Originally Posted by justonemoreproject
When I bought the boat, I updated the battery switch to a Blue Seas Switch that controls the rate of charging and prevents overcharging from solar and trickle chargers. for the house bank and starting battery and gives the option of choosing 1 or 2 or combining them.
Thanks for your help.
The only Blue Seas item that comes close to what you describe is their Dual Circuit Plus switch which when combined with an ACR is packaged as an Add a Battery.
It combines the batteries in parallel when a charge source is present just the same way as if they are wired together and separates them when the voltage drops below 12.35 for 10 seconds or 12.75 for 30 seconds. It does not control charging in any other way.
6 volt golf cart batteries are certainly the best value and you will have a house bank of between 225 and 240 AH depending on brand.
As posted if one of the 3 batteries toy currently have is in good condition you can keep it as a dedicated start battery.