Periodically, Consumer Reports will do an interim update of an earlier test, and they recently did that with their evaluation of car batteries.
They reported the extremely poor performance of AutoZone’s most expensive batteries–the ones that use Absorbed Glass Mat (AGM) technology. While CR has been impressed with other AGM batteries, and they have liked Auto Zone’s “conventional” batteries, they reported that their 3 samples of the Duralast Platinum AGM failed at five weeks, six weeks, and three weeks, respectively. These samples were all Group Size 48.
So, then they bought some new samples of the Duralast Platinum AGM in group size 65. This time, all four samples failed before 12 weeks had elapsed.
So, as CR, said, “Buyer beware with this new battery”.