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: Traffic Sign Recognition System (TSR) (Some models)
The Traffic Sign Recognition System (TSR) helps prevent the driver from overlooking
traffic signs, and provides support for safer driving by displaying traffic signs
on the active driving display which are recognized by the Forward Sensing Camera
(FSC) or recorded in the navigation system whil ...
Mazda 6 Owners Manual: Front oil seal
FRONT OIL SEAL REPLACEMENT
1. Disconnect the negative battery cable.
2. Remove the spark plugs. (See SPARK PLUG REMOVAL/INSTALLATION.)
3. Remove the Cylinder head cover. (See Cylinder Head Cover Installation
Note.)
4. Remove the drive belt. (See DRIVE BELT REPLACEMENT.)
5. Remove the front dr ...