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: Glass panel adjustment
1. Fully close the glass panel.
2. Measure the gap and height between the glass panel and body.
3. If not as specified, loosen the glass panel installation screws and
reposition the glass panel.
Clearance
a: -0.8-1.2 mm {-0.032-0.047 in}
b: 0 mm {0 in}
4. Tighten the installation scre ...
Mazda 6 Owners Manual: Front seat disassembly/assembly
Warning
Handling the front seat (side air bag) improperly can accidentally
deploy the side air bag, which may seriously injure you. Read AIR BAG SYSTEM
SERVICE WARNINGS before handling the front seat. (See SERVICE WARNINGS.)
1. Disconnect the negative battery cable and wait for more tha ...