Waterproof marine power supply system with integrated convection passage

A metal enclosure for a power supply system, the metal enclosure comprising:

• an upper wall and a lower wall positioned opposite each other;
• a first peripheral wall and a second peripheral wall positioned opposite each other, wherein the upper wall, the lower wall, the first peripheral wall, and the second peripheral wall collectively define an interior region and extend from a first end to a second end;
• a convection passage wall extending between the lower wall and either the first peripheral wall or the second peripheral wall and from the first end to the second end, wherein the convection passage wall separates the interior region into a convection passage and a component space;
• and
• a first plurality of internal fins extending inwardly to the convection passage from at least one of the lower wall, the first peripheral wall, the second peripheral wall, and the convection passage wall;
• and
• wherein the metal enclosure is configured to couple to a first end cap at the first end and a second end cap at the second end such that the component space is sealed against water intrusion and the convection passage is not sealed against water intrusion.