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: Nonreturn valve inspection
1. Remove the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION.)
2. Siphon the fuel from the fuel tank.
Note
Nonreturn valve is integrated in the fuel tank.
The nonreturn valve is normally closed by the spring force.
3. Verify that the nonreturn valve is closed.
If the nonretu ...
Mazda 6 Owners Manual: Selector lever removal/installation
1. Disconnect the negative battery cable.
2. Remove battery and battery tray.
3. Remove the air cleaner compornent. (See INTAKE-AIR SYSTEM
REMOVAL/INSTALLATION.)
4. Remove the console.
5. Remove the dashboard compleat. (See DASHBOARD REMOVAL/INSTALLATION.)
6. Remove the SAS control module. (S ...