[mpg_numbers_guy]

This is true, and if one is looking long term then lithium would potentially be the better option. Its increased efficiency and more compact energy makes it good for those who want the last little bit of efficiency...at a higher initial cost. Most people do not keep their cars long enough to cycle through the lifespan of a lithium 12V, so the cost savings that might've occurred are merely passed to the next owner, leaving the original owner with a net loss.