I've read most of the info in the WIKI about improvements to the electrical systems, and I’d like to submit an idea for modifying my system to the group for comment, advice, ridicule, or whatever you can offer.
Boat is 1988, with 4 Trojan T105s as house bank, and a separate starter battery aft of the engine. Right now, the boat still has the 1-2-Both switch, and then an older West Marine 50 A combiner was added, along with a Blue Sea On-Off keyed switch for managing the starter battery located aft of the engine compartment.
I know there are different schools of thought, one which promotes keeping the starting battery as a "reserve", and using the house batteries to also start the engine. My concern with that is if you don’t regularly use the “reserve” battery, how certain can you be that there’s nothing wrong with it? In my truck, I’ve had batteries that “seemed” OK voltage wise but couldn’t crank the engine over. The way I’m looking at it, if I use the reserve battery as a regular starting battery every time, I’m going to quickly recognize when it isn’t healthy, and then I can fall back on my house bank in that one case to get me home. Also, I've never liked 1-2-Both switches and would like to eliminate mine.
With that in mind, I’ve set out to separate the two banks in a different way. I found an interesting switch at Blue Sea that is a dual circuit “On-Off” switch (#5511e). It has an optional position allowing combining the two circuits, but for the most part it is used simply to turn on or off both circuits at the same time, but keeping them isolated from each other. Then for charging, I’d use Blue Seas m-ACR to combine the charging cycles.
This seems to me to be a simple solution and it would allow me to eliminate the 1-2-Both switch (and its inherent operator errors). I drew out a simple diagram in MS Powerpoint and attached it to this post (I hope...) (Yes, I know there should be fuses, etc. I just kept this diagram very simple for this discussion.)
Thoughts? Suggestions? Any reason this wouldn't work?