I had gone with the Auto Zone over a couple of years back. Then last
November 2006, had to exchange it under the Duralast's Gold 3 yr. free
exchange. Not sure if it is brand unigue, but I have a suspicion that
they do not like the cold of winter very much>>LOL. This year went to
J.C. Whitney (Online) and bought this charger/maintainer that I have
previously posted about, and loving it. Now it can sit and sit and sit,
since IMO the Miata is primarily my fun, good weather, head to the beach
car. And when I start it up now, that battery turns over like it is run
daily, all the time.