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: After repair procedure
Caution
After repairing a malfunction, perform this procedure to verify that the
malfunction has been corrected.
When this procedure is carried out, be sure to drive the vehicle at lawful
speed and pay attention to the other vehicles.
1. Connect the WDS or equivalent to the DLC-2.
2. Turn th ...
Mazda 6 Owners Manual: Mounting the Spare Tire
1. Remove dirt and grime from the mounting surfaces of the wheel and hub, including
the hub bolts, with a cloth.
WARNING
Make sure the mounting surfaces of the wheel, hub and lug nuts are clean
before changing or replacing tires: When changing or replacing a tire, not
removing dirt and gri ...