<img src="/forums/images/graemlins/lol.gif" alt="" /> I love your decription of lead acid battery theory! There's a little more to it than that but, there ya go, that's one reason why the Optima costs more. The spiral cell design combined with gell electrolyte can take a lot more vibration that a standard Car batery regardless of it's age. In a stardard batt. the vibration can also knock the goody (lead sulfate) out of the grids where it's supposed to be contained and it piles up in the bottom of the battery causing a short. That's why Marine batteries have a larger space in the bottom for the stuff to accumulate. Small boat batteries (I don't mean small batteries) are subject to brutal beatings in a light chop, much worse than off roading.