早く (hayaku) means “soon” in Japanese. This build is named so because that’s what I kept telling my friend for whom the board is for.
- Haya HB83 shortboard (made by @bevilacqua) , because my friend wanted a small board
- 10s5p 30Q battery (cells from @PowadangaBoi), to maximize range, while being 10s for safety
- Bestech D596 80A BMS from @BigBen, to omit having an anti-spark
- Focbox ESC. Original plan was a cheap TB one (hence 10s), but focbox fit better, and this build deserves it.
- Caliber II trucks, because they were cheap. The color matches the deck perfectly.
- Kyro soft angled risers for stability
- Evolve 97mm GTR wheels, because of the color scheme
- Abec wheel pulley from @ShawnyP
- Maytech 6374 150kv motor from @seaborder for dirt cheap (unsensored)
- @Boardnamics mount with idler
- Nano X remote (from @Moros), because it easily fits in your pocket, and is quite reliable
(Prices and smaller items will be added when the board is finished.)
Building the Battery
Because of the limited space in the Haya, I had to get creative with the battery. The original plan was to use PCBs above the p-groups and cell level fusing, but at just 5p I decided against it in the end, and there is pretty much 0 room in the enclosure for any serious wiring above the cells. After scrolling through other builds, I discovered that everyone with Hayas either route the wires on the side, or increased the enclosure height by adding additional layers to the deck, which I would never do.
Because of that, The only way to fit all the cells into the deck was by doing this:
That’s right – the cells are welded with nickel, and then folded! This required a creative welding setup, because I couldn’t just weld the 5 groups together and then unfold them – I needed the folds to all be in the same direction, so that I could solder the balance wires afterwards. Welding nickel while the pack is laying on the ground was also unfeasible, because I couldn’t apply pressure to the nickel and cells to make a proper weld.
Introducing – the hanging dong approach:
I cut up a small book, and used its hard covers as a surface to hold the cells, while the connected tail went through a hole in the middle of this bench. The welding process itself took only 3 days – 1 to add all the fishpaper rings and glue the cells together with silicon, 1 to cut up all the nickel, trim its corners, flatten it with a kitchen hammer, and clean it with isopropyl alcohol, and then a day to weld everything. I would do 10 welds, 1 on each cell for the adjacent groups, and then clean the welder tips with sandpaper, to ensure consistency.
After that came the wiring. At first I tried to see if I could solder a wire directly to a nickel strip connecting the whole group without heating up the cells, but the heat definitely transfers at that distance, so I don’t recommend doing it.
All the other connections I did by again having 5 nickel strips folding, and soldering to the end of them. That way the cells did not heat up at all.
Next came the balance wires. Because the cells of each p-group aren’t electrically parallel (no nickel connecting them), I had to make sure my balance wires touched each cell of a group to keep them at the same voltage. This took days.
Because of the limited space, I couldn’t add anything to the sides of the pack, so fishpaper is only above and below. I covered the nickel connections with kapton tape, and then packing tape. This way you can visually see if any of the connections happens to break.
By the way, this is the carbon fiber reinforced version of the Haya deck. To make space for the battery, I slightly cut away from the center beam. Or more like, burned away, due to shitty tools:
I also filed down a few spots to give wires more room to flex, as well as channels for the charge port and power button, which I drilled holes for in the tail, where the usual truck mounting holes are.
The only power button I had that was short enough to fit was a momentary one, but even then I had to add some stainless steel washers to extend the hole.
Because the button is momentary, but the BMS e-switch requires a latching one, I decided to use a relay, permanently powered by the first p-group of the battery pack. I also had to make the motor wires shorter, and ESC wires longer so that they would connect and fit in the enclosure. The Focbox is upside down so that the heat spreads through the metal lid of the deck.
The flywheel pulleys are bolt-on, and the holes don’t line up. I’m using 3 screws instead of the usual 6.
I attached the motor clamp with red loctite, aligned everything up perfectly, and then noticed that the idler interferes with the wheel! I was under the impression that 97mm wheels would still work, and maybe they do, but with a shorter belt. For the time being I replaced the screw with a smaller one, but OOF
So, here’s a list of all the problems with the board:
This mount with an idler provides resistance one way, but not the other way. In this case, with the idler below the belt, the friction is when traveling forward, so free-roll is terrible. On my brother’s board the mount is inverted, so the idler is above the belt, but then he gets a different problem – the belt skips when breaking!!! I think that if you get a mount with idlers, it should be one with 2, otherwise you get the same problems as having a mount with no idlers.
The ESC interferes with the relay! (Or maybe it’s the button wires running next to the phase wires, idk.) When it’s off it will turn on, when it’s on it will turn off. This means I have to use a latching switch, but I cannot find any that would be no more than 12mm in diameter, and less than 21mm in height so that it would fit in the drilled hole
THE BMS SHUTS OFF UNDER FUCKING LOAD (Even an 18W DC step down converter triggers it to turn off instantly 2/3 times. You can’t give a friend a board that shuts off randomly!)
So that’s where this build is at currently. I need your guys’ help to finish it! I’ve spent ages looking for a button; I’m convinced none exists and I just have to go for a cheap plastic switch with no LED. The BMS I will try replacing I guess, unless someone can figure out what’s wrong with it. See my post for more info:
The motor mount I think I will replace with the non-idler version from @Boardnamics, so that I can keep the current clamp. I see that the version with an idler has been changed to allow for any wheel size now, but knowing that the belt will skip with it makes me hesitant. since the motor is just 150kv, I could buy a larger motor pulley if I get slippage from riding.
I flew back to LV this week to finish the board. 1st thing I did was replace the BMS for one of the waterproof charge-only Chinese ones. Luckily the same balance lead connector fit, so I didn’t have to do much resoldering. I also swapped the soldered-in fuse with one of those plastic in-line fuse holders. This allows the fuse to be easily replaced in case of a faulty charger.
Then, instead of using the BMS e-switch, I put in a Flipsky smart anti-spark push-to-start switch. They actually use the same exact button as I had already epoxied in (also 5V), so all I had to do was resolder the wires The push to start functionality is pretty janky I think; you kinda have to push it fast, and then stop it, for it to trigger. Having a button therefore is nice.
Finally, I was going to replace the motor mount with one from Whooshboards, but sadly I did not have the correct sized belt for that. (However, damn, that mount is awesome. So easy to assemble, highly recommend.) Luckily, I got new idlers in the mail from @Boardnamics that fit behind the wheel, allowing you to use whatever sized wheels you want. That + a 15T pulley, and having the belt a bit tighter than I’d like, eliminated any belt skipping.
I put the lid on, went for a test ride, and noticed that the battery cells must be jumping up and down on rough roads, so afterwards I put a layer of foam under the battery, and the lid still fit on Here are the final pictures:
I also experimented with HFI, but it was always worse than running just in unsensored mode, so I stuck to that. Overall, I’m very happy with how this board turned out. While building I had my doubts if a short board so high from the ground would feel good, but it actually rides really well The kicktail has so much clearance that you can easily do turns without scraping it against the ground.
At the moment vesc settings are:
60A; -40A Battery
50A; -50A Motor
Range should be ~45km
Max speed I think is around 37km/h
(Will update these values after they’ve been tested)
Since this build is my friend’s, I made sure to note down the price of every single component I bought. So in case you’re wondering what the real cost of an esk8 like this is (minus tools), here goes:
|Haya HB83 deck||@bevilacqua||225.81€||included||225.81€|
|Maytech 150kv 6374 motor||@seaborder||25€||7.5€||32.5€|
|motor bullet connectors||@Klaerke91||5€||???||5€|
|motor mount and belt||@Boardnamics||32.88€||7.76€||40.64€|
|new idler (2x)||@Boardnamics||9.13€||6.40€||15.53€|
|48x Samsung 30Q cells||@PowadangaBoi||140.86€||included||140.86€|
|10x Samsung 30Q cells||electricboardsolutions.com||44.95€||free||44.95€|
|10mm x 0.15mm nickel||electricboardsolutions.com||8.97€||free||8.97€|
|Khiro angled risers||sickboards.nl||8.95€||free||8.95€|
|Caliber 2 trucks (50 and 44)||blue-tomato.com||50€||10€||60€|
|Evolve 97mm GTR wheels||evolveskateboards.de||119€||14.80€||133.80€|
|Enertion Nano X remote||@Moros||30€||10€||40€|
|10s 2A charger||@Lobap||15€||10€||25€|
|Flipsky anti-spark switch||AliExpress||41.34€||4.16€||45.50€|
|15t steel pulley||@atenner||8.84€||3.54€||12.38€|
|4x regular riser pads||local skate shop||10€||10€|
|Bolts (hardware)||local screw shop||~5€||5€|
|Heat shrink & solder||local hardware store||~5€||5€|
|Neutral cure silicon||local hardware store||2€||2€|
|Neopreme foam sheets||Amazon||7€||prime baby!||7€|
Not too bad if I say so myself