On Tue, 8 Jun 2004 21:17:33 -0400, "Marty S." wrote:

I'm running 2 12-volt batteries running in series to power my 24-volt
electric motor in my jon boat (on an electric-only reservoir) and I want to
run a fish finder. Here's my question -- can I safely run the fish finder
off of one of the 2 12-volt batteries while running the 24-volt motor? Or,
is that going to burn up the fish finder? Should I just invest in a couple
of 6-volt lantern batteries instead?

One of the batteries is referenced to GROUND, the other is not.

If you connect your fish finder across the battery that is referenced to
GROUND, you should be fine. If you make the mistake of connecting across the
*other* battery, what the fish finder "thinks" is GROUND will actually be 12
volts *above* GROUND, which sooner or later will be revealed to be A Bad
Thing...

/daytripper