Hmmmm .... my at least 7 year old laptop computer never looses the values that I can set into the non-volatile storage portion of it's BIOS when I remove it's "big battery". I believe there's a little round button battery in it that keeps it's non-volatile storage sections active and set. If so, my computer has never had this little button battery replaced and to this very day I still don't lose any BIOS settings ... so this little battery is able to do it's thing for years.
COME ON ... vehicle manufacturers!! Step a little further into the 21st century and if you're going to load up your vehicles with computers ... do it right.
By the way, I changed the battery on my 2005 Ford V10 years ago and paid no attention to powering it's electronics while doing this. It ran rough afterwards for a bit, but soon smoothed out and has been fine ever since.
