"Lone Warrior" | Trampa HS11 | 80100 Single Motor 2WD | Arc200 | E-TOXX Chaindrive

DIY Builds
1

Hey guys and girls, this is my very first build, started only 6 weeks ago :slight_smile:

Background

About 1.5 years ago I learned about electric hydrofoils in a Lift video on YouTube. Then I found out that you can actually build an eFoil yourself for less than the 12k$ a Lift costs. So I joined the efoil.builders forum, started planning, designing stuff and gathering parts. But due to time and money constrains (and no workshop) I never came very far and I was afraid I would never finish the project and have ~800€ worth of parts idling around.
I was trying to find something else I could do with the main components (motor, esc, battery) that I already had that would be a bit easier to complete and maybe a tad cheaper as well. So I stumbled across the esk8 community and saw those awesome electric MTBs. I also figured I would use an MTB more often than an eFoil, as it is much easier to transport.

So, when judging my build, please consider that the main components weren’t chosen for an esk8 originally and that this board is just an attempt to make use of what I already had.

The Build Concept

An eFoil only has one motor and one (beefy) motor controller. The 80100 I got was meant to be used in a direct drive setup. That is why it’s a 80kv motor, a bit awkward for an esk8. I also have a second spare 80100 so I could theoretically run dual motors, but I only have one Arc200 ESC. I can’t get a second one as they are discontinued (which is a shame because they are awesome motor controllers).
So I decided to take a somewhat strange path and run a single motor setup, but driving both rear wheels. So “single motor - 2WD”. For this I swapped out the shaft for a much longer one so that the motor could drive two E-TOXX chains, one on each side, for both rear wheels. Obviously this locks the rear wheels together, forcing them to run the same RPM all the time. I knew that this would put some strain on the whole drive train when cornering and that it probably would make the board want to go straight all the time. But my feeling was that it wouldn’t be too bad, especially on wet and muddy surfaces.

For being able to get some serious amps out of the ESC, I use a 15.9x10cm anodized aluminum heatsink. Batteries are only two 8Ah 15C Turnigy Graphenes. They are enough for now, but I will upgrade to a li-ion pack in the future.

The board was purchased as a whole from @Trampa. HS11 deck 16ply, Infinity trucks, Superstar hubs, 8" Primo Alphas, ratchet style bindings.

20191219_141840
20191219_1418404032×2268 3.88 MB

First Impressions

I had two successful first test rides today. Nothing broke, nothing went up in flames :smile:
I was very pleased by the sound of the drivetrain. The true sinusoidal control of the Arc makes it practically inaudible. What remains is the satisfying sound of well lubed chains - nice.
Another great feature of the Arc was very apparent as well: It measures and calculates the back EMF so well that the startup from a standstill is absolutely smooth and immediate, although the motor is sensorless.

I started off with battery and phase currents at 80A. As both the motor and the drive got barely warm I tried 100A battery and phase current on the second ride. Acceleration was almost scary now. I had to fight some speed wobbles, so I stayed at 80-90% throttle most of the time. According to the GPS tracker app top speed was 42 km/h (26 mph). I will tweak the settings a lot more and also increase the phase current further, as the Arc seems to be a bit bored :smiley:

The more interesting question was obviously: How does the board handle with a solid rear axle? Would I be doomed to ride straight lines like on a railway track? As it turns out this was an absolute non-issue for me. I don’t have anything to compare against and I am sure a two motor board will handle better. But for me who only knew regular longboards until now, the board felt pretty carvy and handled well. In no way does it feel like I am on a track. I can do complete turns or circles with ~4m radius. I don’t know how this compares but to me it feels alright.
Overall I am super happy about how the board feels. I don’t get the urge to upgrade to dual motors at the moment. Battery is more important.

20191219_182532
20191219_1825321074×806 142 KB

Pictures

20191219_141750
20191219_1417504032×2268 5.07 MB

20191219_141912
20191219_1419124032×2268 4.12 MB

20191219_141847
20191219_1418474032×2268 3.55 MB

20191219_141851
20191219_1418514032×2268 3.41 MB

The motor sprockets are glued with Loctite 638.
20191219_141855
20191219_1418554032×2268 3.45 MB

Arc200 bolted to 15.9x10cm aluminum heat sink. Seems to work wonders.
20191206_194158
20191206_1941584032×2268 1.93 MB

PETG enclosure for the ESC and receiver. Fixed to the board with three M4 screws and thick rubber washers in between.
20191217_200540
20191217_2005404032×2268 2.36 MB

20191217_180747
20191217_1807474032×2268 1.69 MB

The battery box is fixed using 3M Dual Lock. I used two long strips lengthwise and several shorter strips in between so that they are perpendicular to the longer ones, hoping that this way they can take different kinds of force and vibration.
20191217_200443
20191217_2004434032×2268 2.27 MB

Specs

  • Deck: Trampa HS11 16ply
  • Wheels: Trampa Superstar, 8" Primo Alpha
  • Trucks: Trampa Infinity
  • Bindings: Trampa Ratchet
  • Motor: APS 80100 80kv sensorless
  • ESC: Freefly Arc200 200A
  • Drivetrain: E-TOXX Dual Chaindrive
  • Battery: 2x 6s Turnigy Graphene 8Ah 15C
  • Battery Box: B&W Outdoor Case 500
  • ESC Enclosure: 3D printed in extrudr PETG
  • Heatsink: 15.9x10cm anodized aluminum
  • Remote: GT2B

Video

Acknowledgments

At this point I would like to thank Jenso/@NoWind from E-TOXX for this awesome precision machined chain drive kit and the help and great support I got from him. Due to my awkward motor kv I needed a different reduction and Jenso provided me with 12 teeth sprockets with the hubs machined down so they would fit. He even modified one of the motor adapters to fit a bearing to support the shaft on the side opposite of the motor. E-TOXX is very much recommended!

40 Likes
2

Love the concept of single motor 2wd and looks like you pulled it off nicely.

#chainsforlyfe

5 Likes
3

If I had started fresh without any components already in my drawer, I likely would have gone with dual motors like everyone else. But now I am very pleased with this concept. Less parts, less problems? Time will tell :smile:

1 Like
4

I love it :+1:t3::+1:t3:

1 Like
5

This looks super clean, well done, even more with the single motor

Do you have access to energy usage on the ARC? Would be interesting to see if it’s more or less efficient than a dual motor setup

2 Likes
6

I approve this message. Super sick build man!

1 Like
7

Nice build ! Take care about the crAPS motor, dust/sand/mud/water/everything you can find on offroad ride have killed my both 8085 (cheap bearings, bad sensor, overheat, smoke) , so i’m back to 6374 closed quality motors, a little bit less power but a lot more fun and security for me.

2 Likes
8

Sick build mate! I wonder how single motor 2WD would go with narrower trucks? So it’ll look and perform “normal”, but have the potential to have more power for the same space due to full width stator length. So much potential!

3 Likes
9

So powerful! :crazy_face:
Do you want to change the topic to ‘‘DIY Builds’’ :grin:

1 Like
10

I will pull the logs after my next ride. I am also interested in that, as well as actual drive temperature etc.

I battle hardened it with epoxy on the rotor and clear coat on the windings. I also want to add a 3D printed cap to the rotor, so it’s more or less closed. I hope that helps :smile:

Smaller track width means less difference in wheel revolutions, so it can only be better :grin:

Thanks, not sure how I forgot that :smile:

2 Likes
11

Great idea, too bad it’s not done by APS when you buy it, i drove them on 120A, insane torque, have a lot of fun bro

12

Thanks. Did they get hot at 120A? That would be my next setting.

2 Likes
13

on normal use : only warm but at 50Wh/km consumption on the forest mud or ski slopes, it’s about 40/50 celcius (with a 2° outside temp)

its hard to compare because mine have some issues (cogging, hazar react etc) so maybe good ones don’t heat

14

Ok, thanks. That sounds fine to me, magnets degrade at 80°C I think. The enamel coating can take more probably. I’ll regularly check the temp by hand :sweat_smile:

15

Great build! And I also like the name, good choice :relieved:

1 Like
16

best way for heat control :joy:
what kind of epoxy do you use ?

17

As I had no idea I chose one more or less randomly. It’s DD Composite 4300 with 390 hardener.
That’s the rotor. The stator already had clear coat on it, I added a few layers of Plastik 70.

3 Likes
18

Update

I changed quite a bit on the board. Also I now have BLE telemetry and data logging via a custom app - this will give me some interesting insights.

Sealing the motor

I sealed up the motor with a two part 3D printed cap and several small insets that perfectly fit into the gaps on the motor base. The insets are epoxied, the cap is screwed and further sealed with Sugru.

20191227_125708
20191227_1257084032×2268 1.82 MB

20200120_150234
20200120_1502344032×2268 4.8 MB

Heel straps

I now have Trampa heel straps. When I ordered the board I could have gotten these for a discounted price, but I thought “why the hell would I need that?!”. I learned it during my very first ride :joy:

Impressions

They are a great add on. It just gives a comfortable feeling of safety, especially when it is wet on the board. And I can lean into turns better.

20200120_160312
20200120_1603122016×1134 2.67 MB

ESC enclosure

I re-did the ESC enclosure. Before it was a 3D printed provisionary solution. It was a one part enclosure, sealed up with Sugru, so I couldn’t open it for maintenance etc.
I now use a Serpac ABS IP67 two part enclosure that I can open if I need to. The heatsink on the top stayed the same.

20200120_160338
20200120_1603382016×1134 2.76 MB

20200120_160333
20200120_1603334032×2268 6.37 MB

Trampa Barrels

Before the barrel/elastomere upgrade I was on springs with yellow dampas. While that was fine for carving, it felt very unstable at 30+km/h or on sudden throttle releases.

Impressions

Riding with the barrels is a night and day difference in terms of stability. It is astonishing how super stable and safe they feel, no matter how fast I go or how fast a accelerate or brake. Before I was super afraid to approach vmax, now I can ride at ~44km/h easily and I can pull the throttle as hard as I can and remain full control and stability (at least until I up the current settings once more :grin:). Who still has springs: just upgrade, it is worth it. Didn’t lose any turning ability either. These things are just great.

20200120_160328
20200120_1603282663×1498 4.14 MB

BLE live telemetry and logging app

Pulling logs via USB sucks if the port isn’t easily accessible and it would be nice to check the battery voltage during the ride. So an app would be great. Unfortunately the Arc200 is a pretty niche controller and a discontinued one as well. So no app, just a Windows GUI.

So I made my own telemetry and logging app for the Arc200. The Arc has built in BLE which you can use with the Windows GUI. Unfortunately I didn’t manage to get the Arc to answer my handcrafted messages, neither did it respond to simple replay “attacks” using messages I captured with wireshark. I didn’t want to spend too much time on this and I knew that polling telemetry via UART works (it is documented more or less), so I decided to make my own Metr Pro like UART module using an Arduino and a BLE module.
The Arduino simply polls telemetry packets from the controller via UART, repacks and relays them via BLE in my custom format.

The app itself then only took a weekend. It can do the following:

  • Show live telemetry like battery voltage, phase and battery current, throttle and ESC temp
  • Record all telemetry packets during rides, export the resulting log to .csv
  • Show per ride and all-time stats
  • Vibration alarm if battery voltage becomes too low or ESC gets too hot

(the max speed gauge is broken, need to fix that)

Screenshot_20200120-163824
Screenshot_20200120-1638241080×2280 222 KB

When I look at the log from today and remove all data points where the throttle is 0, so I only look at actual riding time, I get the following average values:

  • Avg. Motor Current: 15A
  • Avg. Battery Current: 8.5A
  • Avg Speed: 17.3km/h

Peak values are as seen on the screenshot. Ambient temp was ~6°C so pretty cool but not super cold. The heatsink does a great job apparently, ESC never got above 19°C despite some pretty steep hills and longer ~40kmh sections.

Overall

I am super happy with my board now. All I want to change in the medium term is the lipo battery. It performs well until now, and range is ok (~12-15km) but more is better and I want a li-ion pack some day.

Also I need to print a modded GT2B case because the stock one didn’t like my first real crash :sweat_smile:

22 Likes
19

Do you have links to that enclosure and heatsink?

20

Glad to hear this, I have the barrels in my hand but board no assembled yet, and they are really hard

And doing your own app is another level

2 Likes