Ah Mickstr. It is winter and you have been cooped up with Covid. Saving all sorts of money and now you need to spend it. I get it.
Nice battery. 12 volts 150 AHr. 82 pounds.
Cost about $233 online plus shipping. Minimum 4
What ever you do look at the whole system. Spend money frugally. The TV and the Refrigerator will eat into your battery system depending on how they are used. That 150 Amp hours really is only 75 AHrs of usable time. 2 batteries at 160lbs (like adding another crew member who sits there) means 150 Ahrs of available power.
I refer you to the expert on this subject. MaineSail
Here is his link that discusses the system. The Alternator and what you need to keep your new batteries preforming for more than a couple year. And the challenges of insufficient alternators in the system.
A Deep Cycle Battery Assassin The alternator pictured here helped to destroy a very expensive bank of TPPL AGM batteries in under two years. These batteries need an absorption voltage of 14.7V. The highest voltage I recorded on this vessel was 13.58V at the battery terminals. At this
marinehowto.com
"What you need will depend largely on use, bank size and desired daily Ah consumption as well as battery chemistry type. You will also need to consider your maximum desired engine run time. If you only day sail, and tie to the dock every night with shore power charging, converting the factory alternator, to a higher performance model, will gain you little. This is why; it’s all about use."