Valve-controlled lead-acid VRLA battery is a battery with a safety valve that can be recharged while the valve provides gas leakage and reduction of internal pressure. These batteries do not require any maintenance because there is no need for adding water during their working life. SYSTEM SUNLIGHT S.A. produces batteries with two types of separators: AGM and GEL. Both technologies allow maintenance of constant distance between positive and negative plates, allowing also complete reaction of the active materials with electrolyte, so that eliminate appearance of short circuit. Absorbent Glass Mat (AGM) separator is made of porous fabric with glass micro fibers, resulting in better circulation of oxygen in order to recombination on the negative plate. Maintaining low current during battery charging decreases the level of corrosion of positive plates and extends battery life. Gel separator is micro porous gel material that is characterized by excellent stability at high temperatures and mechanical strength. Gel technology is particularly suitable for use requiring a large number of cycles and resistance to specific operating temperatures.