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: Replacing a Wheel
WARNING
Always use wheels of the correct size on your vehicle: Using a wrong-sized
wheel is dangerous. Braking and handling could be affected, leading to loss of control
and an accident.
CAUTION
A wrong-sized wheel may adversely affect:
Tire fit
Wheel and bearing life
Ground clearance ...
Mazda 6 Owners Manual: General procedures
PRECAUTION (CLUTCH)
Clutch Pipe Removal/Installation
Note
A common reservoir is used for the clutch and brake system fluid.
1. If clutch pipes have been disconnected any time during the procedure, add
clutch fluid (brake fluid), bleed the air, and inspect for leakage after the
procedure ...