Understanding Battery Lifespan to Avoid Data Center Downtime

Gregory Ratcliff, Director of Life Cycle Management Services
Emerson Network Power, Liebert Services

When striving to achieve consistent and efficient operation, the UPS system is critical to data center emergency power systems.  While tests and assessments are often completed to safeguard these systems, a UPS is only as reliable as the batteries that support it. In fact, recent Emerson Network Power research on critical infrastructure shows that nearly 37 percent of down units are due to battery failure.

In order to properly protect UPS systems and data centers as a whole, data center managers must have a comprehensive understanding of the true life of batteries, how battery performance is affected throughout the lifespan, and strategies to ensure batteries are performing at their optimal level.

Data center managers often make a common but costly mistake regarding battery lifespan, confusing battery design life with battery service life. Battery design life is determined by the manufacturer and takes into account cell design and battery aging under controlled conditions in the manufacturer’s laboratory. Battery service life considers how application, installation, real-world operating conditions and maintenance practices impact battery aging.

This common misunderstanding often leads to improper battery maintenance. If data center managers only consider the design life or the manufacturer’s warranty, batteries are often set up and then ignored for years, with no preventive maintenance or testing throughout the life cycle. This can lead to costly battery failures and unplanned downtime. In reality, when supporting the UPS, batteries fail in less than half the time stipulated by the manufacturer design life because a variety of issues, including incoming power faults resulting in UPS engagement, manufacturing defects, high or improper room temperatures, excessive charge current, overcharging and over cycling, loose connections, and strained battery terminals.

Failure to understand the lifespan of a battery and ways to ensure its optimal performance can have serious consequences on a data center. Unplanned downtime, extended business interruption, and failure of the backup system in the event of an outage are all likely scenarios. Given that high data demand requires organizations to be available 24/7, unplanned downtime is simply unacceptable, not to mention detrimental to an organization’s bottom line and reputation.

While data center managers understand the drastic consequences of downtime which can include the loss of their job, it remains a pressing issue that is plaguing data centers around the world. Most of the organizations surveyed in Ponemon Institute’s “2013 Study of Data Center Outages” had at least one unplanned outage in the previous 24 months. Respondents averaged two complete data center shutdowns over a two-year period, with an average duration of 91 minutes.

The lengthy duration of data center outages correlates to a lack of resources and planning, as only 38 percent of survey respondents agree there are ample resources to bring their data center up and running if there is an unplanned outage. Another indication that organizations are not proactively addressing the risk of unplanned data center outages is that only 36 percent of those surveyed believe they utilize all best practices in data center design and redundancy to maximize availability.

The investment to properly maintain battery strings is worth the peace of mind sought by many data center managers and is almost always less cost than what an organization would incur during a lengthy outage. Downtime from UPS system failure, most often caused by battery failure, is the third most expensive cost of downtime at an average of $678,000. This figure includes various costs associated with downtime such as detection, recovery, revenue, end-user productivity, IT productivity and others.

Without reliable battery operation, no UPS system can do its job of providing consistent data center performance and business stability. This is precisely why data center managers need to fully understand the lifespan of batteries and how to incorporate a proper preventive maintenance program. While seemingly simple, batteries are the heartbeat that support mission critical data centers and have a direct impact on availability and overall business success.