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: Battery recharging
Warning
Keep any flammable away from the battery, otherwise evaporated gas
of the battery fluid may catch fire, and cause serious injury or death.
Caution
When removing the battery, disconnect the negative battery cable
first and install it last to prevent damage to electrical compo ...
Mazda 6 Owners Manual: Inside Trunk Release Lever (Some models)
Your vehicle is equipped with an inside trunk release lever that provides a means
of escape for children and adults in the event they become locked inside the trunk.
No matter how careful adults might be with keys and locking their cars, parents
should be aware that children may be tempted to p ...