Jump to content

💪 EUC pull force test results - reviewers please do this!


Recommended Posts

1 hour ago, Freestyler said:

Sorry to hear that Francois. How much is that little stunt going to cost you?

Thanks, 300-350 Euros it seems. The wheel just ran out of the 1y warranty.
I hope this costly mistake will prevent others to experience the same!

1 hour ago, Freestyler said:

Glad to hear you are committed to testing your other wheels as well, I just hope it won't be damaging.

Yes. I'll be a lot more careful:

  • Only short peaks, less than half a second.
  • Never consecutive
  • Turning off the wheel for 1 min in between each measurement.
1 hour ago, Freestyler said:

I have some updates of my own. I wanted to find out if my assumption of the max phase current in firmware was correct.
I prepared a custom firmware for a forum member that reduced this value from the stock value of 150a (mcm5) down to 50a.
He did a pendulum test and he immediately overpowered the wheel.
So we have proven that this value controls the upper limit of phase amps.

That makes sense, kudos for finding and confirming this control!

1 hour ago, Freestyler said:

We then increased this value to the max value of 250a.
Initially he didn't notice a difference in the pendulum test.
On a follow up report he states that he feels that wheel is more responsive and it's like a 4th mega hard pedal mode was added.
Frankly this could be a placebo effect, so take it with a grain of salt.
We could perform a more scientific test RagingGrandpa if you want, since you have the setup. :)

Uh-ho, 250A is a scary big number, if you see what I mean.

Certainly, measuring the pull force vs max phase current will allow to draw conclusions quickly.
Does the pull force (as well as torque) increase linearly with phase current? Then, same for maximums.

Edited by supercurio
  • Like 1
Link to comment
Share on other sites

On 7/30/2022 at 1:32 PM, supercurio said:

I'm very sad to report the first casualty of this pull force test

Dang.

Of those 17 wheels I've tested thusfar, none were harmed... and I've yoinked my batch-1 Sherman on multiple occasions. 

My personal opinion is your Sherm had a manufacturing defect, which you just hadn't discovered yet (likely because of a lovely, respectful, experienced-rider riding style). You could take it as a success story: your Sherm could have failed during a sudden high-torque maneuver while riding (pothole, etc), and because of this test you avoided a crash. 

Perhaps contact your replacement board seller and ask if they agree that a new board should tolerate overlean, and then test yours immediately after installation. I firmly believe all defect-free controllers should have functional current limiting, which is not damaging when the overload is brief and occurs from a normal (not overheated) starting condition. I think all new controllers should be stress-tested for safety reasons. My favorite method is repeatedly climbing a short grade (with rest time between attempts), until the controller reaches its alarm temperature. It should get hot, beep, cool down, and work normally. If that alarm system doesn't work, it's not doing what the specification promised, and is therefore defective.
 

And you left me in hanging suspense- what was the maximum pull force you managed? :D 
 

On 7/30/2022 at 2:15 PM, Freestyler said:

mcm5
increased to the max value of 250a.
We could perform a more scientific test RagingGrandpa if you want, since you have the setup.

Only if you supply a spare MCM5 controller to sacrifice :) 
 

On 7/30/2022 at 3:39 PM, supercurio said:

Does the pull force (as well as torque) increase linearly with phase current?

Nearly, yes.

But I think Gotway (for example) sets the firmware current limit based on expectations for durability. And Gotway has a reputation for brazen (reckless?) design choices, so I doubt they're holding back. I wouldn't trust those controllers to survive when "hacked" to bypass the original current limit.

  • Like 1
Link to comment
Share on other sites

2 hours ago, RagingGrandpa said:

Only if you supply a spare MCM5 controller to sacrifice :) 

My recommendation was for 180-200a, but the guy said he doesn't care if he burns his motherboard and wanted the max value.

  • Like 2
Link to comment
Share on other sites

On 8/1/2022 at 11:14 PM, Freestyler said:

My recommendation was for 180-200a, but the guy said he doesn't care if he burns his motherboard and wanted the max value.

Yes, that's right)) And thanks to the Freestyler for agreeing to this adventure.
Even I wouldn't do 0km/h tests with such firmware (250A - MCM5), because I understand that these tests have nothing to do with the actual operating conditions of the wheels.
And I want to have a wheel under me that will pull me out of any situation or die, rather than hope that the engineers correctly calculated the phase currents and set the correct limit, after which, in a critical situation, the wheel will simply turn off)))

  • Like 1
Link to comment
Share on other sites

You raise valid points @mrelwood for certain... and that's the challenge with 'data'. What can you legitimately infer from it? Because in reality the only thing data provides is a small number of specific of observations under a given set of test conditions, it is an astonishingly narrow snapshot. And we all know what an odd cat or two can do to observations. Particularly if they're Austrian cats. Still, I do think we should continue to seek quantitative measures even if they don't translate into effects that can be measured by a user while the system is in use.

Remember street rods? Brake horsepower was (and still is—sorta) a common measure of an automobile's "power" and was used to gauge acceleration, straight line speed, (lack of fuel economy)… mostly good for bragging rights but it gave you a possible clue that this motor/transmission/rear end/wheel/tire/track combination might be faster in the quarter mile than that combination. Or not.

Introduce things like traction control, turbo, fuel injection, variable timing, custom ROMs, all wheel drive, launch mode, that huge spoiler and trombone muffler etc. etc. and brake horsepower is reduced to "necessary, but definitely insufficient" as a predictor of whether or not you should race for pinks. If I had a lot more money than I do, I'd put dual motor Tesla electrics into my '86 Trooper... give the better-than-you yuppie in the beemer a little :shock2: moment. (for about a hundred yards)

We're getting to the same spot with wheels... much to the dismay of marketing they're difficult or impossible to reduce to a simple number. My 16X has more Hz than my MTen, and it goes farther and faster and corners better at speed. Has a bigger wheel, more volts, amps, p and mosfets (actually, it might not have more mosfets, it's really an XS), and sports twice the pulling power at stall. But for some reason, the MTen from 0-5 mph feels way more capable than my 16X even though it doesn't even have a tube. In the 0-5 mph measure, my S22 is going to be a real dog.

At any rate I do agree with you 100% @mrelwood, be cautious about the conclusions you draw from this information. Still fun though!

 

(BTW, I reserve the right to remain stupidly smug because my lowly slow old ugly 16X is more beastly in this particular measure than all of the "performance" wheels tested to date. I do fully expect Master will crush everything though, including itself if it tips over on its nose)

Edited by Tawpie
  • Upvote 2
Link to comment
Share on other sites

3 hours ago, mrelwood said:

If someone would bolt down the rims of a car and measure the maximum force that the car can give out, I don't think anyone would extrapolate it into acceleration values either.

No, because cars don't have full torque at 0 wheel speed, whereas EUCs do. :) But I definitely agree that this test has questionable usefulness because it doesn't really model or test any real riding conditions. The only thing it tests is... how hard a wheel can pull a rope attached to its axle, at 0rpm.

I will still stand by my statement that the acceleration values I provided, while not accurate in terms of absolute numbers, should be roughly representative of the maximum relative acceleration between wheels. This is only an instantaneous peak, once you go above 0mph then things will change.

This test should show the maximum torque a wheel can put out. Once the motor starts turning, torque only goes down.

  • Like 1
Link to comment
Share on other sites

1 hour ago, Tawpie said:

I would slice the pie finer and say "maximum thrust the wheel and its firmware will produce at 0 RPM". 'Cuz software rules the world.

Yes, sorry, that's what I meant when I said "wheel". The whole EUC, not just the motor.

Link to comment
Share on other sites

  • 1 month later...
On 9/15/2022 at 12:17 PM, The Brahan Seer said:

My impression from what I've learned, experienced and picked up from reviews in that non suspension wheels always exhibit more torque than their equivalent suspension counterparts
Is this true?

Well, so far, yes. 
And Master 134V should be equal, once it finally proves itself...

On 5/10/2022 at 12:52 PM, RagingGrandpa said:

AM-JKLUdNk7SpKBdbUaeuRVH2AzsWZmmAiPZZ8dKE9bD3Z7mtwnsmQZ4z49j-dO0D68fK4Lm9JeiszpuZcrVUsyddjx1yujQscThgKqfFs1jPDDYvvkgCKqMb3Kr1SfgU5dJZBzZ3Hyi0AVZ_e727e3U85-wbw=w1122-h604-no?authuser=0

Link to comment
Share on other sites

3 hours ago, Bizra6ot said:

what is the limit that is reached
power of the magnets that reaches its limit then skip?

More precisely: the magnetic field is not strong enough to overcome the force of the rider.
The magnetic field has two parts of course: the permanent magnets on the rotor, and the electromagnet on the stator. Electrical current determines the field strength of this second part, so more current gives more force.

When the limit is reached, we mean the field strength has reached its maximum, because the electrical current has reached its maximum. And as we saw, the maximum current is limited by the controller's firmware, which is different in each EUC model, even if models share the same motor.
 

3 hours ago, Bizra6ot said:

why for eg on your pull test you can always reach the limit of the board

In the pull force test, the tire (and therefore motor magnets) is fixed in position by a rope tied to an anchor. And then I apply force on the stator (EUC body and motor coils) with a long lever, which makes it easy to apply a turning force higher than the motor can create. The controller senses the motion of the EUC body, and applies motor current to resist it, up until its maximum current is reached. And then the EUC body (and pedals) dip, in the presence of this very high force. 

"Skip magnets" is a strange phrase I don't use... but yes, the motor begins to rotate, when I overpower it with the long levers.

Hope this helps

 

Edited by RagingGrandpa
  • Like 3
Link to comment
Share on other sites

27 minutes ago, RagingGrandpa said:

"Skip magnets" is a strange word I don't use... but yes, the motor begins to rotate, when I overpower it with the long levers.

Imho "skipping magnets" could be used if stall current would be reached and one forces the motor from one magnet to the next- but as you described firmware cuts off before.

Out of curiosity - this firmware limiting the current is feeling still as a smooth counterforce or one can "feel it"?

By hard breaking or accelerating at lower speeds one hears the typical rattling which i'd call "skipping magnets" - but no idea how much of this is created by the firmware limiting not beeing "smooth"...

  • Like 1
Link to comment
Share on other sites

31 minutes ago, Chriull said:

By hard breaking or accelerating at lower speeds one hears the typical rattling which i'd call "skipping magnets" - but no idea how much of this is created by the firmware limiting not beeing "smooth"...

Yep that's why I asked @RagingGrandpa cause from standstill I was able to reach multiple times 210 to 230A without motor cought(or rattling, what i called skipping magnets too:lol:)/causing pedal dip, then on an attempt it only reached 195 to 199A but this time it cough/pedal dip so i was wondering why it was not related

Link to comment
Share on other sites

  • 2 weeks later...
On 10/1/2022 at 5:54 PM, Freestyler said:

check the numbers to see if we finally got battery current instead of phase current

I think you could distinguish it by testing: 
+ During max-speed freespin, battery current is nearly equal phase current.
+ During stall pulling, battery current is some 4x lower than phase current.

I think one of the parameters must be phase current (because that's what is needed for FET protection limits). So you could check other parameters against the phase current, for this relationship.

(2020 MSX example below- blue battery current is estimated by EUC World, but I think the relationship is realistic) 

AL9nZEVo04-Q1qw2cmPUqj9p5m3vVIJVFzi23OB2Y2HctOOzBmyUxxRjsigZu-ZOAH_Z8yVJvt0OFj-bkss74AlOFoqjUYazzTC4OZXzxbwbcd0Ju67nmnu_K6vFF7XZkx3ZWq1amfFa41fyU-x_lcoE8Wyptw=w781-h481-no?authuser=0

  • Like 2
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...