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: Front wheel alignment
Specification (Unloaded)*1
Normal
Elevated*3
*1 : Engine coolant and engine oil are at specified level. Spare tire, jack
and tools are in designated position.
*2 : Difference between left and right must not exceed 1°30'.
*3 : Distance between wheel center and fender brim is 402 mm {15.8 ...
Mazda 6 Owners Manual: Registering Your Vehicle in A Foreign Country (Except United States and Canada)
Registering your vehicle in a foreign country may be problematic depending on
whether it meets the specific emission and safety standards of the country in which
the vehicle will be driven. Consequently, your vehicle may require modifications
at personal expense in order to meet the regulation ...