Post · Kakapo Social

Finally got to do some dyno runs with the #startergenerator this week.

As I'm able to vary many factors (target drive torque, generating torque, RPM and time), I tested many variations.

tl;dr: They definitely deliver on their 12.5 kW promise, but the stator gets hot quickly, especially at low RPMs and high torque.
I couldn't test the full 55 Nm, only up to 36.6 Nm, as that's the generating limit.

I'm still amazed by the engineering of those things. So much data and protections :D

LeoDJ

@LeoDJ@chaos.social · last year

I spent many dozens of hours losing track of time in #Ghidra (I swear, it's worse than #Factorio)

Until I had figured out the #CAN message handling, signal parsing and where and when which #DTC codes get set.
With that knowledge I could figure out, slowly but surely, what the #startergenerator needs to run.
Even #FBS4 was pretty trivial to circumvent (a single 1 written to the right memory location via #XCP)

And after implementing the ~25 CAN messages in my STM32 code I finally got this today:

LeoDJ

@LeoDJ@chaos.social · last year

There's still a lot left to do.
I need to implement the #XCP stuff into the STM32 firmware, so it can run the #startergenerator stand-alone.
Stuff like:
- Checking the firmware version on the ECU, so it doesn't poke the wrong memory address
- Reading and parsing the status of the motor
- And actually controlling the motor properly instead of just sending it a hardcoded 1 Nm torque request :D

And then also cleaning it up enough, documenting and testing it thoroughly, so it can be published.

LeoDJ

@LeoDJ@chaos.social · last year

We also did a max RPM test of the #startergenerator using one of @patagona's rescued Pylontech batteries, because the 20A of my 1kW lab PSU weren't enough :D

I set the torque limit to 0.7 Nm (out of 55), no RPM limit and let it rip :D
It reached a peak of 43A (~2kW) at the end of the acceleration, settled at 25A (~1.2kW) and reached a peak RPM of 13400.

It was a bit scary tbh :D
(Not sure if the video accurately captured the sound it made)

(Pylontech thread: https://chaos.social/@patagona/113149877881417810 )

LeoDJ

@LeoDJ@chaos.social · last year

The general control loop is also pretty impressive, the engineers at #Bosch SEG definitely did their job well.

The lowest limit I can set is 6 RPM and it runs buttery smooth.

And it has insane amounts of torque. If you hold the pulley really tightly, it slips out of most strong hands at around 6-7 Nm (as reported via the CAN status messages).

This will be really fun once put into some small vehicle :D

(It can also recuperate really well, but can't run in reverse at all)

#startergenerator

LeoDJ

@LeoDJ@chaos.social · 4 weeks ago

Today, I've built a "temporary" test stand, so I can hopefully test the (thermal) performance of the #startergenerator in the coming days.

It was a welcome excuse to finally dabble in some metalworking again :D

Also, those belt tensioners really need quite some force.

3 media

Two starter generators, bolted to square metal tubing, connected with a belt. The left starter generator features a belt tensioner.

Same setup as the last picture, from another angle

Cinematic photo of a single starter generator, seemingly "balancing" on a single mount (but actually being held by the bolt).
Shot by @twizzarak@chaosfurs.social — Cinematic photo of a single starter generator, seemingly "balancing" on a single mount (but actually being held by the bolt). Shot by @twizzarak@chaosfurs.social

LeoDJ

@LeoDJ@chaos.social · 5 days ago

Finally got to do some dyno runs with the #startergenerator this week.

As I'm able to vary many factors (target drive torque, generating torque, RPM and time), I tested many variations.

I'm still amazed by the engineering of those things. So much data and protections :D

1+ more replies (not shown)

Manawyrm | Sarah

@manawyrm@chaos.social · last month

@LeoDJ Did you ever try to use it as a generator? I happened to stumble across a half-broken gasoline power generator, and am wondering if I should try to put one of these into it.
The starter could also act as a starter for the motor, giving it a super fancy extra feature...