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John Eucist

IPS ZERO

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but you can correct the power factor (which changes with speed) so that battery power isn't wasted

What makes you think that battery power is wasted? AFAIK the most energy efficient point of the motor (under nominal load) is pretty close to max speed. I wouldn't be surprised at all if all available speeds of an EUC are below this point where the motor reaches optimal efficiency.

Edited by Mono

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20 hours ago, Chris Westland said:

Sorry for the false attribution @John Eucist.  I recalled reading it someplace in the posts, but can't remember where. It was just a conjecture, but I would like to know if IPS is designing their own motors.

I remember that as well ...

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7 hours ago, Mono said:

What makes you think that battery power is wasted? AFAIK the most energy efficient point of the motor (under nominal load) is pretty close to max speed. I wouldn't be surprised at all if _all_ available speeds of an EUC are below this point where the motor reaches optimal efficiency.

My understanding is that with high current (low power factors) the system losses are greater...

 

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2 hours ago, Pagsy said:

I remember that as well ...

You recall that I said it or that someone said it?  Trying to self-diagnose amnesia here. :pooping:

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12 hours ago, Chris Westland said:

My understanding is that with high current (low power factors) the system losses are greater...

While I don't understand what you mean by "low power factors", I agree that high current is associated to low efficiency (in several ways). And then, the more back-EMF, the lower are the possible currents, because the possible voltage difference, which is the only driving force for current, becomes small.

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12 hours ago, John Eucist said:

You recall that I said it or that someone said it?  Trying to self-diagnose amnesia here. :pooping:

It's "old-timers" disease ...:cheers:

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16 hours ago, Chris Westland said:

My understanding is that with high current (low power factors) the system losses are greater...

 

Maybe you could explain where the power factor effects a battery-driven DC-System? As there is no AC supply on board an EUC, there is no power factor.

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5 minutes ago, Slaughthammer said:

Maybe you could explain where the power factor effects a battery-driven DC-System? As there is no AC supply on board an EUC, there is no power factor.

Everything these days uses brushless motors, not brushed, so these are not strictly DC systems.  They are synchronous motors that are powered by an integrated inverter/switching power supply that produces an AC electric signal to drive the motor.  A brushed motor would have significantly lower torque to weight ratio, less torque per watt, not to mention less reliability and a lot of sparking and EMI.

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And now we have an AC-emitting motor controler, directly wired to the coils of said motor. What magnitude of power factor would occure and what would the effect be?

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5 hours ago, Slaughthammer said:

And now we have an AC-emitting motor controler, directly wired to the coils of said motor. What magnitude of power factor would occure and what would the effect be?

I have no idea.  I assume this is something that the engineers at TI, etc. have to worry about in their chip design, and I'm guessing it is a significant issue in design of controllers for brushless motors.  

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38 minutes ago, Chris Westland said:

I have no idea.  I assume this is something that the engineers at TI, etc. have to worry about in their chip design, and I'm guessing it is a significant issue in design of controllers for brushless motors.  

if it's not a problem with brushed motors, how can it be so difficult to imitate the control law that brushes impose?

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1 hour ago, Mono said:

if it's not a problem with brushed motors, how can it be so difficult to imitate the control law that brushes impose?

I think, in fact, it is a problem created by the commutator, but compared to sparking, EMI, friction, etc. it is not the most significant problem in brushed motor performance.  You could never get the power of a brushless motor from a commutator motor.

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On 12/6/2016 at 7:55 PM, Pagsy said:

I remember that as well ...

 

On 12/6/2016 at 10:13 PM, John Eucist said:

You recall that I said it or that someone said it?  Trying to self-diagnose amnesia here. :pooping:

Sorry I don't remember :) just kidding

I recall someone said it

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On 12/5/2016 at 9:03 PM, John Eucist said:

ne other thing that comes to mind is an earlier post by @John Eucist that conjectured that IPS may have custom built the Zero motor with fewer poles to save weight.  It may be that the overall performance of the new design is still not well understood, or maybe it has inherent weaknesses.  I'd be interested to know more. 

Um... not me.  Unless I have amnesia.  :unsure:

I found out where this quote came from ... @Jason McNeil made this comment (elsewhere in this forum) from his tests of the IPS (apparently he has purchased a number for sale, but they are still caught in customs).  He knows a lot about EUC design, so I feel his guess is pretty credible ...

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4 hours ago, Chris Westland said:

I found out where this quote came from ... @Jason McNeil made this comment (elsewhere in this forum) from his tests of the IPS (apparently he has purchased a number for sale, but they are still caught in customs).  He knows a lot about EUC design, so I feel his guess is pretty credible ...

Thanks. So it wasn't amnesia. :) 

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1 hour ago, John Eucist said:

Thanks. So it wasn't amnesia. :) 

On my part it was, but (rest assured now<_<) it wasn't your forgetfulness.  Since I own an IPS Zero, and like it a lot (it is very light) I've been trying to gather whatever information I can on it (this forum is a big help).  I just purchased an Inmotion V8 from Jason, which should arrive this Wednesday, so was looking through his posts.

Edited by Chris Westland

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On 12/7/2016 at 7:17 PM, Mono said:

if it's not a problem with brushed motors, how can it be so difficult to imitate the control law that brushes impose?

@Mono & @Slaughthammer here is a very nice article on Power Factors in small, low voltage power supplies that you might find informative

Rectifier1__Irect_and_VDC.jpg

Edited by Chris Westland
add pic

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@Chris Westland yeah, but that only applies for power supply units that have a AC feed and output DC, and that is very well known. But a total different situation than in an EUC, where we have a DC supply which is then converted into a controlled AC signal to drive the Motor. I don't think we have to worry about this matter.

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18 minutes ago, Slaughthammer said:

@Chris Westland yeah, but that only applies for power supply units that have a AC feed and output DC, and that is very well known. But a total different situation than in an EUC, where we have a DC supply which is then converted into a controlled AC signal to drive the Motor. I don't think we have to worry about this matter.

Hmmm ... I thought the article laid out the issues and how they arise very well, and you could see how they could carry over to a DC induction motor situation ...

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I hate to say it, but I'm adding my name to the list of people experiencing the IPS Zero Faceplant.  I have a the 340wh version.  Have put 85 great hassle free km onto it.  Temperature was 45 degrees F.  I was on the same route I take every day.  Smooth clean asphalt, I had just turned a corner and was accelerating on a slight incline, then plop.  I'm glad I was wearing gloves which absorbed most of the impact.   On recovery Zero was on its side with the wheel spinning and alarm on.   I am very thankful I wasn't going faster.  I checked, battery was at 49%.  I straightened out the plastic and drove slowly later that day for another 1.5 miles on my return home.  Zero worked perfect and battery down to 43%.  What scares me the most is how can a machine have such a catastrophic failure  to dump the rider off, then work perfectly after?  As much as I loved the Zero, it is being returned immediately.  From what i'm reading, an S1 or V5F might be the replacement.  any suggestions?  Once learning how great EUC riding is, I could not imagine stopping.

IMG_1156.JPG

IMG_1160.JPG

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2 hours ago, BarrieR said:

accelerating on a slight incline, then plop.  I'm glad I was wearing gloves which absorbed most of the impact.

Sounds like it gave out momentarily trying to accelerate too quickly going uphill.  How much do you weigh?  You might consider something with a lot more battery, I think the V5F (not the V5F+), and the S1 have about the same size battery you have in the Zero, under the same circumstances (accelerating up hill at 50% battery), I wonder if they would also cut out.

Those gloves saved you some skin.

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2 hours ago, BarrieR said:

What scares me the most is how can a machine have such a catastrophic failure  to dump the rider off, then work perfectly after?

As one can outlean any wheel, the question is in what way this was a failure. One possibility is that the wheel failed to communicate in advance that it was reaching its limits. Though maybe it happened too fast. If it was not due to unavoidable physical limitations (which is hard to say), it is most likely a software design problem, you might call it a bug.

Edited by Mono

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5 hours ago, BarrieR said:

I hate to say it, but I'm adding my name to the list of people experiencing the IPS Zero Faceplant.  I have a the 340wh version.  Have put 85 great hassle free km onto it.  Temperature was 45 degrees F.  I was on the same route I take every day.  Smooth clean asphalt, I had just turned a corner and was accelerating on a slight incline, then plop.  I'm glad I was wearing gloves which absorbed most of the impact.   On recovery Zero was on its side with the wheel spinning and alarm on.   I am very thankful I wasn't going faster.  I checked, battery was at 49%.  I straightened out the plastic and drove slowly later that day for another 1.5 miles on my return home.  Zero worked perfect and battery down to 43%.  What scares me the most is how can a machine have such a catastrophic failure  to dump the rider off, then work perfectly after?  As much as I loved the Zero, it is being returned immediately.  From what i'm reading, an S1 or V5F might be the replacement.  any suggestions?  Once learning how great EUC riding is, I could not imagine stopping.

 

Can you give us a bit more information.   Was the Zero unlocked to 30km/h (this should be possible at 50km)?  How steep was the incline, and how fast were you going when you hit this incline?  How much do you weigh and how tall (w.r.t. angular momentum force vector that needs correcting)?

The reason I ask is that I have my own theory about the Zero's limitations.  Basically the Zero is IPS' version of the S2 or V5F... both of these are limited to around 16-18km/h max; all 3 seem to have around 400-500W sustained power.  IPS controllers are basically the same, I believe, across their models, and all the other models have good reputations.  I am guessing that if you imposed a 16km/h speed limit on the Zero, that you would never hear of any problems; but at 30km/h it is underpowered.  Just my $0.02.

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6 hours ago, BarrieR said:

I had just turned a corner and was accelerating on a slight incline, then plop.  

Do you have an inclinometer app on your phone?  Just curious what the steepness is.  I'm thinking that at 49%, the sudden demand for power caused the voltage to sag so much that the BMS shut off power momentarily.  And I just remembered that the V5F, while having a similar battery size as the Zero, runs on 84 volts, considerably more than most other wheels.  I wonder if the higher voltage helps protect against BMS cutoff?

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Hello @BarrieR and welcome.

Ah yes! The, "don't have enough battery reserve to accelerate up an incline-face plant".  Know it well.  Good times! Good times!

ive got 340wh too and what I have learned, the face plant way, is that once you're under about 60% with a smallish battery like this, you need to consciously manage your demands on the battery.  Thusly:

* moderate to steep incline: approach with low speed, continue with low speed, make no sudden demands through accelerating or braking ( as not all braking is regenerative)

* slight incline:  approach at lowish  speed.  Do not accelerate. Do not approach fast, then reduce speed once on slope, hoping the reduced demand will save your ass, it won't (don't ask me how I know?)

* any Decline except very steep: any speed you feel safe at, that you think might regenerate power back to the batteries ( trial and error needed here, watch battery level on gauge or app) avoid sudden speed Changes. Be prepared to dismount quickly if you hear any beeps.

* steep decline: VERY SLOW just because it's safer that way. Be prepared to dismount ( keep hands free)

*sudden hard acceleration.  DON'T DO IT

* sudden hard deceleration: DON'T DO IT

* standing still on a steep hill: not for long, high demand will drain battery further

* continuing up a moderate to steep hill that you are currently stationary on: start out very slowly, or, if safe to do so, proceed across the hill, or even slightly down, and turn gently into it once under way.

* bumps, tree roots, kerbs, driveway ramps, pot holes: slowly does it, keep power demand peeks low

* high speed, DON'T DO IT.  Reduce your top speed, because any sudden demands will need the battery reserve you freed up by slowing down.

* showing off to anyone: don't do it, almost always results in a face plant.

* any combination of the above: keep power demand peeks low.

also, avoid puddles (you don't know how deep they are, and why test the waterproofing of your wheel when you don't have to), also, the bottom may be soft mud, or contain rocks, glass, etc.

also, avoid loose gravel, and collections of leaves.

basically avoid anything that may cause you to slip or that may have a surprise waiting for you underneath ( including taking a woman home, who turns out to be a man... SURPRISE!!!?)

I call it actively managing the risks.  I try the other way now and then, and it sometimes hurts.

did I mention: don't ride on top of anything that a fall from, would result in serious injuries or death; think, cliffs, tops of walls, power station chimneys, etc.

and get some bloody protection! Gloves, Good . Wrist guards, better.

dont send your wheel back, it's not faulty, and now it's "used"  just learn to ride within its limitations.

This is not a mature technology like cars, or aircraft, this is the bleeding edge of technology, we are all the Wright brothers, and everywhere is Kittyhawk North Carolina  December 1903.

welcome to the future.

 

and remember: my advice is worth what you paid for it. ?

Oh yeah, please fill in your location info on your profile, you may have a neighbor or two on here.

edit: ah yes the United States.  You definitely have some EUC neighbors right around the corner from you. ?

 

Edited by Smoother

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