"Marty S." wrote in message
...
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?

that should work fine.

As daytripper suggested, it would be a lot safer if you connected it across
the battery that had a connection to "ground". The trolling motor could be
totally isolated, but I wouldn't bet on it. It might be isolated as long as
the aluminum case of the lower unit didn't touch anything else.

The trolling motor should have a "positive" and a "Negative" power lead. If
either side was referenced to ground it would be the negative, so connect
your fish finder across the battery that connects to the negative trolling
motor lead.

As another has said, the fishfinder will create an unequal discharge in the
two batteries, so one will go dead before the other. But unless you sit
fishing for a LONG time the fish finder draw will be insignificant. Now, if
you start running spot lights or similar there might be an issue.

Rod