AT-One electric inline skates (quick update Dec 2020)

[Vanarian]

NOTE : Updated October 10th 2022 - for quick infos please scroll down to "III/Current state of the build" or last page; if you have time look through my development or my thread for more detailed updates.

Hi guys, welcome to my build thread

I/ What is this thread about

(Rev. 2020)

A/Introduction

Thanks to ES awesome community who generously shares key knowledge. Special thanks to JohninCR for his teachings in motor and everyone who kindly helped me on the way !

This thread is old : in 2015 I've started working on building highly powered electric inline skates. Take everything you love in skates. Then boost it all.

It's my take on a realistic and practical application of motorized skates imagined in the manga Air Gear (yep).
Trying to make Alita's Battle angel skates into a real thing. Whatever you call it, as long as it goes strong!

We're now ending the fifth year of development of this project and five long years of overcoming unending hurdles Let's start the sixth year with positive energy.

Let's describe the features !

B/Without control, power is nothing - Under work

You should not control inline skates with a RC transmitter or a command like you do with a longboard. It is not intuitive, your reactions are delayed, you can't predict what you are doing because your legs suffer from an artificial rythm you try to control with your finger... instead of putting up the rythm like you normally do when you ride classic skates.

Thus I aim to develop a hands free control for my skates. Simply let your body do the job and focus on riding. The skates must obey this rule. That's my actual goal, to make the rider forget about the electric stuff and just enjoy the adrenaline.

C/So, let's talk numbers, what power do we talk about? (Gosh a LOT have changed)

My previous rig packed 2x custom E-Max GT4020 50mm.

I recently upgraded to 2x beefier huge motors, heavier but much more torque and power and steel structure all together. It was a way to also simplify the parts so totally worth it.

D/Going fast is cool. Being able to commute for the day and ride back home is cooler.

Let's talk batteries !

Older battery pack was composed of LG HB2 18650 cells. Moved away from it in favor of Molicel 21700 cells. More power and ampacity in a decently compact form factor is ok !

Keyword is to have interchangeable packs to allow more range, no matter the cell. More to come in the future about that.

E/Custom it like you stole it. Heck this sentence sounded right back in the days

Previous design was fully universal compatible. 165, 180, 195, UFS, Trinity, you name it. These came with some compromises in terms of geometry thus limiting performance (and making production more complex).

So I scraped the Fully universal layout in favor of fully focused design for each of the following categories : raised heel 165-195mm, UFS and Trinity.

Benefits are : Better, lighter, stronger, lower frames. Cons : it's obviously more expensive to own multiple models.

I still own in strong condition the following skates (very reliable despite being used a lot) :

- Custom Roces M12 (refreshed, low cuff cut, Flying Eagle liner for a perfect fit, it's the Pro Touring of skates haha)
- Flying Eagle F110 (my speed weapons of predilection)

As said before, The frame is designed to accomodate the powertrain, not the other way around.

As for wheels sizes, I'm a streeter, I like short wheelbase. And I still want my ultra low center of gravity. So I ended up focusing on 3x 110mm wheels and a sexy slalom style base for that nimble high speed agility.

These offer a gorgeous geometry under the feet and ultra low center of gravity.

F/Last for the least, what does it weight : In progress

That's again under work !

I've done my homework in this area and fighting weight is terrible when motors and heavy torque are involved. Despite this and the extra big motor, let's say that it remains, in fact, lighter than most EVs I know. Let's remain <3kg target anyway, accurate number will come later.

Also I noticed that weight repartition was playing a HUGE aspect in the effective feeling of the weight. Which is why many stuff had to evolve again.

We're back to full aluminum metal parts, carbon fiber wasn't suitable for the project.

End goal, the difference in sensation between a classic skate and these must mainly be about the motor power, not the extra weight.


That's all for now, thank you for reading till there

----------------------------------------------------------

II/ Current state of build

-New motors used, bigger stator, wider and stronger structure
-Whole design benefitted from a total overhaul. Stronger, Lower, Tighter, Lighter.
-Swappable battery packs are ok !
-ESC loaded
-ESC box needs another udpate
-I now have teamates to help along the project which is HUGE step forward.

 

[Vanarian]

This post will serve as gallery.
~~~~~~~~~~~~

 

[sk8norcal]

you might get some ideas here,

http://wackyboards.blogspot.com/search/label/~~wacky-rollerskate-motorized

 

[Vanarian]

Now that is cool, thank you for the link! :wink:

EDIT : I'm impressed by what the guy made in his razerblades, making small direct drive hubs like this is a feature in itself. Bundyboots are also impressive. Somewhat more "backyard" built.

Still the same problem anywhere though, nobody is actually riding these, just sitting on it. I want more

 

[Ryuudan]

Nice to see I'm not alone.

I'm working doing the exact same thing for a couple years now.

My project though is a little more humble. I'm using low power motors aiming for range and lightweight instead of speed and power.

heres the preview:
hope it motivates you on your project.
https://www.youtube.com/watch?v=xfJOw7kw8-c

 

[Vanarian]

Nice to see I'm not alone.

I'm working doing the exact same thing for a couple years now.

My project though is a little more humble. I'm using low power motors aiming for range and lightweight instead of speed and power.

heres the preview:
hope it motivates you on your project.
https://www.youtube.com/watch?v=xfJOw7kw8-c

Wow, this is very cool! Thank you for the video, it is really inspiring! Using open skates is also a good idea, I was thinking of getting a pair of XSjado or Doop skates to make a more "civilised" version.. You prove that it is a good idea :wink:

Finally a video showing some real use of electric inlines, I swear that after a night of work this was a breeze of fresh air for me. Thank you very much!

EDIT : By the way I see that this is your first post here so... WELCOME ABOARD

 

[CSN]

Check out landrollers

http://landroller.com/

The bigger wheels are much more suited for speed and road imperfections.

Fewer faceplants maybe.

Maybe easier to add a motor also.


Only downer is that a lot of the popular sizes are sold out. Can find some on ebay. Rumor is a new improved 2015 model is coming out.

 

[Ryuudan]

yeah. no problem. hope your build hasnt stalled.

I finally registered here in ES, but I have been reading this forum for a while. Truth is since I started building the ThundrBlade I've looked everywhere in the internet for information. I even checked patents for info.

About the LandRoller suggestion, I had Land Rollers before. they feel different from normal inline skates, they are good, practical and a lot of fun, but not the same maneuverability. I dont think you could make hub motors work diagonally like that. maybe it can work. I dont know.
You could use the motors elsewhere and transmit the power trough gears, but that would add a lot of noise.

well, I expect to build a new prototype with double the power in 1 month or so, I will make new clips as I have progress.

ps: I love the powerslide open boot design, mine are not doops, but they are from the Nordic Skating but they are very similar to doops.
ps2: I gave up on using UFS and went for a normal 165mm mount, I think for a product its a better choice.

 

[Vanarian]

Check out landrollers

http://landroller.com/

The bigger wheels are much more suited for speed and road imperfections.

Fewer faceplants maybe.

Maybe easier to add a motor also.


Only downer is that a lot of the popular sizes are sold out. Can find some on ebay. Rumor is a new improved 2015 model is coming out.

yeah. no problem. hope your build hasnt stalled.

I finally registered here in ES, but I have been reading this forum for a while. Truth is since I started building the ThundrBlade I've looked everywhere in the internet for information. I even checked patents for info.

About the LandRoller suggestion, I had Land Rollers before. they feel different from normal inline skates, they are good, practical and a lot of fun, but not the same maneuverability. I dont think you could make hub motors work diagonally like that. maybe it can work. I dont know.
You could use the motors elsewhere and transmit the power trough gears, but that would add a lot of noise.

well, I expect to build a new prototype with double the power in 1 month or so, I will make new clips as I have progress.

ps: I love the powerslide open boot design, mine are not doops, but they are from the Nordic Skating but they are very similar to doops.
ps2: I gave up on using UFS and went for a normal 165mm mount, I think for a product its a better choice.

Don't worry my build hasn't stalled, I'm taking time because I can't fund everything at once (and it was a good thing because if I did this, I wouldn't have been able to get VESCs or I'd have wasted money on unused controllers :wink: )

Thank you for the feedback about open boots and Landrollers, I have never riden these before. Actually haven't met anybody with Landrollers too, might consider it later. It is possible to motor them but I don't know how it will perform since there will be weight distribution around the boot and not only at the wheels. It could kill the benefits from the LandRollers conception.

I'll definitely give a shot to Doop skates, but I try my best to keep UFS for easy maintenance.

Please post your build thread once you start your new project!

 

[Vanarian]

Yo~ got a bit of free time today and seeing that I still wait for most of my parts has bored me so I figured I could take a quick shot of my boots and wheels sets, if you wonder what kind of sizes it represents in real life. Please forgive my bad accent :lol:

[youtube]jpdPOyIAliE[/youtube]

EDIT : I'm stupid I didn't put the video in public. Sorry for that.

 

[Vanarian]

Guess who got his mad monsters shipped? These are 4Kw capable 195Kv motors perfectly fit for mid-drive dragster.

EDIT 5 : VESCs coming back from Marcin ! 85Kv motors currently under production, I can't wait to get these in hands These ones will be perfect for hub roadster!

Frames engineering still in due time!

I need to post pictures !

 

[chinyp]

Vanarian, I'm here Ryuudan, I can see that your working on a friction drive eh :wink: haha~.....Van, could you tell me that the 5020 would run on how many specific volts and amps?? And, how did you run it?? I'm still new to these stuffs....

 

[chinyp]

I mean.....Max volts and amps....and it's cool to get a 3d printer!

 

[Vanarian]

Vanarian, I'm here Ryuudan, I can see that your working on a friction drive eh :wink: haha~.....Van, could you tell me that the 5020 would run on how many specific volts and amps?? And, how did you run it?? I'm still new to these stuffs....

For sure! About voltage and amperage, what you must keep in mind is that you should not go above power ratings made by the factory because you will produce too much heat, lose power and strongly risk killing motors. It can be different story with huge motors but with our tiny sized outrunners it is important.

Voltage produces eddy currents (iron losses) and Amperage produces square currents (copper losses), the more you lose the more you waste power into heat. Copper losses rise easily higher than iron losses. In short the higher your voltage the lower your amperage thus the better you will be with your motors.

The 85KV motors I ordered with the group buy are rated for 6S so minimum recommended is 6S (because under this level you will need too many Amps thus produce way too much heat). Personnally I intend to run it between 10S and 14S depending on both power level and battery chemistry (see in cells form there are many options available like Li2Hpo4, LiFepo4, Li-Ion, Li-MP...). I don't intend to go above 1600W but I need to test them once arrived to see how much power these can release. Best for me is to try and get the less amps possible because it will drastically lower heat inside the motors.

My bottleneck is the continuous ratings given for amperage and voltage discharge of the VESC. So I sized BMS accordingly and batteries too.

BTW the VESC is an electronic controller made by Vedder, it actually manages all the motor's timings and needs and it is pretty awesome and compact, perfect for the job. You should check the relevant thread it is titled "10S custom ESC : testers needed!"
And the BMS is a battery management system, it does all the foolproof job for you when you charge and discharge your batteries. With this it is kinda as easy as plugging a smartphone when you want to charge your e-ride.

Thank you for the 3d printer I've waited a long time to get my hands over one, I can't wait to make it work! I need to order filaments first (and the seller must send me accessories).

 

[torqueboards]

So, about the Low KV issue.. not sure if you plan on running a pulley setup with it as well and/or by itself..

I do notice though that the lowest KV isn't always the best. I was testing some lower KV motors with high gearing for more torque and notice it actually struggles to go up a hill especially if you happen to stop in the middle of the hill.

The reason for this is because of the gearing + low KV, it not able to turn the wheels fast enough to get any traction or momentum. So the a bit higher KV would of fixed the issue and I can fly up the hill with less stress on the motors.

So in reality, we should be running mid KV range and change the gearing to adjust IMO.

Not sure if your running a pulley setup but just FYI.

I'm sure, your more technically inclined then myself but just what I've noticed.

 

[Vanarian]

Thank you for the feedback it is precious to me !

That's a strange issue, not sure to understand ; when you say momentum / traction do you mean that it was too slow to keep up with the pace taken before starting the climb (or that it couldn't allow a fast enough pace) and that in case of stop in the middle of the hill it could not slip the wheels a bit in order to take some speed and get started again?

I want to run the 85KV by itself (because it is compact enough to fit like a hub) but I thought also of planning low KV in bigger outrunners which should be belt/pulley-driven, so for mid-drive you do recommend a mid KV not too low? I was thinking of something around 130Kv, is it already too low or with proper gearing do you think that it is ok?

 

[torqueboards]

I think if you run the 85KV by itself w/ no gearing. It should be fine but if you run it with gearing and a high torque gearing 1:3 or so then it will have issues going uphill. You can probably use 1:2 and or closer to 1:1 but I still think higher KV is better because you run into the issue w/ the added drag and spinning resistance of a lower KV motor.

I think it's similar to Ben's calculation of 8000RPM. Lower KV motors actually cause more drag due to being lower KV but offer more torque. They spin less freely (so it seems).

So I think just going uphill (15%+ incline) with the added load of 180-200 lbs person too low of KV doesn't spin the motors fast enough to climb the hill faster and/or go up the hill normally. It's just too slow especially with the load and lower KV to gain any momentum. So you can pause in the middle of the hill and/or slow down but to re-accelerate and move forward it bogs down.

I'm sure, on flat ground you'll have more torque but for hills I don't think it works out but works against you.

Ex. 240lbs single motor 10S. 192KV motor struggles to bring him up a 15% incline versus a 260KV motor flies him up the hill with the exact same setup. Sure, gearing ratios differ but it makes sense. *Might be a 149KV/162KV motor or lower than 192KV. IMO 192KV should still be fairly fine. Can't remember exactly.

I honestly think 230KV is the sweet spot IMO. You can go up and down from 6S to 12S and 1:2 to 1:3 variations with ease. The setup should run perfectly fine going uphill/downhill you can adjust from gearing ratios.

 

[LEVer]

...

I want to run the 85KV by itself (because it is compact enough to fit like a hub) but I thought also of planning low KV in bigger outrunners which should be belt/pulley-driven, so for mid-drive you do recommend a mid KV not too low? I was thinking of something around 130Kv, is it already too low or with proper gearing do you think that it is ok?

Just go hub all the way my friend, especially now that you have connections with the motor manufacturers. It's the way of the future. Don't worry about the low kv, just slap higher voltage on them and they will tackle anything. The formula of low kv motor + higher voltage has been proven on E-bikes, and gives you the whole range of performance from low speed to high speed. Higher voltage also give you more range, just look at Boosted's range of 6 miles on 2500mah batteries and dual motors. They get that from the 40 volts.

The thing with high kv motors is that they like to spin fast or else they will heat up when you try to run them at low speed with load. So then people gear them down with like a 4:1 reduction so that they don't go flying off to the sunset. Well, that's good for acceleration, but what about coasting and braking? With that tall gearing, when you let go of the throttle the bigger pulley wheel pulley will spin 1 revolution while the motor's pulley will spin 4. Those magnets will really bite and slow you down, that's why you have that forward-lurch when you let go of the acceleration. And when you're going downhill and brake all of a sudden, the big wheel pulley carrying your momentum will still try to spin the motor's pulley even though it wants to stop. If the motor pulley doesn't give in, your belts may and they will skip and hop over the teeth. Hub motors don't have these things.

 

[Vanarian]

Actually this is a brilliant idea I'll focus on hubs for now

Didn't think of it sooner but that's Right if the slim 50mm 85Kv perform well since I got already in touch with the manufacturer I can always negotiate whole new motors like 60-70mm with slim profile between 20-30mm of width for bigger power !

 

[chinyp]

My motor!!!! I'm super sad that I couldn't get my hands on those motors T_T..... I plan to get my hands on these motors first before I could do anything else~ Van, if you really did wreck that motor....could you mail it to me?? Haha
I wan to use those dimensions to make my geared hub.... :lol:
Btw, where and which manufacturer you sourced it from? How much was the surcharge you mentioned?? I wanna just order it and pay for the surcharge....desperate and impatience here.... :|

 

[maxchilton]

Just go hub all the way my friend, especially now that you have connections with the motor manufacturers. It's the way of the future. Don't worry about the low kv, just slap higher voltage on them and they will tackle anything. The formula of low kv motor + higher voltage has been proven on E-bikes, and gives you the whole range of performance from low speed to high speed. Higher voltage also give you more range, just look at Boosted's range of 6 miles on 2500mah batteries and dual motors. They get that from the 40 volts.

Higher voltage does not give you more range. It's slightly more efficient then a low voltage setup but that's offset by the cost of high voltage esc and high voltage chargers. Boosted's 6 miles on 2500mah at 40v equals 16.7 w/h per mile which is about the same as other e-boarder with their DIY builds. The e-bike guys who use rc outrunners get similar watts per mile as well.

 

[torqueboards]

I'm pretty sure he meant because of the higher voltage it increases the watt hours which ultimately increases the range/distance.

 

[LEVer]

....

Higher voltage does not give you more range. It's slightly more efficient then a low voltage setup but that's offset by the cost of high voltage esc and high voltage chargers. Boosted's 6 miles on 2500mah at 40v equals 16.7 w/h per mile which is about the same as other e-boarder with their DIY builds. The e-bike guys who use rc outrunners get similar watts per mile as well.

You just said it yourself. There have been posts by riders that used two 6s5Ah and they had slightly more range when they connected it in 12s5Ah (series) than 6s10Ah (parallel). I sort of believe them when I tried it myself, although I wasn't able to record it. When I ran 12s with my Flier ESC, the acceleration was phenomenal and you get to your desired speed right away and happily cruise at it at half-throttle. When I was using 6s, it would take a really long time to get to my desired speed and I would usually be max on the throttle. So my theory is, because it takes time to get to your desired speed and since you are usually always at WOT with 6s, it burns more amps. Don't listen to me, I'm just extrapolating. lol.

I agree with you on the higher cost.

 

[henryv]

Can't wait to see this.

I'm an old school rollerblader and I've been messing around lately with newer frames and big wheels. I'm not sure how I would do it without it getting unwieldy, and I can't wait to see your implementation.

P.S. I've been rocking the Razors genesis skates which are basically the exact same as the M12s. I want to get a set of Xjsados soon too though for powerblading / Big wheel setup.

Where do you plan to mount the cells?

P.S.S. What are those clear UFS frames? Did you make them? Most of the frames That I've seen that are that large are made out of metal, I'd love to try them out.

 

[Vanarian]

I plan to get my hands on these motors first before I could do anything else~ Van, if you really did wreck that motor....could you mail it to me?? Haha
I wan to use those dimensions to make my geared hub.... :lol:
Btw, where and which manufacturer you sourced it from? How much was the surcharge you mentioned?? I wanna just order it and pay for the surcharge....desperate and impatience here.... :|

Sorry there is a misunderstanding, I haven't wrecked any motor! Currently the situation is :
-I have 2 EMax BL5345 which are powerful but too big ;
-I wait (together with the group buy) for the factory (the one who builds EMax motors) to finish 5 customs 85kv motors.

They agreed to get on the adventure because I plan massive orders later from them, otherwise they don't take sample requests I'm afraid :| but don't worry there will be more available later!

Can't wait to see this.

I'm an old school rollerblader and I've been messing around lately with newer frames and big wheels. I'm not sure how I would do it without it getting unwieldy, and I can't wait to see your implementation.

P.S. I've been rocking the Razors genesis skates which are basically the exact same as the M12s. I want to get a set of Xjsados soon too though for powerblading / Big wheel setup.

Where do you plan to mount the cells?

P.S.S. What are those clear UFS frames? Did you make them? Most of the frames That I've seen that are that large are made out of metal, I'd love to try them out.

Thank you! The frame is a Kizer advance and the cells will be mounted right in the baseplate