I don’t have power here at the condo so I bought a Jackery Explorer 1000 with solar panels. I plug my onboard charger right into the power station. After a full day on the water it will recharge 2 group 27’s easily. Sometimes only using 50 percent of stored power.
I recharge it in my condo but at home I put the solar panels out. You could buy a 1000 watt power station and a couple panels from harbor freight to mount wherever you want and be charging the power station all the time.
Then just plug in your boat. You can recharge and plug in for power at the same time. Several guys here saw my setup and bought the same thing. Works great!!! Plenty of YouTube about power stations.
In the picture you can see it only took 45% to recharge my batteries from yesterday.