Getting more power

[ARetardedPillow]

So I have been around plenty of EVs, Eskates, Unicycles, and EScooters (I don't own an EScooter). I currently own the ACM with the tesla motor and control board and the 100v MSX. And as you know the smaller the wheel the more the torque. And my question is this, is there a way we can get more torque out of our wheels? 

I find the MSX very lacking in torque in comparison to all my other EVs. My Eskate so far has the most torque of them all and can hit 40mph+ easily. My ACM has decent torque but its slow as shit. And I have seen the Dualtron scooters and they have massive torque. And in all of these EVs, the top speed is around the same(cept for the ACM). So is there a way we can push more power into the gotway motors? The open source ESC seems really good but man that project is taking a long time.

I'm looking for a way to increase the power of my wheel while having the top speed remaining the same. There's gotta be a way to push more watts into these motors. Ebikes are an example, those shits got power for days but to put it on a unicycle it's difficult due to the way unicycles are "self balancing"

[Chriull]

2 hours ago, ARetardedPillow said:

I'm looking for a way to increase the power of my wheel while having the top speed remaining the same. There's gotta be a way to push more watts into these motors. Ebikes are an example, those shits got power for days but to put it on a unicycle it's difficult due to the way unicycles are "self balancing"

Imho there are two main differences between ebikes/eskates/escooters and EUCs:

- with the first group one can use the motor limits without any prob - they have 2+ wheels, so no danger of overleaning. With an EUC once one uses maximum torque one is just "at the edge of disaster" (faceplant)

- the first group has the power electronics outside, so they are actively cooled by the  airflow of the moving vehicle. With EUCs the power electronics is inside and heatsinks all/mostly just exchanging heat with the "tire chamber".

[meepmeepmayer]

How powerful the wheels react is a firmware issue. I don't think you can do something there.

[ARetardedPillow]

12 hours ago, Chriull said:

Imho there are two main differences between ebikes/eskates/escooters and EUCs:

- with the first group one can use the motor limits without any prob - they have 2+ wheels, so no danger of overleaning. With an EUC once one uses maximum torque one is just "at the edge of disaster" (faceplant)

- the first group has the power electronics outside, so they are actively cooled by the  airflow of the moving vehicle. With EUCs the power electronics is inside and heatsinks all/mostly just exchanging heat with the "tire chamber".

Well yes, an EUC is the only EV with the danger of overleaning. This is seen in gotway wheels, but how can we increase maximum torque. For ex using an arduino to control a different control board that is capable of outputting more power. 

And most of the escooters and eskates don't have the power electronics on the outside, some of them do but most of them are on the inside, and I think we can design something that has the heatsink on the outside of the unit. 

 

7 hours ago, meepmeepmayer said:

How powerful the wheels react is a firmware issue. I don't think you can do something there.

I'm not talking about stock wheels that are on the market. I'm trying to get into DIY EUC territory, like from the ground up

[esaj]

6 minutes ago, ARetardedPillow said:

Well yes, an EUC is the only EV with the danger of overleaning. This is seen in gotway wheels, but how can we increase maximum torque. For ex using an arduino to control a different control board that is capable of outputting more power. 

AFAIK, the motor winding is a trade-off between speed and torque. For the same voltage, higher speed = less torque, or higher torque = less speed. This has to do with the amount of "turns" of the winding inside the motor, but I don't really know much about that. Other than that, using thicker gauge winding causes (or allows) more current to pass through the winding for same voltage, but you may run into size-issues (the winding won't fit inside the motor). EUC motors are different from e-bike motors, they have a lot more poles and magnets, because a more precise and faster control of the speed/torque is needed to keep the wheel upright. With two wheels like in an e-bike, much less poles (and thus bigger gauge wiring) can be used, the highest powered bikes I've seen advertised were 10kW+, no idea how high it can go these days.

An Arduino may not be fast enough for the calculations needed in FOC (and that's assuming the motor drive uses FOC for control), most of the wheels seem to be using STM32F103's or similar, up to 72MHz 32-bit MCUs. Basic Arduinos use 8-bit ATMegas, typically with 16MHz internal clock, they're pretty slow with 32-bit floating point calculations, of course something like fixed-point math can be used to circumvent some of the issues, but probably you'd need something more powerful than an Arduino.

 

6 minutes ago, ARetardedPillow said:

And most of the escooters and eskates don't have the power electronics on the outside, some of them do but most of them are on the inside, and I think we can design something that has the heatsink on the outside of the unit. 

I'm not talking about stock wheels that are on the market. I'm trying to get into DIY EUC territory, like from the ground up

There's a couple of threads in Mods, Repairs & DIY about open source boards/firmware, but to my knowledge, so far no-one here has made a working prototype:

 

There was a guy in the forums, years ago, who had made his own working prototype, but it was pretty slow and somewhat unsteady. Unfortunately I've forgotten his username and have no idea how to find the posts right now. It was controlled by an Arduino and a separate (pre-made, not very powerful and relatively expensive) motor controller that handled the intricacies of driving the motor.  I've also seen at least one motor driven "normal" unicycle -project somewhere, but the max speed was something like <20km/h, and I don't think it had a lot of torque.

I'm not meaning to put you down, but this will likely sound like that: the companies building the commercial wheels try to push the boundaries (especially Gotway) all the time, yet they haven't (so far) produced any super-powerful wheel, although the power has been going up year after year. A number of hobbyists are pushing to create their own firmware / boards. You'd probably get better results joining into the open source -side of things, rather than trying to create your own, if it really was that simple, don't you think someone would have already gotten out at least a prototype?   

As for torque, smaller diameter tire produces more torque for the same RPM, I've heard the Gotway MTen (10" wheel) has huge torque. If you're after that, maybe you should try it out.

[Chriull]

Somehow i cannot really follow you? Or you are missing some basics about the EUC "physics"?

12 hours ago, ARetardedPillow said:

Well yes, an EUC is the only EV with the danger of overleaning.

Yes - so it's about impossible to very hard to use the maximum torque or even getting near to it without many trials and faceplants...

12 hours ago, ARetardedPillow said:

This is seen in gotway wheels, but how can we increase maximum torque.

This is seen with any wheel - once the torque of a wheel is really used one hits within a few seconds the limit and overleans. Before Kingsongs tiltback speed is reached...

Here is an example of an overlean with a "weak" KS16B within ~1.5-2 seconds - and this even with a short acceleration pause inbetween.

The modern wheels got stronger, have more max speed - so with this more acceleration and higher speeds the time till overlean with "maximum" acceleration (torque) will not change too much. To get such an acceleration "usable" in real life without overleaning and faceplanting all the time something like the "time to overlean" tiltback as shown in the end of this above link would have to be implemented in firmware.

The MSX, for example should be by now one of the strongest wheels. Here is a (rough) current (torque) over speed diagram with the limits for the MSX:

The current limit of ~150A was arbitrarily choosen by me - by a gotway representative a couple of years ago a current limit of 120A was stated.

Did you ever get to the current limit while trying to use maximum torque? You have wheellog logs of your trials? If you send me the logs - i can show you with the graphs how much torque you did not use from the EUC  

In the above example of an MSX overlean just around ~80 Ampere were "used" for accelerating - here the rider could have gone way up and increase acceleration (torque) much more!

Here is another link, in regard to a wheels "zippiness" - how to "mechanicly" get the "torque" out of an EUC:

One has to "jump" on the very front end of the pedals to get the wheel accelerating hard - but not too much, so one stays within the current limit or one just "splashes" on the ground...

If one has not enough weight to reach the current limit by this, one could use a backpack with additional weight.

The torque is proportional to the current, and current is limited because the burden for the mosfets and wiring is already at it's limit - so by really trying and using the MSXs possibilities one could easily reach regions were the MOSFETS and/or the wirings/connectors get in danger of melting/frying...

12 hours ago, ARetardedPillow said:

For ex using an arduino to control a different control board that is capable of outputting more power. 

You could use more powerfull mosfets, improove the cooling, rewire the motor connections with thicker cables (unfortionately very limited by the axle hole) so the wheels survives the burden - but for getting the max torque out of a wheel you have to really push it!

More  than an arduino longer pedals could help getting torque out of the wheel, as long as the limits of the EUC are not fully utilized.

12 hours ago, ARetardedPillow said:

And most of the escooters and eskates don't have the power electronics on the outside, some of them do but most of them are on the inside, and I think we can design something that has the heatsink on the outside of the unit. 

But they have the compartment with the power electronics in free air with the airstream cooling it? At least they could easily change the design to get the heatsink into the airstream if needed. Not so easy with an EUC.

[Electroman]

Shenta Tsai who first designed the sick, hyper efficient Mobipus controllers after finding nothing on the market good enough to fit him requirements, well he also could not find a hum motor good enough apparently? But seems not like it was the wingdings he swapped by the magnets, to some holding a very high standard and high tolerances and had them fitted.

I mean in this regards I'm like a darn parrot, I repeat what the true experts in this field of chasing crazy high efficiency systems, but sure sounds great what they are doing and the motorcycles using these systems looks very powerful indeed. But I mean makes sense to me at least, electrical systems you want no waste = chasing hyper efficiency?

I mean just the videos of simple mopeds and lighter bikes swapping the controller makes a huge difference, makes me dream about what our wheels could do (firmware aside) lifting efficiency up to these levels instead, but of course like with everything else it's gonna cost too but wonder if not worth it. Power is the main thing I want more of,  better torque even from larger diameter wheels and of course maximum battery life, battery management.

That open source controller project is very interesting for sure, I wanted to build my own wheel but just too time consuming, too much to learn and expensive too. But using a MSX like test bed and start playing with controller, possibly even something inside the hub motor or even a new one? If the controller problem is solved that would open up some doors would it not?

[Andrii]

There is a guy in Russia who manufactures motherboards to control BLDC motors for bikes and EUCs. There are a few versions of his board cappable of up to 10kw max power output and up to 100v. There is a special mode to control engine by tilt of the board = EUC Mode. He provided detailed instructions how to set up and adjust the motherboard. You can find lots of videos on his chanel. https://electrotransport.ru/ussr/index.php?topic=27281.0

 

[Chriull]

On 7/1/2019 at 1:08 AM, Electroman said:

But I mean makes sense to me at least, electrical systems you want no waste = chasing hyper efficiency

Maybe electric efficiency can/could/should be optimized (a bit), but most is lost within the BLDC motor. If one looks at this (example) graph highest efficiency is under maximum torque near no-load speed.

Maximum power output is reached at half maximum (no load) speed - in this example at 1825 rpm - there the efficiency of the motor is ~50%! (1)

This motor losses are the main losses experienced at EUCs - in the normal to low speed ranges the efficiency is just horrible. And this can only be changed by using geared motors

This figures are of course for maximum possible torque at each speed - so not really relevant for EUC riders, but the notorious faceplanters... Would be interesting to see figures with lower loads!

[mrelwood]

Wheel torque might be possible to be increased slightly through electronics and especially the firmware, but @ARetardedPillow, you should go back to the beginning for a while.

What determines the amount of wattage applied to the motor?

You do. By leaning forward. If you lean too little, not much power goes in, no matter the control board.

I’m absolutely certain that you haven’t utilized the MSX’s available power nearly to the max, so electronics is not the issue. A larger diameter wheel requires a bigger lean. Nothing can change that.

What I did to help me accelerate with less effort on the MSX was to install raised sidepads (my larger pedals must help as well). If I want to accelerate fast, I lean and crouch. My knees hit the sidepads and tilt the wheel forward with more force than I could ever apply without them. And the MSX zooms forward with a lot less effort.

[ARetardedPillow]

On 6/29/2019 at 8:10 AM, Chriull said:

Somehow i cannot really follow you? Or you are missing some basics about the EUC "physics"?

Yes - so it's about impossible to very hard to use the maximum torque or even getting near to it without many trials and faceplants...

This is seen with any wheel - once the torque of a wheel is really used one hits within a few seconds the limit and overleans. Before Kingsongs tiltback speed is reached...

Here is an example of an overlean with a "weak" KS16B within ~1.5-2 seconds - and this even with a short acceleration pause inbetween.

The modern wheels got stronger, have more max speed - so with this more acceleration and higher speeds the time till overlean with "maximum" acceleration (torque) will not change too much. To get such an acceleration "usable" in real life without overleaning and faceplanting all the time something like the "time to overlean" tiltback as shown in the end of this above link would have to be implemented in firmware.

The MSX, for example should be by now one of the strongest wheels. Here is a (rough) current (torque) over speed diagram with the limits for the MSX:

The current limit of ~150A was arbitrarily choosen by me - by a gotway representative a couple of years ago a current limit of 120A was stated.

Did you ever get to the current limit while trying to use maximum torque? You have wheellog logs of your trials? If you send me the logs - i can show you with the graphs how much torque you did not use from the EUC  

In the above example of an MSX overlean just around ~80 Ampere were "used" for accelerating - here the rider could have gone way up and increase acceleration (torque) much more!

Here is another link, in regard to a wheels "zippiness" - how to "mechanicly" get the "torque" out of an EUC:

One has to "jump" on the very front end of the pedals to get the wheel accelerating hard - but not too much, so one stays within the current limit or one just "splashes" on the ground...

If one has not enough weight to reach the current limit by this, one could use a backpack with additional weight.

The torque is proportional to the current, and current is limited because the burden for the mosfets and wiring is already at it's limit - so by really trying and using the MSXs possibilities one could easily reach regions were the MOSFETS and/or the wirings/connectors get in danger of melting/frying...

You could use more powerfull mosfets, improove the cooling, rewire the motor connections with thicker cables (unfortionately very limited by the axle hole) so the wheels survives the burden - but for getting the max torque out of a wheel you have to really push it!

More  than an arduino longer pedals could help getting torque out of the wheel, as long as the limits of the EUC are not fully utilized.

But they have the compartment with the power electronics in free air with the airstream cooling it? At least they could easily change the design to get the heatsink into the airstream if needed. Not so easy with an EUC.

I'll get the wheellog data next time for you to check it out, currently whenever I try to accelerate hard and lean a lot the wheel starts beeping at me and I take it easy. 

Its currently summer here in NYC and I will add fans to the wheel to help cooling as whenever I check darknessbot my temperature is usually over 50C. And for the wiring part, I would like to increase the wire size but the axle hole is too tiny. 

I am going to try to research more and increase my knowledge of electronics and maybe change the mosfets if thats even possible 

[Mono]

On 7/2/2019 at 11:28 AM, Chriull said:

This figures are of course for maximum possible torque at each speed - so not really relevant for EUC riders

That is may be worth to emphasize. I assume that efficiency at lower speed is much better with lower output torque, but there were no conclusive data on this the last time it was discussed, IIRC.