The AGM (absorbed glass mat) type of car battery is the most common type in modern cars. How do you properly charge it? What do you need to do?

One Duralast Platinum AGM battery in the common group 48 size failed our tough life test at just five weeks; another bit the dust after six weeks.

The AGM type of battery is the most common in modern cars. Charging it is a little different to a standard lead acid battery, but it's still pretty easy.