We have 2 "C-8DH" batteries. Are all the cells interconnected or individual? Do I need to confirm that the water level stays the same? It is a bit lower in one battery's cell than the other. Thank you!

Hello and thank you for your question. Each cell is individual. While a battery should only be filled after it is completely charged. Before charging, make sure there is just enough water to cover any exposed plates. After charging, add enough distilled water to bring the level to the bottom of the vent, about ¾ below the top of the cell