Lawrence Johnson wrote:

> Bill, if you follow the Bentley wiring, then the relay is only closed when the
> voltage output from the alternator exceeds the voltage output from the battery.
> This can only happen when the engine is running. Consequently, the aux. battery
> is not connected through the relay until the engine is running. It contributes
> nothing on start up.
> -Larry J

Privately I was asked:
<Theoretically, this could happen the first time you crank and spin the
  alternator or is there some safety I'm not aware of?>

My answer was:
I see your point. Next chance I get, I'll put a voltmeter on my relay and see just
when it closes. I believe that the 'alternator' light on the dash is powered by
exactly the same differential between alternator output and battery output. I'll
check this light and see if it winks out while cranking. With my old (dying)
alternator, this light would stay on until I rev'd the engine to boost alternator
output. Perhaps that's the real trick: the alternator only puts out >12v at higher
revs >850 (idle). I'll check that out too.
-Larry