My first e-board

[gratoo]

Hi guys,

So after numerous days of researching and reading I finally came up with a list of components for my first e-board project.
I was hoping for a second opinion to double-check my choice as well as some answers for a couple questions I had.

So here's my component list:

- Turnigy Aerodrive SK3 - 6354-215kv Brushless Outrunner Motor
- HobbyKing® ™ 150A High performance Brushless Car ESC
- Abec11 Flywheels Longboard Wheels 83mm
- ZIPPY Flightmax 5000mAh 6S1P 20C
- Wii Kama Wireless Controller
- Nunchuk Extension Cable for Nintendo Wii
- Arduino board
- IMAX B6-AC Charger/Discharger 1-6 Cells (GENUINE)


And the 2 questions:

1) I hesitated a very long time for the motor. I couldn't decide between 50mm and 63mm. My top picks were SK3 6354-215, 6364-213, 5065-236, 5055-280.
Is there a noticeable difference between those 4 motors in terms of power/torque/speed? Would I even feel the difference between those 4?

2) At first I wanted to get 2 packs of 3S batteries and mount them in serie to get a 6S. It was simply to gain a bit of space below the board. But it's a little more expensive and I've read that most chargers only charge one battery at the time. So do you think it is worth worrying about it?

For info I'm 149 lbs, will probably ride up to 15 mph max and mostly on flat ground.

Thanks,
-Stef

 

[made_in_the_alps_legacy]

welcome I guess you estimated your transmission ratio ?

As far as question 1) is concerned, 63mm motors are robust and tend to be prefered choice for mountain board rider
In the other hand, the trend for e-board going on tarmac is a downsizing to 50mm motors : they are generally sufficient.
(i belive each of the motors you mentionned have different specifications)

For question 2) a 6s charger should be able to charge 2 x 3s at once for the price of some more cables

 

[torqueboards]

1.
I'm fine with 50mm but 63mm doesn't hurt either. 63mm will give slightly more torque and be more robust, won't get as warm, etc. Might last longer but 50mm are also cheaper and have seemed to last just as long. Benefits of 63mm also is that you have an 8mm shaft versus 50mm's 6mm shaft.

2.
2 packs on 3s is cheaper and easier most of the time. 3S 5000mah pack is only about $20 bucks. You can get a parallel balance board that is $10 bucks and charge up to 6 packs total at a time.

I would go with 50mm and (2) 3s packs. Saves the most money and with your rider weight you shouldn't have any issues.

 

[gratoo]

Thanks a lot for the feedback guys. That's very helpful.

No I haven't figured out the transmission ratio yet. It's still unclear to me how to precisely define it. I've seen the calculators for it but I'm still not sure how realistic they are.

I'm only planning on using the board on the asphalt. So it's seems that 50mm is enough. I'm not too worried about the price since it's only $10 or $20 more for a 63mm. I was more worried about the clearance under the board. Do you guys think that a single 5055-280 could be enough for instance?

What's the advantage of the 8mm shaft over the 6mm? Is it stronger or it's because it fits more pulley/gears? (I'll probably be CNCing my own). By the way how do you couple the shaft to the gear? Do I need to make a keyway in the shaft?

Cool for the 2 x 3S! I'll probalby go with that then. It doesn't seems like more maintenance from what you're describing and it save me a bit of space under the board.

Here's the soon to be motorized spaceship:

 

[made_in_the_alps_legacy]

- The transmssion ratio is to be found knowing on one hand the top speed you want,
and motor kv, battery voltage and wheel diameter on the other hand.
There has been quite a lot of discussion how predictive the evaluation can be, but as long as you don't go for inflated tyres, the effective speed will be close to the theoretical one.
Here is an example taken from my e-board :

- To fix the motor sprocket, the keyway is generally the preferred option, some uses set screws, some are welding the sprocket to the axle…
- Browse around to see how single 50mm motor powered e-boards are behaving, you should get confidence if it fits your target
- Smaller axle diameter allow smaller sprocket - I am not sure if all the 50mm motors do have 6mm shaft, I think some are 8mm, what I personnaly don't like with 63mm motor is at least the weight (I have been using 6374 of 750g, while a 5065 could be less than 500g)

 

[torqueboards]

8mm over 6mm is most likely mediocre. I wouldn't bother too much. Main difference is it's bigger and you have more options for a motor pulley at 8mm versus 6mm.

Keyway and set screw is the best way to fit motor pulley and the shaft. Since, you are machining your stuff it's not too hard. Sandpaper and/or dremmel and making preferably 2 flat spots for set screws works as well.

 

[gratoo]

Alright! So based on what you told me and more reading (I also stumbled on your nice step-by-step Torqueboards, very cool stuff) I changed a few things.

I changed some components to:

- SK3 5055-280kv
- (2x) ZIPPY Flightmax 5000mAh 3S1P 20C
- EZRUN-150A-PRO
- Blank Pro 83mm wheels

I calculated my ratio:

motor: 6216 rpm = 22.2V * 280kV
ratio: 1/3
wheel: 2072 rpm
wheel diameter: 83 mm
wheel circumference: 261 mm
max speed : 32 km/h = 6216 * 1/3 * 0.083 * PI * 60/1000

I've also tried calculating the battery theoretical autonomy:

11.1(V) x 2 x 5(Ah) x 20(C) / 1510(W) = 88 min

Does that sound right?

 

[made_in_the_alps_legacy]

Does that sound right?

not too bad note :
- 6s pack should be considered almost empty at 22.2V, 25V is a better guess for top speed evaluation.
- 1510W is the rated power of your motor, 20C is the max your battery can discharge - you may achieve your top speed before reaching your motor rated power and battery max discharge rate.(More about "battery range" and "average speed" HERE))
there is anyway something fishy in ur riding time method, proposed alternative evaluation :
22.2V x 5 Ah = 111Wh
111Wh/1510W = 6min

 

[beto_pty]

Just rode my board (in the name of science) on 5 ah 6s full speed (no coasting) and got 8 kms... 13 minute riding time...

 

[psychotiller]

Just rode my board (in the name of science) on 5 ah 6s full speed (no coasting) and got 8 kms... 13 minute riding time...

Makes perfect sense. I can go almost 10 miles full speed on 10 ah 6s.

 

[gratoo]

Haha thanks guys! I knew 88 min was to good to be true but 6 min seemed so low. That's why I thought I'd have to multiply it by the C rating.
Alright then, it makes sense. And I guess it lasts longer if I don't ride full speed all the time.

Have any of you tried regenerative braking?
1) Is it worth it? (I've read that the gain is very small)
2) Can any ESC be used for this purpose?
3) Is it a lot of wiring to set up?

-Stef

 

[beto_pty]

no, no, yes..

 

[JackHMcD]

⏆⏆⏆⏆

 

[beto_pty]

Quick question, Will gearing ratio change my ride time? Like say 1:2 vs 1:4 assuming riding at the same speed.

of course if you get the motor to turn in its sweet spot it will do better than if it is unde/overloaded... decide upon your most probable, most usual speed and gear for that... however dont expect your milage to double...
also the previous examples of range where all out max speed.. Ive gotten over 22 kms out of 10ah 6s driving like miss daisy..

 

[psychotiller]

Haha thanks guys! I knew 88 min was to good to be true but 6 min seemed so low. That's why I thought I'd have to multiply it by the C rating.
Alright then, it makes sense. And I guess it lasts longer if I don't ride full speed all the time.

Have any of you tried regenerative braking?
1) Is it worth it? (I've read that the gain is very small)
2) Can any ESC be used for this purpose?
3) Is it a lot of wiring to set up?

-Stef

From everything I've read it seems like, for our purposes, regenerative braking is hidden next to a pot of gold, cloaked under 4 leaf clovers, guarded by unicorns, under a rainbow.

 

[beto_pty]

next to a sign that reads
"Awesome Regen ESC Tomorrow" :lol:

 

[gratoo]

Hi there, it took a while but I finally finished my build! I went for a solution that doesn't modify the original board and doesn't require welding the motor mount to the truck. It is controlled via a Wii Nunchuk and an Arduino board.

Here's a quick video: https://youtu.be/T3ooozgZmCk

 

[made_in_the_alps_legacy]

congrats and thxs for sharing! how much weight is it ?

 

[Vulthor]

Well done!

So finally what is your distance cover, time and top speed with some test?

Good choice for the music on your vidéo (back to the future )

Warning: no helmet is bad bad bad; safety for you and viewers :wink:

 

[gratoo]

Thanks guys!

I don't know for the weight yet, I don't have a scale at home. I'll try to borrow one.

Here's my tracking data from the following day:
http://www.sports-tracker.com/workout/stéphanebersot/55c2a8a6e4b0e6dddb194227

Don't believe the displayed top speed since there's a spike at the beginning. According to the rest of the data it seems that it's more around 30 km/h which still seems a bit much to me. The crazy thing is that I actually cut the top speed by 50% via the Arduino because that thing was way too crazy for me.

You're totally right for the helmet. I simply forgot to take it on that day. I bought a dirt bike helmet to ride in style!

 

[whitepony]

your music choice on the video made me happy

 

[sl33py]

Thanks guys!

I don't know for the weight yet, I don't have a scale at home. I'll try to borrow one.

Here's my tracking data from the following day:
http://www.sports-tracker.com/workout/stéphanebersot/55c2a8a6e4b0e6dddb194227

Don't believe the displayed top speed since there's a spike at the beginning. According to the rest of the data it seems that it's more around 30 km/h which still seems a bit much to me. The crazy thing is that I actually cut the top speed by 50% via the Arduino because that thing was way too crazy for me.

You're totally right for the helmet. I simply forgot to take it on that day. I bought a dirt bike helmet to ride in style!

I use our luggage scale (strap goes around the handle of your bag so they don't charge you extra) - works perfect around the truck of a skateboard and accurate enough for me.

Love the video and music as well! Your grin on a couple of the passes totally made me laugh. Like a kid at Christmas! Gotta love it!!

I have had good luck using an app called Strava. Seems to be accurate. I use it for distance, elevation, avg speed, and top speed. I'm usually just cruising around though so nothing too accurate is really needed. I used it to test the distance my batteries would do on 8Ah and got 9.6 w/ a little left if needed (3.7v cell iirc). Seems to be an accurate top speed compared w/ the calculator i got a while back from beetbocks. I had one run faster (30mph) but it was slightly downhill behind my house, so i think it was accurate as well. I built it and geared it for a top speed of 25mph.

 

[gratoo]

Pretty cool, thanks for sharing!

Yeah I had to pick that music! I was also wearing my Back to the Future t-shirt that day =P

 

[tremendo]

Thanks a lot for the feedback guys. That's very helpful.

No I haven't figured out the transmission ratio yet. It's still unclear to me how to precisely define it. I've seen the calculators for it but I'm still not sure how realistic they are.

I'm only planning on using the board on the asphalt. So it's seems that 50mm is enough. I'm not too worried about the price since it's only $10 or $20 more for a 63mm. I was more worried about the clearance under the board. Do you guys think that a single 5055-280 could be enough for instance?

What's the advantage of the 8mm shaft over the 6mm? Is it stronger or it's because it fits more pulley/gears? (I'll probably be CNCing my own). By the way how do you couple the shaft to the gear? Do I need to make a keyway in the shaft?

Cool for the 2 x 3S! I'll probalby go with that then. It doesn't seems like more maintenance from what you're describing and it save me a bit of space under the board.

Here's the soon to be motorized spaceship:

Which deck did you use? Looks like Landyachtz Drop Hammer?