Sailing things right

Short stats for my single 450W panel.
So, in a winter month a single panel produced 20kW of power. Could be more by 25-30% if I don't connect to the shore power.

So, the plan is to triple my solar batteries or even quadruple if I'll be able to. Then to double my power storage. Now I have 3kWh AGM batteries, effectively providing me with 1500W of power stored. I'd like to have 3-4kW. And switch to 48 volts, and switch to lithium.