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: Abs (abs/tcs) hu/cm removal/installation
Caution
When replacing the ABS (ABS/TCS) HU/CM, configuration procedure
must be done before removing the ABS (ABS/TCS) HU/CM. If configuration is
not completed before removing the ABS (ABS/TCS) HU/CM, TCS will not work
properly (with TCS model).
Do not drop the ABS (ABS/TCS) HU/CM. Re ...
Mazda 6 Owners Manual: Battery Runs Out
Jump-Starting
Jump-starting is dangerous if done incorrectly. So follow the procedure carefully.
If you feel unsure about jump-starting, we strongly recommend that you have a competent
service technician do the work.
WARNING
Follow These Precautions
Carefully: To ensure safe and correct ha ...