Tesla SDU+OI and EVS-BMS Integration?

Topics concerning the Tesla front and rear drive unit drop-in board
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elShankos
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Tesla SDU+OI and EVS-BMS Integration?

Post by elShankos »

Hi All,

So I have a Tesla rear SDU+OI board going into a Subaru Legacy and am now in the stage of drawing up some wiring diagrams etc.
I probably should have done all of this before I bought things but hey ho!
Here is my conversion thread: https://www.diyelectriccar.com/threads/ ... on.208076/

So I have all the motor and other hardware bits so far - batteries and BMS not yet. I am strongly considering going with the new EVS-BMS from Citini as I have the Tesla CMUs already and according to them it doesn't look like the SimpBMS is going to be making a come back:
https://citini.com/product/evs-battery- ... nt-system/

And I have been trawling through lots of posts and the documentation etc and based on their typical block diagram for an EV application that looks like this:
image.png
I have made my first draft (probably has dodgy bits) of my equivalent block diagram which looks like this:
image.png
So here goes with some questions to the community:

1) Anyone else done something similar to this and willing to share experiences? Maybe with SimpBMS? I.e. an OI SDU arrangement where the controller manages the closing of the main contactors and pre-charge?
2) Or do people use /some additional overarching system which talks to the BMS and also the motor controller and then controls the main contactors?
3) How to integrate an emergency stop into the system - i.e red, dash mounted button to shut down inverter and open main contactors?
4) How to initiate a shut down of inverter and open main contactors if BMS is unhappy? I.e. what pin on OI board to send a signal to (or loss of 12V high)
5) What size main fuse are folks using for the rear SDU? I have a 630A Tesla fuse but maybe its too big?
6) The OI SDU board doesn't have a facility to close the main -ve HV contactor - how have other people managed this?

Any tips, suggestions, comments welcome! Thanks a lot!
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