The problem I have with your set up is that I have a surveyor coming by
every 6 months during construction and reporting back to my insurance
company. Everything has to conform to ABYC standards and 11.7.1.2.1. says
I have to have a way to isolate the house bank from everything else or I
will get a nasty letter.

I have found two solutions though. The stock Hitachi/Yanmar alternator is
an N type and the negative side of the regulator comes out of the case on a
terminal that is tied to the ground terminal. The other is that banks under
800 CCA don't have to be isolated.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"Al Thomason" wrote in message
...
Glenn,

I too have two alternators, stock that I use for the starter battery
and a large LN for the house battery. But in my configuration I do
not use any 1/2/all switches on the alternator feeds. Just keep it
simple: The stock alt goes to the Starter battery, and the LN goes to
the house battery...

Where I do use master switches is in the feeds to the sub-pannels.

On the House DC Sub Pannel I have an on/off switch to the House
battery. This is a master disconnect and does tie into the LN field
ckt. For the Nav sub DC pannel I use an A/B/All switch so I can
select to feed it from the house battery (Normal), or put it over to
the Starter battery (backup). Wired this way it also give me a way to
connect the two systems together if needed (very unusual situation).
I do not have a cut-off switch on the starter batter.

I did it this way to keep the two systems 100% Issolated and simple.
Buy putting the A/B switch on the DC Sub Pannel feeds (instead of the
alternator outputs) I can gain reliability without making the
charging system complex.

-al-


On Thu, 16 Feb 2006 22:53:36 -0500, "Glenn Ashmore"
wrote:

Working on installing the regulator and battery switches for Rutu. The
complicating factor is that I have a BIG Leece-Neville charging the house
bank and the stock Yanmar alternator charging the starter battery. There
are two battery switches. A straight on/off at the house bank and a
1/2/Both at the engine.

The 1/2/Both switch has a field disconnect feature to prevent damage if it
is operated with the alternator running but in the normal arrangement
switching the hot side it only works for one alternator. The
Leece-Neville
is externally regulated but the stock alternator in internally regulated.
I am thinking that by switching the field ground rather than the hot side
I
could get it to work for both. The LN is not a problem because I know how
it is wired but I can't figure out how the stock Yanmar field is grounded.
The Yanmar installation manual doesn't mention the alternator wiring.

Is there a way to bring the field ground on a stock Yanmar alternator out
to
a switch?