteran folk do not take the attitude that some may hold that this was an extreme case and so it doesn't really matter in the big picture. To me, it very much does.

I will be equally happy if updates happen and it passes the test. 

If another test happens and the wheel does better but still fails, I'll try to contextualize the extent of that failure to my own circumstances at that time.

Hope this helps.
 

Edited July 14, 2020 by winterwheel

[Alj]

16 hours ago, Chriull said:

 

Could be we see soon some metal film capacitors in parallel to the electrolytic capacitors. They can take much more peak/ripple current. This was at least a hint in an electronics forum from one who seemed experienced...

The current will depend on the energy stored (i e capacitance), and film capacitors will have much smaller value meaning they will take much less current. the particular issue here is a combination of 1. Improper capacitor location. Electrolytic caps do not like high temperatures (no more than 100C) and they should not be mounted on top of hot components, such as MOSFETs here 2. Cheap capacitor brand (low quality) 3. Need to specifically pick capacitor with low ESR for high current applications.

Also why would it be such a big current there flowing through the caps? If you just short charged cap it will not explode like this. Most likely the problem is overheating  due to suboptimal PCB design and poor heat dissipation.