Is it a direct transfer or Bpay? Check your transfer limits as you may not have one high enough to do it all in one go. You may need to call your bank to get it upped prior to sending. Depending on the method, their bank, your bank etc. it may be an overnight transfer (or even 2 days in limited circumstances) so a transfer after the cut-off on Friday evening would not be seen by Tesla until Tuesday AM. Simple answer is line up your ducks, understand your bank's limit and cut-off time, and do it no later than Thursday day. The interest is negligible (and if it is more the $6 a day please let me know what account you have!).
I'm with NAB (for what it's worth.)
If I do a transfer using Internet banking, my limit is currently $5000/day. (if I remember rightly.) I can increase that to an absolute maximum of $40,000/day. This means, in my case, doing three transfers over three different days (one transfer on each day).
Or I can go to a bank branch, show my ID and otherwise verify my identity to the teller, and do it all in a single lump sum that way. I'm leaning towards this approach - faster, simpler, and means that I'm not increasing my transfer limit to a level that I am very much not comfortable with.
Short version: get in touch with your bank and ask. This is not a difficult problem to solve.
You are being very generous assuming getting 3% in a working acct and then not paying tax on it! Mine at 1.5% and my company tax rate is more like $21 net a week.
As others have said: mortgage, sweet mortgage. Every dollar I put into mine saves me an effective 3.09%
after tax (since the interest is not tax deductible). Or maybe 4.4% before tax. (Ballpark. Probably a bit more than that.) So for a $100,000 purchase, that's $3,090 per annum, or about $8.47 (again, after tax) per day.