Introduction: Diy Electric Skateboard
After 2 years of research I have build my first electric skateboard.
Since I have seen an instructable on how to build your own electric skateboard I have been in love with diy electric skateboards. Making your own electric skateboard is a form of multidisciplinary art for me. It involves mechanics, electronics, design and so on. There are a lot of engineering disciplines involved with building your own electric skateboard and that's why I'm so fascinated about it.
In this instructable I will explain how I have build my budget electric skateboard.
A special shout out to the electric skateboard builders forum for all the help. If you want to make your own electric skateboard be sure to check out the forum!Probably every question you have is answered there, also feel free to ask me
The images that are not my photo's are images found on google, I do not own them but listing every link is a little bit to messy.
If you like this instructable make sure to vote for me! :)
Step 1: The Plan
This is my first diy electric skateboard and I wanted to make a cheap one. The first thing that you will experience is that electric skateboards are pretty expensive. A lot of cheap diy boards are around the €500 or so and I found that still pretty expensive. That is also the reason I have spend so much time reading and researching about diy electric skateboards.
If you build your own electric skateboard you need to set some minimal requirements. Mine were:
- minimal range of 7 kilometers (around 4 miles)
- minimal top speed of 24 km/h (15 m/h)
- easy to use
I don't need a lot of torque because in the Netherlands we don't have realy steep hills or so but it still would be nice to have.
With these requirements in your mind you can choose the parts for your build!
Step 2: Parts List
Because I wanted to make a cheap board I have ordered a lot from banggood. The advantage of banggood (or other sites like aliexpress) is the low pricing, the disadvantage is the long 20 days shipping. So keep that in mind when ordering all the parts!
The prices may fluctuate a bit depending on sales, local prices and shipping.
- Motor (€56): https://www.banggood.com/Racerstar-6368-BRD6368-2...
- Drive train kit (€15,6): https://www.banggood.com/Electric-Skateboard-Acces...
- Better motor mount (€13,5): https://www.banggood.com/Electric-Longboard-Skateb...
- Extra belt (€1,7): https://www.banggood.com/10mm-Synchronous-Belt-Pul...
- 120A ESC (€43,95): https://www.banggood.com/Racerstar-120A-ESC-Brushl...
- 2x 3S 5000mAh 20C zippy Lipo's (€21,4): https://hobbyking.com/en_us/zippy-flightmax-5000ma...
- 6S BMS (€14,9): https://hobbyking.com/nl_nl/6s-li-ion-pcm-charge-4...
- Remote + receiver (€18,8): https://www.banggood.com/2_4GHz-Radio-Remote-Contr...
- 25.2V Laptop adapter (€9,75): https://www.banggood.com/25_2V-2A-Smart-Charger-Fo...
- ESC programmer (€5,75): https://www.banggood.com/Racerstar-LED-Program-Car...
- Battery level indicator (€5,75): https://www.banggood.com/12V-6-63V-LCD-Acid-Lead-L...
- XT90 antispark plug (€3,1): https://www.banggood.com/Amass-Anti-Spark-Sparkpro...
- 2 meter 12AWG black wire (€4): https://www.banggood.com/DANIU-2-Meter-Black-Silic...
- 2 meter 12AWG red wire (€4): https://www.banggood.com/DANIU-2-Meter-Red-Silicon...
- Charger port (€1,3): https://www.banggood.com/Waterproof-3A-5_5-X-2_1mm...
- Big latching button (€2,9): https://www.banggood.com/12V-5-Pin-19mm-Led-Metal-...
- Little momentary button (€1,65): https://www.banggood.com/12v-4-Pin-12mm-Led-Light-...
- 3s JST-XH balance leads (€4): https://hobbyking.com/en_us/jst-xh-3s-wire-extensi...
- toolbox from hardware store (€2,50)
- second hand longboard (€30)
Step 3: Anatomy of an Electric Skateboard
The electric skateboard consists of three main parts: the motor, the esc and the battery. These three main parts are also the the parts that will need the most of the research. I will go over how you can choose between all the options. Maybe I'll not go to deeply in to every specification but I am making some in depth video's about how to choose the parts.
For electric skateboarding a brushless dc motor is recommended, because of the power it can deliver in such a small motor.Almost the most important specification of a brushless dc motor is the KV-ratio. KV stands for: rpm/Volt applied to the motor. So if you apply 10volts to a 190KV motor, you will get 1900 rounds per minute. The higher the KV the lower the torque (force) the motor can output. It's not easy to find the right KV-ratio for your board. The usable KV-ratio for electric skateboards is between 100 and 300 KV. If you have a high voltage battery (like 10s) you want to go for a lower KV, that's because a 300 KV motor • the 37v of a battery = an rpm of 11100. That is a little bit to high rpm for electric skateboards. I have used a 280KV motor, because I have a 6s battery, so a low voltage, and I still wanted a decent speed so I choose a higher KV-ratio. This thread may help you for finding the good KV-ratio.
There are still many specs to go over but I will make video's about it soon!
For the ESC it is pretty simple: you just want to go for the VESC but if you are like me and have a limited budget, you go for the rc car ESC. The ESC has some specs you need to consider. The max amperage, the most common ESC in electric skateboarding is the 120A esc. That ESC can handle 120Amps and that will be fine for sure. The maximal voltage needs to be considered too, that will depend how much battery cells you can hook up in series. If you want to have a sensored motor set up you will need a sensored ESC, otherwise the sensored motor is just a normal motor. The last specification you want to look up for is if it has UBEC. UBEC means that you can hook up the reciever directly to the ESC without any external powersource. Almost every ESC has UBEC but it's smart to search for it too.
You have two categories of batteries: LiPo and Li-ion. Disclaimer: I am not an expert on this topic. LiPo and Li-ion batteries have almost the same electronic characteristics. They have the same maximal voltage of 4,2v and nominal voltage of 3,7v. LiPo batteries are a little bit cheaper but are more fragile, Li-ion are more expensive but are less fragile. There are thousands of other considerations to think about but that is for a video I will make in the future. But what I have heard on the forum is, correct me if I am wrong, that Li-ion is the way to go if you have the money for it. If you have a tight budget like me: go for LiPo.
You can also find all the basic information on the electric skateboard builders forum too.
Step 4: Attaching the Pulley's
Attaching the pulley's is an important part for the electric skateboard. With the drive train kit that I've bought came the two needed pulley's.
Attaching the pulley's was pretty straight forward, because the screws and bolts were delivered with them, but I ran into two problems: The inside bore diameter of the smaller pulley was to small and my wheels are solid urethane without any holes to put a bolt in.
The small pulley, which goes on the motorshaft, had a too small inside bore diameter. The inside bore diameter was 8mm while the motorshaft has a diameter of 10mm. Most of the electric skateboard motors have a motorshaft diameter of 8mm but unfortunately this one not.
I solved this problem by drilling a bigger hole in the pulley. I used a 10 mm drillbit and a drillpress to drill the hole straight. It was an easy solution but the pulley could shatter. Because the pulley was pretty thin around the hole already. If the pulley broke I would have ordered a new pulley with the same teeth and with an inside bore diameter of 10mm.
Mounting the big pulley on the wheel. I have solid wheels on my longboard so I had to drill throught the whole wheel to mount the pulley.
I drilled holes for the screws with the needed drillbit on the 'inside' of the wheel (see picture). With the inside of the wheel I mean the side that is facing the truck, in the picture it is also explained. I was lucky enough to have a pulley that fit perfectly on my wheel, the pulley slid smoothly in the inside of the wheel. Because I didn't have to worry about the pulley being straight on the wheel. I have drilled everything with a drillpress again because I wanted the straightest holes possible. I marked where I needed to drill by alligning the pulley and just drilled through the screw holes with a small bit in the wheel for a few millimeters. Then I drilled those holes throught the whole wheel with the needed bit.
Because the screws that were included in the kit were a little bit to short I needed to do something for that. The main problem was that the screw head limits the distance the screw can go in the drilled hole. It was solved easily: I drilled with a bigger bit on the 'outside' of the wheel back in the holes. Because I did that I was able to put the screws further in the wheel than before. It is explained in the pictures too.
After that it was just a matter of fastening the screws and I was done.
Step 5: Mounting the Motor
Mounting the motor to the truck created the most hassle of all parts. It turned out that the mount I bought was crap. There are more people that have used the mount and the mount snapped in a short period of time they told. The issues I had were: the mount kept wiggling and the motor didn't fit on the mount. That's why I recommend this mount: https://www.banggood.com/Electric-Longboard-Skateb...
I will order this one soon and I hope that in the mean time my current motor mount won't snap.
Mounting the motor to the mount:
The kit don't have bolts delivered with it to mount the motor to the motor mount. So you need to buy new ones from a local store. The mount comes with a routed inlet for the motor to slide in. Unfortunatly the motor I bought is to wide for that inlet. that's why the motor mount is turned with the 'wrong' side facing the outside.
Mounting the mount to the truck:
There are different ways to mount a mount to the truck. The most common ways to mount it is by welding, clamping or screwing it on the truck. The kit can just slide on the truck and screwed tight to truck. If the truck has a bigger diameter hangar than the whole in the mount you can file the hangar to the desirable diameter.
The screws that come with the kit have a pointy end. That pointy end causes still the mount to, no matter how strong you fasten the screws, wiggle. You need to buy seperate bolts with flat ends, that works considerably better.
The bolts in the mount, the ones that clamp on the truck the most, will loosen up over time by vibrations. There are a lot of vibrations in a skateboard so it is a big deal. The solution for that is loctite. Loctite is an expensive life saving 'glue' for an electric skateboard. It ensures the bolts to not loosen up by vibration. Loctite is difided in different strengths: soft, medium, strong. Medium strength is recommended for electric skateboards because it will prefent the loosening but you are still able to unscrew everything. I have used soft strength and it sucks.
Step 6: Electronics
The electronics are pretty straight forward. The electronics consist of soldering and/or connecting parts together. The only thing you need to do is following the wiring diagram I made. I will post a video about the electronics soon to explain everything better. If you have any questions, you can ask me or what is recommended: go to the electric skateboard builders forum. For an electric skateboard this is not the most complicated wiring.
Some handy things to know:
You need good cables for connecting the battery to the ESC etc. The recommended thickness is 12 awg but you can go super safe and buy 10 awg cables.
Everyone uses XT90 antispark connectors, but why? First of all safety, if you place one between the battery and everything you can disconnect the batteries if something goes wrong. But there are many people that use it as an on/off switch. That is because you can't use a normal little button between the battery and everything. That is because the ESC can ask an amperage of 60 amps for instance and a simple button can't handle such a high amperage.
And last of all is connecting the motor. You don't realy have a certain order to connect the motor wires to the ESC. You just need to connect the motor and press the trigger on the remote, if the motor doesn't turn the right way you only have to switch two wires with eachother and you'll be good to go.
Step 7: Adding an On/Off Button
To get a on/off button on your enclosure you'll need to extend the button on the ESC. It can only be done if you have an antispark switch pcb or an ESC with a built in on/off button.
Soldering wires to the button:
To solder the wires to the button you need to uncover the button. The plastic casing is held together by four screws that hold the heatsink. So you first need to unscrew the four screws and then it is easy to uncover the button. When the button is uncovered you can solder two wires to both solderpoints of the button and then the cover can be screwed on again. Because the wires obviously have a width, the casing can't close fully again. To prevent that you can grind a bit away from the casing where the wires come out of it with a dremel. This all is an easy task, if you don't let it fall like me (see video), and it is very practical so I recommend doing this mod.
Here is the instructable that inspired me to do this:
Step 8: Wiring the BMS
To charge the batteries I have choosen to use a BMS. There are two options for charging: a BMS or a LiPo charger. They have both their own advantages but the reason that I chose the BMS is because the ability to charge the battery with a simple laptop adapter.
A BMS is a pcb that monitors the batteries and keeps them in balance.
The BMS I have bought is only for charging the battery because it can't handle the high power consumption of the motor.
Connecting every cell to is pretty straight forward. The diagram that you can find online explains it pretty good. To connect the two 3s batteries to the 6s bms I soldered two 3s jst-xh balance leads to the BMS. The BMS comes with a 6s balance wire already so it's only a matter of soldering, but be careful: it can go wrong if you make a mistake. That's why I recommend you to test everything if you are done without plugging the batteries in. I did that too with a multimeter and checked every balance pin's voltage.
You can see how everything needs to be soldered in the pictures.
There were two things not clear when doing this and are maybe handy to know. The first one was where the ground wire (GND) of the second battery needed to be soldered, it turned out that the ground wire can be soldered to the third cell balance wire (see picture to understand). The second thing was where to connect the charger positive and negative to. The negative charge wire has a special indicated spot on the BMS himself so that wasn't that easy to find. The positive charge wire needs to be connected to the main positive wire from the battery. If you connect the positive charge wire to the balance lead of the sixth cell, what I did on the first time, it will damage the battery. So on the second picture I did it wrong, the red wire called 'positive charging lead' needs to be on the positive of the battery.
Step 9: Choosing the Enclosure
Ofcourse you will need an enclosure for your build. The purpose of the enclosure is to protect the electronics against water and getting crushed. The main difficult parts of making an enclosure are: the flex and the concave the deck has. These variables can make it hard to make an enclosure.
There are a lot of ways to make your own enclosure. You can make it out of wood or metal, you can 3D print it or vacuum form your own plastic case. I went with the cheap and easy way. This is certainly not good looking, but it has some style in my opinion. I bought a screw sorting box locally and used that as enclosure.
This is the easier solution because you dont realy have to encount the flex and concave in the board. Because the box is from plastic it can bend a bit with the deck his curves. This solution is also by far the cheapest option, the screw sorting box was only €2,50.
I do want to do vaccuum forming in the future with ABS sheets because that looks quite good. But if you want to do it right now you can maybe use this sheet:
For inspiration you can go to a thread like this one from the electric skateboarder builders forum:
Step 10: Protecting the Batteries
Besides the BMS you'll need other protection for the LiPo's. One of the disadvantages of LiPo's is that LiPo's can be damaged structuraly which can result in explosion, fire and unhappy you. To prevent that I have choosen to make a cage out of foam for in the enclosure.
I had some foam laying around and I drew out the outlinings of the battery and cut out the battery slots.
Step 11: Designing the Enclosure's Inside
I bought two screw sorting boxes so that I can make one like a prototype to sort everything out.
First I cut out all the inside walls of the box so the inside was empty. The dremel is a handy tool to use when doing this.
The only part in the enclosure that needed some modification were the batteries. Because the batteries can't handle vibrations that good I wanted to make a foam cage for them. I measured the width of the enclosure where the batteries were going to be installed and substracted that by the width of the two batteries combined. The picture says enough but I made a foam cage that was thick enough to fit in the width of the cage and used the same thicknes for every wall of foam.
When the inside was empty I also began thinking about the placement of every part. This is entirely based on your own likings. A good tip is trying to use the existing walls in the box for structure and potential places to mount something to. Although I had cut out the walls, I marked the walls that I didn't want to cut out in the final box, because I could mount the ESC to it for instance. Designing the inside of the enclosure was exualy one of the hardest things for me because it requires a lot of skill.
Designing the enclosure is a lot of placing the parts in the enclosure and shuffling them around. One thing to look out for are the wires: for electric skateboards it is necessary to use thick wires that can handle the high current. Those thick wires are not very flexable and will take up quite a lot of space, watch out for that!
Step 12: Finishing the Enclosure.
I bought a new box to cut everything the same way but with a nicer finish. I sanded every corner or cutting slot with sandpaper smooth so it had a better look.
The parts in the enclosure are mounted with glue. The foam cage for the batteries, ESC and buttons for instance. The glue around the buttons, charge plug and xt90 antispark plug also function as making the enclosure a bit more waterproof.
The batteries are held on their place by the foam cage and by some velcro.
Step 13: Mounting the Enclosure
I went with attaching the enclosure with screws.
To get the screws good in the deck you need to drill for every screw a hole in the deck. That isn't too difficult, the only thing is that you need to drill on the griptape side. In that way the griptape doesn't get damaged that much.
Step 14: Future Improvements
I don't realy have had the time to ride enough on my skateboard to conclude what needs improvement but I found some improvements already by building the board so I am going to list them.
First of all I want to try to make an enclosure for another build out of ABS. I am realy interested in how vaccuum forming works etc. and it hopefuly looks amazing. The next improvement I want to do is in the batteries, I am hoping I can make a Li-ion batterypack and get a bigger pack so I have more range. The motormount was a big problem too, next time I want to probably make one myself.
I also want to play with lighting on my electric skateboard. I am working at the moment on something for my skateboard and will post something about it in the future! So be on the look out for that ;)