@VerityZooms, did you ever make progress on your efforts in this thread?
I'm considering accessing the 12V system for another purpose, and would love to hear anything you learned along the way.
Yep! Got sparks, car shut off, I was overly scared, everything was fine when I finished and reconnected it.
Just remember that since the accessible terminals in the X are
not the actual battery posts, but rather the opposite end of the battery's leads, you need to reverse the traditional wisdom of the battery (disconnect the
hot lead from the battery's hot terminal first). The goal, of course, for anyone reading along, being to avoid creating a short-circuit across the chassis if you slip and drop whatever lead you disconnect first … traditionally, if you disconnect the hot lead
from the battery, and you drop it, you either drop it against the chassis (where the negative-lead is already grounded, thus doing precisely nothing), or back onto the battery-post, which merely has the effect of restoring the normal, non-shorted circuit. (Not great for the electronics; but also a lot less bad than an exploding lead-acid battery, amirite?)
However, since we don't have access to the actual battery, then if we're holding the
other end of the hot-lead, and we drop it, it has the opposite effect: if it touches any part of the chassis (or worse, some unfused electronics' terminals), then there's a short-circuit: +battery → +lead → chassis (or worse, an expensive piece of electronics) → −lead → −terminal. Do not want! Instead, you disconnect the
negative lead from where it attaches to the chassis (see photos above) first; in this case, your worst case, dropping that lead anywhere within the chassis, is again simply resuming the (properly fused) circuit.
Secure that lead well, so it cannot come into contact with the chassis, before beginning work on the positive lead's attachment to the distribution box.
Not as ideal as disconnecting directly at the battery, but
waaaay easier than trying to get access to it.
Apologies if that's obvious to you; just recording it for posterity coming across this thread.
I've already had to do this twice, and am looking forward to installing two
more systems on the 12V bus (thank you, 2500W DC-DC converter! ); so I'm going to disconnect it
one last time and install a
RigRunner, and further installation or reconfiguration can be done in a moment with Anderson PowerPole plugs (and properly fused ) … without fiddling with the Tesla's distribution block or battery leads again. lol.