While lithium batteries may have a higher starting price than other marine battery solutions, the longer life and maintenance-free nature of lithium batteries can result in significant cost savings in the long run.
The exact capacity of the battery you choose will depend on the voltage rating and range requirements of your demand scenario. With these two conditions in mind, the higher the capacity of a single unit, the fewer the batteries, and the more reliable the electrical connections of the system are to protect your boat and yourself from potential hazards.
In general, the larger the ship, the higher the voltage required. And in addition to the energy needed to power your boat, consider the appliances, equipment and systems you will use. Make a list of power requirements, including projected power usage and run time, to determine the capacity and number of batteries needed to maintain a steady power supply.