With 4D and 8D batteries the placement and orientation of cells is different than a typical 6V GC2 or 12V G24, G27 or G31.


In a 4D battery the cells are rectangular, as shown here with the red lines. As such the cells on 4D batteries are best mounted so the long length of the battery runs bow to stern. This puts the narrowest profile of each cell oriented to minimize positive and negative plate uncovering during sailing conditions.


The red lines represent the cell dividers inside the battery box. Each rectangle/cell is sealed from the others. The battery could also be flipped around so port / starboard are opposite the the long sides of a 4D should face port/starboard...