The battery system is an essential part of an uninterruptible power supply (UPS), but, in many cases, can be the weak link to the reliability of a critical environment. The two main types of battery systems utilized by most UPS systems in use today are the valve-regulated lead acid (VRLA) battery and the flooded battery, sometimes referred to as vented or wet-cell battery systems.
The flooded battery is referred to as vented because it allows gases to escape during the recharge process. These batteries lose fluids during the recharge process, requiring replenishment, which means regular maintenance is a necessity.