Would a Sherman beep if it runs out of torque?

[supercurio]

Hi everyone!

The Sherman certainly beeps at high speeds - depending on voltage, and it's often said to be at 70% of power; by the way: what is the source on that?
It looks like it's implemented safely enough as we haven't seen many reports of cut-out at high speed on the Sherman.

However I wonder if there are any beep before the wheel runs out of torque and have the pedals dip forward at low to medium speed, during an acceleration, from a bump or going uphill.

I remember @evX_Mick mentioning "low speed cutout" experiences in his podcast with Law Laxina in November 2020.
Is that still a thing with the more recent firmwares?

On my current V10F or 16X running out of torque always triggers alarm beeps. On the Kingong, it will be matched with the "minimum safety margin" in app reaching 0% or -1%.
On both, it's very hard to run out of torque at low speeds.
However on the 16X, it's not hard at all to run out of torque above 30 kph / 19 mph and gets pedals to dip forward.

What about the Sherman today? Will it beep or will it dip without warning?
 

Cheers,

[RagingGrandpa]

I can make Sherman dip easily using the pendulum idle maneuver, and it does not beep.

But how would beeps help?

You're describing a scenario where the force required to balance the rider has reached or exceeded the EUC's capability- once that occurs, the pedals will immediately begin to collapse. If the beeper sounds at the same time, ok, but the dip has already happened.

I think 16x reinforces this point: it beeps for excessive loads like you mentioned, but many 16x riders have discovered that the beep is not a sufficient warning to react to and avoid a pedal dip or crash, at speeds above 25mph.

Beeps help during gradual acceleration, but during sudden maneuvers they simply come too late to matter .

[Chriull]

1 hour ago, RagingGrandpa said:

I think 16x reinforces this point: it beeps for excessive loads like you mentioned, but many 16x riders have discovered that the beep is not a sufficient warning to react to and avoid a pedal dip or crash, at speeds above 25mph.

Although KS have a real "% to overlean" warning beep with their "88% used up" alarm.

Just with brave acceleration it takes just some tenth of a second from the beep to the overlean.

Not really enough time to change anything, but ti get the hint that something is going to get really wrong very soon...

Maybe they should change the beep to some king of satanical laughter? 

[supercurio]

Thanks for your replies, and good questions 

8 hours ago, RagingGrandpa said:

I can make Sherman dip easily using the pendulum idle maneuver, and it does not beep.

Okay good to know it can dip easily at very low speeds.

It's consistent with the motor being wound for speed and not for torque, and reports of controllers burning in some climbing or off-road conditions.

Quote

But how would beeps help?

You're describing a scenario where the force required to balance the rider has reached or exceeded the EUC's capability- once that occurs, the pedals will immediately begin to collapse. If the beeper sounds at the same time, ok, but the dip has already happened.

I think 16x reinforces this point: it beeps for excessive loads like you mentioned, but many 16x riders have discovered that the beep is not a sufficient warning to react to and avoid a pedal dip or crash, at speeds above 25mph.

Beeps help during gradual acceleration, but during sudden maneuvers they simply come too late to matter .

Yes that's an excellent example:

On the 16X, torque alarm can too often be heard either:

• right before the pedal will or would dip
• during pedal dipping
• slightly after you started to recover from pedal dipping already

Clearly, there's a little bit of a latency, and generally the safety margin provisioned is too narrow to offer reliable safety.
That's why riding a 16X aggressively, although a fun experience is also kind of unnerving because it puts the rider at the edge of falling forward any time there's an acceleration or when riding near top speed.
Today I heard my first 16X braking torque alarm as well - it worked. I never over-leaned the 16X, although the pedal dipped plenty of times already, from just a bit to pretty far forward for half a second (scary).
All and all, clearly not ideal but effective if paying consistent attention.

 

And that's why I mentioned the V10F. This is a wheel that I never over-powered. Pedals always rock solid, only providing squish according to their settings.
Always beeping before anything would happen, giving enough time to reduce pressure. So I think it is possible to implement.

 

7 hours ago, Chriull said:

Although KS have a real "% to overlean" warning beep with their "88% used up" alarm.

Just with brave acceleration it takes just some tenth of a second from the beep to the overlean.

Not really enough time to change anything, but ti get the hint that something is going to get really wrong very soon...

Maybe they should change the beep to some king of satanical laughter? 

Yes Kingsong's 88% beep is so close to overlean that it has the benefit of... being respected, unlike some other alarms 

I'm guessing if the Veteran Sherman had a 70% to max torque alarms on accelerations, climbing and braking, it would avoid a few burned motherboard and what is described as "cut out" in various scenarios.

 

So if I understand correctly, you guys would confirm that the Sherman has no torque alarm, correct?

I wonder how to tell when you're close to overpowering it, at the limit of acceleration or braking then.
Do you think that the only option is sensing if the pedals start to fall off and stop pressing instantly?

Edited May 12, 2021 by supercurio

[DjPanJan]

@supercurio Only routine how protect myself from overlean is smartwatch and eucworld monitor current and phase curent and stop pushing when EUC go close to edge number(watch+phone start vibrate). You just need make this 80% alarm self like i do on inmotion V10F is 28A on ks16x 32A MSP 120A this numbers is not exactly is what euc report. I work 14+ days to find ideal spot on sherman and still cant find "sweet spot" actualy in my research im in point where my sherman number is too mutch conservative and alarm is trigered i think too early(personaly incrasing this slowly becasue weather is more and more warm and what euc can handle if outside is 10celsius can damage euc if is 30 celsius).

Yes i am heavy with gear i atack 120kg almost this is on maximum what manufacturer recomended  i fully respect this and belive me ,not overlean euc again is my priority i almost died when this hapend me firstime on MSP in 55km/h(pure rider fail).

Here is libre office table with eucworld data where i extremly testing sherman 25-30km/h into incline with bumps and patholes until i experience hard pedal drop(medium pedal mode) and almost crash but i testing this mean i acelerate by knee not full body lean then sherman have chance recorver self from this situation.

All numbers in table is extreme numbers and 99,9% my ride never atack this high numbers before or after. My version eucworld is beta 2.5.8 warning canot be comapred with public versions in this version is remake curent consumption in sherman compared to "old public" versions. 

What i learned sherman is realy fine to 3000w over 3000w  my motor start vibrate groan make strange noise and sufer hard. If you reach 4500W sherman start vibrating/shaking hard and sound realy bad definetly not healty sound like pernament damage coming soon. Pedal dip trigered when motor touch 7587W 90.49A curent and 205.20A phase curent becasue euc fall into deep pothole and need that many power to try keep me in level. 

Here is attached table you can play with data.

Be great if more people with sherman share they logs from eucworld when go inclines or have some dips ,we can find exacly safety spot where alarm can triger and save riders from problems/crashes/EUC motor wring damages. First we all need same "newer" version of eucworld for data to be comparable.

Simply say actualy i use CURENT ALARM 35A and CURENT PHASE disabled(still every ride i experiment with numbers)

I no want scary anyone about sherman power with 35A curent i can climb all inclines(where car are alowed) here in Beskydy Mountain or simply say everywhere where asphalt is , can climb with sherman and 120kg rider if alarm trigger i just change push to not triger alarm again.

Not all shermans is same we own version V2 in podcast EVX speak about vanila batch one. I think veteran change some parameters in frimware ETC is just non simply comparable.

Here i add first DIP ride where dip hapend second before my hearthrate jump to 158BPM:

https://euc.world/tour/597831009228180

Here is long incline 5000m long nonstop incline on asphalt to "PUSTEVNY" and continue on trail to "RADEGAST" statue.

https://euc.world/tour/597956398312174

 

EUC data vycuc overlean2.ods EUC data vycuc overlean2.xls

[RagingGrandpa]

12 hours ago, supercurio said:

I wonder how to tell when you're close to overpowering it

Experience

For paved surfaces with gentle maneuvering, speed is the main indicator of remaining motor headroom- so you learn to monitor speed. And to recognize special situations: headwind, uphill grade, potholes, etc.

For irregular surfaces with aggressive maneuvering, direct experience (falling!) is the basis for most riders.

My longest-Sherman-ownership local rider also mentioned that when you near the limits at high speed (the 'gentle maneuvering' kind of riding), the pedal stiffness control begins to feel subtly different, softer and lazy to respond to changes in foot pressure. These sensations are felt, not heard, and take experience to recognize and react to.

 

Without experience, new riders can keep it simple if they:

1. Buy an EUC powerful enough that you cannot cause it to 'dip' at 20mph on a flat paved surface without powerpads.
   I think current-production MSuper's (C30 included), Nikola's, V11 (and likely V12), and all larger wheels meet this benchmark, for riders 90kg and under.
    
2. Learn to hear the beeps, and don't ride past them

[Chriull]

4 hours ago, DjPanJan said:

Be great if more people with sherman share they logs from eucworld when go inclines or have some dips ,we can find exacly safety spot where alarm can triger and save riders from problems/crashes/EUC motor wring damages. First we all need same "newer" version of eucworld for data to be comparable.

Current is just one number involved in determining overlean risk/safety margin.

Phase/motor versus battery current are two very different measures.

The second one is the speed.

Edit: And last but not least battery voltage has an direct influence, too.

Current acceleration/burden is of interest, too.

So current alarm setups from different riders are only safety margin measures for this one rider with his personal riding style/behaviour. As this covers (hopefully) with his speed and acceleration preferences all (most) parameters.

Once the behaviour changes - either slowly over time or in because of distraction/stress/... - the alarm is "very relative" again.

Motor current alarm, as often used from GW riders is perfect as motor wire and mosfet protection.

Edited May 12, 2021 by Chriull

[Chriull]

13 hours ago, supercurio said:

So if I understand correctly, you guys would confirm that the Sherman has no torque alarm, correct?

I wonder how to tell when you're close to overpowering it, at the limit of acceleration or braking then.
Do you think that the only option is sensing if the pedals start to fall off and stop pressing instantly?

One big step to tell if one is close to overpowering is to understand the principles of overpowering. If one is fit in physics https://forum.electricunicycle.org/topic/7855-anatomy-of-an-overlean/?tab=comments#comment-107721 could be hopefully a nice start.

With this knowledge and some logs were the ?70%? alarm beeps occured one could try to examine if this alarm is torque based or not.

 

[supercurio]

Fantastic research @DjPanJan, I see that we share the same concerns on the lack of alarms types on the Sherman.
This new EUC World app version will certainly help a lot by having representative numbers for amps and power.

The limits you set on your 16X are pretty conservative compared to what I reach almost every ride (45A+ vs your 32A, 49A here for instance)
I wonder if it's because you target a sizeable safety margin or if you need to compensate for the extra inertia and reaction time as a heavier rider than me (67kg)

Super useful comments on the motor sound as well, it seems to be the best indicator of what's going on without leveraging data.

 

@RagingGrandpa indeed with experience, you start to feel a lot from the pedals behaviour, how and how much they give in. But in a way it's underwhelming that it would be needed. I rely on that on the 16X as well, since alarms can be late and prefer soft mode including also this reason: it's easier to tell.

@Chriull yes in terms of motherboard health, it's likely necessary to have a current based alarm, no doubt.

 

@DjPanJan I started to make an EUC World plugin app, with the initial goal of controlling LEDs according to wheel data.
But it's also in my plans to experiment with custom smart alarm algorithms. The whole thing will be open source.
In case what's already available in EUC World is lacking, we could certainly try different algorithms there, connect to custom beepers instead of bluetooth speakers to avoid latency.

 

Lastly, sometimes the Sherman runs out of torque because it self-destructs trying to propel a rider going uphill at slow speeds on a steep climb, as it happened to a local rider in our Stockholm group yesterday.
It's pretty silly that LeaperKim didn't implement alarms for that instead. It must cost them quite a bit in warranty claims from launch given how many reported burned motherboards.

 

Answering my own question in the first post thanks to all your replies:

No it does not beep if it runs out of torque. It either lets the rider over-lean, or burns up by dumping too much current in its MOSFETs.

App alarms look like they're an absolute requirement!

[RagingGrandpa]

1 hour ago, supercurio said:

Sherman runs out of torque because it self-destructs trying to propel a rider going uphill at slow speeds on a steep climb

Guys. Sherman is a high speed motor. Stop the offroad hillclimb torture

[supercurio]

8 hours ago, RagingGrandpa said:

Guys. Sherman is a high speed motor. Stop the offroad hillclimb torture

I think it's an excuse we've heard since the beginning that I'd like to challenge.

Sure, it's a high speed motor.
But the Sherman free spin is the same as a Begode EX.N and only a few small % higher than an MSP high speed once corrected for odometer inaccuracy.
The EX.N and MSP HS don't burn their motherboard when going uphill. MSP HS can overheat, but then protects itself.

The real reason the motherboards burn is the lack of testing and characterisation of what the controller limits are, and implementation of these observed limits into alarms and other protection mechanisms (like tilt-back).
I don't think we should give them a pass on that because the wheel can spin slightly faster than the ones made before it.

You can see in this last video that Daniel thought that it's a very powerful wheel, therefore it should be fine climbing a hill, right? While @Mike Sacristan could predict with high confidence what would happen without being able to prevent it as Daniel was going ahead carried by his enthusiasm.

 

Anybody has a good contact at LeaperKim engineering / product ownership? This is 100% software, entirely fixable.
The reduction in warranty claims and improved brand image might be enough incentives to convince them to address this flaw.

[RagingGrandpa]

22 hours ago, RagingGrandpa said:

Guys. Sherman is a high speed motor. Stop the offroad hillclimb torture

If you want to do this kind of riding, the C38 and C40 are excellent, buy one!
 

13 hours ago, supercurio said:

The real reason the motherboards burn is the lack of testing and characterisation of what the controller limits are

No... the reason they burn is overload

But I take your point: the reason they allow you to reach overload is their controls and alerts aren't set quite accurately enough to prevent you from sustaining operation at 105%.

Yes, we should expect continued improvement in this area, from our EUC developers.
In the meantime, the practical solution is "stop the abuse"

[supercurio]

2 hours ago, RagingGrandpa said:

But I take your point: the reason they allow you to reach overload is their controls and alerts aren't set quite accurately enough to prevent you from sustaining operation at 105%.

Yes, we should expect continued improvement in this area, from our EUC developers.
In the meantime, the practical solution is "stop the abuse"

You got my point 

To be a practical solution, please define abuse.

 

Not a rhetorical question: I'll have a Sherman soon.
I'll be riding by myself, and with friends: what is safe use, what is abuse?

Is that defined by a % of incline? How much does weight is an influence? Which duration? How much speed and acceleration? How much wind? What about of outdoor temperature? How much loose grip like roots, rocks or gravel adds to the mix.
Or does a Sherman has to be used only on entirely flat paved roads, and anything else is abuse?

Edited May 14, 2021 by supercurio

[RagingGrandpa]

The Sherman should be used on roads suitable for highway passenger cars.
(And pathways of similar grades and surface quality.) Dirt roads are fine.

Look at the surface, and ask yourself "Could a Ford Fiesta drive here?" 
If the answer is no, you're taking more risk.

It's your property - take as much risk as you like
But please don't act surprised if your motor cables melt through the side panel or your board releases its smoke, after you try to ride your 80lb street wheel up a ski slope.

[supercurio]

Reading your description, it seems like common sense, thanks for the description.

Then a minute later I realised that I live on a hill.
There's a sequence of 2 steep streets here, similar in gradient and distance to the one where Daniel's Sherman burned.

Cars definitely drive there, and the 16X beeps if I accelerate too much. I wonder if it means I should take another route with the Sherman?

Like @DjPanJan, I'll instrument that extensively and listen very carefully to the motor sound then..

 

I'll try to get to talk to a LeaperKim rep via my seller also. Help welcome 

[Rawnei]

Does any LeaperKim representative read these forums? All manufactures should have a PR person that has some level of reading/communication on here IMO.

[supercurio]

Another example of the Veteran Sherman not having sufficient alarms, leading to rather spectacularly burn motherboard:

In the video description @Jack King Song mentions the likely absence of MOSFET temperature sensor which could be a hardware limitation preventing a fully safe alarm implementation.

He also says that after having a motherboard burned on the Sherman he owned previously, Leaperkim flashed a custom firmware which seemed more robust.
I probably what this firmware as well!

But still, absolutely terrible results right here. How quick the wheel can self-destruct is astonishing.
Since it's such a quick and easy test to reproduce, Leaperkim has no excuse for programming the controller so inadequately.

Quoting him from description and comments:

Quote

The highly rated Veteran Sherman EUC's lack of protection really surprised me. I had this wheel, and didn't have any issues, I am now under suspicion that they flashed my wheel with a custom firmware.
Climbing a 30 degree grassy hill really pushes the performance and safety limits of these wheels, they should not burn.
The Veteran and EXN (to my understanding) both lack mosfet thermometer, even then in worst case scenario it should only burn out the fuse or mosfet not the motherboard catching on fire. The community has spoken loud and clear about the need of safety precautions on EUCs.

The wheel I had was first production batch, they have since claimed to increased the safety on Shermans  (through firmware), my own personal sherman which had later firmwares didnt have this issue. However the condition the motherboard was left in after this test was horrific:
 1) QC on firmware is not good enough leading motherboards to still blow like this after a steep hil climb, and even worse than production batch.
 2)After I blew the board on my first batch production sherman they flashed my wheel with a custom firmware to prevent such things but not to general production use. My own wheel after firmware updates would not blow and I had climbed many steep climbs on it. 

Something with their QC has gone wrong, maybe they changed the mofsets manufacturer... I'm not sure. But as a Veteran Sherman fan I will no longer defend a brand that allows their controllers to blow up like this. 

euc only monitors what the wheel was initially tracking. aka it wont tell you how much load the mosfet is if they havent put that into the desing of the wheel.

 

Edited June 2, 2021 by supercurio

[.....]

On 5/11/2021 at 1:17 PM, Chriull said:

Maybe they should change the beep to some king of satanical laughter? 

Maybe similar to the old blu tuth disconnected. But instead. yu is disconnected tu muwahaha.

 

@supercurio I havent cooked my sherman yet and I've ridden it up roads that take a 4wd to get up on gravel for the incline. I've also ran it up a 13 degree (24% grade ish? yup, still confused about that) concrete slope without issue. I notice that with ALL of my wheels, I can hear the motors groaning when I accellerate hard up the incline. Its not rocket science and you dont have to pay much attention. I HAVE heard the overpower beeps on my mten and 18L when donkey leaning up hill, purposely but gently finding the limit. I assume Veteran has the same protections, but they only work when you aren't willfully being destructive.  Every 'test' I've seen, is with abandon for signs of failure, as they WANT to see the euc fail. In the GW vs Vet vid made, would he have stopped after a successful climb? Uh no, he cooked both freaking wheels, to prove a point. I didnt see any Kingsong wheels taking that abuse. Maybe next time he'll initiate the ride until destroy test, last?  It only took my dumb ass a few moments to realize the sherman makes a barely tolerable offroad wheel. Good thing I wasnt buying it for offroad. Too bad the one I did buy for offroad, was less capable than a girl's huffy bicycle. Fwiw, I dont drive my vehicles at max rpm for miles and miles, just because I think they should be able to. Of course, none of mine get fixed on someone else's dime either.

I wouldnt fret too much about it. Unless your driveway is so damn steep your car has a hard time when its wet, you should be fine. If you do hear excessive groans or notice temps climb when riding similar grades, dont be an idiot and slow down or take a break. I understand that we all want confirmation before burning something up. But, this is the Chinese euc market here. Even if one wheel makes it, the exact same wheel on a different build day, may not. The good news is that the Sherman is going UP in value and people are chomping for it. If you get one, it groans horribly on your hill, you can sell it and break nearly even. Don't underestimate the extra power soft grass and deep gravel can make. The same grade on pavement may destroy a wheel on soft earth. Also take note  that the vet vs gotway rider wasnt your typical light weight chinese guy. Of course, if you're a typical American, maybe his stature IS close.  I would be VERY cautious to assume that ANY wheel maker will send out free replacements to us mere buyers with no affiliation, when we cook boards climbing hills that near their inflated claims. Yeah, like we REALLY expected ANY wheels to meet spec claims under typical conditions. laughable.

Edited June 3, 2021 by ShanesPlanet

[supercurio]

4 hours ago, ShanesPlanet said:

@supercurio I havent cooked my sherman yet and I've ridden it up roads that take a 4wd to get up on gravel for the incline

I notice that with ALL of my wheels, I can hear the motors groaning when I accellerate hard up the incline. Its not rocket science and you dont have to pay much attention.

Yes it sounds like the most reliable indicator for now without an app is the motor sound.
With an app I guess, it would be either a current or power alarm.

4 hours ago, ShanesPlanet said:

I HAVE heard the overpower beeps on my mten and 18L when donkey leaning up hill, purposely but gently finding the limit. I assume Veteran has the same protections, but they only work when you aren't willfully being destructive.

At this point, I am very confident that there is no such protection on Veteran. No protection at all.
Each video you can find - and there's quite a few shows that the board is giving all the current it can until it burns
The 10p battery packs don't act as safety bottleneck.

4 hours ago, ShanesPlanet said:

Every 'test' I've seen, is with abandon for signs of failure, as they WANT to see the euc fail.

Well if it's a test, the purpose is to find the limit, right.
I'm more concerned by the videos where someone is just exploring the forest like this one (apologies for the Youtuber being obnoxious)

4 hours ago, ShanesPlanet said:

I wouldnt fret too much about it. Unless your driveway is so damn steep your car has a hard time when its wet, you should be fine.

I don't have a car, but my place is next to a hill and it's just like that.

4 hours ago, ShanesPlanet said:

If you do hear excessive groans or notice temps climb when riding similar grades, dont be an idiot and slow down or take a break.

I'll definitely listen for that and look into alarms, either from EUC World or my own implementation until Leaperkim comes with a fixed motherboard or firmware.

4 hours ago, ShanesPlanet said:

I understand that we all want confirmation before burning something up. But, this is the Chinese euc market here. Even if one wheel makes it, the exact same wheel on a different build day, may not.

I remember you were not impressed with the S18, but I wouldn't say it's Chinese so it's all the same.
Although neither the 84V battery nor the motor or controller are super strong I'm very impressed by the 16X climbing capabilities for instance.

4 hours ago, ShanesPlanet said:

The good news is that the Sherman is going UP in value and people are chomping for it. If you get one, it groans horribly on your hill, you can sell it and break nearly even.

My main concern are:

• following friends in the forest and accidentally burn the Sherman board and miss the summer season by waiting for a replacement board.
• crash and get hurt because it doesn't warn before running out of torque

4 hours ago, ShanesPlanet said:

Don't underestimate the extra power soft grass and deep gravel can make. The same grade on pavement may destroy a wheel on soft earth. Also take note  that the vet vs gotway rider wasnt your typical light weight chinese guy. Of course, if you're a typical American, maybe his stature IS close.  I would be VERY cautious to assume that ANY wheel maker will send out free replacements to us mere buyers with no affiliation, when we cook boards climbing hills that near their inflated claims. Yeah, like we REALLY expected ANY wheels to meet spec claims under typical conditions. laughable.

You're right, that's part of the concern besides the wait: paying out of pocket for a product that failed instead of matching the advertised spec.

I wonder if the rumoured new beefier motherboard would have stronger components or temperature sensors on the MOSFETs with suitable programming.

[RagingGrandpa]

3 hours ago, supercurio said:

At this point, I am very confident that there is no such protection on Veteran. No protection at all.

8 hours ago, ShanesPlanet said:

overpower beeps on my mten

 

MTen beeps when you overlean not because of a current threshold, but for other reasons (pitch angle during overlean; low battery voltage during sag; 80% speed dropping very low as a function of battery voltage).

If you can overlean an EUC at low speed, it's direct evidence of a firmware duty limit (current limit).
If the firmware had "no protection at all," a low-speed overlean could draw hundreds of amps, vaporizing components instantly. (The same 'vaporized instantly' effect that happens when overtemperature leads to shorting and we get the "popcorn sound" fireworks show, as shown above.)

Sherman, and all modern EUC's, have a firmware duty limit.

Being a high-speed motor, it's pretty easy to find the Sherman duty limit using an aggressive pendulum maneuver. Its pedals dip and recover gracefully without damaging the EUC.

 

This hillclimb overloading scenario is not a "peak current" problem, but rather a sustained for many seconds current and resulting temperature problem.

We don't want our EUC manufacturers to castrate the peak current threshold to solve a sustained overloading problem. Peak current is what keeps you upright after hitting an unexpected pothole on regular streets: we need every amp we can get!
 

3 hours ago, supercurio said:

stronger components

This would help, but doesn't seem practical... they're already using the massive-package TO247 drivers, and two sets of them in parallel. That package can sustain about 90A through its legs, so 180A maximum for a pair. To reach even higher currents safely, we need physically larger conductors- either a 3rd parallel chip (like Monster Pro has), or changing to a different package altogether, which would require a very different physical layout for the controller and heatsink. Maybe some day... but it won't look anything like today's Qty12 TO247 controllers.

 

3 hours ago, supercurio said:

temperature sensors on the MOSFETs

The part that melts first is the through-hole leg conductor of the TO247 package. We can't directly measure temperature there.

But it's not such a mystery about when overload is occurring: the controller is commanding the duty cycle, after all. Continuous duty limits (software timers, etc) could be refined further. Board or heatsink temperature measurement is useful and practical, and simplifies the protection logic by avoiding the need for complex estimations. EUC manufacturers would just need to spend the development time calibrating these protection behaviors more accurately...

 

TL;DR: Veteran's hardware is reasonable; preventing this kind of overload damage could be achieved with a few extra man-weeks of firmware development.

 

Edited June 3, 2021 by RagingGrandpa

[DjPanJan]

Real reason why this sherman conbustion is heat this we know but what is realy trigger this?

I have two scenarios/variants in head how this hapend/trigger:

Variant 1 : people who burn ignore motor vibration and sufering? And just lean hard and want sherman faster acelerate into inclines? This make extreme heat spot on board and wring becasue sherman canot transfer electricity/power to kinetic moving becasue small magnets (compare to MSP example) But some videos i watch there was no big inclines just constant inclining to small hills and some board fried.

Variant  2 : In inclining not push "hard" and try ride with minimal aceleration close to none and try keep sherman go uphill constant speed wiithout ambition to acelerate and when motor vibrate or groan try lean back to minimalize "pain" to motor and generate heat in whole system? (this is how i try use sherman in inclines) Can in this case burn board too becasue small constant stress?

Is sad we no have eucworld/any data from this acidents to make this more clear what hapend if is becasue overpushing or just becasue long small stress what in some point make crytical point/fail.

Personaly i need know what triger this burn if is just long small angle incline ridie (climb to mountain on asphalt) or must be short intense incline where rider want acelerate more to big incline.

My early spring tests is obsolete now becasue eucworld version is changed (diferent number reading) and i make all incline  test in +-10 celsius temperature. When i want remake test last ride i just give up in half of hill because temperature hit 60 celsius (my eucworld alarm setings) and weather temperature was almost 30 celsius in shadow.

And i realy no want fried sherman before holiday   Now i have traumatic inclines anxiety after all this videos what i watch about burned shermans.

For claraification my riding weight(geared +backpack) is on edge sherman official alowed rider weight.