Battery switches-1989 300 Weekender-twin 454s with direct drive

[ks65609]

Our recently purchased 300 has the following battery switch set up with a three battery bank. Two of the batteries are from what I can see 680 CCA, and the third (new battery) is a series 27 deep cycle. I am not sure of the series of the other two batteries just yet.

Both Guest switches

-Switch one- on or off selection
-Switch two- 1, both, 2, and off selections

I think I understand Switch two can be used to isolate a battery while at anchor or for charging any combination of batteries while running.

I do not understand the purpose of Switch one.

I am hoping a member may have the same or similar set up and might be willing to give me a hand in understanding what I have and how to manage it properly.

The boat received very good electrical survey marks in that the wiring was in very good condition, well routed, clean and secure. It appears no modifications have occurred since the boat was manufactured however unsure.

Thanks
Ken

 

[ks65609]

UPDATE !!

I contacted Sea Ray directly regarding wiring schematics and not available for a boat of this vintage. However the service customer support was excellent in that with a couple of e-mails I had a very good explanation of how the battery switches should work if not changed since original installation.

The on/off switch controls the port engine starting battery whereas the second switch controls the other two battery banks as if simply a two battery bank system. However an emergency start switch is located on the instrument panel to connect all batteries in parallel is required.

I simply need to manage the second switch for house battery purposes.

I have found Sea Ray's customer support very helpful in the past as well.

 

[SCORPIO]

Good info, my 89 300DA is set up the same way and I too have wondered exactly why they used two switches, now I know, thanks.

 

[ks65609]

Good info, my 89 300DA is set up the same way and I too have wondered exactly why they used two switches, now I know, thanks.

Thanks
The more I think about it the more sense it makes. The batteries on the weekender are in a row between the two engines. I had to have the center battery replaced, which the marina technician did with a series 27 deep cycle. I am hoping it is connected to the two battery bank switch and if so will be used as the house battery once I figure out the correct switch setting.