Intro: Homemade Electric Longboard
In the past, I've shared a few longboards I've built on Instructables, but this time it's a little bit different, because it's ELECTRIC!
In this I'ble, I will outline the tools, parts and steps I took to create this fast, long range electric longboard.
Hope you guys enjoy!
If you guys like it, please vote for me for the"Make It Move" Contest!
Step 1: Gather Tools and Materials
Here's the list of tools used for this project:
- step drill bit
- metal file
- vise grip
- rubber mallet
- drill press clamp (this is all I have, but a bench vise would be better)
- soldering iron
Here's the list of materials/parts used for this project:
- hub motors for electric skateboards (I used 2 for dual motor setup)
- dual hub motor ESC + receiver + transmitter combo (available on eBay or AliExpress)
- 8000mAH 3S LiPo batteries (I used 2 to connect them in series to create a 6S battery pack - more on this later!)
- a complete longboard with trucks (I reused one of the longboards I've built in the past - you can see my other I'bles to check them out!)
- 2 extra longboard wheels that match the hub motor wheel size
- 14 gauge sheet metal (for the battery + esc enclosure)
- metal shears
- shrink tubes
- 9 pin aviation plug
- 6S balance charger
Step 2: Take Measurements of Your Hub Motor (for Modifying Existing Trucks)
There are custom built trucks out there for these hub motor setups, but I wanted to minimize the cost of this project, so I decided to modify my existing trucks to fit the hub motors as they mount slightly differently than a standard longboard wheel.
As you can see in the first photo, the hub motors have a motor built into the wheel, and my hub motors had a square hole for the trucks to fit into to keep it in place, and these motors are almost flat on both sides whereas a regular longboard wheels are usually tapered in the center.
In order to fit these hub motors into my trucks, I had to remove a precise amount of material off my trucks to reveal the shaft. You can see the illustration in the second picture. Note that I also have to remove material on the regular wheel side of the trucks in order to make both sides equal in length when the motor and the wheels are in place. This will all make more sense in the next few steps.
I drew on my notebook all the critical dimensions of the wheels, to find out how much material had to be removed from the trucks.
Step 3: Modifying the Trucks (with a Hacksaw and a Metal File)
This step has quite a few pictures, so I will include bullet points that match with the picture numbers, but the goal of this step is to make a slit across the arm of the truck and twist off the access metal to reveal the shaft that's inside, and leave a square shaped arm for the hub motor to fit into. Hopefully in the end, it'll all make sense.
Considering how much brute force there is to complete this step, it actually didn't take long at all to complete, so I think it was totally worth the effort.
Photo 1 - Photo of an unaltered, regular truck
Photos 2 to 3 - I put some masking tape on where I need to make the cut
Photos 4 to 5 - I used a hacksaw to make a slit across the perimeter of the arm of the truck. Be careful here not to go too deep or you will start to cut into the shaft!
Photos 6 to 7 - I used a drill press clamp to hold the truck in place and used a vise grip to break the unneeded metal free. Keep twisting and rotating the vise grip while pulling to get the excess metal completely off the shaft.
Photo 8 - Photo of the trucks with the excess metal taken off. Notice that there are grooves on the shaft that held the metal together. This needs to be filed off.
Photo 9 - Photo of the shaft with the grooves filed off with a metal file.
Photo 10 - I put another layer of tape to show where I need to make the next cut. This time, I don't actually need to cut anything, just file off the material to create a square shaped arm that can go into the hub motor.
Photo 11 - I used a metal file to slowly remove the material to create a square shape. Go slowly and check frequently to see if the trucks fit into the hub motor.
Photos 12 to 15 - Photo of the modified truck. Note the square shape that will match the hub motor insert.
Photos 16 to 17 - I repeated slit, clamp, twist modification on the other side of the trucks so that the regular wheel can sit further into the trucks to keep the lengths of the trucks equal relative to the center, as illustrated in picture 2 of the previous step.
Photos 18 to 19 - Photos of the longboard with hub motors and wheels attached
Step 4: The Electronics
If you aren't too familiar with the electronics, the first picture shows a simple wiring diagram for the longboard.
The "S" term in LiPo batteries mean "cells in series".
For my setup, I wanted a 6S battery, and also wanted a low profile, so I combined 2 3S batteries and put them in series to create a 6S setup.
**BE CAREFUL - LITHIUM BATTERIES ARE EXPLOSIVE AND YOU NEED TO BE EXTRA CAUTIOUS WHEN HANDLING THEM. MAKE SURE NONE OF THE TERMINALS EVER GET SHORTED AS THEY CAN CAUSE SPARKS AND POTENTIALLY EVEN FIRE. I'D RECOMMEND AGAINST ALTERING LITHIUM BATTERIES IF YOU ARE INEXPERIENCED.**
For connecting 2 3S batteries in series, the second picture shows all the wiring, including the balance charging leads. The POWER leads get connected to the ESC, and the balance leads are needed when charging the batteries.
Step 5: Wiring and Soldering the Electronics
First, I laid out all the electronics the way I would have them laid out on my board.
I then cut and soldered all the wires together following the wiring diagrams in the previous step.
**DO NOT STRIP THE WIRES ALL AT ONCE AS OPEN WIRES CAN CAUSE SHORTS. ONLY STRIP ONE WIRE AT A TIME THAT NEED TO BE SOLDERED. USE AS MANY SHRINK TUBES AS YOU NEED AS THE LAST THING YOU WANT IS AN INTERNAL SHORT AND A CHEMICAL FIRE.**
TIP #1: put some masking tape and label each wire so you know which wires need to be soldered together. For soldering thick gauge wires, wrap a thin wire around the splice. It strengthens the joint, and keeps wires compressed.
I added a 9 pin aviation plug for my balance charging leads. I numbered each of the prongs on the plug, and I mapped each prong with each of the cells on the battery.
TIP #2: again, solder 1 wire at a time, and put a shrink tube after each soldering work. This will ensure that you don't get a short during the soldering process.
*IT IS CRITICAL TO MAP THE CELLS AND THE PLUG CORRECTLY AS 1 WRONG WIRING CAN CAUSE A SHORT
Once the longboard part of the wiring is complete, I made a custom cable for balance charging my longboard as well (See picture 13).
Step 6: Building the Enclosure
There are many enclosure ideas out there, and some have used lunch boxes, built their own fiberglass enclosures, etc, etc..
I decided to use sheet metal and the result was pretty good.
I first scored on a sheet metal with a sharp tool, and cut the outline out with a shear.
I then clamped the sheet metal with hardwood pieces and used a rubber mallet to start bending the sheet metal.
A step drill bit was used to drill 2 holes on the enclosure: 1 for the power button and 1 for the balance charging aviation plug.
I then drilled a bunch of holes around the perimeter of the enclosure, which will let me screw the enclosure directly on to the board.
Step 7: Add the Enclosure and Grip Tape.... and Ride!
Once the enclosure was built, I laid out all the electronics in the enclosure, then screwed the enclosure on to the bottom of the board.
At this point, the longboard is basically done!
Some future improvements to consider is to waterproof the board to protect the electronics.
For my setup, I am getting roughly 30km/h as my top speed, and more than 10km for range.
I hope you enjoyed this I'ble!
If you guys like it, please vote for me for the"Make It Move" Contest!