The picture shows the first parts of the electrical system. One charger CHAMP III 12v/7A from PRIMEPOWER It is very compact and waterproof, ideal for a little boat.

There is also six 17 amp hours Exide Sonnenschein gel batteries. Gel batteries have a better cycle life, they can be cycled deeper and more times than Agm batteries. Agm batteries can are better for starting engines but on board there is no engine.

More about gel batteries