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: To Operate the System
The High Beam Control System (HBC) operates to switch the headlights automatically
between high and low beams after the ignition is switched ON and the headlight switch
is in the AUTO and high beam position.
The High Beam Control System (HBC) determines that it is dark based on the brightness
...
Mazda 6 Owners Manual: Child-Restraint Precautions
Mazda strongly urges the use of child-restraint systems for children small enough
to use them.
You are required by law to use a child-restraint system for children in the U.S.
and Canada. Check your local and state or provincial laws for specific requirements
regarding the safety of children ...