Charger wiring
The battery charger is the only wiring except for an (optional) automatic bilge pump that is connected directly to the batteries. This direct connection is necessary to insure the delicate balance of charge sensing for the charger is not corrupted at the selector switch. I have a Professional Mariner Fly Back charger that has given outstanding service for over ten years. These guys know marine electronics! Pro Mariner also makes testing equipment for checking gavalinic corrosion so you can be sure their chargers are not going to create stray currents to destroy your underwater metal. I had two DEKA deep cycle batteries last 8 years with this sweet charger. It's silent until the cooling fan goes on (rarely) and makes no 60 hz buzz in my radio or stereo when we are on shore power. In fact the unit is so "clean" electrically commercial jets use Pro Mariner as a charger/12v source because the units are so dependable!If you check out EBAY you might be able to find "Factory Reconditioned" FlyBack units. You will find a 10 amp unit satisfactory for your needs on a 323. I really love mine- In fact it is on station right now with it's green LED glowing indicating a full charge and float voltage right now in the berth in Atlantic City. Do yourself a huge favor and upgrade when you are able. You can charge 3 banks with this unit. With only two battery banks the FlyBack chargers require you to jump two of the outputs. This is explained in the instructions.