At 09:14 PM 9/20/2012, Rocket J Squirrel wrote:
>hours of driving in between, sometimes with just a couple. In the latter
>case I need fast bulk charging followed by topping off using the DC-DC
>charger to give me a  bit of extra charge for the next location.

If you need fast bulk charging, get a proper marine regulator that
will do it, running the alternator flat out and keeping track of
battery temperature so it can determine the proper bulk-stage end
voltage.  The built-in automotive regulator on the Bosch alternator
won't.  You may have to replace the alternator with one that will
stand constant high-output operation, or provide extra cooling air to
the existing one (as well as modifying a regulator assembly to be
just a brush carrier and bring the field connection out to the
external regulator).

As Dennis says, you're overcomplicating.

Yours,
David