Possible electric skateboard

[showbox]

Hello,

I have started thinking about building an electric skateboard and ended up at this excellent forum.

All current designs involve a single motor driving one rear wheel via a timing belt.

My idea is to use small diameter (was thinking about 40mm max) RC brushless motors mounted on each truck driving the wheels via a gear down reduction.

Essentially creating a 4WD skateboard.

Questions:

1) Does this seem possible or is it crazy? Please point out all pitfalls.
2) Anyone point me to possible motors as a starting point?
3) Possible controllers that feature re-generative braking?

Thanks.

 

[etard]

Welcome to the forum my friend! I have been waiting for someone to show up and build a decent skateboard.

First let me say that while regen sounds like a noble cause, and maybe with a vehicle that travels at highway speed and carries enough inertia to actually regain alot back on deceleration it might be good. You definately don't want it in a skateboard, of all possible vehicles where regen would result in injury, I would put the skateboard at the top of the list. But, I guess this is how the current electric skateboards slow down huh? Or maybe they use a disc brake?

Also, I think Altered skateboards are going to be hard to improve upon, especially with the wireless trigger and decent performance. I would just buy one of these and upgrade to Lipo batteries. I can't see anyone wanting to go faster than 20 mph on one of these anyway.

Not to discourage, I would love to see a homebuilt. I'm sure you could get some body spitting torque considering how small your wheels are, using a relatively cheap rc motor and sensorless controller. You know, now that I think about it there is much room for improvement! If you could devise a wireless hand throttle, there rest could be done. Go for it man! How do you intend to get power to the wheels considering the need for the axles to move freely in order to steer?

 

[kenkad]

Hi,
This website has been mentioned in other threads. This effort was directed toward a skateboard application. http://scolton.blogspot.com/search/label/3ph
kenkad

 

[showbox]

But, I guess this is how the current electric skateboards slow down huh? Or maybe they use a disc brake?

Yes the regen is for slow down, not environmental reasons. It is not practical to have brakes on skateboard wheels.

If you could devise a wireless hand throttle, there rest could be done. Go for it man! How do you intend to get power to the wheels considering the need for the axles to move freely in order to steer?

Wireless control can be done using existing bluetooth or zigbee solutions.

My idea is to mount the motors on the axle (in skateboard term "truck"), hence the reason for requiring smaller diameter motors.

 

[showbox]

http://fastestelectricskateboard.co.uk/shop/index.php?act=viewProd&productId=13

Is an example of the current drive system.

The motor is mounted on the truck driving one rear wheel.

Essentially I want to copy this for all 4 wheels using smaller motors.

 

[recumpence]

Man, this is really easy......... I have looked into this myself.

Just buy a standard RC pistol grip RC system ($80 or so). Futaba is a great brand. JR is good also. That automatically gives you wireless, pistol grip, and it will work directly with the RC controllers (obviously) and about $100 worth of Lipo. Yes, you must go with Lipo for size considerations.

Nearly all RC controllers have electric brakes. So, no issue there.

What you need, is 4 motors, 4 controllers (no, you cannot use one large controller to drive multiple sensorless motors), and an RC pistol grip controller. Piece of cake!

You only need 100 to 200 watts per motor. So, you can get away with some very basic motors for this.

To save time, I would look at the rear wheels designed for existing electric skate-boards. If I remember correctly, they make wheels with belt teeth molded in. I could be wrong on that, though.

Matt

 

[Metallover]

Make sure to get a controller with linear brakes (i.e. for cars, usually) or else you will get thrown off the front. Read the description for sure. Mechanical brakes might be the way to go.

If you need a radio, pm me. I could ship it to you (in the US) for $10. I have 3-4 cheap am radios that came stock with rc cars. If you want a nice one, there's one from hobbycity that's 2.4ghz and I've heard good things about it. It's only $25 Here's a link - http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idproduct=10608

If you go with an RC system, some things need to be considered
-BEC (dc-dc converter) to power the rx (receiver) if one isn't built into the esc ~$6 at hobbycity
-Servo wire/connectors to make an adapter (if you run more then 1 esc from one radio, you can buy adapters premade too)
-When setting up your radio, make sure not to put the antenna/radio receiver anywhere near other wires, especially phase wires. Glitching won't be fun
-Make sure you have a way to charge your lipos (balancing charger) and a LVC. I have a $4 "lipo monitor" from hobbycity and it has lights to indicate a few voltage ranges and a buzzer when the lipo drops below 3.2v/cell.

If you attach an outrunner directly to a wheel, it will probably spin way to fast or be out of the power/efficiency range of the motor. You also have a lot of weight on the bearings. I would go for a drive system with 1-2 motors or at least support the wheel so the weight isn't on the motor. People worry about bearings when they attach a chain to an outrunner; imagine what standing on it would do. :|

And one last thing about electric skateboards. My friend had one. It was a razer 180-350w lead acid battery board. It was scary as heck to ride, at least for the first time. Skateboards have small wheels and are harder to control. You might not want to go above 20; make sure to calculate your speed before you buy. I'm not saying you shouldn't do a skateboard; I think it's awesome.

Good luck with your project!

 

[showbox]

Cool thanks for the advice guys.

I am moving house at the moment but will look to start the build in Feb.

I will start with two wheel drive with 200 watt on each wheel using purchased rear wheels with in built teeth and timing belt.

The only thing really left to sort out is the modified skateboard truck.

Essentially I need a bracket on each end to mount each motor. Current electric boards only need to mount one motor so only have one bracket.

Off-the-shelf standard trucks are made, via casting, out of a soft aluminum alloy.

Does anyone know if you can weld to this type of material? Any other suggestions on how to attach the bracket?

Anyway it will be full steam ahead by the end of feb..

 

[Steff]

This sounds like an interesting project, sure hope you keep us updated on the progress!

Btw, where are you getting loose parts for electric skateboards, e.g. large trucks, wheels with the built in teeth etc.?

I was thinking of building one myself, though simpler of course (4wd sounds like a real challenge for a skateboard).
My goal was to find a suitable brushless motor and a controller, then steal some parts from my current electric skateboard of unknown (chineese) origin and get it all working together. But I decided to start smaller instead, and just aim to finally get my boards SLAs upgraded to LifePo this year...

Well here's the list of different online sources for electric skateboard spare parts I've found so far, if that can be of any assistance:
http://www.alteredelectricskateboards.com/parts.htm
http://www.e-glide.com/
http://www.greenskate.co.nz/
http://www.e-ride.ca/Electric_VehicleParts/Parts_Other.htm
http://www.eightballboards.com/acatalog/Electric-Skateboard-Spares.html
http://fastestelectricskateboard.co.uk/shop/
http://www.rokitscience.co.uk/online_store/

Good luck with the build!

 

[etard]

Shoebox,
Are you going full RC setup on this? I am not understanding using two 200 watt motors when one 1000watt motor can be so easily applied? Think of all the syncing and repetitious steps you will save by only going with one motor. For a motor mount you probably get away with aluminum angle stock, or better yet follow Bubba's lead and build a wood box to hold all your electronics as well as mount you motor. I will be following your progress for sure. I have always wanted an electric skateboard to power uphill and bomb down unpowered, well except for gravity.

 

[bluthermal]

shoebox,

I own a mostly stock (except for the deck) Exkate/Altered Proline 600 (600W motor) skateboard. I'm also pretty familiar with their older and current products. I've also ridden both 2 wheel independent rear wheel drive and 4 wheel independent all wheel drive skateboards that were basically kluged together with multiple parts of older skateboards by a guy I used to work with. He used parts of smaller sized powered skateboards because of size, weight, and power considerations.

Both the 2 wheel independent drive and the 4 wheel independent drive setups were in my opinion a step up from 1 wheel drive, and well worth developing from a drive and ride-ability standpoint. The disadvantages are the added complexity, cost, weight, and power requirements (not to mention potential for klunkyness), that for most people, will far outweigh the advantages.

As far as the speed goes, at 20 mph, you get one or two steps before you go down (hard for me).

Regarding changing the standard SLA batteries to another chemistry, be sure to make sure you know the controller/electronics you're using will be able to handle the extra voltage (that Lipo for example makes) for standard battery configs. I know from experience that the current Exkate/Altered 36V brushed controllers work OK with 3 SLA batteries that charge up to a maximum typically of 39.X volts, but anything over 39.X+1 may fry parts of the electronics. For example, I know my LiFePO4 battery that typically charges up to 41.X volts will fry something on their stock electronics.

Good luck with your project.

 

[bluthermal]

Oops, I meant showbox.

 

[MonsterFC]

Im making a badass electric skateboard with an old school Creature deck. Im getting all the parts separate and piecing it together as i pick up parts and work out a configuration. i plan on using a pushbutton throttle placed through the deck in a position that is comfortable with my footing so i can step on the button for acceleration. I am working on an affordable configuration to mount the motor with the trucks and i have yet to decide on a chain or a belt. Probably gonna use 2 or 3 12v 10-12Ah lead acid batteries wired to a 24 or 36V... ummm maybe like 400-500W motor. Still have to see which ones i want but i get a part with every paycheck. Im a technician in the Navy and this is gonna be a badass little side project.

 

[sk8norcal]

good luck, but I wouldn't use sla batteries,

this is the best e-skateboard I have seen so far,
http://www.endless-sphere.com/forums/viewtopic.php?f=35&t=37230

 

[sn0wchyld]

I havent had a chance to read all posts (past my bead time ) but its been done. and boy, does it WORK!! mind you, it was a guy with a mountain-board. he had 4 motors, 4 controllers, 1 for each wheel. the motors could also be used as breaks. I'm planning on doing a similar 2wd one myself this summer.

search around for humbleboatrc or somthing like that... he's got some youtube vids, he's a member of ES and has a bit of a build log on the hobbyking forums.

ah, here we are...
[youtube]QKTgbubRxXk[/youtube]
[youtube]GqCQI419obg[/youtube]

damn, every time I see these vids it makes me want to foreget about bikes and just go build some mtboards! it hardly looks difficult!

You could always mount skate trucks/wheels to a mtb, you'd have great rolling efficiency but the space for lots of batts! good luck mate. Subscribed, cause I wanna see what you come up with!!

 

[sk8norcal]

search around for humbleboatrc or somthing like that

HumboldtRC
http://wackyboards.blogspot.com/2011/06/4wd-electric-skateboards.html

You could always mount skate trucks/wheels to a mtb, you'd have great rolling efficiency but the space for lots of batts!

I wouldn't do that, skate trucks don't mate well with mtboards, wrong angle, wheel bite, etc.
and u can't put skate wheels on mtboard trucks.
and for a skateboard/longboard (no bindings), I wouldn't put batteries between your feet on top of the deck, it would be awkward for feet placement.


papo's board is the way to go for a longboard...