What is a UPS (Uninterruptible Power Supply) without backup power? Backup power can be the batteries or flywheel that rides an outage until the main power or an alternate backup power source such as a generator comes on.
Most large data center sites will have a string of wet-cell batteries in a separate room to maintain power to equipment until a generator comes on line or the main power resumes. A wet-cell battery or lead acid battery consists of a lead metal anode and a lead oxide cathode, both of which are immersed in a solution of sulfuric acid.
Smaller data center facilities typically have sealed batteries or valve regulated lead acid batteries (VRLA) that are combined in a cabinet next to the UPS. Lead acid batteries contain a solution that must be maintained while VRLA batteries require far less maintenance.
When dealing with lead acid batteries caution must be taken. First, the voltage that these batteries in large strings provide can be deadly if safety precautions are not taken. Safety should be paramount when dealing with any type of battery.
It is highly desirable to leave the maintenance and repair of these kinds of batteries to a trained professional. If you are capable of working with lead acid batteries always use extreme caution when handling them. Wear gloves, goggles and old clothes. The sulphuric acid in lead-acid batteries will burn skin and eyes and destroy cotton and wool clothing.
Here are ten tips for maximum safety:
- Someone should be within range of your voice to come to your aid when you work near batteries;
- Have plenty of fresh water and soap nearby in case battery acid contact skin, clothing, or eyes;
- Wear complete eye protection and clothing protection. Avoid touching eyes while working near batteries. Wash your hands when done;
- If acid contacts skin or clothing, wash immediately with soap and water. If acid enters eyes, immediately flood eyes with running cool water for at least 15 minutes and get medical attention immediately;
- Baking soda neutralizes lead acid battery electrolyte. Vinegar neutralizes spilled NiCad and NiFe battery electrolyte. Keep a supply on hand in the area of the batteries;
- NEVER smoke or allow a spark or flame in vicinity of a battery or generator;
- Be extra cautious when working with metal tools on, and around batteries. Electrical potential exists that could short-circuit the batteries or other electrical parts; this may result in a spark which could cause an explosion;
- Remove personal metal items such as rings, bracelets, necklaces, and watches when working with a battery. A battery can produce a short-circuit current high enough to weld a ring, or the like, to metal causing severe burns;
- If a remote or automatic generator start system is used, disable the automatic starting circuit and/or disconnect the generator from its starting battery while servicing to prevent accidental starting during servicing; and
- Whenever possible leave it to the pros.