Regardless, the battery equipped in the USDM Mazdas which are Japan built, are NOT maintenance free batteries... they are in fact "low maintenance" batteries... they DO need to be maintained, especially after a hot summer where electrolyte has evaporated and/or stratified electrolyte has occurred after high cycles... "low maintenance" batteries are better suited for warm climates due to thicker plates and spaced larger, at the expense of cranking amps... if you don't maintain them, it becomes crap!
the so-called "maintenance free" batteries, simply have more electrolyte filled up... so full in fact that if the charge isn't near 100%, the car's alternator will try to fast charge them enough to cause the electrolyte to expand and seap out of the caps... causing a huge mess on the battery/under the hood... very typical of the Johnson Control batteries... they still will fail if you let the electrolyte run low! Even Interstate recommends that you check/maintain them in their guides
use ONLY distilled water (less than $1 at walmart), and carefully top off each cell... the electrolyte level is hard to see from the battery case, so a good ballpark level is about 1cm below the bottom of the filler hole in the Panasonic batteries... if not available, use clean rain water... using tap water will cause cell damage due to impurities and other chemicals in the water, causing a chemical reaction which leads to damage