My switches were set up with the Port Battery as #1 and the Starboard battery as #2. The switches are fabricated with two terminals for batteries... one terminal for the starter. So under normal conditions to start the engines you would have the Port switch set on #1 and the Strbd switch set on #2... The numbers designate the batteries.... not the engines. During mooring you can turn the port battery switch to "off" and leave the strbd switch to #2. Then if the starboard (#2) battery goes dead from stereo and accessories... you put both switches to #1 and start the engines. But... keep in mind... You have to be very careful about how the boat is wired. If any accessories are cross wired or the batteries are "bridged" somewhere downstream in the wiring... having two switches won't isolate the batteries. When I wired my boat from the stem to the stern... I was very careful about isolating both charging systems. The port battery and alternator fed only the port gauges and trim motors. The starboard battery and alternator fed the right gauges, trim pumps, dash lighting and all accessories for the boat such as stereo and cabin lighting. So when I turned the port battery switch to "off". That battery wasn't feeding anything. I could run the Strbd battery dead and still have one fully charged battery for starting. But... If I had cross wired one accessory or bridged the wiring under the dash, both batteries wouldn't have charged seperately.

Sorry for hijacking this thread. How about a 3 battery system ? The '89 Bullet I sold had 3 batts. The '88 I took out from the moth balls used to have 3 but the previous owner changed to 2. I have the schematic from Cig but nothing on the 3.
Here's some pics of the '89 w/3

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I have a spare 3 pole Professional Mariner battery isolator if you can use it. Balances input from two alternaters and distributes it evenly to 2 or 3 batteries, keeps batteries from draining each other too.

Pm or email me the scoop- does it have a schematic?

Will check the literature that came with it. Also have a drawing from TAG at Formula I can fax to you. There is probably info in the Professional Mariner website too. Will PM additional info after work.

I'll be out a few days- will catch up Monday- thx

perko website has diagrams and instructions

http://gator49.hostgator.com/~zeromy...603%20Inst.pdf

Here is also a diagram (if you can read it). It adresses the use of a common alternator and two batteries through a blocking diode. Note that you don't want to switch these devices wile the motor is running.