Tesla LDU board contactor control pins current sinking

Topics concerning the Tesla front and rear drive unit drop-in board
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luisrayas3
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Tesla LDU board contactor control pins current sinking

Post by luisrayas3 »

I'm currently sourcing the contactors for the HV setup and am curious about the current sinking ability of pin 6 on the LDU board. In the diagram posted on the LDU support forum (download/file.php?id=680&mode=view) the control pin (6) is hooked up directly to the contactor coil. Now on the other hand the current image on the wiki shows an intermediate relay driven from pin 6 and driving the contactor coil (https://openinverter.org/wiki/images/b/ ... iagram.png).

So I'm interested in knowing what the control pin is designed to sink; the pick-up current for e.g. https://www.gigavac.com/sites/default/f ... t/gx16.pdf is as high as 3.8A.

On a related note, with the ignition contactor drawing a steady 0.64A (see Gigavac) it seems the contactors eat as much as 3.8+0.64=4.44A of the 5A budget limited by the shared 5A fuse. I have seen the control board run over 0.56A on the bench, does it make sense to have separate fuses for the contactor coils?
Isaac96
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Re: Tesla LDU board contactor control pins current sinking

Post by Isaac96 »

Assuming pin 6 is connected to one of the big drivers (for precharge and main contactor) I seem to remember it's a BTS133TC driver -- that's rated for 7 amps load and max 21 amps. So it should be fine. Separate fuse might be wise anyways. Though that does go to ground, which is usually not fused unless you're extra cool and use a double-pole breaker.
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luisrayas3
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Re: Tesla LDU board contactor control pins current sinking

Post by luisrayas3 »

Thanks for the info that helps give confidence I won't blow the board with a larger contactor coil. For the fuse situation I was thinking something like this image, does that make any sense or am I worried about the wrong thing here?
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