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: Input/turbine speed sensor inspection
Caution
Water or foreign objects entering the connector can cause a poor
connection or corrosion. Be sure not to drop water or foreign objects on the
connector when disconnecting it.
1. Disconnect the negative battery cable.
2. Remove the battery and battery tray.
3. Remove the air cl ...
Mazda 6 Owners Manual: Dsc system inspection
Preparation
1. Verify that the battery is fully charged.
2. With ignition switch on, verify that the ABS warning light goes out after
2.4 seconds.
3. Turn the ignition switch off.
4. On level ground, jack up the vehicle and support it evenly on safety
stands.
5. Shift the transaxle to N posi ...