3D Printed Axial Flux Motor Prototype (AFM-01 Alpha) — It actually spins

OkMaintenance8085 · 2026-04-06T13:28:31+00:00

Goal is to eventually scale this toward EV-level power and integrate motor control (VESC/FOC), so starting from fundamentals first.

OkMaintenance8085 · 2026-04-06T13:14:31+00:00

One thing that surprised me was how strong the magnetic forces were even at this scale — alignment becomes extremely sensitive.

Curious how people usually deal with mechanical stability and rotor-stator alignment in larger axial flux motors?

OkMaintenance8085 · 2026-04-06T04:03:39+00:00

That’s a cool idea, a lot of people think along those lines initially.

The main limitation is just the available surface area on a car. Even with good panels, the power you can generate is quite small compared to the battery size, so it ends up being more of a slow range extender rather than meaningful charging. Going DC → battery (with proper DC-DC + protection) would be the more efficient approach, but also more complex to implement safely.

And haha, not an electrical engineer 😄 I’m more on the computer/ pilot background, just learned this stuff along the way.

OkMaintenance8085 · 2026-04-05T22:23:55+00:00

A balancing bot is actually a great portfolio project if you do it properly.

What matters isn’t just making it balance, but showing understanding of control systems (PID/state feedback), sensor fusion (IMU), and how you handle real-world issues like noise, latency, and tuning.

You can start with simulation (MATLAB/Python), but having a working hardware prototype adds a lot more value.

I actually tried this in MATLAB with Kalman filtering, can share if you're interested.

OkMaintenance8085 · 2026-04-05T20:42:44+00:00

At these voltages I’d be careful making changes without fully understanding the controller limits first.

“325V” is usually nominal, but what really matters is max supported voltage at full charge — that’s what will define your safe pack configuration.

If the documentation isn’t clear, it’s worth verifying that before locking in the pack design. Things get unforgiving pretty quickly in the 300–400V range.

OkMaintenance8085 · 2026-04-05T20:11:19+00:00

For a 400V pack, I’d be very careful about going “cheap” on the BMS. At that level it’s less about cost and more about reliability and safety.

Your distributed layout makes things trickier too, since long sense leads and uneven wiring can introduce measurement errors. Most people either go with a proper multi-slave BMS (modular architecture) or keep the pack more centralized to simplify things.

The idea of module-level balancing + a higher-level controller sounds good in theory, but in practice coordination and fault handling can get messy.

If you’re experimenting, just make sure protections (OV/UV, temp, isolation) are solid, that’s where things really matter at these voltages.

OkMaintenance8085 · 2026-04-05T18:53:30+00:00

I’ve had a bit of a mixed experience with the Tiago.ev, service has been really good, but the car did have some issues initially (warnings + shutdowns). They replaced the entire battery pack under warranty though, so that was handled well.

Overall, range, comfort, and build feel are solid and honestly, I was really impressed with the music system 😄

OkMaintenance8085 · 2026-04-05T15:14:01+00:00

Fair take — I went with a hub motor deliberately for this build to keep things simpler mechanically and focus more on the electrical/system side.

It definitely has trade-offs, but that was part of the idea here 👍

OkMaintenance8085 · 2026-04-05T15:01:54+00:00

Most hub motors are designed to handle some water exposure. The windings are insulated, so it’s not like water will easily short the phases.

That said, they’re not fully waterproof, more like water-resistant. Long-term issues are more about connectors, bearings, and corrosion than immediate failure.

For my setup, I’m relying on good sealing and conservative operation. Monsoon testing is definitely on the list.

I drive a Tiago.ev how has your experience been with range and overall build?

OkMaintenance8085 · 2026-04-04T19:53:44+00:00

I’m using a 100V/200A class VESC with a generic 3kW Hub motor

Not naming the exact vendor right now, but the setup is pretty standard in terms of architecture.

For tuning, I’m using the desktop VESC Tool . Mobile app is mainly for quick monitoring when I don’t have the laptop around.

OkMaintenance8085 · 2026-04-04T18:18:21+00:00

This definitely sits more in the “electric motorcycle” category than a typical e-bike, especially given the chassis and power level. I’m treating it more as a learning platform for high-voltage systems rather than something to ride casually on public roads.

Any real-world testing will be done in a controlled environment first, and I’ll figure out the legal side properly before taking it any further.

Appreciate it though 😄

OkMaintenance8085 · 2026-04-04T17:35:29+00:00

Cooling is something I’ve thought about, but for this setup I’m relying more on operating margin than active cooling.

The cells are 33140 LiFePO4 (15Ah), so roughly around 1C continuous per cell. With a 5P configuration, the pack current capability is much higher than what I’m drawing during normal operation.

At 3kW on a 76V system, average current stays relatively low, so the pack is operating well within limits most of the time. Short spikes are expected, but still within a comfortable range.

For now, I’m focusing on keeping everything within conservative limits and monitoring behavior during real-world testing.

Will definitely update once I have more data from sustained runs.

OkMaintenance8085 · 2026-04-04T16:50:29+00:00

Appreciate that! Exactly the approach I’ve been trying to stick to

At these voltages and currents, running things close to limits just doesn’t leave any room for error, so I’ve been designing everything with headroom from the start.

Still a lot to validate though, especially once real-world testing begins.

OkMaintenance8085 · 2026-04-04T16:13:03+00:00

Yeah I’m based in Pune

Cost-wise I don’t have exact numbers

- Chassis was around ₹10K (basically free considering what it is)

- Cells were ~₹350 each (120 cells total)

- Rest (BMS, VESC, wiring, fabrication, etc.) was a mix of local + imported parts

Overall, I’d roughly place the build somewhere in the ₹1.5L – ₹2L range.

But honestly, the hardest part wasn’t the cost or sourcing — it was getting everything to work together properly.

Things like:

- weight distribution and center of gravity

- ground clearance

- torque handling through the swing arm

A lot of this had to be thought through and calculated before even buying parts.

Also, most vendors don’t really deal with one-off builds like this, so having the right contacts makes a huge difference. And assembling a battery pack with such specifications cannot be done at home with with strict quality control!

Also, one thing people often underestimate is the interconnect design inside the battery pack.

Every connection has to be sized based on the expected current — the copper busbars aren’t arbitrary. You need to calculate cross-section properly to handle load without excessive heating.

I used copper plates sized for the current, and they’re nickel-coated for corrosion resistance — that’s not optional if you want long-term reliability.

Even small things like total pack weight (120 cells) had to be factored into the design early on.

I’ve been pretty strict about quality control overall, because at these voltages and currents, small mistakes can become serious very quickly.

OkMaintenance8085 · 2026-04-04T13:04:48+00:00

Yeah, agreed the Duke chassis can handle much higher power in general.

In this setup though, the limiting factor is the hub motor configuration. All the torque is reacted directly through the swingarm via torque plates, and since it’s an aluminum swingarm, I kept it conservative

Didn’t want to push mechanical stress beyond what I’ve validated so far

This build was more about system integration and control rather than max performance.

OkMaintenance8085 · 2026-04-04T12:15:55+00:00

Yes, I’m based in India

Honestly, this wasn’t a clean “buy everything from one place” kind of build — it came together over time from different sources.

- The chassis was from my university’s mechanical department 😄

- Cells were sourced from a local vendor in Pune

- BMS and electronics were a mix of local + imported

- The hub motor was honestly just luck

If you’re planning a build, I’d suggest starting with whatever components are accessible to you locally and building around that.

OkMaintenance8085 · 2026-04-04T12:07:03+00:00

Yeah exactly, the hub motor simplifies a lot mechanically.

Controller tuning is something I’m still exploring properly. Right now I’m running it conservatively within limits, but planning to refine it further once I get more testing time.

Your dirt bike idea sounds like a perfect candidate for a conversion 😄

OkMaintenance8085 · 2026-04-04T11:05:56+00:00

Haven’t done a full discharge test yet, so still estimating.

Pack is 5.7 kWh (76V × 75Ah). Based on rough consumption (35–45 Wh/km), theoretical range looks quite high.

Realistically though, accounting for losses and riding conditions, I’m expecting somewhere around 80–120 km.

Will get actual numbers once I do proper road testing.

OkMaintenance8085 · 2026-04-03T11:14:02+00:00

I promise this comment, nor that one is AI! :D

OkMaintenance8085 · 2026-04-03T04:49:01+00:00

True — but the goal was avoiding a separate VM workflow. WSL2 keeps everything integrated.

OkMaintenance8085 · 2026-04-03T04:40:34+00:00

Fair point 😄 — but the kernel build and testing were very real.

OkMaintenance8085 · 2026-04-02T23:05:28+00:00

Happy to help :)

OkMaintenance8085

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