Mitsubishi MOTORS Colt 2007 Owner's Manual page 358

Maintenance
Checking the battery electrolyte level
The inside of the battery is divided into several compartments.
Checking the electrolyte level in each cell after removing the
cap.
8
8-16
If the part marked (A) inside each cell is below the surface of
the electrolyte (B), the electrolyte level is normal. Top up the
electrolyte with distilled water if necessary. Do not add overfill
the cell; spillage during driving could cause damage.
Check the electrolyte level at least once every four weeks,
depending on the operating conditions.
If the battery is not used, it will discharge by itself with time.
Check it once every four weeks and charge with low current as
necessary.