openinverter forum

I’m tuning my Fiat 500R -73 and I have some questions regarding the SDU and rpm when not running it on 96S.

My nominal voltage is 204V and on top of that the fiat sports 12” wheels The Diameter is approx. 521mm which results in approx 10kmh per 1000rpm on the SDU. I'm still in the tuning process and yesterday I was able to reach 80kmh (gps). My guess is that this is the max speed I can get given the voltage and size of wheels. Is it possible to get the SDU to spin faster by altering config? What should I try in that case? Any ideas?

Running 5.35.R

This is my config:

{
"boost": 3000,
"fweak": 180,
"fweakstrt": 300,
"fconst": 270,
"udcnom": 204,
"fslipmin": 2,
"fslipmax": 3,
"fslipconstmax": 4,
"sincosofs": 2048,
"fmax": 270,
"dirchrpm": 100,
"dirmode": 1,
"ocurlim": 1200,
"pinswap": 0,
"potmin": 464,
"potmax": 2350,
"pot2min": 257,
"pot2max": 1218,
"potmode": 1,
"throtramp": 10,
"throtramprpm": 20000,
"ampmin": 5,
"slipstart": 40,
"sinecurve": 0,
"throtfilter": 4,
"brakeregen": 0,
"regenramp": 3,
"regentravel": 20,
"offthrotregen": -50,
"cruiseregen": 0,
"regenrampstr": 40,
"maxregentravelhz": 100,
"brklightout": -50,
"bmslimhigh": 50,
"bmslimlow": -1,
"udcmin": 156,
"udcmax": 236,
"idcmax": 450,
"idcmin": -200,
"idckp": 2,
"idcflt": 9,
"tmphsmax": 85,
"tmpmmax": 300,
"throtmax": 100,
"throtmin": -100,
"accelmax": 1000,
"accelflt": 3,
"iacmax": 800,
"chargemode": 0,
"chargecur": 0,
"chargekp": 80,
"chargeki": 10,
"chargeflt": 8,
"chargepwmin": 0,
"chargepwmax": 90,
"idlespeed": -100,
"idlethrotlim": 50,
"idlemode": 3,
"holdkp": -0.25,
"speedkp": 0.25,
"speedflt": 5,
"cruisemode": 0,
"cruisethrotlim": 50,
"udcsw": 185,
"udcswbuck": 540,
"tripmode": 1,
"bootprec": 0,
"pwmfunc": 2,
"pwmgain": 100,
"pwmofs": 0,
"canspeed": 1,
"canperiod": 0,
"nodeid": 1,
"controlid": 63,
"controlcheck": 1,
"manualstart": 0,
"fslipspnt": 0,
"ampnom": 0
}

Increase fmax

I did set fmax to 270 to allow a max speed of approx 100kmh.

Calculated like this:
Wheel diameter = 505 mm → circumference ≈ 1.586 m
Gear ratio = 7.56:1
Motor has 4 poles
Target speed = 105 km/h

Wheel RPM ≈1,103.6 RPM
Motor RPM=1,103.6×7.56≈8,344.9 RPM

f= 8,344.9×4/120 ≈ 278.16 Hz

Did some testing today, dont have a long enough track. Had to ease off the throttle to regaing tracktion.

I tried to set Samples per line: too 1000 to get higher resolution but when I do the logging stops. Running 5.35.R.

Are you running CAN attached ESP? That doesn't work well with high burst rates.
When calculating fmax you must take slip into account, also it cuts back before actually reaching fmax

I’m just logging from the web interface.

Ok, I will increase fmax and give it a try.

Thank you.