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: Transaxle fluid temperature (tft) sensor removal/installation
Warning
When the transaxle and ATF are hot, they can badly burn. Turn off
the engine and wait until they are cool before replacing the ATF.
1. Remove the oil pan. (See CONTROL VALVE BODY REMOVAL.)
2. Disconnect the TFT sensor connector.
3. Remove the TFT sensor.
4. Install a TFT senso ...
Mazda 6 Owners Manual: Transaxle oil inspection
1. Park the vehicle on level ground.
2. Remove the oil level plug and washer.
3. Verify that the oil is near the brim of the plug port.
If the oil level is lower than the low level, add the specified amount
and type of oil through the oil level plug hole.
Specified oil grade
API Ser ...