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  1. bamitsram

    How many Amps can this 3500W rated QS hub motor actually take? (build planning)

    While you have it open put some kind of temperature sensor in there, even if it is just one of the cheap stand along eBay modules with cable sensor. That way there is no guessing about temperature
  2. bamitsram

    Cheap FOCer (VESC 4.12 based design)

    SMD FETs are fine, but you run into routing issues, heatsinking issues and board space issues much sooner than with through hole FETs, these 3 things alone make using SMD FETs pretty impractical without taking anything else into consideration.
  3. bamitsram

    Cheap FOCer (VESC 4.12 based design)

    You'd want your combined rise and fall times to be less than 1% of the switching period, or 500ns. I wouldn't increase the gate resistor more than 20~ ohms otherwise it will take a long time to enhance the MOSFET for good rdson, if you do use 20ohms I suggest you parallel if with a diode for...
  4. bamitsram

    Cheap FOCer (VESC 4.12 based design)

    I think if you put one of the two big caps up the other end of the PCB and ran fat traces/copper to it it would help significantly
  5. bamitsram

    Cheap FOCer (VESC 4.12 based design)

    Slowing rise time shouldn't hurt efficiency, the load is inductive so its current shouldn't be able to rise instantaneously. To fix up the fall time you can put a diode in parallel with the resistor to turn off fast, so there isn't a loss in efficiency with the current flow. Voltage rating...
  6. bamitsram

    Cheap FOCer (VESC 4.12 based design)

    On a design like yours, if you have decent bulk capacitance, you might just be able to tweak the series gate resistors to slow the rise time a tad to cut out the ringing, rather than adding snubbers, otherwise a film cap of 1-2u would probably be enough
  7. bamitsram

    Cheap FOCer (VESC 4.12 based design)

    I think stop test when the temperature stops rising by less than 3 degrees c/minute or the case hits 65 degrees c (that is the temp where a skin burn will occur in 1-4 seconds), any temp higher than that is unacceptable on the case.
  8. bamitsram

    Cheap FOCer (VESC 4.12 based design)

    Yeah, less work and less waste to do it that way - plus, people might put different connectors or signals on different cables and would have to redo connectors anyway
  9. bamitsram

    Cheap FOCer (VESC 4.12 based design)

    Since everyone has different connectors on their existing setup, and some people have minimal connectors, I was going to have bare phase and battery wires leaving, so people could put their own connectors on. For I/O connectors I was going to use a SP16 style weatherproof aviation connector, and...
  10. bamitsram

    Cheap FOCer (VESC 4.12 based design)

    Do you have a external pullup or larger than default capacitor on the NRST pin? This can cause issues with not resetting/starting up correctly
  11. bamitsram

    Cheap FOCer (VESC 4.12 based design)

    Schematics done, doing the last bits of layout at the moment. Approximate dimensions are to fit a 15 Fet green time/xld controller case, so 168mm long, 73mm wide, max component height 25mm. I do plan on releasing all of the design files. No, I am using Altium, its what I use in my day job and...
  12. bamitsram

    Cheap FOCer (VESC 4.12 based design)

    Hey there Shaman, this is bgdwiepp from the VESC project forum, sorry for my absence over christmas/new years, spent quite a bit of time with family, but now I'm back at work I have more thinking time. I've been going through the design and replacing components and circuits with generic...
  13. bamitsram

    LegStrong - Open-Source HW/SW controller (FOC + Bluetooth)

    It is true, coreless motors have near 0 hysteresis loss because of the air "core", however, eddy current losses at high powers are huge because of the high commutation speed, unless wound with litz wire, which is overall less efficient because insulation between strands reduces packing density...
  14. bamitsram

    LegStrong - Open-Source HW/SW controller (FOC + Bluetooth)

    For most vehicles, 150-300v @150a seems like a lot of power, and it is, but at low RPM, if you limit to 150A your starting torque will suffer immensely, and you need very precise control over this powerful starting torque. Hall effect sensors are the way to go, unless, like TESLA you can braze...
  15. bamitsram

    LegStrong - Open-Source HW/SW controller (FOC + Bluetooth)

    I am familiar with the recent design trends, I work in the industry and my employer provides an excellent continual improvement program. Yes, i am aware that they have them with built in isolation, but then there is no price difference between a shunt + modulator with isolation and a closed...
  16. bamitsram

    LegStrong - Open-Source HW/SW controller (FOC + Bluetooth)

    You need something to feed the ΔΣ, usually a current shunt with an appropriate low pass filter or a hall effect sensor... At high currents, a shunt is out of the question. Because its huge (bigger than a closed loop hall for the same current), has a terrible accuracy (worse than halls), terrible...
  17. bamitsram

    LegStrong - Open-Source HW/SW controller (FOC + Bluetooth)

    That is fine though, you don't need all of those features. High res PWM alone is enough, a M4 core with a decent clock speed will get you everything else you need. On high power motor controllers you use Closed-loop hall current sensors, meaning dc-150khz frequency response, 0.5% accuracy, 0.1%...
  18. bamitsram

    LegStrong - Open-Source HW/SW controller (FOC + Bluetooth)

    If i recall correctly, the f334 series have high res pwm much more suited. Additionally, if you want a decent ADC, you have to use an external ADC, there are limits to what you can do on a fab process designed for logic vs a fab process for analog, you will pretty much never find a high spec ADC...
  19. bamitsram

    E-Cruiser / Harley build

    I dont think leafs were bought into australia, i bought a full leaf pack from a vehicle with 30,000 km on it from japan, delivered for $3300aud~ About half of that was shipping, customs, taxes and fees. A capacity check showed 60.5ah/62ah. Either import a pack or try find someone who has...
  20. bamitsram

    LegStrong - Open-Source HW/SW controller (FOC + Bluetooth)

    I haven't used the MP6534 specifically, I have used the MP6530 though, and I got it from Mouser, very cheap, only $6000 for a reel. If you wish to make small, efficient, cheap FOC controller, you don't need a very strong gate drive, you aren't driving huge FETs.
  21. bamitsram

    LegStrong - Open-Source HW/SW controller (FOC + Bluetooth)

    I am an EE with a lot of experience in high power analog design. I can competently design a flexible discrete high power stage, with a decent high voltage regulator (isolated or not), to provide power to the drive and digital circuitry, high speed analog protection features, basically just...
  22. bamitsram

    LegStrong - Open-Source HW/SW controller (FOC + Bluetooth)

    Are you planning on keeping this a low power controller? As the TI DRV8302 are very integrated similar 60v rated controllers are very common (see vedder esc). I would be interested in contributing to a 100v+ 100A+ controller project using a more discrete solution.
  23. bamitsram

    Fazer Conversion Completed

    the easiest way to test the windings is with an LCR meter (or just an LC meter) as the reading from an ohm meter will be too low to interpret. check the inductance (l) of all the windings to see if they are approximately the same for halls, power them with 5v, put a dmm between the hall signal...
  24. bamitsram

    E-Cruiser / Harley build

    Ahh, i should have seen. Yeah, i looked into that - i literally couldn't find a single place in NSW who was qualified by the RTA to do chassis inspections for engineering certificates on motorcycles, I assume it would be similar in QLD. Thats because Tesla aren't using standard off the shelf...
  25. bamitsram

    E-Cruiser / Harley build

    These things already handle like a boat. Stick your biggest enertrac or qsmotor hubmotor in it - its not going to make handling any worse, simplifies the mechanics and gives you a massive room for batteries. For batteries, sling the long portion of a leaf pack between your legs, 24 modules is...
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