Pic. 1.189. Checking the battery electrolyte level
Check the electrolyte level in the battery at least once a week. If the electrolyte level in the battery is low, remove the battery caps and add the required amount of distilled water. The electrolyte level must be between the lower and upper marks on the housing wall (pic. 1.189).
Do not fill with distilled water above the upper mark.
Check the density of the electrolyte in the battery with a hydrometer. Maintaining the required electrolyte density is especially important in the cold season. If the electrolyte density is low, charge the battery.