Nice job, I think it’s a good idea I wouldn’t have thought about it.
I love the manual in reverse.
Holy shit this is impressive. I’m curious how the board knows to stop sending power to the battery (when braking) and to send it to the resistor instead.
Also I really want wheelie mode for my EMTB because trying to balance my wheelies manually is hard.
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Can you control the speed when you do a manual?
I think he could by leaning forward more.
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Wow dude, amazing. Some cool features I’d love to rip off in there if only I was smart enough lol.
This is a true diy board!
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The current implementation is that the voltage (and then the current) applied to the power resistor is proportional to the excess current to the battery. For example, if you set the max battery regen current to 10.0 A and you actually are measuring 10.1 A, you multiply this error (10.1-10 = 0.1 A) by a gain (e.g. 20 V/A) and you obtain the voltage to apply to the resistor (in this case, 0.1 A * 20 V/A = 2 V).
I have to say I have not done the tuning of this gain yet, because I am not capable to brake hard AND at high speed at the same time. I think I would just loose balance. I really need to build a testrig to test that safely.
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Of course, this closed-loop control only works if the gain is large enough. If it is too low, it won’t limit the regen current to the battery enough. If it is too high, however, it may become unstable.
Yeah full brake full speed is sketchy but can be done. I was wondering what physically is reading these voltages and deciding where the current goes?
This is the first time that I’ve seen a flux capacitor used on anything other than a DeLorean.
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Wow…that is an astounding build! Thank you for sharing it with us and I look forward to hearing more as you test and refine it.
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Physically, the battery current and the power resistor current are measured with a Hall-effect sensor (I am using this one). When the current flows through, the sensor outputs a voltage proportional to the current, that can be read by an analog input of the microcontroller.
What “decides” where the current goes is a single half-bridge (it is kind of a double switch, you normally need 3 of these for driving a brushless motor) that is dedicated to that, and sets whether some current should flow into the resistor or not. Like a drain tap for water. Note that the current will then flow both to the battery and the resistor. Not sure if this is clear, it is difficult to explain.
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WTF, this has more engineering and R&D behind it than most production boards! 
You must really have a ton of spare time! 
Very unconventional solutions to the problems a lot of us deal with.
Okay, snarky remarks aside, this board is awesome! Definitely interested in seeing you test the braking power dissipator, I want to see how hot it gets when braking down a steep hill 
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This is amazing. Like seriously amazing. What do you do for money? Engineer maybe? I can’t even fathom half the stuff you did here. Design your own remote/esc’s, lighting control. Not even getting into the machining of custom parts lol. Really impressed. Like, you figured out so much shit on your own here. Very cool.
How much did this build cost you?
Oh ya, last thing, bend your knees a bit more when riding. Keep center of gravity low and above the board (not that you weren’t), it’ll start to feel very comfortable quick. Then you’ll have to remove the speed limitations. You’re gonna love this ride! All the cools.
Thanks for sharing!
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Holy fuck, Ive been wanting to get an app on my smartwatch to do that stuff, that’s so cool! You’re really pushing the limits of diy
I don’t have so much spare time, unfortunately… This is why this board took forever to design and build. I started the design and ordered the first parts in 2017!
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Yes, I have a mechanical engineering degree. I was PhD student at the Swiss federal institute of technology of Lausanne until very recently. Now it’s time to go working in the industry again!
This is the approximate breakout of the cost of this board:
| Part | Amount in € |
|---|---|
| Motors (with one spare) | 138 |
| Power cables + connectors | 43 |
| Signal cables + fuses | 76 |
| Bare PCBs | 277 |
| PCB components + charger | 547 |
| Pulleys + belts | 86 |
| 18650 cells (with spares) + nickel strips | 174 |
| BMS (with one spare) | 134 |
| Complete Icarus board | 395 |
| Larger trucks + griptape | 105 |
| Misc: paint, glue, screws, ball bearings, 9V battery, nGen filament, etc. | 250 |
| kWeld spot welder | 293 |
| Total | 2518 € |
This board costed quite some money, compared to its power. But the goal was to have fun and to learn as much as possible!
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Thats some high end stuff, awesome work! Did you use shielded wiring for the encoder?
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Yes, I used a shielded cable for the encoders. These cables are very close to the motor cables, and are critical for the operation of the motors, so the shielding is important. I used this which is quite typical:
https://www.distrelec.ch/fr/cable-multiconducteur-blindage-cuivre-cy-pvcx-14mm-gris-ceam-li-ycy-10x0-14/p/15577853?track=true&no-cache=true
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Not joking around for sure 
I came to learn that using shielded wiring is quite important too, use it for my CNC mill now.
Now this, is DIY balls deep. Well done! Thank you for documenting and sharing your build!
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