Car battery - Maintanence Free

This type of battery comes with a seal so that you couldn't pry open the cover for adding water to the electrolyte. Such batteries typically have a clearly written note saying "Do not open". These batteries due to their inherent behavior don't need an electrolyte recharge.
In the same note, maintanence accessible batteries need electrolyte recharge. NOTE: Dont use any water other than distilled water for this purpose, as tap water might have chlorine and other chemical contamination that might reduce the purity of the electrolyte and in some cases lead to reduce shelf life of the battery

Yoko