Project Fig-Leaf

[james@N52E01]

Hi all, sorry it has been a long while since the last update. We’ve been making steady progress and the rear battery box is almost finished. Once it is installed we just need to finalise designs for the front battery box. Will post some pictures soon. The main issue has been the lack of available space at the front, the Gen 1 Leaf inverter is quite bulky so we are exploring other options...



Currently I’m trying out a Prius Gen 3 inverter with Damien’s v1b logic board and going through the FOC tuning procedure. The motor spins the wheels merrily when the car is suspended, when we dropped the car to test drive, motor ran smoothly but there was a serious lack of power. Testing with 140v test battery so not expecting massive speed but it can put out 150A so was hoping for reasonable torque. Pulling away, with foot to the floor (potnom reading 100% the car very slowly built up speed pulling up to 18A after about 5 seconds. No issues with voltage sag, (approx 146v down to 140v under that load) so I suspect there may be a parameter I haven’t adjusted properly restricting the current supply. See below:

Code: Select all

{
  "curkp": 32,
  "curki": 20000,
  "curkifrqgain": 50,
  "fwkp": -100,
  "dmargin": -2000,
  "syncofs": 54768,
  "polepairs": 4,
  "respolepairs": 4,
  "encmode": 4,
  "fmax": 400,
  "numimp": 60,
  "dirchrpm": 100,
  "dirmode": 4,
  "snsm": 12,
  "pwmfrq": 2,
  "pwmpol": 0,
  "deadtime": 130,
  "ocurlim": 300,
  "il1gain": 4.5,
  "il2gain": 4.5,
  "udcgain": 5,
  "udcofs": 0,
  "udclim": 540,
  "snshs": 5,
  "pinswap": 8,
  "bmslimhigh": 50,
  "bmslimlow": -1,
  "udcmin": 0,
  "udcmax": 520,
  "idcmax": 5000,
  "idcmin": -5000,
  "tmphsmax": 150,
  "tmpmmax": 300,
  "throtmax": 100,
  "throtmin": -100,
  "chargemode": 0,
  "chargecur": 0,
  "chargekp": 80,
  "chargeki": 80,
  "chargeflt": 8,
  "chargepwmin": 0,
  "chargepwmax": 90,
  "potmin": 500,
  "potmax": 4089,
  "pot2min": 4095,
  "pot2max": 4095,
  "potmode": 0,
  "throtramp": 100,
  "throtramprpm": 20000,
  "throtcur": 1,
  "brknompedal": 0,
  "regenramp": 100,
  "brknom": 0,
  "brkmax": 0,
  "brkcruise": -30,
  "brkrampstr": 0,
  "brkout": -50,
  "idlespeed": -1,
  "idlethrotlim": 50,
  "idlemode": 3,
  "speedkp": 1,
  "speedflt": 4,
  "cruisemode": 0,
  "udcsw": 0,
  "udcswbuck": 540,
  "tripmode": 0,
  "pwmfunc": 0,
  "pwmgain": 100,
  "pwmofs": 0,
  "canspeed": 0,
  "canperiod": 0,
  "manualiq": 0,
  "manualid": 0
}

[johu]

More throtcur!

[james@N52E01]

thought it would be something obvious! Thanks Johannes!

[james@N52E01]

It’s weird as it’s set to 1, I would have thought 100% throttle would be drawing 100A. Could this mean there is a gain issue on the current sense as well then?

[celeron55]

throtcur=1 means 100A at 100% for sure, at the motor. At the battery it will be something less, depending on the PWM amplitude. PWM amplitude mostly depends on the motor speed if you're not driving the motor particularly hard.

[johu]

Don't know the gain of gen3 current sensors (because nobody uses the parameter database, damn it). But if it is not correct the resulting output current also won't be.


EDIT: wait, actually somebody posted Gen3 parameters: https://openinverter.org/parameters/view.html?id=17 . 4.5 seems correct.

[james@N52E01]

Thank you very much guys;

celeron that explanation helps fill in some blanks as I could see il1 and il2 plotted behaviour seemed to be related to RPM which makes sense now.

Johannes, full disclosure, I used Bigpie’s Gen 3 inverter + Outlander parameters from the database as a basis for my inverter parameters so gain values will be more or less the same. I was able to check udc at least with a multimeter and it was accurate. Not sure if there is a procedure for calibrating IL gain for the Prius inverter.

I’ll try adjusting the throtcur value (carefully) for drive testing on Thursday and post some footage.

[Bassmobile]

Great work. This is a fun little project!
Watching with eager eyes now. Give us a little test drive video with that updated `"throtcur": 4.5` value!

[james@N52E01]

Thanks for the comments and support! Testing today went well, throtcur was definitely the culprit. As promised, here’s some (not very exciting) footage with throtcur set to 4.5

[mdrobnak]

Looking good! Just...get those batteries _inside_ the car.

-Matt

[james@N52E01]

Lol! Fear not, those are just for testing around the garage and will absolutely not be going anywhere near the finished vehicle

[johu]

This is even more outrageous then my first test run (notice the fancy user interface)

[james@N52E01]

I love it! Command prompt all the way

[steveknox]

James., we should probably not mention the "batteries catching fire" incident then, right? That'll remain between us.

[james@N52E01]

Don’t know what you are talking about Steve, I prefer to think of it as a pyrotechnic fuse incident The Nickel busbar between 2 cells melted at about 80A after 2 seconds... as we all knew that it would. The cells were barely warm but there was a bit of melted plastic around the break

Before I get a lecture on C ratings, material thickness and thermal runaway, I’ve made it clear from the start that these cells are being pushed intentionally way above their factory rating in a controlled setting for a couple of seconds at a time. Material failure was inevitable.

[SciroccoEV]

One advantage of an old school conversion, is that you don't even need a controller to move the vehicle around under it's own power.

[james@N52E01]

Very handy! Love the lift, if only the conversion was that simple to install

[james@N52E01]

Here is an expertly spliced photo of the spot values for IL1, IL2 and UDC in the test video above. Nothing too exciting but as you can see the car accelerates gently with about 80 motor amps. Those cells do sag quite a bit under load

[james@N52E01]

Just wanted to share some pictures of the almost finished rear battery box which will house 20 of the gen 1 Leaf cell modules.

I wanted to use as many of the original leaf connectors as possible, but as you can see the battery box connector plugs straight into the HVJB so it didn’t leave much room for insulation. I quickly designed a terminal housing to go round it.

[james@N52E01]

We were lucky enough to be invited to demonstrate the Fig-Leaf at the Figaro Owner’s Club’s 30th Anniversary event. Here’s a quick video of how the day went with big thanks to forum members Steve Knox and Jason Wright for all their help!



If you’d like to know more, here’s a link to the build blog

https://www.fig-leaf.org/post/the-fig-l ... ggiversary


.

[mdrobnak]

Nice job! Looks like it came out quite nicely.