My Perko switch also has the field disconnect, but it doesn't protect my
alternator. The protection is only afforded to some alternators. I'm away
from home now and don't have the specifics, but the alternator on my 3 liter
MerCruiser isn't protected by the Perko. As soon as I figure out which of
the wires on my alternator to use, I'll connect the Zap Stop.
I did label the Perko switch to remind me to turn off the ignition before
switching. I only use the switch to disconnect everything while the boat is
trailered, and to rotate which battery gets used for starting duty on a
given day. Both batteries are the same, and neither is wired as a house
battery on my runabout.

" JimH" jimhUNDERSCOREosudad@yahooDOTcom wrote in message
. ..

"Rick" wrote in message
...
I would suggest installing a battery combiner rather then the switch.
Run
the 24 to start and the 27 as the house. Anytime the engine is running
the
24 will charge first and then the 27.

If you really want a switch install a zap stop.

I had a switch and would forget to switch etc-etc just like everyone
else
with a switch.

By the way if you switch off with the engine running the alternator
diodes
will blow. That why the zap stop.




The switch is a Perko with alternator field disconnect. It is already
purchased.

What do you think of the need to use #1 gauge vs. #2 or #4 for a 10 foot
run
from battery #2 to the switch? Chuck was estimating a demand of 250 amps
(for the starter) using the estimator found in this link:
http://www.ancorproducts.com/