LDU Board - Not getting Powered Up - Now OVERCURRENT

[mtrehy]

Hi All,

I have the LDU logic board installed in a Tesla LDU (LDU or unknown origin). I have power going to the 23 pin connector on the ldu but it seems as if the board is not powering up, i.e no wifi available and no current at all is being drawn.

I have removed the inverter cover and nothing obviously not connected so I checked continuity from the pins on the 23 pin connector to the rear where they connect inside the inverter and I'm not seeing any continuity. For example pin 1 which is 12v ignition seems to have no continuity through to the smaller plug at the internal side of the connector. I have attached a pic, and if you look closely I think this 12v pin is the one that I have drawn a red arrow towards - it seems discoloured? I have also shown with a yellow arrow a bit of strange material inside the connector - I can't get in there as it has a clear perspex cover which is glued in place.

Anyway, can anyone tell me how best to test what is going on here? How I can be 100% sure whether or not 12v is reaching the logic board...?

If anyone is familiar with this Tesla connector that I have shown and whether I am testing it correctly I would be very grateful!

Thanks

[P.S.Mangelsdorf]

Hi All,

I have the LDU logic board installed in a Tesla LDU (LDU or unknown origin). I have power going to the 23 pin connector on the ldu but it seems as if the board is not powering up, i.e no wifi available and no current at all is being drawn.

I have removed the inverter cover and nothing obviously not connected so I checked continuity from the pins on the 23 pin connector to the rear where they connect inside the inverter and I'm not seeing any continuity. For example pin 1 which is 12v ignition seems to have no continuity through to the smaller plug at the internal side of the connector. I have attached a pic, and if you look closely I think this 12v pin is the one that I have drawn a red arrow towards - it seems discoloured? I have also shown with a yellow arrow a bit of strange material inside the connector - I can't get in there as it has a clear perspex cover which is glued in place.

Anyway, can anyone tell me how best to test what is going on here? How I can be 100% sure whether or not 12v is reaching the logic board...?

If anyone is familiar with this Tesla connector that I have shown and whether I am testing it correctly I would be very grateful!

ThanksIMG_20230411_172839.jpgIMG_20230411_172919.jpg

If I remember correctly, it is not a completely uncommon for that connector to be damaged.

Zero EV/Felten typically has some available, but they are out of stock
https://shop.fellten.com/shop/ldu23dbte ... 3785#attr=

I'm not sure if anyone else carries just that part.

In terms of testing, when you try to connect, do any lights come on (on the EVBMW/Open Inverter board), if so, which ones and what is their status (constant, flashing, etc)?

[Boxster EV]

I think I have one spare if needed

[mtrehy]

THanks gents, I've ordered one from Zero Ev, which is one they make themselves (not oem). Should have that tomorrow so will report back (hopefully with good news).

https://shop.fellten.com/shop/ldu23db-l ... 2873#attr=

[mtrehy]

SO some progress. I installed the new connector and it all lights up and I can connect via wifi!

I did not however manage to get the motor to spin. I only have 2 x 12v batteries in series. The driveshafts started to move very slightly and then it keeps blowing the 32a fuse that I have between the battery and positive contactor. Is this likely to be down to having too little voltage or unrelated?

Cheers!

[johu]

#1 reason: encoder A/B swapped

Put a 2 or 3 kW heater element in parallel to your fuse, otherwise you can kill your inverter rather quickly.

[mtrehy]

Cheers Johu, I wired the encoder as per:

viewtopic.php?t=76

Assuming that the image is looking into the the harness connector (wires at the back), I wired it:

pin 1 to pin 17 encoder gnd
pin 2 to pin 16 (encoder b)
pin 3 to pin 10 (encoder a)
pin 4 to pin 9 encoder 5v

I think my drive unit is a very early one - should I try swapping A & B?

[P.S.Mangelsdorf]

Cheers Johu, I wired the encoder as per:

viewtopic.php?t=76

Assuming that the image is looking into the the harness connector (wires at the back), I wired it:

pin 1 to pin 17 encoder gnd
pin 2 to pin 16 (encoder b)
pin 3 to pin 10 (encoder a)
pin 4 to pin 9 encoder 5v

I think my drive unit is a very early one - should I try swapping A & B?

Yes, it appears to be very common for the encoder wiring to be swapped, especially on earlier units.

[mtrehy]

Brilliant! The thing spins. I'm not entirely sure what fixed it. I gave it 36v and swapped the encoder pins and spins nicely. One very minor thing is that it seems to spin forward when it should be reverse but that's no issue.

So big thumbs up for the zero ev replacement 23 pin data interface connector. Seems strange though - I don't know the history of the motor but nothing I have done since I have had it could have damaged that connector so would have to assume that it was damaged when it was in the original vehicle but I can't see how that would happen through crash damage.

I wish I had bench tested this thing at the outset rather than installing it and then discovering this problem - I had to remove the entire rear suspension, rear battery box etc to get the ldu in and out.

[catphish]

One very minor thing is that it seems to spin forward when it should be reverse but that's no issue.

Openinverter doesn't really care which way is forwards and which way is backwards, it'll provide 100% torque and power in both directions. If it spins the wrong way, the accepted solution is just to swap the forward and reverse wires coming from the gear selector into the inverter.

Hopefully one day someone will add a software option to switch the direction, but nobody's ever really cared

[P.S.Mangelsdorf]

I wish I had bench tested this thing at the outset rather than installing it and then discovering this problem - I had to remove the entire rear suspension, rear battery box etc to get the ldu in and out.

I think most people have had to deal with the same. I had some issues that required the inverter cover to come off a few times, definitely not fun.

[mtrehy]

So I now have it in the car and 250v but as soon as I now touch the throttle pot it gives OVERCURRENT error.

With it still in the car I have removed the 2 orange HV connection covers checked continuity with a meter.

I have continuity between the HV B- terminal and all 3 of the HV phase terminals.

I am very reliably (cheers CS) been informed that this is very likely inverter failure but I guess out of total exasperation and desperation I thought I'd run it past here also in the vain hope of getting positive news!

It was turning ok with 36v out of the car, I then installed into car and connected up the proper 250v. The only other thing that happened during this was that I wired the encoder plug wrongly but I have since rectified that. When I first tested it yesterday it turned a bit and very slowly (I didn't notice the overcurrent error yesterday but it may well have been there). Today I "corrected" the encoder wiring and tried to test again and got no movement at all and now I get immediate OVERCURRENT error.

Any thoughts greatly appreciated!

Update,

So I've now disconnected the 3 HV phase busbar bolts and now only have continuity between B- and one of the phases...

[EV_Builder]

Not sure if the LDU board suffers from blowing fets when doing fw updates with hv connected?

How is the lubrication organized in the LDU? Reverse running might involve solving oil pump...

[EV_Builder]

Oh and about your measurement make sure you are not measuring through diodes of the fets if they have them. Pretty sure if you use the search option you find the way how to measure.

[catphish]

This was a case of a bad IGBT in the LDU.

It's the second time I've seen it, everything works at low voltage, but then switched to high voltage and a moderate amount of current flows, one of the IGBTs goes short circuit and that's the end of the LDU.

Replacement LDU with same logic board and settings worked fine.

I assume this is a symptom of accident damage causing an emergency HV shutdown in the original vehicle, but can't be sure. Just luck of the draw when purchasing I guess.