A
deep cycle battery that is designed for
automobiles, such that it is of the roughly-correct
size and has compatible
terminals. However, deep cycle automobile batteries are, by necessity,
at least 50% larger and heavier than conventional shallow-cycle
automobile batteries, so they do not
fit in all automobiles. That is because deep-cycle batteries are characterized by their
electrodes
having a low ratio of surface area to volume, and the
amperage of a
battery is determined by it's
quantity of electrode surface area, and automobiles require a certain minimum amperage to start. The
advantage of deep-cycle automobile batteries over shallow-cycle batteries is that the former, unlike the latter,
have thicker electrodes, such that the electrodes are very resistant to crumbling and can easily be rebuilt when the
battery is recharged. That means that the battery is much less likely to die in a given situation.
Deep-cycle automobile batteries are expensive, being on average 4 times as expensive as conventional
shallow-cycle batteries. The benefit is well worth the cost though, as people that have deep-cycle batteries in
their automobile(s) may never have a dead battery again. The most space-efficient and mass-efficient
deep-cycle automobile batteries are those that implement spiralcell technology.