Alright guys, here is my first (successful) build after a month or two of riding and tweaking. Incredibly basic, no custom-fab of any kind, just some parts strapped on to a deck. This will also serve as a mini-review of hobbyking’s all-in-one esk8 kit, more of my thoughts on which can be found in the main HK esk8 thread.
First of all, an overview of my background: I have been skating and especially longboarding since I was around 10 years old, and I built my first board when I was 12, pressed (well, clamped) my own deck and all. I also have about 8 years experience in unmanned aircraft, and run a company building fixed wing cargo UAVs. This has given me a lot of experience with the same type of motors and batteries as are used on Esk8s, though I must say the VESC platform is incredible and I wish all escs were this configurable. Some of you may remember I joined this forum around a year ago as a design student, with big plans of building a tiny, AWD belt drive board using high-kv racequad motors and lower voltage lipo packs to create a powerful, lightweight penny-size electric boards. This, unfortunately, turned out to be pure student’s Hubris, And after around $3000 of my own investment and plenty of prototypes built, the fact that this ugly beginner single-drive is my first successful Esk8 build should tell you everything you need to know about how that previous endeavor went.
Anyway, the build:
Batteries are two Gens Ace TATTU 6s 7AH lipo packs in series for 12s. I used these because I can get them at trade price through my company, so for me they were the best price to performance option. 12s, 310 watt-hours is really nice for power and range too, I can get three or four serious riding days on these packs between charges.
Controller is just a cheap Quanum car radio, as it’s simple and gets the job done. I’ll be cadding up and printing a custom case for it to make it better for Esk8 use and less gun-shaped, as especially where I live in the SF Bay area people panic if they see something that looks even slightly like a gun. (On that note, I’m really getting tired of hobby companies making their car radios look more and more gun-like. This one even has a “mag-release” style button to drop the battery tray free.)
Now on to the main event: Hobbyking’s Turningy Esk8 kit. First things first, I was very impressed with the quality of the core parts of this kit, especially for the money.
The motor is a thing of beauty, really unique compared to the ubiquitous “chamfered cylinder with some vent holes and a shaft” that we’re used to seeing on basically every other motor on the market. Someone really put some time into designing this motor to look the part, and it goes a long way to making this kit feel properly high-end. The super-low KV (125) combined with aggressive gearing make for an unbelievably torquey setup, though at the expense of top speed. I have no issue with the speed personally, on 12s I get a top speed of 26-27mph (my local bike path has a radar speed readout in the 10mph zone through a park, great for top-speed test runs late at night.), But I think on anything below 10s this setup would be somewhat underwhelming at speed.
The ESC has seen a bit of controversy on here, firstly because they originally used the VESC name without authorization, and secondly because it ships in FOC mode despite not having the extra cap to make FOC safe. Personally, I have been running it in FOC with a 60-amp current limit, riding hard up and down MT. Tamalpais for a couple hours at a time, and I have yet to see any issues aside from the esc getting a bit warm (maybe 70c) by the end of a long climb. Just to be safe, I’ve taken a couple of 5v fans off an old bike ESC and spliced them into the 5v power output that goes to the receiver. I cut away the heatshrink above the FETS and other high-current components and stuck the fans on top, and have never felt the esc get even lukewarm since. Overall the esc performs great, FOC gives perfect standstill starts and the braking is limited only by the single-drive’s traction.
All the hardware included is surprisingly nice. My only real issue was that the included truck bushings are garbage. Picked up a set of nipples orange (I’m 130lbs, most riders will want purples on these trucks) off Amazon and the trucks feel great now. Somewhere in-between the stability of calibers and the agility of paris’s, and I think I actually prefer these trucks to either of those. The driveline parts are all solid, pulleys are machined aluminum and the belt is good quality. The mount is also super solid, no play at all and feels seriously beefy. MAKE SURE TO LOCTITE ALL THE SCREWS!
My build itself is incredibly basic, didn’t even build an enclosure. I used the included battery straps with some of alofthobbies’ “battery stop” adhesive rubber grip pads to keep them from moving. Went with top-mounted batteries because I didn’t like having such thick batteries underneath. I’ll eventually be vac-forming an enclosure and putting them on the bottom, but for now this works great and gives really nice clearance for speed bumps etc.
As for performance, I (almost) couldn’t be happier. The acceleration in insane, and the top speed is honestly faster than I need even with the low kv and short gearing. I’ve done plenty of longboarding and downhill riding, and I’ve gone a lot faster than 27mph in the past, but riding this thing in traffic and around other people and obstacles, I rarely go above 20. Maybe this will change as I get accustomed to the board, but for now I’m happy. 2.6kw is plenty for me at the moment.
My only problem with the board is inherent to any single-drive build, and that’s that I would really like more grip for accelerating and especially braking. I’m giving serious consideration to the idea of buying a second motor, ESC, and hardware set so as to make a dual-drive. This much torque deserves the traction to get it to the road, and the added braking power would be very welcome. If I go this route, I’ll likely go with around 25% longer gearing, as that way I’ll be able to make a bit more practical use of the power and have a more balanced setup as opposed to just a pure torque monster. Of course, going dual-drive will require the motors to be mounted on opposite sides of the truck as the motor is too long to do a traditional parallel dual-drive. If I do this, I’ll make sure to post an update. 5.2kw 12s dual drive sounds pretty fun.
So far though, it’s just a great reliable, powerful, no-nonsense long-range build, and I’m super happy with it.