All tubular batteries behave similarly to start with, but obviously, not all tubular batteries are the same. The difference lies in the composition of the alloy in the positive support structure, as well as in the way that the main back bone of the plates, called the SPINE, is cast.With the help of Torr Tubular technology, Exide tubular batteries use the high pressure 'HADI' casting process at 100 bar, while most other manufacturers use gravity of low pressure casting processes. The spines in Exide tubular batteries are cast from low antimony lead alloy, with selenium, copper, tin, and arsenic, to protect the lead support from anodic corrosion.A scanning electron microscope (SEM) study reveals the differences in machines that use gravity or low pressure casting, and those that are 'HADI' casting.