Battery Water
WARNING: This page is about a different car, the 2010 Volvo V70, 2009 Volvo V70, and 2008 Volvo V70. However, it is still accessible from the selected car via links, so may be relevant.
Battery water is distilled or deionized water and must be used to top up the battery if the electrolyte level is low. Regular tap water must not be used because it contains substances which may damage the battery.
For maintenance-free batteries as well as sealed batteries (AGM) it is not possible to fill battery water.