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
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 
Great build! And I also like the name, good choice 
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best way for heat control 
what kind of epoxy do you use ?
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.
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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.
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
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.
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.
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 
). Who still has springs: just upgrade, it is worth it. Didn’t lose any turning ability either. These things are just great.
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)
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
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Do you have links to that enclosure and heatsink?
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
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Sure. Thats the enclosure. It is also available with top mounted screws (“R” option). I opted for bottom, because the heatsink would be a bit too large and overlap the holes. This way I have to leave out one middle screw though (still 5 left, so it will be fine).
https://www.serpac.com/s-series/172.aspx
They have a lot of other dimensions as well:
https://www.serpac.com/s-series.aspx
Heatsink:
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Thanks, it isn’t that hard if you have some experience, I do app development part time alongside my computer science studies
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That’s my “metr pro” module. It’s a Teensy 3.2 microcontroller board and an Adafruit BLE module. I’m a bit mad at Freefly because they used 5v logic for UART. There are basically no ready-made boards with inbuilt BLE and 5v logic or 5v tolerant pins. So I have to use two boards with a lot of wires. Sad.
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did you have to extend the motor axles in any way?
Or did it come that long?
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from the looks of this motor its 218mm from on end of axle to the other, close to 9" holy cannoli thats a big motor
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It is a big motor indeed. But the shaft still isn’t long enough. And it has a thread on one side.
I replaced the shaft with a 292mm hardened steel one.
Interesting that Flipsky specs it at 148A max, APS says 200A. I guess I’ll better not go beyond 150A, the motor does get pretty warm (not hot), even in very low ambient temps.
I am running 110A motor and battery atm, I wanted to up that to 125A motor next because the ESC is absolutely unimpressed (20°C max at 6° ambient).
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Some great updates @Benjo! Good to hear the heelstraps are a good buy, might have to get them aswell 
And I am still contemplating the barrels, are they also better for offroad riding?
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Thanks
I tested the barrels in 80% off road situations and I was happy. But I didn’t notice that big of a difference compared to the springs here, except that just like on the street general stability while accelerating or braking is way better. My guess is that a lot of the instability that springs have does come from this rebound/bounce back effect. You don’t have that with the barrels. And in my opinion this helps in every situation, off road or not.
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Okay thanks for the explanation, very helpful!
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Wondering if you have pics of this process, replacing the motor axle
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What part of this process? There are like 3 parts, disassembling the motor (includes removing the old shaft), modifying the new shaft (circlip groove, flat spots for the grub screws) and finally putting in the new shaft.
- I made a detailed post about disassembling the 80100 over at efoil.builders.
- I cheated on this part because I don’t have the right tools and the shaft is hardened steel, so not easy to even scratch it. I skipped the flat spots for the grub screws and instead glued the shaft into the bell with Loctite 638. I also don’t use a circlip as there is basically no axial load on the motor, also the bell is secured by the large bearing.
- This is as easy as securing the shaft with either loctite or the grub screws.
It is important to measure or calculate how long the shaft needs to be and how far it must be pushed into the bell.
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Lathe.
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