11.0 battery wiring

[mbefus]

New 1981 11.0a owner here. It appears that the PO made some changes to the battery wiring, but I’m hoping to confirm. Does anyone with original wiring have a photo of how it was wired? Or able to explain?

I had also hoped to find a complete wiring diagram…but looks like maybe they were never made public.

The thing I’m curious about is why the house battery positive is wired to the starter battery positive? (See photo)

 

[dlochner]

The photo didn't make it.

This would put the batteries in parallel which has some advantages in terms of capacity and battery life.

Much has changed in the land of batteries and battery management since your boat was built. It is likely the PO tried something different. How well he did, no one knows.

Standard practice back in the day was to have the alternator output be connected to the starter. This ensured that whatever battery was used to start the engine would be charged and it reduced installation costs for builders and reduced warranty claims for engine manufacturer and boat builder.

The 2 batteries were separate and connected to a 1-2--Both switch. This article gives an excellent description of the pros and cons of that arrangement.

1/2/BOTH Switch Considerations

1/2/BOTH Battery Switch Considerations - Ever wonder how to make the 1/2/BOTH switch easier to use, let this article explain how to do that.

marinehowto.com

 

[Stu Jackson]

Why not repost the photo here?

 

[Stu Jackson]

Here's a basic wiring diagram. If you don't have a combiner, use the B on the switch.