Tesla SDU main contactor not closing [SOLVED]

[qmedia2651]

My SDU logic board after precharge the main contact will not close precharge is ok . But the main relay not closing. Using sdu drop in logic board V6. Please someone advise can I close the main contact manually with a external switch?

[johu]

Moved this here as it has nothing to do with the charger.

On the topic: is the relay driver given 3.3V? I.e. the left pin IC9 should be 3.3V when the inverter is in run mode. If so, check if the DC switch output (Pin 3 of the main connector) is pulled to ground, i.e. with a small light bulb. If so, check your wiring and relay.

[qmedia2651]

Yes I have led set on pin 11 and 3 pin 11 lights up for a few seconds then turns off but led on pin 3 no light.
Please advise
PS I am using 344 vdc
My udc is 1.59 can't be !?

[johu]

pin 11 will switch off after 5s if udcsw/2 volts have not been reached, i.e. udc < udcsw/2
Something is wrong with your HV wiring/fuse/contactor or, less likely, voltage sense.

[qmedia2651]

See pics

[qmedia2651]

Thank you Johu take care

I have 344DCV at inverter cable's

[Isaac96]

What value of 'udc' do you see with 344v at the inverter? What value with 0v?
Values of parameters 'udcgain' and 'udcofs'?

[qmedia2651]

udc = 1.59 with and without 344v
ucdgain = 6.15, dcv =0v
udcofs= 0 , dcv=0

[Isaac96]

Either a) you don't have voltage at the inverter or b) the voltage sense circuit is borked.
You stated you have 344v at the inverter cables.
So your voltage sense isn't working for some reason.

Check for cold solders on the board? (I don't remember how the SDU voltage sense is set up to be honest).

[johu]

SDU board gets a voltage signal on pin 1 of the 24-pin gate drive connector. Whats the voltage on pin 1 with HV on?

[qmedia2651]

Going to pull the inverter out again. will get back ASAP got to get this motor running so i can get it to the shop and start designing the sub frame for my 1991 300CE Mercedes Benz now called
300CEV. I will be using Fusion 360 for frame design
Thanks all for your help take care

[qmedia2651]

Found no voltage at pin 1 of 24 pin with 344v on .with pre- charge relay on about 1mv reading

[johu]

That means the bus voltage sense circuit has some fault, maybe a minor one. Unfortunately I don't know how it works, maybe you can find some optical sign of failure.
Or the DC voltage does not quite make it into the inverter.

[qmedia2651]

How much current is required to spin this motor ? can it be the battery pack I'm using ? 400vdc infinity Q50 pack but it had 360v they been sitting for 4 months went down to 344v.

[Isaac96]

Your pack should be fine. If you have DC at inverter then the pack is plenty, the issue is either in the inverter (that voltage sense circuit) or as Johannes said power might not be getting all the way to the inverter. Have you measured voltage at the inverter end of the wiring?

[qmedia2651]

Thanks Isaac96 take care looks like another inverter will look for one on Ebay

Here are the pictures of the inside of the inverter input HV
Any thing abnormal?

UDC=1.78V now

[qmedia2651]

I see that the SDU HV cables have a small box connected to the + HV cable.
My cable doesn't have that I have my own HV Box and fuse. CAN THAT BE A PROBLEM WITH THE INVERTER.

See picture

[qmedia2651]

See picture

[Isaac96]

No, you don't need that box. Connectors look fine too. Looks like it's the inverter then.
If you have contactors on do you get voltage at the inverter end of the cables?

[qmedia2651]

Yes I do 344v

In the pic correction Vd is 230mv not 230.5v.
Input voltage =output voltage = 344vdc
Therfore this proves that the capacitors are changing .

After checking all voltage and continuity of IGBT conn 5
And continuity from pin 1 to R31 to Pin 11 on the STM32

My conclusion is that the 24 pin IBGT conn 5 ,pins are not connecting to the inverter pins.

Need part number for 24 IGBT conn 5 it's not on the bill of materials list.

Any one out there please advise

[qmedia2651]

Looks like my IGBT Connection 5 is bad any one knows the info for this connection model number ect ..........

[qmedia2651]

Today I put in a new logic board from JLCPCB supplied with Damien's Gerber file they sent me 5 populated boards.
And found same results as with the former one .
CONCLUSION BAD INVERTER. WELL SHIT HAPPENS.
LOOKING FOR A SDU INVERTER.

I hope the Gerber files are good.

[qmedia2651]

Just got a inverter waiting for its arrival

[qmedia2651]

Hopefully this one will be OK

[Peter]

Hi qmedia2651. I am looking for a replacement inverter, could you let me know who may have one please ? Thanks. Peter