Do data center and network room UPS systems use lead-acid batteries?

Although alternative energy storage technologies such as fuel cells, flywheels, lithium ion, and nickel cadmium batteries are being explored (see White Paper 65, Comparing Data Center Batteries, Flywheels, and Ultracapacitors for more details) data center and network room UPS systems almost exclu-sively utilize lead-acid batteries.

Do flooded or wet cell batteries need a separate room?

Vented (flooded or wet cell) batteries have a very long life but present significant complexity of installation and maintenance, the most significant being the need to build a separate battery room. These limitations have historically restricted the application of vented cells to very high power installations.

Why do flooded cell batteries need a visual inspection?

Grid growth causes loss in mechani-cal strength and eventually leads to loss of contact with the grid. This is why visual inspec-tion of a flooded cell battery is required. The internal resistance increases and the capacity decreases.

What are the characteristics of a vented battery?

Characteristics of the vented battery include the following: VRLA batteries have been utilized for approximately 20 years. This technology offers a higher power density and lower capital costs than traditional vented cell solutions. VRLA batteries are typically deployed within power systems rated below 500 kVA.

What happens if a battery fails in a vented battery?

A common mode of failure in vented batteries is a shorted cell because the dross material collecting in the bottom of the container eventually creates a short between the plates. This failure mode reduces capacity of the cell, but the string can still provide energy to the UPS.

What causes electrolyte loss on vented batteries?

Ironically, a common cause of electrolyte loss on vented batteries is dripped liquid during specific gravity inspections, as part of routine maintenance. The primary hazard is that areas wet with battery leakage constitute conductive paths to ground that can pose a very serious risk of ground fault.