Here is a build I put together about 5 years ago: The Electrotechnics V3
I’ll start with the battery, I assembled a 12s3p flexible flat pack out of LG HG2 cells (20A 3000mAh) using my preferred flavor of construction at the time, soldering silicone insulated wire to the cells. I’ve never had an issue with soldering, you just have to use the right techniques, but it is easy to mess up the cells if you don’t do it right.
Above to the left is a close up of the cell bussing technique (on a different build) and to the right are the cells setup in the 12s3p config and bussed together.
I finished it off by adding a Bestech BMS and an xt-30 charge port. I also cut out an aluminum heatsink for the BMS, since the balancing resistors would get quite hot while charging.
Next, for the drive train I picked out the Torqueboards TB218 trucks and needed to figure out a motor mount. So I drew up a mount in CAD and got to cutting.
I cut out wood pieces as a mock up:
Once fit was confirmed, it was time to cut some aluminum:
The mount is a two piece, a clamp for the caliber style truck profile and an adjustable motor mount plate with slots for motor adjustment and an idler pulley. In hindsight I should not have removed as much material on the mount plate where it bolts to the clamp, it ended up cracking there after 3 years a couple thousand miles.
I 3D-printed some HTD-5M wheel pulleys out of PETG plastic and mounted everything up on the trucks, using a couple stacked bearings and an idler/tensioner pulley. I used orange 97mm urathane wheels, a $30 ebay special and they did not disappoint, I still have them today.
Here it is all mocked up with the FocBox Unity motor controller:
The motors are KEDA 56-63 motors at 195Kv, I did have to shorted the shafts and grind a flat on them, as it was intended for a collet style prop adapter.
Oh and for the remote control I had assembled together a Firefly Nano remote.
I double sided sticky taped the battery and focbox to the bottom of the board and added a few velcro straps for support to take it for the first ride.
At this point, summer was over, and school was getting bust so the board stayed in this configuration for the next 6 months of riding to and from class. It was fun having a very obviously DIY’ed board during college. Lots of people would ask about it and thought it was a really cool project.
Now that the semester was over it was time to finish off the board with an enclosure and new grip tape, so the grind began to complete it before the winter break ended.
More CAD and a while lotta cutting and sanding later I had a positive enclosure plug:
Foam for test fit and MDF for the final:
After hours of sanding and painting it was starting to look good:
Then it was time to make the mold:
Then came plug removal, it was tough, that thing was really stuck in there, despite the draft angle and smooth edges:
It didn’t come out perfect but with a bit of patching with gelcoat and lots of wet sanding it turned out alright:
So it was time to make the first enclosure:
It was far from perfect but not terrible for my first resin infusion layup attempt.
After trimming and sanding it looked pretty good on the board:
After a few more trial runs of enclosure making and process refinement I put together what was supposed to be an orange enclosure, however it ended up red after the epoxy went in.
1 surface layer of thin fiberglass, Kevlar/CF hybrid 2x2 twill, then two sheets of CF 2x2 twill, followed up with another later of fiberglass to make sure the inside was not conductive. No infusion this time, just a good old fashion hand wet-out layup.
After trimming and sanding here is the mockup of the electronics in the new enclosure:
And here it is after wet sanding and mounting to the deck. I played around with a few fastener configurations before ending up using some double start screws intended for use in plastics.
To finish it off, I gave it a thick coat of epoxy, let it cure, then sanding it smooth again and finally polished it to a shine! This was not a trivial process at all, but it did look good once finished.
And there it was complete, not a minute too soon…the evening before school started back up.
Now fast forward another 6 months later, I still had the original grip tape from when I bought the deck. It was time to make something custom that completed the look.
So I started with a paper and pencil which ended up in CAD as usual.
After some zaps on a laser cutter with black and orange grip tape, the idea was materializing:
The ET logo in the middle looked a bit clunky and I don’t claim to be any sort of graphics designer, but I thought it turned out pretty good overall and completed the look of the board.
