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: Foreword
Outline
There are two on-board diagnostic functions: Operation mode, which
inspects for and indicates correct operation of the input signals to the
control module, and condition detection mode, which indicates troubles in
the system.
The two functions can be done using either of the f ...
Mazda 6 Owners Manual: Hazardous Driving
WARNING
Be extremely careful if it is necessary to downshift on slippery surfaces:
Downshifting into lower gear while driving on slippery surfaces is dangerous. The
sudden change in tire speed could cause the tires to skid. This could lead to loss
of vehicle control and an accident.
When dri ...