Why Lithium-Ion Batteries are the Best Choice for Data Center UPSs

Research shows that uninterruptible power supply (UPS) failure remains the primary cause of data center downtime, accounting for about one-quarter of unplanned outages. The battery is most often the culprit when a UPS fails. Given the high cost of downtime, organizations should protect critical IT equipment with high-quality UPSs based on lithium battery technology.

There are multiple types of lithium batteries available on the market, including lithium-ion and lithium iron phosphate. Although each has advantages and disadvantages, lithium-ion batteries are the better choice for data center UPS applications.

Understanding Battery Performance

Under normal operation, a UPS converts input power from AC to DC to charge the battery when it’s not in use. UPS batteries are “trickle charged” — electricity is supplied to offset the battery’s self-discharge rate and keep the battery fully charged.

When an electrical outage is detected, the UPS’s inverter reverses to convert DC to AC and the load is transferred to battery power. UPSs aren’t meant to provide a long-term power source — the typical transfer time is less than 10 minutes. However, the transferred load consumes a lot of power.

Several factors play a role in the battery’s ability to handle the sudden demand:

• A battery’s cycle life is the number of times it can be charged and discharged before it must be replaced.
• The maximum depth of discharge is the percentage of the overall capacity that may be utilized in a cycle without impacting battery performance.
• Energy efficiency is the difference between the amount of energy discharged by a battery and the energy required to charge it.

Drawbacks of Lead Acid Batteries

Older UPSs are based on valve-regulated lead-acid (VRLA) batteries. Depending upon environmental conditions and depth of discharge, a VRLA battery lasts about three to six years or 500 to 1300 cycles. The recommended depth of discharge is less than 50 percent, and the energy efficiency of a VRLA battery is about 70 percent.

It takes about eight hours to fully charge a VRLA battery, followed by a cool-down period to reduce the risk of a thermal runaway. VRLA batteries must be cooled like IT equipment, with a recommended operating temperature of 68 degrees to 77 degrees. They require regular testing and maintenance, including resistance and torque checks.

Benefits of Lithium Technology

Although lithium batteries cost more, they outperform VRLA batteries in all of these aspects. They have a lifespan of seven to 10 years and a depth of discharge of at least 85 percent. Their energy efficiency is 95 percent or more. A lithium battery can be fully charged in an hour and does not require a cool-down period.

Lithium batteries also have a much higher energy density than VRLA batteries. A 1kg lithium-ion battery can store up to 200 watt-hours of electricity compared to just 25 watt-hours for a 1kg VRLA battery. UPSs based on lithium-ion batteries weigh less and have a smaller footprint, which means they are easier to install and take up less space in the data center. They are virtually maintenance-free.

Comparing Lithium Technologies

Lithium iron phosphate batteries have a cycle life of up to 10,000 cycles and are not degraded in higher operating temperatures. They are chemically stable and generally not subject to thermal runaway, which provides safety advantages.

However, a 1kg lithium iron phosphate battery offers just 90 watt-hours to 120 watt-hours of electricity. Lithium-ion is the better choice for the data center due to its energy density and lighter weight.

How Rahi Can Help

Rahi is a global IT solutions provider that Rahi maintains long-standing relationships with leading UPS manufacturers, including Enconnex, Tripp Lite, and Vertiv. As a certified global reseller and distributor, you can rest assured that you’ll be receiving the latest, reliable technology products on the market at the lowest possible price. Let our data center infrastructure specialists show you how lithium battery technology can benefit your data center and help you choose the best UPS for your use case. Allow our unique ELEVATE services to provide your company with the most advanced lithium battery solution to support efficient operations, maximize ROI, and prepare your business for success.