I’ve read alot about SiC-FETs throughout the year, how they’re s’posed to be superior in HV designs but never seen anyone incorporate them so far. Any thoughts on this?
I think my favorite part of this build is the sheer insanity of it. If OP’s calculations are correct, this board has a good chance of being limited in its acceleration by traction.
Four go-kart racing slicks won’t provide enough traction. I’m trying to wrap my mind around how utterly ridiculous that is.
My current board has clocked in at 28mph with only one driven wheel. It feels like a rocket ship when I floor it. And my board isn’t really limited by one wheel drive.
This is going to be awe inspiring to watch.
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I have several SiC mosfets, those are either 900 or 1200 volts. You would want GaN,https://pl.mouser.com/ProductDetail/GaN-Systems/GS-010-120-1-P-E01-MR?qs=%2bEew9%2b0nqrB2GFgqM79EvQ%3D%3D but to get low enough resistance 10 of them in pararel is just about right. At $15 per one mosfet it is not economically viable to use them. Switching at 20ns is fast enough, no need to go at 0,1 ns. Finding fast enough drivers is difficult and ringing would go ito GHz range. Done that once in my life and once is enough. Only '80 vaccuum tube oscilloscope could see the spikes.
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I’d just like to tag @ngv-nextboards, this is your competition I’m sure you’ve seen some of there videos
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yet to see one on video even do 40mph… its been years now, screenshot or it didnt happen lol
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PCB’s have arrived today.
Assembly will follow tomorrow, as it is over 11pm here.
At first only 1 pcb will be populated, as i am not 100% certain everything is ok. Components are pricey after all.
Filtering capacitors will also be ommited to set dead time properly, to be added with soldering iron later when initial setting is complete.
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Nice man looks soo good!
can’t wait to see how this thing turns out.
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Quick tip, make sure lots of silicon holds he caps in place. Vibrations break the legs off if there isn’t support
this thing is going to be a monster!
Nice progress! Looks like your routing the battery positive net to the high side FETs on internal layers? I don’t know of any other high current controllers doing it this way, hope it works well for you
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Any high current path is routed on total of 3 layers in pararel to improve current distribution. Bottom layer is one big ground plane, with only small areas not being ground. Tracks are much wider than open solder areas - those were made to have room for soldering extra copper on top and botom sides respectively. This pcb is good for about 200 amps as it is, for targeted 350-400 amps motor current additional 4mm dia copper wires will be soldered onto it.
PCB is now assembled.
First was applying solder paste through dedicated stencil:
And the pcb after lifting stencil:
All the components were carefully placed with needle-sharp tweezers:
And after a trip through reflow oven components are soldered in place:
Bottom side was done with a soldering iron due to small component count:
For now PCB is partially tested. Step-down converters that supply voltage to logic are working fine and deliver proper voltage (12,6v to gate drivers and 5,0v to anthing else) to remaining components. Op-amp section that feeds signal from current sense resistors also works fine. One mistake was found, as on a main step-down i put 1 ohm resistor instead of 1uf capacitor which resulted in circuit not starting. After 10 minutes it was fixed and running, nothing blew.
Today a friend of mine is coming with a programming interface and software wil be loaded into MCU. I hope to test it somehow during weekend, however not on full power as motors are not yet complete. For now sensitivity of current sense was increased for better debugging, resulting in a limit of -80/+200 amps. After startup is complete it will be reduced to give designed useful range of -200/+600 motor amps, as this involves only changing 2 resistors.
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-200/+600 amps on 12bit adc xD you will have resolution of 0.2A/step 
Also you know that you will need to change code configuration for voltage dividers and etc to get those currents correct values?
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Nice progress
What are the size of the PCB? And how you will mount them? 4 staked or 2 stacked on each side of the battery?
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My friend knows how to change configuration values, he already has compiled code ready. Resolution is 3x worse than in original VESC, but there is no going around ADC resolution, 0,2A/600A is 0,03%. Fine enough. Going for higher resolution is pointless bencause of noise induced in the circuit anyway. As for placement ESC will go under deck in front and back, between battery and truck. PCB is 100 mm wide by 92mm long. It wont use any enclosure, instead i will coat with ample amount of urethane resin for complete waterproofing,l i want to be able to swim with it. Two ESC will be mounted side-by-side to a single heatsink 200mm wide 50mm thick 60mm long. Entire assembly will hide behind tires (looking from the side).
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@FullMetal_Machinist that is amazing and just by looking at PCB a realized that you are crazy fellow countryman
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Dude, you are like the Jesus of eskate. Holy crap! Love all of the custom work. And can’t wait to see the final build.
I will be amazed if you can stay on it under a full acceleration, but if anything, sounds like a new sport. Bull riding, but on an eskate… Who can stay on? lol
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Water bull riding lol
@FullMetal_Machinist what about if something fails and you need to get the the electronics? How do you get the resin off
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When ESC is adjusted and tested there will be no “something failed so i want to change a component”. No DRV6302 present. Wiring will be soldered permanently. Everything else than mosfets is with more than sufficient margin, main step-down works fine up to 140 volts. Safety limit in place that cuts it off at 90 volts. Mosfet drivers up to 125 volts. If it goes there will be nothing to salvage, as short circuit current of my monster battery exceeds 2000 amps. Before the fuse manages to do its job there will be a hole in pcb through which you can put a finger. There are several videos of ESC burning with normal lipo battery. Nothing remains. https://www.youtube.com/watch?v=JwDwEHQCk5g Components that are not fried are “uncertain” enough not to use them again for anything important. Only damage that can be caused to ESC is by electrolysis eating away component leads. Under such assumption making a solid block of urethane out of it is the only logical solution. Using plastic casing for ESC means having seriously reduced cooling, heavier overall, bigger by at least 3 cm each direction and sealing all wires going through is a pain in the ass. As for my choice of resin here is an explanation: Epoxy is not elastic and tends to crack and tear components out of pcb, ask Jens Kappel for “epoxy roxy”. Went through this with one of my customers, who wanted to hide PCB from unwanted sihgt with colored epoxy. Everything had to be redone with urethane. Cause is thermal cycling through resin glass temperature. Polyester resin will also peel off after like 50 thermal cycles, with small chance of not pulling away components. Urethane is much better. Cost the same, doesnt smell nearly as bad. Remains elastic like forever. I want to be able to ride my board in all conditions, snow, mud, heavy rain etc. Have fun. I want to grab garden hose and wash dirt away when i get home from the woods, as i do with my regular mountainboard. Motors (windings) will be coated internally with other type of resin and 100% waterproof. Battery and other stuff can easily have sealed enclosures, especially when i make custom carbon tray for the battery and remaining electronics (limiters and traction control) is the size of a fist and doesnt have nearly as much thick wires coming in.
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I thought you were going to epoxy the battery lol