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: Bonnet removal/installation
Warning
Removing the bonnet without supporting can be dangerous. The
bonnet may fall and injure you. Always perform the following procedure with
at least another person.
1. Disconnect the windshield washer hose.
2. To remove the bonnet hinge, remove the front fender panel.
3. To remov ...
Mazda 6 Owners Manual: Lane Departure Warning
If the system determines that the vehicle may deviate from its lane, the lane
departure warning (beep sound, rumble sound*1, or steering wheel vibration) is activated
and the direction in which the system determines that the vehicle may deviate is
indicated in the multi-information display and ...