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: Air bag module and pre-tensioner seat belt deployment procedures
Warning
A live (undeployed) air bag module and pre-tensioner seat belt may
accidentally deploy when it is disposed of and cause serious injury. Do not
dispose of a live (undeployed) air bag module and pre-tensioner seat belt.
If the SSTs (Deployment tool and Adapter harness) are not ava ...
Mazda 6 Owners Manual: Warning Indication/Warning Lights
These lights turn on or flash to notify the user of the system operation status
or a system malfunction.
*1 The light turns on when the ignition is switched on for an operation check,
and turns off a few seconds later or when the engine is started. If the light does
not turn on or remai ...