Introduction: Electric Longboard | 20mph | 10 Miles

I'll start by saying this was an incredibly rewarding project that I'm able to use every day. If you haven't had the chance to ride an electric longboard, it is like no other mode of transportation, fast, fun, and portable. Commercial electric longboards start around $1,000 which is tough to swallow for a financially struggling college student, thus my expedition started to design and build my own! Plus it was a good way to keep my 3D modeling skills sharp!

This project ended up costing me around $400 since I was 3D print a lot of the components and built my own longboard deck, which you can learn how to do here.

Lets get started!

Step 1: Parts List and 3D Model Download Links

Hands down the most difficult part of this project was figuring out what specific parts I needed, making sure they all worked together, and making sure they were all in stock. I put together a comprehensive list of all the components I used throughout the build process, where I bought them from, and how much they were. Hopefully this sheds some light and helps guide you through choosing components.

Since I also have access to a 3D printer, I wanted to take full advantage of it and save some money. I 3D printed the motor mounts, the gear on the wheel, the electronics mounts, and the electronics case. I wanted to do this right, which meant I needed a 3D model of EVERYTHING on the board. This was incredibly time consuming, but I uploaded all the 3D models I made to thingiverse, so feel free to use them as you please!

Step 2: Schematics

Let's start with the electronic speed controller and work our way out:

Electronics Speed Controller (ESC)

This is the brain of the board, it controls how much power the motor is recieving based on the input from the user via remote controller. With a programming card (see parts list), you can change how quickly the board accelerates, how much it brakes, if it drag brakes (automatically slows down), and many more options, this is really useful and allows you to tweak the board to your own riding style. The ESC comes with its own switch, which will turn the ESC (and effectively the whole board), on and off.

Motor

There are many, many different types of motors out there, but for an electric longboard application, you will almost always see brushless outrunner motors. You'll want to look for one with a low Kilovolt rating (<300Kv) as it provides enough torque to propel you forward. The motor is connected to the ESC via 3 phase wires, which you will have to fiddle with the order of their connections to get your motor to spin in the correct direction for your board set up. Some brushless motors also offer a sensored setup, not really necessary, it simply ensure it will never hiccup when starting from complete rest.

Battery

Most electric longboards (and mine as well) use lithium polymer batteries (or LiPo) due to their incredibly high weight to power ratio. You'll want at least a 6S or 6 cell battery pack, for a better form factor, I wired two 3S or 3 cell batteries in series to provide the 6 cells that will keep you riding for miles. The battery is then wired to the ESC, but I also added an antispark switch on the positive (red) line. this XT90 antispark connector allows you to connect the battery pack without a large amount of sparking, which isn't really necessary but also nice to have. The LiPo batteries also come with balance cables, which are used for charging the batteries and make sure all the cells in the packs are charged evenly.

Battery Adapter Board

This adapter board converts the two separate balance cables into one cable that allows by balance charger to think that it really is a single 6S pack and chargers it as one. This means you can charge both batteries at once instead of having to charge them separately.

Remot Control (RC) Receiver

This little device will come with you RC remote controller and allows your handheld controller to talk to the ESC to tell the motor to speed up, cruise, or brake. There is a cable coming from the ESC that connects to the RC receiver and turns on/off with the board.

Motor Gear

Gear mounted to the motor, usually 15 tooth. Do NOT try to 3D print this piece, it will fail!

Step 3: Mechanical Design | Wheel Gear

So there is a gear on the motor and a bigger gear on the wheel, a belt is connected between the two and that's how the board is driven forward. There are multiple different ways to attach the gear to the wheel: from drilling into the wheel, to buying adapters that fit into the wheel. I decided to buy a set of wheels that have "spokes" or spaces around the center the wheel, and 3D printed a gear designed to fit those cutout. This was by far the easiest way of tackling this design problem. There are two pieces to this gear: the actual gear itself which is on the backside of the wheel, and the outer shell that faces towards the road. 6 M8 x 2.75" bolts hold everything together.

Both the design files for the gears to be 3D printed and the link to the aluminum gear that mounts to the motor can be found on my parts list.

Step 4: Mechanical Design | Motor Mount

The motor mount, is always the most difficult part about actually building an electric longboard. Some people cut out and weld metal plates to their trucks, or buy expensive motor mounts that clamp onto the board. I was inspired by user Nick_Tesla's design (https://www.instructables.com/id/3D-Printed-Electri... of a fully 3D printed motor mount and decided to design my own jumping off of his idea.

There are 3 parts to this motor mount, two of them are inserted onto the truck and are secured together using two 1/4"-20 threaded rods. Another piece is held onto the main motor mount by another set of threaded rods. This means that you can wedge washer in between the gap and tension the belt.

I printed these pieces with 75% fill density in PLA and they work wonderfully. I've ridden then over 20 miles without any signs of wear.

These motor mounts are designed specifically for the trucks that I bought, they perfectly fit around the truck's geometry. I have links to the trucks I used off of ebay in the parts list section, they were fairly inexpensive.

Be sure to use a threadlocker for the final assembly, lots of vibrations while riding and bolts/set screws WILL come undone if no threadlocker is used!

Step 5: Mechanical Design | Electronics Mounts

There are lot's of different ways people have held their electronics to their board. Some people have used tupperware containers, others zipties, or velcro. I decided to design and 3D print brackets for each electronics component. These brackets would be held in place with really small wood screws (about 1/4" in length), but if I were to do it over again, I'd go with longer screws since they were a pain to install.

Again these were printed in PLA around 40% fill density.

They ended up working extremely well, they all fit very snug against the board and allowed me to have a slimmer case in the end.

Again, filed for all the components I used can be found in the parts list/3D model link section. Make sure to account for the correct tolerances while designing, I added around 1/16 of an inch on all sides to make sure the could be assembled without bending the plastic pieces too far.

Step 6: Mechanical Design | Electronics Container

I wanted a really sleek electronics container, one that people would question if the board was bought or made at home. The biggest challenge was figuring out a configuration for the electronics that would allow for the overall dimensions to fit inside my 3D printer's build platform.

I integrated the ESC switch into the electronics case so it was easily accessible from the outside of the board. I also added ventilation holes for the ESC.

I added a slot by the ESC switch with was suppose to be for the antispark switch. I initially wanted to be able to remove a part of this switch to disconnect the batteries while not in use. This didn't work at all. the vibration from riding always jiggled the connection of the antispark switch loose and caused my board to randomly shut off while riding, not fun. Instead I just ziptied it all together and fit it within the case.

You'll also notice the two charging wires coming out of the back of the electronics case, I designed a little cavity for the ends of the wires to sit in while not being charged. This will allow for the wires to be held securely instead of flopping around while riding, you can see this little cave for the wires in the first image in the bottom right, it's the little square section. It works surprisingly well!

Step 7: Charging

To charge the board, I simply connect up the 7 pin balance cable to the charger. and the deans to banana plug connector which comes with the charger. I then entered my battery's info like type, number of cells, and capacity, and then let it do its thing!

It takes about 2 hours to fully charge. I'm really happy with the charger and highly recommend it (link in the parts list section).

Step 8: Riding Statistics

I used a GPS tracking app called Cyclemeter to measure my distance, speed, and elevation while riding.

I brought the board to a local park fully charged and rode around 7.8 miles, when I got back I connected the board back to my charger and it indicated I still had around 25% battery left. With a little math you'll get a full range of around 10 miles.

Next I brought it to a flat straight away and wanted to test the top speed of the board. I ran it a couple of times and pretty consistently stayed between 18-21mph as the top speed, not too shabby!

Step 9: Future Changes/ Suggestions

After showing this off to a couple engineers at work, I found the main flaw is the lack of removable batteries. LiPo batteries can be very dangerous and should be inspected regularly. With my current design it is very inconvenient to take the electronics cover off and inspect the batteries, simply because I wasn't thinking about battery safety.

In the future I plan on redesigning the electronics cover to allow the batteries to be pulled out and disconnected from the board. Everything else has been working wonderfully!

Please let me know if you have any questions, hopefully this will give you enough confidence to start designing and building your own!

-MattCarl

Comments

author
ZainebA (author)2017-01-14

Hello I want to use the same 3D motor mount design but a different motor which is 280 KV brushless motor. https://hobbyking.com/en_us/turnigy-aerodrive-sk3-...

Will the motor be fit for the same design you assembled?

author
DIYPro0505 (author)2016-12-28

Hi! I have a quick question to ask, if i get a motor that says it needs 8s-10s to operate, can i use a 6s battery? Im asking this because i cant find any 8s esc and dont want to put out $100+ for one. The motor im planning on using is https://hobbyking.com/en_us/turnigy-aerodrive-sk3-... Thanks!!!

author
KoenS1 (author)2016-11-17

nice build tutorial! I just started to make my own. https://youtu.be/yWeLAkTYFoY (build log)
I will try to make the best quality board under 400 $

author
pandadude (author)2016-09-16

Great 'ible man! I make a bunch of boards with a vacuum press and many of my amigos have converted to electric as you have but were certainly not the 'documenting' type. This is a great service to novices (and lazy people) that makes the engineering involved with this project managable to someone without a machine shop at their disposal (as me and my friends do, being at an engineering school), albeit requiring the 3D printer. I'm not as confident about the massive use of PLA as you seem to be, but this is great either way.

author
Matt Carl (author)pandadude2016-09-21

Thank you, that means a lot! I was really frustrated with how hard it was to find information on how to build one so I wanted to be really explicit with the tutorial. I printed the motor mount at 75% infill which makes it really solid. The first version I printed was at 40% and cracked after 20 miles or riding but these haven't budged after 50 miles. Thanks again for looking!

author
DarylO3 (author)2016-09-20

im doing a science research project for my senior year and definitely going to build one of these! You inspired me man! Thank you

author
Matt Carl (author)DarylO32016-09-21

That's awesome, it's a really fun project and definitely helped strengthen my engineering and design!

author
MartinL175 (author)2016-09-12

Would there be any advantage to doing this with two motors? How well does the braking work?

author
MartinL175 (author)MartinL1752016-09-12

Also is there any way you can make a smaller RC transmitter?

author
JakeG52 (author)MartinL1752016-09-13

You can just use an arduino. The motor controllers work with regular PWM, or "servo-code" outputs. Get a no-name arduino for $4 each on ebay, if you want wireless, get a $1 radio trans/receiver (433mhz or 355 mhz as examples, get the legal frequency for you country). It should be about the easiest thing to code, just a few lines since you only have one output. That would be under $10, and you could program it to have a steady acceleration throttle curve, or anything fancy you want.

You could also use brushed motors, they have dirt cheap (like $5) motor controllers, and just use like a drill motor (but you would have to re-cad it, and I know not everybody has used CAD software before, but it is a cheap alternative).

I'm planning on doing something similar, but going for all wheel drive, twin motors with differentials in the trucks. It will be a while till I get time, cost should be around $45-50 +battery and board choice.

author
Matt Carl (author)JakeG522016-09-14

Very true, that's definitely another way of doing it. I've even seen a video on someone literally using a lithium ion powered drill attached to a wheel to power it. It would be a cool project to write the software that controls the motor!

author
Matt Carl (author)MartinL1752016-09-13

Yes! Someone made a 3D printable case modification for the RC transmitter and cuts the size in half, it's the next thing I'm going to make:

http://www.thingiverse.com/thing:922378

author
Matt Carl (author)MartinL1752016-09-13

Two motors means higher torque, you'll be able to bomb up steep hills, have crazy acceleration and a higher top speed. The braking system works great, I'm able to program the ESC and change what the max amount of braking force it. It's really helpful when you're going a little too fast for comfort.

author
JakeG52 (author)Matt Carl2016-09-13

This is a pretty awesome design, you did a good job. I particularly like the mount where it clamps onto the trucks. I know I would take cruising in style over walking any day! That's no joke about the "too fast for comfort", your hitting around 20 mph with that board. Excellent job!

author
kylegilbert (author)2016-09-10

Amazing! Love the video.

author
Matt Carl (author)kylegilbert2016-09-10

Thank you!

author
alaaaaaaaaan (author)Matt Carl2016-09-13

Great build. Are you still able to use the board normally if say, the batteries give out?

author
Matt Carl (author)alaaaaaaaaan2016-09-14

Thank you! Yup, although there is still some resistance in the motor that makes it significantly tougher to cruise, it's basically constantly slowing you down. Definitely possible to ride it if batteries give out, it's just not a pleasant as if you were on a board without a motor.

author
suitux (author)2016-09-13

Wow, nice job dude! I'll make it and I'll post photos!

Thank you!!

author
Matt Carl (author)suitux2016-09-13

Thank you! Please do, I'd love to see it!

author
iamwildman1 (author)2016-09-10

Thank you for the inspiration to

author
Matt Carl (author)iamwildman12016-09-11

No problem, I'm glad to hear it inspired you!

author
tysonmooney (author)Matt Carl2016-09-12

hey matt you have inpired me for this job iam have been trying to make my own electric long board all year and i am also doing this for my year 12 majour work

if you have any other tips and anything that could help me would be really help full

author
Matt Carl (author)tysonmooney2016-09-12

That's awesome, I'm so happy to hear that! Let me know if you have any questions or run into any roadblocks, I'd be happy to help!

author
VadymK2 (author)2016-09-11

superb. it is something I was looking for! thank you!

author
Matt Carl (author)VadymK22016-09-11

Thank you, I appreciate the kind words!

author
svigness (author)2016-09-11

cool dude

author
Matt Carl (author)svigness2016-09-11

Thank you!

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