This topic will be for the build of my first electric skateboard.
Riako and OKP have already given me some pointers in my presentation topic.
Sorry for writing in english, but it is much easier for me! :oops:
I promise I will make an effort to improve my french! :roll:
My objective:
An awesome looking board that is not too long but not so short that becomes unstable.
Top speed around 40~45km/h;
Range of about 35~40km;
Enough power to climb some hills!
So I haven’t decided all the components, and I’m counting on your help to decide on the best choices and where to buy them from.
So here is a list that will be updated as I choose every component:
Transmitter:
GT2B, will print a case for it, probably this one.
Around 30eur from amazon UK. Ordered from amazon.co.uk on 04/01/2016.
Trucks:
Caliber II 184mm 50º from easyriser.fr
Around 66eur. Ordered from easyriser.fr on 29/12/2015.Received on 05/01/2016
Bearings:
Amphetamine Titanium! Ordered from easyriser.fr on 29/12/2015. Received on 05/01/2016
Wheels:
Orangatang Kegel 80mm 80A from easyriser.fr.
Around 70eur. Ordered from easyriser.fr on 29/12/2015.Received on 05/01/2016
Motor mounts:
Dual diagonal mount kit in DUAL REAR setup, from aliendrivesystems! Ordered on 04/01/2016.
Around 250eur. Received on 13/01/2016
Batteries: Ordered 8x 5000mAh 3S 20C Turnigy batteries (plus XT60 and XT90 connectors) from HobbyKing on 29/12/2015.
Around 19eur eur each.Received on 08/01/2016
ESC’s:
VESC 4.1 x2 from esk8.de.
Around 300eur. Ordered on 04/01/2016.Received on 14/01/2016
Deck:
Urskog Krona Jacaranda 38.6". Also ordered Venom bushings and Riptide cups. Ordered on 05/01/2016.
Around 150eur. Received on 08/01/2016
Motors:
Enertion 6355 x2 from enertionboards.com in dual rear setup.
Around 200eur. Ordered on 05/01/2016.Received on 12/01/2016
Regarding the case, I should warn you that the stl files from Badwolf will print a really thin walled case.
You have an alternative from StephM (who is a contributor of this forum) which is way more robust.
I have printed the pieces but not yet assembled the remote. http://www.thingiverse.com/thing:1013293
Hey !
OKP already test all this stuff, so you could be sure they’re a good parts for your build
Trucks take the 50°, you like to carve more !
12S is good in 5000mah min I think… OKP make many test. Or you got Paulfred who got a good autonomy.
If you take a Alien drive kit you gonna have all what you need to the mecanical part drive thing : Motor mounts, Drive belts,Drive hub, Motor pulley, it’s already « program » for your Number of teeth I think
look here its a dual diagonal kit but you could put it in dualrear, just 6374 mm motor are to long, so you need 6355 mm motor !
For your wheel, you have le flywheels 83mm 78a who are good or the Kegel 80mm and the Seismic 85mm
For the bearing okp have some to advise you
Have a nice day
Regarding the case, I should warn you that the stl files from Badwolf will print a really thin walled case.
You have an alternative from StephM (who is a contributor of this forum) which is way more robust.
I have printed the pieces but not yet assembled the remote. http://www.thingiverse.com/thing:1013293
It works with a GT2e (very similar to GT2b).
Thanks for the heads up. I’ll only start printing cases and thoroughly looking at their design once I get the remote.
The one you suggested seems good, so thanks!
Hey !
OKP already test all this stuff, so you could be sure they’re a good parts for your build
Trucks take the 50°, you like to carve more !
12S is good in 5000mah min I think… OKP make many test. Or you got Paulfred who got a good autonomy.
If you take a Alien drive kit you gonna have all what you need to the mecanical part drive thing : Motor mounts, Drive belts,Drive hub, Motor pulley, it’s already « program » for your Number of teeth I think
look here its a dual diagonal kit but you could put it in dualrear, just 6374 mm motor are to long, so you need 6355 mm motor !
For your wheel, you have le flywheels 83mm 78a who are good or the Kegel 80mm and the Seismic 85mm
For the bearing okp have some to advise you
Have a nice day
Thanks for the tips!
50º trucks it is then!
The Kegel wheels look ok to me, so I’ve chosen those, but always open to change if there is a good reason in terms of the skate’s performance!
Do you think that kit could work for me? Could I mount it as a dual rear?
In the description at aliendrivesystems.com it says:
This Kit uses a 32T x 15T
Any motor other than an Alien Power Systems motors made need modifying in order for the drive pulley to fit correctly
So is this gearing good for my objective?
And do I have to modify the motors or mounts to fit the Enertion motors?
The Kegel wheels look ok to me, so I've chosen those, but always open to change if there is a good reason in terms of the skate's performance!
Do you think that kit could work for me? Could I mount it as a dual rear?
In the description at aliendrivesystems.com it says:
This Kit uses a 32T x 15T
Any motor other than an Alien Power Systems motors made need modifying in order for the drive pulley to fit correctly
So is this gearing good for my objective?
And do I have to modify the motors or mounts to fit the Enertion motors?
Many rider have tis Kegel and in 80A it seems to be cool !
yes Paulfred mount it in dual rear, and maybe okp on is new one (!?), and I gonna take one too to pass in dual rear too :twisted:
Yes, I have a 32T x 15T in single motor actualy, it’s a perfect combination. If I remember well, okp change for 14T to le motor poley…
The motor is delivrery already ready to receive your poley and motor Shaft for Alien Motor. If you take Enertion is same practice with maybe a better quality , the 63mm diameter motor is “standart” so no problem normally. But for the motor Shaft, maybe its better to take your motor polley at enertion …its seems to be the same practice, but enertion is in 8mm drive shaft so just to be sure.
I will make almost the same configuration, to pass in dual rear > 2 x motor 6355 with Alien Drive System.
(sorry for my english)
Thank you, that’s a good read!
I’m still unclear as to the best gearing and battery combo for my « needs ». The wheels are the kegel 80mm, the motors are 6355’s, as for the battery I haven’t figured it out yet…
I’ll read it a couple more times, and hopefully OKP can give his opinion and feedback on this matter.
Your range depends a lot of your average speed. What should it be ?
In any case, if you go further than 15kph, I assume you could hardly reach 40 km range, without considering hills climbing…
For the gearing, I need this scheme :
Ratio of gearing is: r = w_hub / w_motor = Z_motor / Z_hub (for French people, Z = Teeth and w = angular velocity)
if you go for 12S, that is to say 3,712 = 44.4V, with a 190 kv (I assume, provided vedder advices), your motor will run at
N_motor = 8436 rpm, or w_motor = (2pi*N_motor)/60 = 883.41 rad/s
a maximum velocity at V = 45km/h = 45/3.6 = 12.5 m/s, wheel hub angular velocity will be: w_hub = V/r_wheels (r_wheels = wheel radius in meters), that is to say w_hub = 12.5/0.040 = 312.5 rad/s
And eventually, ratio should be: 0.35
With a 36T hub pulley, your motor pulley have to be a 13T.
With 36T/14T, you could reach 50kph.
With 36T/15T you could reach 53kph.
This is the theory.
Note : this model doesn’t consider the frictions losses.
Jason from enertion, claims that 36T/15T is the best ratio for efficiency. I have read that below 15T, there will be only 5 teeths in mesh, torque transmission is reduced by 20 %. But, according to okp, torque is better at 14T. So, I can’t figure out what is the best choice.
(I may have made some calculus mistakes, but it is the idea by and large)
Edit: I really have made calculus mistakes. r_wheels = 0.040 m
And eventually, ratio should be: 0.35
With a 36T hub pulley, your motor pulley have to be a 13T.
With 36T/14T, you could reach 50kph.
With 36T/15T you could reach 53kph.
This is the theory.
Note : this model doesn’t consider the frictions losses.
Jason from enertion, claims that 36T/15T is the best ratio for efficiency. I have read that below 15T, there will be only 5 teeths in mesh, torque transmission is reduced by 20 %. But, according to okp, torque is better at 14T. So, I can’t figure out what is the best choice.
(I may have made some calculus mistakes, but it is the idea by and large)
Edit: I really have made calculus mistakes. r_wheels = 0.040 m
Many thanks for that Skirk!
After reading the vedder article, I did some calcs and .35 was also the number I arrived at, and 36/13 the gearing I figured.
I’m going to buy 2 sets of 13/14/15T from enertion, that way I can switch them and arrive at my own conclusions in real world testing.
I need to talk to Richard from aliendrive to understand if his dual mount kit is OK for my needs.
Last thing is the matter of the battery, still not sure which way to go. I keep seeing 12S, but how can I get good range, what combo of battery packs should I use in order to maximize power and range? Is there anyway I can get a 9Ah or 10Ah 12S setup? 3x4S? Would this be benficial? Maybe I’m talking rubbish, so I’m really hopping for some of your ideas!
There are some theoretical arguments to say that the higher the voltage, the better the autonomy.
Between 10S and 12S, there was no real proof in practical expriments.
What is to be considered is always the product voltage times capacity.
For instance you can expect a similar autonomy with :
10S (voltage) 6000mAh (capacity)
12S (voltage) 5000mAh (capacity)
Regarding the C rating, OKP tried the 10C (which is the lowest you can get). General concessus is that the 10C are not recommended.
20C is only marginaly more expensive but significantly better in terms of acceleration (and probably durability).
All that beeing said, it is difficult to come up with an equation to compute the autonomy.
The best is to try to find people with similar setups and check their range … and ajust it to your requirements.
If your system is well designed, you can also imagine to have a couple more batteries in the backpack.
My setup (still not finished) has two 10S 4000mAh batteries. I can carry a third battery in my backpack in case I am too short to get back home without pushing.
- I usually get 12S 5AH on my setup to keep them light (my Boosted like is 6kg ready to ride)
prefer the Tekton bearings (they are awesome)
Richard dual mount will be perfect for your requirements
good choice on the Otang Kegels 80A
get also some venom bushings and riptide cup; they will change completely your ride.
Thanks OKP!
Yes, you mentioned you use 4x 5Ah 3S LiPo’s in series, but you never mentioned what range you achieve.
That combo will make it light and cheap I think, so it wouldn’t be hard to have spares, but I’d have to make it so they would be easy to swap out on the go.
Any other suggestions?
3x Tattu 9000mAh 14,8V 25C 4S = 12S 9Ah - Probably too expensive, heavy, and big to fit?
3x Tattu 6750mAh 14,8V 25C 4S = 12S 6750mAh - Cheaper, but maybe not worth the extra 1650mah?
Will take you up on your advice regarding the bearings, bushings and cup.
Thanks again! Feel free to guide me along this, your help is precious OKP!
depends, you usually ride between 25 and 40km/h, sometime you push because of pedestrians… sometimes you get to 50km/h. Versatile riding. I think that 5AH is a good compromise (especially for 80 euros the full pack) to start with on 12S, and then you can move to something else if you need (or just add one pack and you can switch and get more coverage)
Wow… I really couldn’t imagine reaching 40km range for 25km/h speed.
I was considering making a sum up of physics behind electric skateboard (power calculus and consumption), but it seems that my model is wrong. I have to check this ! Thanks for this answer by the way !
