"Chuck Gould" wrote in message
oups.com...

Calif Bill wrote:


This is a small boat, not a trawler. Either battery will start the boat.
If the switch is on 1 then the battery connected to 1 on the switch will
start the boat and run all the electronics. Like wise on 2. Both will
connect the batteries in parallel. Both hooked up. Run the switch in #1
for a while and then next time run it in #2. If you run it in both, and
you
have a battery failure, you may end up with no starting battery. One bad
battery adn one dead battery. None, just disconnects both batteries for
storage. I find it much better to add another switch and install a
battery
combiner. Run the starting battery on 1 and all the electronics on 2.
Then
when you are running both batteries will charge and when not running,
only
the electronics battery will be drawn down.

Fine, as long as both batteries are "deep cycle" rated. People who
install a light duty
"starting battery" and then discharge it subtantially for house use (as
would occur with the practice you describe) will be buying new
baterries a lot more often than needed.


Lots of the small boats use the combo starting/ deep cycle battery for both
sid3s. But the main point, is they do not have a house battery setup and a
starting battery setup. The switch connects which ever battery selected to
the output of the switch and the output of the switch is wired to the motor.