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: After repair procedure
Caution
After repairing a malfunction, perform this procedure to verify that the
malfunction has been corrected.
When this procedure is carried out, be sure to drive the vehicle at lawful
speed and pay attention to the other vehicles.
1. Connect the WDS or equivalent to the DLC-2.
2. Turn th ...
Mazda 6 Owners Manual: Engine Start Function When Key Battery is Dead
CAUTION
When starting the engine by holding the transmitter over the push button start
due to a dead key battery or a malfunctioning key, be careful not to allow the following,
otherwise the signal from the key will not be received correctly and the engine
may not start.
Metal parts of ot ...