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: Service procedure
Inspection, adjustment
Inspection and adjustment procedures are divided into steps. Important
points regarding the location and contents of the procedures are explained
in detail and shown in the illustrations.
Repair procedure
1. Most repair operations begin with an overview illustr ...
Mazda 6 Owners Manual: Sunroof unit removal/installation
1. Disconnect the negative battery cable.
2. Remove the headliner.
3. Remove the glass panel.
4. Disconnect the front and rear drain hose from the sunroof frame.
5. Remove the bolt A, and then remove the rear set bracket.
6. Remove the bolt B and nuts, and then remove the sunroof unit.
7. In ...