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: General procedures
PRECAUTION (SUSPENSION)
Wheels and Tires Removal/Installation
When a wheel is installed, tighten it to 88-118 N·m {9.0-12.0 kgf·m,
65.0-87.0 ft·lbf}.
Suspension Links Removal/Installation
Tighten any part of the suspension that uses rubber bushings only after the
vehicle has been lowered ...
Mazda 6 Owners Manual: Washer fluid-level sensor inspection
1. Disconnect the negative battery cable.
2. Remove the washer tank. (See WASHER TANK REMOVAL/INSTALLATION)
3. Insoect for continuity between the washer fluid-level sensor terminals
using an ohmmeter.
4. Verify that the windshield washer motor operates.
If not as specified, replace the ...