charger/inverter selection and updating electrical system on a Gulfstar 37
So I just bought my first boat, a Gulfstar 37. It hasn't been surveyed yet (and I guess technically it isn't mine yet, since I can still reject it...), but when I looked at it I saw what I think is the battery charger, and it is some metal box that looks like it's from the 70s. The boat was built in 1979, so this isn't impossible. I'm told it's been on a mooring for the last 18 years (at least two owners worth), so it probably hasn't been connected to AC power in a long time. I assume I'll need to replace the charger. I have no idea how many amps I'll need. My understanding is the battery charger powers all your 12V equipment when AC power is available. I'll be living aboard, and I'll be adding 12V refrigeration.
If I'm going to go to the expense of replacing the charger, I'd like to do it right. I'd like something that can do in-depth monitoring and management of the batteries (unless this is best accomplished with a separate device -- advice?). Though I don't really need it (I have no plans to be away from the dock for extended periods), if the additional cost isn't too high, an inverter would be nice. I'm pretty sure if I'm going to ever get an inverter, it will be the type that's built into a charger because I like the seamless switchover you get when the dockside AC is disconnected -- none of your AC electronics lose power. I probably want a pure sine wave inverter.
Another thing I probably don't need since I have no plan to use right now is a solar charger, but again, if it could be a feature of the main charger/inverter and could be had for only a little more money, I'd like to go for that. I don't know when/if I'll be adding solar panels, but I'd like to have the controller built into the rest of the electrical system rather than tacked on if I ever do it.
Any suggestions on models that meet some or all of these requirements? Are my requirements insane? I don't want to spend too much money.