Search found 31 matches

by bamitsram
Apr 27 2019 7:03pm
Forum: Motor Technology
Topic: How many Amps can this 3500W rated QS hub motor actually take? (build planning)
Replies: 21
Views: 2398

Re: 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
by bamitsram
Feb 25 2019 5:42pm
Forum: E-Vehicles General Discussion
Topic: Cheap FOCer (VESC 4.12 based design)
Replies: 212
Views: 29869

Re: Cheap VESC (VESC 4.12 redesign)

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.
by bamitsram
Feb 06 2019 1:04pm
Forum: E-Vehicles General Discussion
Topic: Cheap FOCer (VESC 4.12 based design)
Replies: 212
Views: 29869

Re: Cheap VESC (VESC 4.12 redesign)

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 fast tu...
by bamitsram
Feb 05 2019 11:21pm
Forum: E-Vehicles General Discussion
Topic: Cheap FOCer (VESC 4.12 based design)
Replies: 212
Views: 29869

Re: Cheap VESC (VESC 4.12 redesign)

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
by bamitsram
Feb 05 2019 8:54am
Forum: E-Vehicles General Discussion
Topic: Cheap FOCer (VESC 4.12 based design)
Replies: 212
Views: 29869

Re: Cheap VESC (VESC 4.12 redesign)

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 doesn't r...
by bamitsram
Feb 05 2019 3:10am
Forum: E-Vehicles General Discussion
Topic: Cheap FOCer (VESC 4.12 based design)
Replies: 212
Views: 29869

Re: Cheap VESC (VESC 4.12 redesign)

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
by bamitsram
Feb 01 2019 11:03am
Forum: E-Vehicles General Discussion
Topic: Cheap FOCer (VESC 4.12 based design)
Replies: 212
Views: 29869

Re: Cheap VESC (VESC 4.12 redesign)

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.
by bamitsram
Jan 31 2019 10:19pm
Forum: E-Vehicles General Discussion
Topic: Cheap FOCer (VESC 4.12 based design)
Replies: 212
Views: 29869

Re: Cheap VESC (VESC 4.12 redesign)

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
by bamitsram
Jan 31 2019 6:34pm
Forum: E-Vehicles General Discussion
Topic: Cheap FOCer (VESC 4.12 based design)
Replies: 212
Views: 29869

Re: Cheap VESC (VESC 4.12 redesign)

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 pro...
by bamitsram
Jan 25 2019 10:28am
Forum: E-Vehicles General Discussion
Topic: Cheap FOCer (VESC 4.12 based design)
Replies: 212
Views: 29869

Re: Cheap VESC (VESC 4.12 redesign)

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
by bamitsram
Jan 23 2019 11:59am
Forum: E-Vehicles General Discussion
Topic: Cheap FOCer (VESC 4.12 based design)
Replies: 212
Views: 29869

Re: Cheap VESC (VESC 4.12 redesign)

@bamitsram Your design sounds incredible! I love the attention to safety details and making the gate drivers swapable for more powerful versions. 150v max voltage is incredible and definitely suites a 12 FET design. I do have a few questions. How far along are you in the design? What are the approx...
by bamitsram
Jan 21 2019 11:12pm
Forum: E-Vehicles General Discussion
Topic: Cheap FOCer (VESC 4.12 based design)
Replies: 212
Views: 29869

Re: Cheap VESC (VESC 4.12 redesign)

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 equivalents,...
by bamitsram
May 29 2017 9:48pm
Forum: E-Bike Technical
Topic: LegStrong - Open-Source HW/SW controller (FOC + Bluetooth)
Replies: 35
Views: 10337

Re: LegStrong - Open-Source HW/SW controller (FOC + Bluetoot

Most of that is not really the case anymore. Coreless axial flux motors operate at high ERPM, require high PWM speeds and reach 98% efficiency. There's many other motor topology with similar functions like this https://hobbyking.com/en_us/turnigy-typhoon-ferrous-loss-free-helicopter-motor-800kv-600...
by bamitsram
May 28 2017 5:49am
Forum: E-Bike Technical
Topic: LegStrong - Open-Source HW/SW controller (FOC + Bluetooth)
Replies: 35
Views: 10337

Re: LegStrong - Open-Source HW/SW controller (FOC + Bluetoot

I was thinking more of cases where you want to run 150-300V at around 100-150 amps. There's a lot of interesting motor designs around that aren't used in ebikes much because the controllers aren't good enough such as coreless axial flux and some inrunners with extreme ERPM values. Once you have a c...
by bamitsram
May 24 2017 4:24pm
Forum: E-Bike Technical
Topic: LegStrong - Open-Source HW/SW controller (FOC + Bluetooth)
Replies: 35
Views: 10337

Re: LegStrong - Open-Source HW/SW controller (FOC + Bluetoot

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 loop hal...
by bamitsram
May 24 2017 8:08am
Forum: E-Bike Technical
Topic: LegStrong - Open-Source HW/SW controller (FOC + Bluetooth)
Replies: 35
Views: 10337

Re: LegStrong - Open-Source HW/SW controller (FOC + Bluetoot

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% lin...
by bamitsram
May 20 2017 10:25pm
Forum: E-Bike Technical
Topic: LegStrong - Open-Source HW/SW controller (FOC + Bluetooth)
Replies: 35
Views: 10337

Re: LegStrong - Open-Source HW/SW controller (FOC + Bluetoot

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% line...
by bamitsram
May 19 2017 11:00am
Forum: E-Bike Technical
Topic: LegStrong - Open-Source HW/SW controller (FOC + Bluetooth)
Replies: 35
Views: 10337

Re: LegStrong - Open-Source HW/SW controller (FOC + Bluetoot

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 on ...
by bamitsram
May 19 2017 12:01am
Forum: E-Scooter and Motorcycle Photos & Videos
Topic: E-Cruiser / Harley build
Replies: 17
Views: 3651

Re: 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 already don...
by bamitsram
May 18 2017 9:28am
Forum: E-Bike Technical
Topic: LegStrong - Open-Source HW/SW controller (FOC + Bluetooth)
Replies: 35
Views: 10337

Re: LegStrong - Open-Source HW/SW controller (FOC + Bluetoot

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.
by bamitsram
May 18 2017 4:21am
Forum: E-Bike Technical
Topic: LegStrong - Open-Source HW/SW controller (FOC + Bluetooth)
Replies: 35
Views: 10337

Re: LegStrong - Open-Source HW/SW controller (FOC + Bluetoot

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 leaving t...
by bamitsram
May 18 2017 1:52am
Forum: E-Bike Technical
Topic: LegStrong - Open-Source HW/SW controller (FOC + Bluetooth)
Replies: 35
Views: 10337

Re: LegStrong - Open-Source HW/SW controller (FOC + Bluetoot

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.
by bamitsram
May 17 2017 11:47pm
Forum: E-Scooter and Motorcycle General Discussion
Topic: Fazer Conversion Completed
Replies: 16
Views: 2284

Re: 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 and g...
by bamitsram
May 17 2017 6:44pm
Forum: E-Scooter and Motorcycle Photos & Videos
Topic: E-Cruiser / Harley build
Replies: 17
Views: 3651

Re: 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 18650s,...
by bamitsram
May 17 2017 4:21am
Forum: E-Scooter and Motorcycle Photos & Videos
Topic: E-Cruiser / Harley build
Replies: 17
Views: 3651

Re: 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 24s @1...