97mm Flywheel Clones + Custom gt4020 (50mm) 85kv

saul

1 W
Joined
Apr 1, 2015
Messages
64
Location
Los Angeles, CA
Finally piecing together a build, heres what I have...

Parts:
97mm Flywheel Clones
Torqueboard's Bolt on v1 motor mount
36" DropTrough Bamboo/Maple
Caliber II 50 10" trucks
16t/ 36t htd 5mm x 9mm (upgrading to 12 or 15 i think)

Electric:
85kv Emax gt4020
http://www.emaxmodel.com/brushless-motor/gt4020.html
https://endless-sphere.com/forums/viewtopic.php?f=31&t=71188
VESC v4.10 (Enertion)
2s x 6s multistar 10c 5.2ah (Swapable)
Torqueboard's Mini rc tx/rc (for now)

When I have time to make a prettier version of this
https://41.media.tumblr.com/6a3aee4aef09d6194fedbaf51e0c3d21/tumblr_o2u5kqn3as1v905p6o1_340.jpg
and test out this.
https://endless-sphere.com/forums/viewtopic.php?f=35&t=73812

Photos:
Board
tumblr_o2u4s9LW9L1v905p6o2_540.jpg


Lights
tumblr_o2u4s9LW9L1v905p6o1_540.jpg


Motor
tumblr_o2u4r1BqWM1v905p6o1_540.jpg


Single Side?
tumblr_o2u4s9LW9L1v905p6o3_540.jpg


Or Balanced?
tumblr_o2u3kwPwyh1v905p6o1_540.jpg


3d printed tpe Flexible (and Strong)
First try
tumblr_o2u56q1JPO1v905p6o3_400.png


New Version
tumblr_o2u56q1JPO1v905p6o1_540.png


tumblr_o2u56q1JPO1v905p6o2_540.png



to be continued... :pancake:
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Vanarian said:
So cool!

I can't help but feel proud see one of "my" motors on your build! Please shoot a video when you have time :wink:


I'll post a video later so you can see you motor in action, at least for a test.


torqueboards said:
Let us know how that motor works out. I'm somewhat interested.

I bet i'd have your attention if it were a dual or quad drive! 8)
but thats for later.

Seems like the trend has been higher voltage and lower kv motors, with vesc gaining support i think this will be a good test of the lower limit to kv, at least for belt drive.
 
Hi
Wow, that is a low KV motor. Not seen one go as low as 85KV.
I am by no means an advocate for high speeds and prefer torque to speed so also very interested in how this performs.
The 4020 surely is not really the motor dimensions? What are the real dimension? I do not seem to be able to find a data sheet or specs of the 85KV version.
Doing the calculations I come up with a theoretical speed of about 18mph. Real speed will be less. Like I said, no speed demon myself and if that is what you want then great.
 
Actually you can't find a datasheet as this is a bit custom version which not yet on the market, but once his (and my units) have proven to be powerful it will become available.

E-Max gives strange names to their model, actually this is a narrow 50mm motor. Total width is 30-35mm.

Speed with this much gear reduction at 6S should effectively remain under 20mph, but I personally plan on using mines with minimum 37V plus hub hence the choice of Kv. That's what I'd recommend but you never know.

Hopefully Saul will like them! :p
 
WeeChumlee said:
Hi
Wow, that is a low KV motor. Not seen one go as low as 85KV.
I am by no means an advocate for high speeds and prefer torque to speed so also very interested in how this performs.
The 4020 surely is not really the motor dimensions? What are the real dimension? I do not seem to be able to find a data sheet or specs of the 85KV version.
Doing the calculations I come up with a theoretical speed of about 18mph. Real speed will be less. Like I said, no speed demon myself and if that is what you want then great.


I think 4020 is the stator size, the actual can is 50 x 46mm (d x l),

I'm not looking for crazy speed either, there are hills that can do that already, just want something that can hopefully get up some of them.
I figure it will get about 16mph and then if i really want speed i can get a 32t hub gear to get around 22mph...

I want to go out and do a test ride already but I'm having some strange "cogging" issues... Hopefully someone can help me figure it out on the vesc fourm.
You can see the issue around 25s
https://drive.google.com/file/d/0B4_1KKUphqtDcjJuejRqa2UtVWc/view?usp=sharing



Printed the battery Box. went overboard but it will give some very good protection.

tumblr_o2z2i1rsVN1v905p6o4_500.jpg


tumblr_o2z2i1rsVN1v905p6o3_500.jpg


Did not plan on so much white, hope it can stay cleanish.
tumblr_o2z2i1rsVN1v905p6o4_500.jpg
 
my guess is the motor doesn't like the 50+volts you're running through it and you'll probably smoke it the second you put any load on it.
 
maxchilton said:
my guess is the motor doesn't like the 50+volts you're running through it and you'll probably smoke it the second you put any load on it.

What do you mean? The OP is running 6S = 22.2/25.2V. That is the factory testing of GT4020 motors from E-Max so that's not the origin of his cogging issues at 0 load.
 
maxchilton said:
my guess is the motor doesn't like the 50+volts you're running through it and you'll probably smoke it the second you put any load on it.

its only on 6s right now, and it was a setting issue because of the low kv.
even still 12s is only 50v max, and i probably will only charge to 4.1 so 49ish.

anyways its not the volts that smoke a motor, its the amps. :twisted:
 
Sorry, not quite following here.
I took it you were using the two 6S batteries to make a 12S system, I calculated the speed on that.
You say though that you are using a 6S system. From that though I calculate - using data given in first post - a theoretical speed of only 10mph.
I may not be a speed demon but that is a bit low. (IMHO)
Can't see that catching on, though if you are happy with it then that is the only important thing.
 
It is going to be 12s, just configuring the vesc on 6s because I read somewhere on here that bldc tool doesn't like high voltage.


torqueboards said:
Not including losses... so you'll actually only get about 7-8mph.
This is pretty much a normal cruising speed on a kick board, wouldn't mind this for a long flat ride, would probably last forever...
or for letting friends try it out, i feel like most will underestimate the kick on 12s...

Anyways, nearly have the settings worked out. will hopefully have some time to do the final touches and go for a test ride but lots of assignments to do first...

@torqueboards is there a trick to getting your wheel pulley centered? the last bit of wobble keeps making the belt want to slide off...
 
12s with more batteries? Have you calculated the amp draw, because you really want to keep those batteries at 3c, hitting 10c is going to shorten the range, and life of the battery.

saul said:
It is going to be 12s, just configuring the vesc on 6s because I read somewhere on here that bldc tool doesn't like high voltage.


torqueboards said:
Not including losses... so you'll actually only get about 7-8mph.
This is pretty much a normal cruising speed on a kick board, wouldn't mind this for a long flat ride, would probably last forever...
or for letting friends try it out, i feel like most will underestimate the kick on 12s...

Anyways, nearly have the settings worked out. will hopefully have some time to do the final touches and go for a test ride but lots of assignments to do first...

@torqueboards is there a trick to getting your wheel pulley centered? the last bit of wobble keeps making the belt want to slide off...
 
torqueboards said:
@Saul - If your belt is sliding off it's because your motor pulley is not aligned properly. That's usually my issue.


thanks, I was able to see the wobble and get it lined up straight enough after a few tries.. i think i'm going to try a 3d printed spacer/insert to help set it in place easier and with more surface to hold.
 
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