Introduction: DIY $150 Electric Longboard
Electric vehicles are cool and there is no doubt about it. Especially electric skateboards! Ever since I saw Casey Neistat riding boosted board I wanted to try this on my own. Price of the boosted is high or even very high so as usually I thought that instead of buying one I will simply build it myself. So there it is I managed to build it for about $150 (I know this may sound too cheap, but actually I spent a little bit less than that, I bought a really cheap longboard for about $50 and even with $30 18650 battery pack that I made it is still below $150) it can drive with a max speed of 24km/h and drive 15km on a single charge (with my DIY18650 battery pack)
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Step 1: Parts
There is a lot of different motors, ESCs, pulleys and batteries that you can use for this project. Here is what I decided to go with. I bought the longboard locally it was just about $50.
As the battery for this project, I used my old LiPo batteries. You need to power the ESC with 6S battery so I used two 3S packs and connect them using this connector. I want to replace those batteries with 18650 and BMS, I am not a huge fan of LiPos.
If you don't want to make motor mount on your own as I did, you can try using this one but it may not fit your truck.
Step 2: Making the Motor Mount
I wasn't sure if any of the motor mounts that are available online will fit truck of my longboard so I thought that it is a good idea to make it on my own since I have Dremel CNC that can mill aluminum. I decided to start with prototyping the shape of this mount with a 3D printer. I did a rough design in Fusion 360 and after an hour of printing my first prototype was ready, I got it really close to what I wanted to have right on the first try. After 5 different designs, I got one that was perfect so I headed to my workshop to machine it out of aluminum on a Dremel CNC because obviously 3D printed part for that is not strong enough.
Setting up this milling was easy to do just 3 pockets to cut and one contour cut. Pockets went amazingly well, shiny surface, perfect dimensions. But there was a problem with contour cut and there was a small shift on each layer so I had to cut out the part manually.
After assembling I dropped the longboard accidentally and the mount got loose so I had to reinforce it with a 3D printed clamp (100% infill, 4 perimeters, PETG filament).
Step 3: Attaching Pulley to the Wheel
To attach the pulley to the wheel we need to drill 5 holes in the wheel. In my case, I also had to print support for this pulley because it was a little bit too deep in the wheel. Drilling those holes is quite simple to do, use a standard drill bit that you would use for metal or wood and go slowly, it's easy to melt this rubber. After that simply put in place those 5 long screws and try to perfectly center the pulley in order to make it work great. You can find my 3D printed support design below.
Step 4: Assembly
Start by drilling two holes in the aluminium plate to attach 3D printed clamp. Then fix a motor to the plate with 4 screws, don't tighten them completely yet. Put the mount on the track and fix it as strongly as possible. We can also put a smaller pulley shaft on the motor shaft. Now it's time to mount a wheel with a pulley that we attached previously. And the last thing, add belt and tighten it by moving a motor and now you can tighten the motor screws.
Step 5: Electronics
Electronics connection is extremely simple in this project we need to connect the batteries and thanks to XT60 connectors there is no way to do it wrong, we also need to connect the motor to the ESC (just 3 cables). If the motor spins in the opposite direction just swap two of three cables and it will change. It's really as simple as that, there is nothing more to do with electronics connection.
Step 6: 3D Printed Case
I always try to make my projects as professionally as I can, a simple 3D printed case can really add a lot to your project. It's also always good to spend more time on measuring and designing in CAD then reprinting the part especially when it takes few hours to print it.
I end up with two different design of the case, a smaller one for LiPo batteries and a bigger one for my 18650 battery pack. You can find both of them below. For smaller case, there is also a flap to print and you should use threaded inserts in order to be able to fix the flap to the case. Keep in mind that the way that smaller case is attached is really not reliable and it can break easily, I fixed that with a bigger case.
Step 7: Drive!
It's time to test your very own electric skateboard. Grab a remote, put your helmet on and skateboard on the ground. You need to turn on both the skateboard and the remote. Gently push the throttle up, be careful if you never ride any electric skateboard before it's easy to fall. It takes some time and practice to master riding an electric skateboard, but that's a lot of fun and is a great way to go through crowded streets!
Step 8: DIY 18650 Battery Pack
LiPo batteries that I used were in a really bad condition, I knew that I will have to replace them soon. So a week after finishing my electric skateboard I bought some 18650 batteries to make my own battery pack. I decided to go with 6S 3P pack that means 3 batteries in parallel and then 6 of those in series, together 18 batteries. The proper way to make this kind of battery pack is to spot weld it, unfortunately, I don't have a spot welder because of that I had to solder them. Soldering those batteries is not recommended, it's easy to destroy them that way. To solder them I used nickel strip, that's what they use for spot welding. This pack turned out slightly bigger than my LiPo batteries so I had to redesign the case and print it again. In order to properly and safely charge the batteries, we need to solder the balancer connector to the pack and connect it to the BMS (Battery Management System). The problem is that BMS that I used can output max of 15A, that's too low for an electric skateboard. That's why I connected my XT60 connector directly to the battery and not to the BMS, that way we don't have over discharge protection from the BMS fortunately electric ESC substitute has the low voltage protection and it will shut down the motor when the voltage of the battery is too low. Completely unprofessionally I protected all of the battery terminals with insulation tape, not professional but works fine :) Then I added the charger port to the BMS, put all of that in the 3D printed box and mounted to the skateboard. And it was time to test the skateboard again, this time with the proper range test, if you want to see the results check out videos about this project on my youtube channel!