Tesla LDU Overcurrent Parameter Problem

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RiPower
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Tesla LDU Overcurrent Parameter Problem

Post by RiPower »

I have a Chevrolet pickup with a Tesla Sport LDU on the rear axle. I am not completely satisfied with the parameters or the driving behavior of the LDU. I will describe this problem here and hope someone can help me:
Here are the parameters with which I have been driving the LDU since January and which unfortunately always cause an overcurrent error, the error occurs when you accelerate fully from about 80 kmh, up to 80 kmh the acceleration is very sluggish anyway and then it suddenly comes on quite violently .
boost": 1850,
"fweak": 258,
"fweakstrt": 400,
"fconst": 450,
"udcnom": 327,
"fslipmin": 0.96,
"fslipmax": 1.5,
"fslipconstmax": 9,
I discussed the problem with Johannes Hübner and asked how to lower the overcurrent, he told me to increase fweak, I did this up to the point when the overcurrent stopped coming. Unfortunately, the LDU has been totally weak or even weaker in the lower speed range since then and only brings little torque. I've tried it again and again and got these values, but the drive is still totally sluggish up to 80 km/h and from around 80 km/h it starts really jerkily. However, since I changed the values, tmphsmax keeps coming back. The values ​​​​of Johannes have always led to an overcurrent shutdown for me. When I spoke to him on the phone he told me to increase "fweak" in small increments. I did it. I went from 258 to 330 to stop the overcurrent error, but unfortunately I weakened the drive. If I decrease "fweak" again, the overcurrent shutdown comes back. I'm looking for a solution to increase the power of the motor at lower RPMs and reduce the power at high RPMs so that I no longer have overcurrent shutdown.

Here is the complete set of parameters with my change of fweak, which did fix the overcurrent problem but weakened the drive.
{
"boost": 1850,
"fweak": 330,
"fweakstrt": 400,
"fconst": 450,
"udcnom": 315,
"fslipmin": 0.96,
"fslipmax": 1.5,
"fslipconstmax": 9,
"sincosofs": 2048,
"fmax": 540,
"dirchrpm": 100,
"dirmode": 3,
"ocurlim": 1200,
"udcgain": 7.5,
"potmin": 25,
"potmax": 4000,
"pot2min": 0,
"pot2max": 0,
"potmode": 0,
"throtramp": 100,
"throtramprpm": 20000,
"ampmin": 10,
"slipstart": 55,
"brakeregen": -50,
"regenramp": 100,
"regentravel": 20,
"offthrotregen": -70,
"cruiseregen": -30,
"regenrampstr": 50,
"brklightout": -1,
"bmslimhigh": 100,
"bmslimlow": -20,
"udcmin": 240,
"udcmax": 350,
"idcmax": 5000,
"idcmin": -5000,
"idckp": 2,
"idcflt": 9,
"tmphsmax": 85,
"tmpmmax": 180,
"throtmax": 100,
"throtmin": -100,
"iacmax": 5000,
"ifltrise": 10,
"ifltfall": 0,
"chargemode": 0,
"chargecur": 0,
"chargekp": 80,
"chargeki": 10,
"chargeflt": 8,
"chargepwmin": 0,
"chargepwmax": 90,
"idlespeed": 250,
"idlethrotlim": 50,
"idlemode": 3,
"holdkp": -0.25,
"speedkp": 0.09,
"speedflt": 5,
"cruisemode": 0,
"udcsw": 240,
"udcswbuck": 540,
"tripmode": 0,
"bootprec": 0,
"pwmfunc": 0,
"pwmgain": 100,
"pwmofs": 0,
"canspeed": 1,
"canperiod": 0,
"nodeid": 1,
"fslipspnt": 0.96,
"ampnom": 9.53
}
I drive a 1998 Chevi K1500 Silverado with 2 x Tesla Power (SDU + LDU)
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Matra Murena 1983 with Tesla SDU
various electrical conversions for customers: https://ripower-elektrofahrzeuge.de/
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Jack Bauer
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Re: Tesla LDU Overcurrent Parameter Problem

Post by Jack Bauer »

"fslipmin": 0.96,
"fslipmax": 1.5
Where did these values come from? because that right there is your problem.
https://openinverter.org/parameters/view.html?id=16
I'm going to need a hacksaw
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Re: Tesla LDU Overcurrent Parameter Problem

Post by catphish »

As I mentioned briefly on the other thread, I definitely think your slip parameters are incorrect. Try setting the fslipmin and fslipmax to the recommended values: fslipmin=0.87 and fslipmax=3.09.

However, I don't believe this is the cause of your overcurrent tripping, I think it is just reducing your torque (and likely causing the huge increase in torque and current that you described at around 80km/h).

Your ocurlim is set to 1200A. This is the correct value for a SDU but likely much too low for a LDU. I suspect this is the real reason for your tripping. Try setting this to 2000A or to the default (and maximum) value of 2500A.
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Re: Tesla LDU Overcurrent Parameter Problem

Post by RiPower »

Thank you for your hints. I deliberately lowered the slip value to reduce the torque, Johannes gave me this tip:
viewtopic.php?t=2178
I have the problem that my LDU goes to the cardan shaft and I haven't found a company in Germany that can build me a cardan shaft that can handle the full torque. I have attached photos of my vehicle and the cardan shaft for you to get an idea.
DSC_0014.jpg
DSC_0003.jpg
DSC_0001.jpg
2022-10-17 13.48.29.JPG
2022-10-17 13.47.47.JPG
That's why I'm worried about raising fslipmax.

Thank you for the hint with ocurlim, no idea how this value got there. I think this will solve my overcurrent problem.

I will test in the next few days and give feedback.
I drive a 1998 Chevi K1500 Silverado with 2 x Tesla Power (SDU + LDU)
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Matra Murena 1983 with Tesla SDU
various electrical conversions for customers: https://ripower-elektrofahrzeuge.de/
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Re: Tesla LDU Overcurrent Parameter Problem

Post by catphish »

RiPower wrote: Tue Oct 18, 2022 8:09 pm Thank you for your hints. I deliberately lowered the slip value to reduce the torque, Johannes gave me this tip:
viewtopic.php?t=2178
I have the problem that my LDU goes to the cardan shaft and I haven't found a company in Germany that can build me a cardan shaft that can handle the full torque.
If you don't want the large increase in torque above 80km/h, you might want to reduce fslipconstmax too.
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Re: Tesla LDU Overcurrent Parameter Problem

Post by RiPower »

Can you please explain to me the connection between fslipmax and fslipconstmax.

My goal would be a slightly higher torque below 80 km/h and constant acceleration above 80 km/h. In other words, a little more torque under 80 km/h, less torque over 80 km/h.
I drive a 1998 Chevi K1500 Silverado with 2 x Tesla Power (SDU + LDU)
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Matra Murena 1983 with Tesla SDU
various electrical conversions for customers: https://ripower-elektrofahrzeuge.de/
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Re: Tesla LDU Overcurrent Parameter Problem

Post by catphish »

fslipmax is the amount of slip applied at 100% throttle below the speed defined by fweak (330Hz, 9900RPM).
fslipconstmax is the amount of slip applied at 100% throttle above the speed by fconst (450Hz, 13500RPM).
Between fweak and fconst, the slip varies proportionally from fslipmax up to fslipconstmax.

So in your configuration, slip will be 1.5 up to 9900RPM, 5.25 at 11700RPM, and 9.0 at 13500RPM. I've attached a chart showing this curve.

Torque and acceleration are the same thing (if you ignore air resistance) (because acceleration is force divided by mass, and force is torque divided by your wheel size).

Torque is controlled by a combination of slip and voltage, but slip increasing from 1.5 to 9.0 over such a small RPM range will likely be very noticeable.
Attachments
slip.png
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Re: Tesla LDU Overcurrent Parameter Problem

Post by RiPower »

Thank you for the very detailed and understandable explanation. I'll try to do some trips tomorrow and implement your advice. I'll get in touch.
I drive a 1998 Chevi K1500 Silverado with 2 x Tesla Power (SDU + LDU)
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Matra Murena 1983 with Tesla SDU
various electrical conversions for customers: https://ripower-elektrofahrzeuge.de/
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Re: Tesla LDU Overcurrent Parameter Problem

Post by m.art.y »

RiPower wrote: Tue Oct 18, 2022 8:09 pm I have attached photos of my vehicle and the cardan shaft for you to get an idea.
Hi, have you mounted the LDU sideways and run rear differential via cardan shaft from LDU gearbox? You're only using one output from LDU gearbox? The other one is plugged? How are the gearing ratios and performance when it's used like that? Wonder if this can be done with a Leaf motor/gearbox combo too?
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Re: Tesla LDU Overcurrent Parameter Problem

Post by RiPower »

Yes we have changed the LDU gear ratio, there is a conversion kit for that:

https://zero-ev.co.uk/shop/teslagearse ... y=48#attr=

Then I fixed the differential and had a shaft built with which I can get the power from both LDU outlets on one side of the LDU. You have to check whether this is also possible with the Leaf engine. It is important that you include the wheel size and the translation of the rear axle drive of the vehicle in which you want to install the engine in your calculation.
I drive a 1998 Chevi K1500 Silverado with 2 x Tesla Power (SDU + LDU)
+
Matra Murena 1983 with Tesla SDU
various electrical conversions for customers: https://ripower-elektrofahrzeuge.de/
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Re: Tesla LDU Overcurrent Parameter Problem

Post by RiPower »

The LDU is now running great, your tips have really helped me a lot. I raised fslipmax to 2.2 and lowered fslipconstmax to 6. It evenly accelerates the car to 100 km/h in just under 7 seconds and then continues to do so up to 150 km/h. I'm very happy with that, I see the LDU settings as complete.

In combination with the SDU on the front axle, it will certainly reach 100 km/h in less than 5 seconds, but unfortunately my settings with the SDU were not so successful, but I will report on that in the other thread.
I drive a 1998 Chevi K1500 Silverado with 2 x Tesla Power (SDU + LDU)
+
Matra Murena 1983 with Tesla SDU
various electrical conversions for customers: https://ripower-elektrofahrzeuge.de/
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