Tesla Large Drive Unit Support Thread

Topics concerning the Tesla front and rear drive unit drop-in board
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rjmcdermott81
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Re: Tesla Large Drive Unit Support Thread

Post by rjmcdermott81 »

Looking for some suggestions on next steps for troubleshooting. I have an issue that is becoming progressively worse. I now can't drive my car a full block without getting an overcurrent error.

Here is the sequence of events as best as I can piece them together. I've been redoing the entire car so driving has been extremely limited.
(Default Settings)
1. Bench testing: Low voltage testing, I was melting wires. I had a troubleshooting session with Johannes and he helped me identify that it was my encoder wiring. Fixed that and I was good to go. Bench testing was all good.
2. Full voltage testing in the car. No issues with the Tesla LDU that I can specifically recall. I may have had it turn off on me once but I am not sure. I gave it maybe 30% throttle at times and it broke the tires loose.
3. Because I was running the cooling through the batteries + the Tesla my coolant was running slower than necessary. On a longer test drive (40 blocks) it hit the tmphsmax of 85 C and the drive unit shut off.
4. Fixed cooling, now runs below 40C. Did more test driving.
5. At some point, during my test drives I would have the drive unit feel like it went into Neutral and the only way to get it back running was to reboot it. I did not see a lasterror.
6. Tonight, still with default settings when it shut off after 10 blocks of driving I had an overcurrent error

(Loaded Jon's parameter settings)
7. After loading Jon's parameters my Voltage is showing as higher. My udc is 440.43V when my pack is only at ~360V - is that normal?
8. With Jon's parameters I'm still getting the same behavior. Minimal throttle, half a block and the drive unit feels like it goes into neutral and I have the overcurrent error.

Questions/thoughts:
1. I may have wrapped my wiring at some point during this process to finalize things. Is it possible that my encoder wiring is causing issues when I hit a bump? Any way to test this?
2. Is my LDU bricked :)?
3. My ocurlim is set to -2500. I see posts saying that changing it to positive might be a good test. Should I do this?

Version: 4.96.R-sine

Thanks,
Ryan
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Re: Tesla Large Drive Unit Support Thread

Post by johu »

Can only comment on udc reading high, everything else is for the Tesla nerds. The default value for udcgain is 6.09. That should bring udc back to normal.
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Re: Tesla Large Drive Unit Support Thread

Post by EV_Builder »

How sure are you about the temperature reading? Could it be that it has air trapped? 45degrees lower is huge improvement so huge that I would fear the measurement. Half in air/ water? The temperature of the water leaving the inverter / motor how high is that one?
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Re: Tesla Large Drive Unit Support Thread

Post by jon volk »

Did you calibrate the throttle?
I would also update to the newer firmware.
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Re: Tesla Large Drive Unit Support Thread

Post by Boxster EV »

Suggestion after you’ve tried the above is to determine whether you have coolant leaking into the rotor area.
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Re: Tesla Large Drive Unit Support Thread

Post by EV_Builder »

Boxster EV wrote: Thu Apr 21, 2022 11:16 am Suggestion after you’ve tried the above is to determine whether you have coolant leaking into the rotor area.
Yeah good one too. Check the encoder sealing I think it is.
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Re: Tesla Large Drive Unit Support Thread

Post by jon volk »

Also, I think the settings that are included have POT2 settings that require a brake pressure sensor. Setting POT2 min/max values to 4095 should help eliminate some variables.
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Re: Tesla Large Drive Unit Support Thread

Post by rjmcdermott81 »

Thanks for the input. Here is my update:
  • I update to firmware: 5.14.R-sine
  • I have my POT2 settings at 4095
  • I confirmed coolant is flowing through the hoses to/from the drive unit
  • No coolant leaks visible
After the firmware update when I attempted to drive. When I apply throttle in fwd/rev the car jitters forward/backward. It feels like it would if there was an encoder setting wrong or not connected properly. I didn't apply much throttle out of fear of it causing issues. My encoder setting is set to A/B which is where it has been since my low voltage testing.

Do I need to make an encoder change after upgrading the firmware?

Thanks again for all the help/support

Here is an output of my settings/readings: https://drive.google.com/file/d/1b6hUi7 ... sp=sharing
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Re: Tesla Large Drive Unit Support Thread

Post by EV_Builder »

Why are your amps at 5000? I think that should be lower / solved first.
(idcmax/idcmin /iacmax)
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Re: Tesla Large Drive Unit Support Thread

Post by Boxster EV »

EV_Builder wrote: Thu Apr 21, 2022 4:01 pm Why are your amps at 5000? I think that should be lower / solved first.
(idcmax/idcmin /iacmax)
Default params. Not the issue here.
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Re: Tesla Large Drive Unit Support Thread

Post by johu »

udc = 436 and udcmax=425 but that would only limit regen. Still set udcgain so that you get a correct reading.
The other parameters that EVBuilder mentions are just deraters, many don't use them so that's not causing trouble. I can't see anything apparently wrong. 5.14 has Jons fweak mod that also has a distinct parameter, just can't think of the name
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Re: Tesla Large Drive Unit Support Thread

Post by jon volk »

These are the parameters I use for normal driving, not set to kill, with the firmware mods.

@rjmcdermott81 The deadness of half your pedal is from slipstart being at 55. This is a holdover of trying to avoid low speed/low throttle shudder that the updated firmware fixes on the LDU. My updated parameters should be a better place to start.

EDIT, be cautious using all these parameters. Idle and regen are all linked to CAN inputs Im providing so your results may not be suitable based on whatever state this snapshot was taken.
Attachments
params 7.json
(1.06 KiB) Downloaded 88 times
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Re: Tesla Large Drive Unit Support Thread

Post by EV_Builder »

ok in order to be of more use i made a small comparison:

Diff:
In John's:
- Boost : 130 lower;
- fweak: 22 higher;
- udcnom: 10 lower;
- fslipmin: (2.37-0.87) higher
- fslipmax: 0.09 higher;
- fmax: 110 higher;

i cant find all the parameters in the JSON (which are on the web screen)...
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Re: Tesla Large Drive Unit Support Thread

Post by Boxster EV »

Jon’s missing some hidden parameters, need the full list for a LFL comparison, otherwise it won’t play well with mix n match.
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Re: Tesla Large Drive Unit Support Thread

Post by jon volk »

I thought there was a display all flag to include hidden parameters but I might be imagining that. All the hidden stuff is mostly "do not touch or youre gonna have a real bad time" parameters. But as I say, use caution.
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Re: Tesla Large Drive Unit Support Thread

Post by rjmcdermott81 »

Okay I think I have my marching orders. I'm going to fix some parameters, specifically slipstart, UDCgain, and I'll stare/compare others.

Quick question. In a post from @Boxster EV I saw him make a recommendation to lower the occurlim when doing testing to avoid damage to the drive unit. Is this something I should do? Is that the ocurlim parameter and does anyone have a recommended setting for testing?
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Re: Tesla Large Drive Unit Support Thread

Post by jon volk »

Raising fweak and lowering fslipmax are good ways to limit power. Any of the software current limiting when used to the extreme can cause oscillations that can counterintuitively induce an overcurrent.
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Re: Tesla Large Drive Unit Support Thread

Post by rjmcdermott81 »

DUDEZ. Just got back from an extended test drive and I was literally shaking with excitement when I walked in.

The car is so smooth now, zero jitters, no weird power cuts, no ocurlim, linear pedal feel.

I made the following updates:
  • Updated to 5.14.R-sine
  • Loaded Jon's settings from the Parameters site
  • set boost to 1720
  • set slipstart to 32
  • Adjusted my udcgain so that udc matches my BMS
I didn't go over 30mph or pull more than 100 amps for my testing. Trying to get the car to Radwood this weekend and after that I'll do more rigorous testing. For now I'm over the moon. Thanks for all the quick help and input @johu, @EV_Builder, @jon volk, and @Boxster EV!
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Re: Tesla Large Drive Unit Support Thread

Post by P.S.Mangelsdorf »

rjmcdermott81 wrote: Fri Apr 22, 2022 3:02 am DUDEZ. Just got back from an extended test drive and I was literally shaking with excitement when I walked in.
There's nothing like the first successful test drive, I think I was laughing for a week after mine. Glad you got it fixed!
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Re: Tesla Large Drive Unit Support Thread

Post by Boxster EV »

Quick question. My UDC at pre-charge always reads accurately, however very occasionally when closing the main contactor I get an overcurrent because UDC drops significantly when going from waitstart to run. I'd love to resolve it but short of checking the LDU current sensing connections, I've run out of ideas.

Grateful for your thoughts.

Waitstart:
4B670861-6972-4DC6-8927-CB8F45AFAA71.png
Start:
743C0F31-FDD6-405C-B24C-CA4A49AA056E.png
P.S It's a good opportunity to investigate as I've currently got the drive unit hanging out the car.
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Re: Tesla Large Drive Unit Support Thread

Post by EV_Builder »

Are main relais switched on when you turn on the inverter?
Looks/feels like turning on makes the voltage drop itself.
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Re: Tesla Large Drive Unit Support Thread

Post by Boxster EV »

EV_Builder wrote: Mon May 02, 2022 7:18 pm Are main relais switched on when you turn on the inverter?
Looks/feels like turning on makes the voltage drop itself.
The inverter is on and pre-charge completed which registers the correct voltage (pic 1 above). Upon closing the main contactor the logic board is measuring a voltage drop either spuriously or actual (pic 2 above).

The issue only happens occasionally but I’d like to get it sorted.
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Re: Tesla Large Drive Unit Support Thread

Post by EV_Builder »

Can you make a graph with the WiFi dongle?
Maybe that helps? I also would disconnect everything else en check if it reproduces.
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Re: Tesla Large Drive Unit Support Thread

Post by Boxster EV »

EV_Builder wrote: Mon May 02, 2022 8:54 pm Can you make a graph with the WiFi dongle?
Maybe that helps? I also would disconnect everything else en check if it reproduces.
I tried to replicate the fault about a dozen times this evening. Of course it played ball every time. 🤨
224C737D-F92A-4A67-9082-6395272EF80A.png
Edit: couldn’t replicate this so I’ve chucked the motor back in the car and it been fine.
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Re: Tesla Large Drive Unit Support Thread

Post by canadasconvert »

I am having a problem with my Inverter. Here is the background: Tested motor/inverter on bench with 187V (1/2 the full pack). Wifi Open Source Interface confirmed voltages, current, etc. Mounted motor/inverter in car with approx. 220V batteries and did test runs forward & reverse in alley 200m-300m at a time. Installed full 360V battery pack in car and spun motor up while on jack stands - everything worked. Rewired the Main Disconnect Switch and tested the car again on jack stands - now it wont run. My start up sequence is to manually close the contactors in the proper sequence and time delays. I did notice after I rewired the Disconnect Switch that the pre-charge relay sometimes would not close due to faulty 12V supply. I may have closed the main contactor and pressed the pedal without the pre-charge contactor closing. I checked the wifi Opens Source Interface Spot Values and the F/N/R switch works and I can read motor temps but the UDC shows 1.43V. I also get a CURRENT LIMIT error message. I can confirm all contactors are working and there is full 360V through main fuse. I pulled the inverter cover and when powered up the Open Source Board has a solid red LED, a solid green LED and a blinking green LED illuminated. I also looked at the IGBT's and found a single bubble in three IGBT's. Each bubble was about 1.5-2mm dia. See pic. Looking for advice on what to check next.
IMG_2784.JPG
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