10S custom skate ESC: testers wanted!

[makepeace]

SDP-SI has models of their pulleys ready for download as STEP files; I just derive the geometry from there.
Been itching to make a truly parametric drive pulley model, though...

That was the first thing I tried. Took one look at the first profile I downloaded and did some measuring and it was *completely* off compared to the published data for these pulleys (tooth height and width). Maybe it was just a 1 off, but I decided I couldn't rely on those models for accuracy.

But yeah me too.. Would be awesome to have some parametric pulley and gear models for Solidworks. I'm sure you can get toolbox packages for them.

 

[Jan Christian]

When I build a board I dont want to save weight by going with a smaller motor.
I also like the benefit of high voltage.
So if people absolutely have to use belts I think this motor would be good for a dual diagonal build: http://alienpowersystem.com/shop/63mm/alien-6374-outrunner-brushless-motor-130kv-3200w/

 

[Svenska]

Low Kv is what we want. I just got a fried NTM 50-60.

How many windings should I put on? How does one even calculate that?

In the past I build my own motors but that was following a guys "how to" to be found here:

http://www.aerodesign.de/peter/2001/LRK350/index_eng.html

Most of the information is in German but maybe you guys get something out of it? It's pretty comprehensive but all aims to get the RPM for a given prop.

How to get Kv?

 

[torqueboards]

That 130kv is pretty nice. I should have some 5065 200kv motors soon. If anyone is interested.

 

[vedder]

Regarding KV, I explained it a bit here: http://vedder.se/2014/10/chosing-the-right-bldc-motor-and-battery-setup-for-an-electric-skateboard/
Don't be fooled by lower KV values. If you have a 14-pole motor with a given size, the low kv version is not likely to run cooler at all. If you rewind a motor or reconnect it to a star connection, the motor efficiency at a given speed and torque will not change at all, unless you manage to squeeze significantly more copper into it. If the ESC is the bottleneck regarding overheating it will help, but in my experience that is usually not the case. To run with lower gear ratio and lower motor speed, you need either a bigger motor or a motor with more pole pairs, which is difficult to build with 50mm diameter.

 

[Sune_P]

Great work, count me in!

 

[HumptyDumpty]

Count me in!

 

[lpbug]

Hi Austin, I haven't posted in a while because I was mostly busy with internship and now school is back in session. I really like your idea for the ESC. I was looking into something similar a while ago and it still remains of interest for me. I read that your design generates 95% of torque at startup, but what is it exactly that allows you to do this? Is there a trade off you made somewhere? Nice work, keep it up!

 

[made_in_the_alps_legacy]

Once I receive the new ESC PCBs with temperature sensors, I will log the temperature and currents while testing. I will also implement further current limiting when the heat is getting too high in order to make the ESC as bullet proof as possible.

Hi Vedder, thxs for your preliminary results - I am looking forward to know more based on measurements of power, temperature and speed

 

[vedder]

Hi Austin, I haven't posted in a while because I was mostly busy with internship and now school is back in session. I really like your idea for the ESC. I was looking into something similar a while ago and it still remains of interest for me. I read that your design generates 95% of torque at startup, but what is it exactly that allows you to do this? Is there a trade off you made somewhere? Nice work, keep it up!

It is actually my design, Austin and the Dexter found my ESC post recently and currently support my development. Regarding the startup, I wrote a post about it a while ago:
http://vedder.se/2014/08/startup-torque-on-sensorless-bldc-motors/
The trade-off would be that it requires many computations and thus a powerful microcontroller. 95% is nothing that I have measured, I just wrote it to express that it works well and consistently. I'm still working on improving the startup further by sending short pulses into the windings in the beginning to measure the inductance and coupling between them to determine where the rotor is, which hopefully makes it even more consistent.

 

[blitz.128]

Hi,
Count me in too!

 

[Jan Christian]

I see your points vedder. Teori and experience often collide. Thanks for sharing your knowledge

 

[austindavid]

Hi Austin... I read that your design generates 95% of torque at startup, but what is it exactly that allows you to do this?

It is actually my design, Austin and the Dexter found my ESC post recently and currently support my development.

Yup. We figure it'll cost $thousands to get the first prototypes out for testing and ready to produce the first real batch. This whole post is to ensure there's enough interest to justify making more than a few, and possibly set the stage to help with financing. So far we're OK, but we will almost certainly have to take advance orders for the production batch because of the high costs involved. Vedder is giving away his time and expertise, we won't ask him to also give away the financing for all the fried parts.

Speaking of... This project / product needs a name. Any ideas?

 

[drmacgyver]

Speaking of... This project / product needs a name. Any ideas?

The ESCape?

 

[beto_pty]

VESC
Vedder Edless sphere Controller

 

[onloop]

Darth Vedder Project - "The Force is strong with this one"

 

[Texonite]

This whole post is to ensure there's enough interest to justify making more than a few, and possibly set the stage to help with financing.

Count me in for at least 1 unit

 

[vedder]

Some updates:
The 10 PCBs I have ordered from hackvana should have arrived two weeks ago, but there seems to be something wrong with the shipping. I asked them about that a few days ago, and got a reply that they don't know what is wrong, but if they don't figure it out by today they are going to make new PCBs for me. I also ordered three PCBs from oshpark a few days ago just in case, so they should arrive soon.

Once I have tested the new PCBs myself and have had someone else test them, I plan to ask one or two companies for a quote on what it would cost to order 10, 20 or 50 assembled ESCs. After that, if there is enough interest, we need to figure out how to pay for that since I cannot do it by myself.

 

[beto_pty]

Hi
Ill pitch in a grand.
I can paypal it to torque or your account.
You can then subtract from that the price of my 2 units..and reinburse my paypal when you can.
What you are doing is awesome.

 

[psychotiller]

Hi
Ill pitch in a grand.
I can paypal it to torque or your account.
You can then subtract from that the price of my 2 units..and reinburse my paypal when you can.
What you are doing is awesome.

I'll do the same if I can scrape some $$$ together. I agree with Beto.

 

[torqueboards]

Thanks for the offer guys. Glad you guys are just as excited as me.

Guess we'll see where this is headed after the test and we'll see from there.

 

[bandaro]

So what about controllers for these? What are people generally using? I'm an industrial designer so can make up housings that will fit the internals of the cheapie 2.4ghz controllers from hobbyking, in a neat slide glove friendly way. Would people be interested in these?

Current ride is a modified kids scooter(simple controller/motor/batt swap), so I use a hall throttle and servo tester, but I build longboards anyway, so thinking next project when my thesis is done will be a board. I couldn't imagine riding my board around with my RC car controller in hand, I couldn't slide or anything! Even picking up the board would be a pain...

 

[torqueboards]

Most of us are using the Wiiceiver which was created by Austin David. However, I'm sure if you made your controller people would also be interested.

 

[beto_pty]

Most of us are using the Wiiceiver which was created by Austin David. However, I'm sure if you made your controller people would also be interested.

I believe the wiiceiver is about as small as i-d like to go, anything less night be more or a hamper than a help...

Reagarding glove or gesture mounted systems.. (dont know what to call them) is that if you forget (say your index finger controls the throttle) and and wave to someone you die...

what i think would be a true plus is if the VESC (using my suggested name) had an on/off button to turn it on and off without disconnecting the plugs, and had the wiiceiver directly mounted... this would simplify several of the current steps to connection, as simplifying a 3d printed enclosure.

 

[made_in_the_alps_legacy]

Agreed, we need a VESCAWii!!