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: Operation
NOTE
The engine may not start and security indicator light may illuminate
or flash if the key is placed in an area where it is difficult for the system
to detect the signal, such as on the dashboard or in the glove compartment.
Move the key to a location within the signal range, switch ...
Mazda 6 Owners Manual: Odometer, Trip Meter and Trip Meter Selector
The odometer is constantly displayed on the screen when the ignition is switched
ON, and the TRIP A or TRIP B screen can be displayed by operating the INFO switch.
Odometer
The odometer records the total distance the vehicle has been driven.
Trip meter
The driving distance for a specified in ...