Since a maintenance-free battery is essentially sealed, it is not possible to add water or electrolyte to the cells and thus the potential for eye contact with electrolyte is essentially non-existent. As a result, eyewash stations are not required if only maintenance free batteries are charged.hese dual-purpose units can be used to combine an eye wash and a drench hose into a single versatile, economic unit. To use the unit as a fixed eye wash, simply leave the unit in the holder. The dual spray heads will deliver water to both eyes simultaneously.