Jose wrote:
On an aircraft with separate "battery" and "alternator" switches,
should you turn on BAT and leave ALT off during engine start, or
should you turn them both on prior to start?

I leave alt off during start, to prevent a power surge from going
through the alternator.

What would be the source of this surge? If it's such a problem, why don't
automobiles have alternator switches?

The only reason I could come up with having an alternator switch is to make
it easy to pull offline in case of a problem.