A low level of electrolyte fluid will cause the battery to discharge quickly.

Inspect the electrolyte level at least once a week. If it is low, remove the caps and add enough distilled water to bring the level between the upper and lower level (illustration).
Do not overfill.
Examine the specific gravity of the electrolyte with a hydrometer, especially during cold weather. If it is low, recharge the battery.
Battery Maintenance
Battery RechargingMazda 6 Owners Manual: Refrigerant lines removal/installation
1. Remove the battery.
2. Discharge the refrigerant from the system. (See RECOVERY.) (See CHARGING.)
3. Remove the washer tank. (L.H.D. only) (See WASHER TANK
REMOVAL/INSTALLATION.)
4. Remove the air cleaner cover, air cleaner element and air cleaner case.
(See INTAKE-AIR SYSTEM
REMOVAL/INST ...
Mazda 6 Owners Manual: Disconnection of the negative battery cable
Before beginning any work, turn the ignition switch to LOCK position,
then disconnect the negative battery cable and wait for more than 1 minute
to allow the backup power supply of the SAS unit to deplete its stored
power. Disconnecting the battery cable will delete the memories of the
...