What Batteries Are Used in Data Center UPS Systems?

Data center UPS systems primarily use valve-regulated lead-acid (VRLA) and lithium-ion batteries, including lithium iron phosphate (LiFePO4 or LFP). Some facilities also use flooded lead-acid or nickel-cadmium batteries for specialized applications.

A data center UPS battery supplies stored energy when utility power is interrupted, allowing critical equipment to remain operational while generators start, another power source takes over, or systems complete a controlled shutdown.

Battery selection affects more than backup time. It also determines how much space the installation occupies, how often batteries need replacing, and how effectively the UPS can respond to high-power demands.

This article explains the battery technologies used in modern data centers, compares their operating characteristics, and explores how MANLY Battery supports critical backup power projects.

Data Center UPS Battery Types: VRLA, Lithium-Ion, and More

VRLA lead-acid and lithium-ion are the two main battery technologies used in modern data center UPS systems. Both store electrical energy for immediate use during an outage, but their chemistry, energy density, maintenance requirements, and service life differ.

A data center UPS battery system typically contains multiple connected cells or modules arranged to meet the UPS manufacturer’s required DC voltage, power output, and runtime.

The four principal battery categories are:

VRLA Lead-Acid Batteries (AGM and Gel)

Valve-regulated lead-acid batteries have been used in UPS equipment for decades. They are sealed, regulated designs that reduce routine electrolyte maintenance compared with flooded lead-acid batteries.

Two common VRLA constructions are AGM and gel.

AGM (Absorbent Glass Mat) batteries use fiberglass separators to hold the electrolyte against the battery plates. Their low internal resistance supports the high discharge currents often required during brief UPS backup events.

AGM is particularly relevant when a UPS must deliver substantial power for several minutes rather than provide a low electrical load for many hours.

Gel batteries immobilize the electrolyte using a silica-based gel. They are used in certain stationary and deep-cycle applications, although AGM is generally more common in high-rate UPS installations.

VRLA batteries remain widely used because they integrate with established UPS equipment and offer a familiar purchasing and maintenance framework.

Lithium-Ion Batteries (LFP and NMC)

Lithium-ion batteries use the movement of lithium ions between electrodes to store and release electrical energy. Compared with traditional lead-acid technology, lithium-ion systems generally provide greater energy density, lower weight, and longer service life.

Two important lithium-ion chemistries used in UPS applications are LFP and NMC.

Lithium iron phosphate (LiFePO4 or LFP) uses an iron-phosphate cathode. Its thermal stability, cycle durability, and suitability for stationary applications make it an attractive chemistry for critical backup power.

LFP batteries also support intelligent battery management systems that monitor voltage, temperature, current, and battery operating conditions.

Nickel manganese cobalt (NMC) batteries use a different cathode chemistry with high energy density. UPS manufacturers use NMC in selected applications where the cell characteristics and overall system engineering meet power, space, and safety requirements.

Both chemistries can support data center applications when incorporated into properly engineered and qualified UPS systems.

Eaton’s lithium-ion UPS safety documentation discusses the thermal characteristics of LFP, while Vertiv identifies both LFP and NMC among the chemistries used in UPS equipment.

Flooded Lead-Acid and Nickel-Cadmium Batteries

Flooded lead-acid batteries contain liquid electrolyte and allow periodic inspection and servicing. They are found in certain large stationary battery installations where operators have established maintenance programs and dedicated battery infrastructure.

Unlike VRLA batteries, flooded designs require additional attention to electrolyte levels, ventilation, and related maintenance.

Nickel-cadmium (NiCd) batteries use nickel-based positive electrodes and cadmium-based negative electrodes. They can operate across challenging temperature conditions and have a long history in industrial standby power.

NiCd batteries are particularly associated with specialized industrial environments where temperature tolerance and established maintenance practices are important.

For most new commercial data center projects, the practical comparison begins with VRLA and lithium-ion. The other technologies become relevant when specific operating conditions or existing infrastructure call for them.

Data Center UPS Battery Comparison: VRLA vs. Lithium-Ion

The main differences between VRLA and lithium-ion UPS batteries are service life, lifecycle cost, physical footprint, charging behavior, and maintenance requirements.

Both technologies can provide dependable emergency power when correctly sized and integrated. However, their financial and operational characteristics influence how operators plan long-term infrastructure investments.

Service Life and Total Cost of Ownership

Battery service life matters because replacing a UPS battery bank involves more than buying new batteries. Maintenance labor, testing, disposal, installation access, and operational scheduling all contribute to the overall expense.

Schneider Electric’s published UPS analysis identifies typical VRLA service life in the range of approximately 3–6 years, compared with approximately 10–15 years for lithium-ion systems under the conditions considered in its models.

These are planning ranges, not guaranteed lifetimes for every product. Actual service life depends on operating temperature, charging conditions, battery design, and maintenance.

Lithium-ion batteries generally require fewer replacement cycles across a long UPS operating period. This can reduce cumulative labor and replacement expenses.

Total cost of ownership (TCO) should include:

• Initial battery and installation costs
• Expected battery replacements
• Preventive maintenance and monitoring
• Energy consumption and cooling
• Battery disposal and recycling
• Operational work associated with replacement

For example, a facility planning to operate a UPS for ten years should compare the complete ten-year cost of each battery technology rather than simply comparing initial quotations.

Schneider Electric provides a lithium-ion versus VRLA UPS TCO calculator for examining how battery replacement intervals, efficiency, and other assumptions influence lifetime costs.

Space, Weight, and Operating Temperature

Lithium-ion batteries generally provide more stored energy per unit of mass and volume than lead-acid batteries.

For data centers, that difference can influence equipment room design, rack allocation, installation handling, and floor loading.

A compact data center UPS battery installation may leave more room for electrical distribution equipment, maintenance access, or other critical infrastructure.

Temperature also affects battery aging.

Lead-acid batteries are particularly sensitive to prolonged exposure to elevated temperatures. Higher operating temperatures accelerate chemical degradation and can shorten their usable service life.

Lithium-ion systems may support broader operating-temperature conditions, depending on their cell chemistry and thermal management design.

This creates opportunities to optimize battery room layouts and environmental controls. Actual cooling requirements still depend on the complete UPS installation, including electrical losses, ventilation, and manufacturer specifications.

Discharge Performance, Maintenance, and Reliability

UPS batteries must often deliver high power immediately, even when the expected backup duration is short.

A battery’s stored energy alone does not establish whether it can meet that requirement. The cells, internal resistance, permitted discharge current, battery management system, and DC voltage behavior all influence performance.

Lithium-ion batteries designed for UPS service can maintain useful discharge characteristics across demanding power profiles. Their integrated BMS also supports continuous supervision of battery conditions.

In comparison, VRLA systems commonly rely on scheduled inspections, electrical measurements, and external battery monitoring equipment.

For a facility manager, the practical distinction is how each battery technology supports maintenance planning and operational visibility.

The most useful comparison is not simply lead-acid versus lithium. It is the performance of two complete, properly engineered battery systems under the facility’s actual load and runtime requirements.

MANLY Battery Products for Data Center UPS and Backup Power

MANLY Battery manufactures lithium battery products for data center power infrastructure, telecommunications, and stationary backup applications.

Our product range includes high-voltage battery systems and 48V-class rack-mounted LiFePO4 batteries. These configurations support different approaches to energy storage, from centralized data center projects to distributed network equipment.

For a data center UPS battery project, the appropriate configuration depends on the required DC voltage, power demand, installation layout, and equipment interface.

MLP30000U: 307.2V 100Ah Data Center Power System

Core Specifications: 307.2V nominal voltage | 100Ah | Approximately 30kWh nominal capacity | 350.4V maximum charging voltage | 50A maximum charging current

The MANLY Battery MLP30000U is designed around a high-voltage energy storage configuration for data center power applications.

Its most distinctive feature is the combination of a 307.2V nominal DC architecture and approximately 30kWh of stored energy. This provides a substantial energy reserve within a system intended for integration into larger electrical infrastructure.

High-voltage battery arrangements are relevant to data center projects where the power conversion equipment requires a defined DC bus voltage rather than a conventional 48V-class battery bank.

The MLP30000U includes battery modules and associated mounting and connection components. A 10kW inverter-control unit is also identified as an optional accessory, allowing project engineers to discuss the electrical architecture around the intended application.

For a data center installation, the 30kWh rating establishes the system’s approximate nominal stored energy. The power it can deliver to a particular UPS, and the resulting backup duration, depend on the approved system configuration, discharge limits, and UPS operating characteristics.

The MLP30000U is especially relevant for customers planning a high-voltage battery project that calls for capacity planning and system-level integration.

MLP48100: 51.2V 100Ah Rack-Mount LiFePO4 Battery

Core Specifications: 51.2V nominal voltage | 100Ah | 5.12kWh nominal energy | 58.4V maximum charging voltage | Integrated BMS

The MANLY Battery MLP48100 combines LiFePO4 battery chemistry with a rack-oriented design for telecommunications and stationary backup applications.

At 51.2V and 100Ah, each battery provides 5.12kWh of nominal energy. That gives engineers a clearly defined capacity unit when planning backup power for network equipment, communication systems, and compatible server room installations.

A significant feature is the integrated battery management system. The BMS supports battery protection and operating supervision, which matters when a battery spends extended periods in standby service before being called upon during an outage.

The rack-mounted format is also useful for projects where electrical equipment needs to be organized within a designated telecommunications or equipment cabinet.

MANLY Battery supports customization of the MLP48100’s voltage, capacity, current configuration, dimensions, and enclosure-related components. This is valuable for system integrators working with specific equipment layouts and connection requirements.

The MLP48100 offers a practical LiFePO4 platform for engineered 48V-class backup power projects, particularly where modular capacity, rack integration, and customized electrical interfaces are important.

48V 50Ah Telecom Battery for Edge and Network Racks

Core Specifications: 51.2V nominal voltage | 50Ah | 2.56kWh nominal energy | 50A maximum continuous discharge current | RS485/CAN communication

The MANLY Battery 48V 50Ah Telecom Battery focuses on rack-mounted backup power for communication cabinets, network infrastructure, and distributed equipment sites.

Each module stores 2.56kWh of nominal energy. Its 50Ah capacity and 50A maximum continuous discharge current provide defined electrical parameters for planning equipment loads and battery bank configurations.

For edge computing and network installations, this arrangement is particularly useful when individual equipment cabinets require localized backup power.

The battery includes an integrated BMS with protection functions covering conditions such as overcharge, overdischarge, overcurrent, short circuit, and excessive temperature.

RS485 and CAN interfaces also support communication with compatible monitoring or control equipment, subject to the communication protocol used by the complete system.

The published configuration supports parallel expansion with up to 15 matched battery modules. This allows system designers to plan nominal storage capacity in 2.56kWh increments within the supported configuration.

With a compact metal enclosure and rack-oriented construction, the 48V 50Ah battery is well suited to distributed communication and edge infrastructure projects that benefit from modular lithium backup power.

How to Size a Data Center UPS Battery for the Required Runtime

A data center UPS battery should be sized according to the actual critical load, required backup duration, usable battery energy, and maximum discharge capability.

Starting with battery capacity alone can produce an incomplete result, especially for UPS applications that require substantial power over a short period.

Calculate Critical Load and Backup Time

The first step is to identify how much power the UPS must supply during an outage.

Critical loads may include servers, networking equipment, storage systems, essential control equipment, and other devices connected to the protected power distribution system.

Use the actual load in kilowatts rather than assuming that every connected device continuously operates at its nameplate maximum.

Next, determine the required backup time.

A facility with automatic standby generators may design its UPS to maintain power during generator startup and transfer, with an appropriate engineering margin.

A smaller server room without a generator may require enough energy to support an orderly shutdown or a longer interruption.

The basic relationship is:

Required load energy (kWh) = Critical load (kW) × Backup time (hours)

For example, a 20kW critical load operating for ten minutes requires:

20kW × (10 ÷ 60) = 3.33kWh

That figure represents the theoretical energy delivered to the load, not the final required battery bank capacity.

Battery Energy, Usable Capacity, and Discharge Rate

Battery energy is commonly expressed in kilowatt-hours (kWh), while battery capacity is often stated in amp-hours (Ah).

For a battery with a specified nominal voltage:

Nominal energy (Wh) = Nominal voltage (V) × Capacity (Ah)

A 51.2V, 100Ah battery therefore contains:

51.2V × 100Ah = 5,120Wh = 5.12kWh

This calculation is useful for understanding the nominal energy of the MANLY Battery MLP48100.

However, a 5.12kWh rating does not mean the battery can deliver any desired power level for a proportionate amount of time.

The battery must also meet the required discharge current and power.

For the previous 20kW, ten-minute example, assume an illustrative UPS efficiency of 90% and a usable battery energy fraction of 80%.

The preliminary energy estimate becomes:

3.33kWh ÷ (0.90 × 0.80) = approximately 4.63kWh

These assumptions are examples only, not specifications for a particular MANLY battery or UPS.

A real data center UPS battery calculation must also account for:

• Maximum continuous and short-duration discharge current
• Cell performance at the required discharge rate
• DC voltage limits and discharge termination settings
• Battery aging and design margins
• Actual UPS efficiency at the expected load
• The battery manufacturer’s validated discharge curves

This distinction is important for short-duration, high-power UPS applications. A battery bank can have sufficient theoretical stored energy while still requiring additional modules or a different electrical arrangement to satisfy the instantaneous power demand.

Plan for Redundancy, Growth, and Generator Handoff

UPS battery planning should also reflect the data center’s availability requirements.

For installations using N+1 or 2N redundancy, the battery architecture must align with the UPS design and the required independence of critical power paths.

Adding batteries to one shared bank does not automatically create electrical redundancy.

Where generators provide extended backup power, the UPS runtime should accommodate the intended generator startup, synchronization, and load-transfer sequence, including any required contingencies.

Future growth matters as well. A battery bank sized for today’s server load may need additional capacity if the facility increases rack density or adds equipment to the protected electrical system.

For MANLY Battery projects, early coordination between the battery manufacturer, UPS provider, and electrical system integrator helps establish the required voltage, battery capacity, current ratings, and physical layout before final procurement.

Can You Use a Lithium Battery With an Existing Data Center UPS?

An existing data center UPS can use a lithium battery only when the proposed battery configuration is supported or specifically approved for that UPS system.

Matching the nominal voltage is not sufficient. The complete electrical and control interface must be evaluated.

Match Voltage, Charging Requirements, and Discharge Current

UPS battery systems operate within defined DC voltage ranges and charging profiles.

Lead-acid and lithium-ion batteries have different charging characteristics. A UPS originally configured for VRLA may use charging settings that do not match a proposed LiFePO4 battery.

Consider a 48V-class lithium battery with a nominal voltage of 51.2V.

The MANLY Battery MLP48100 has a published maximum charging voltage of 58.4V. The connected UPS or charger must support the battery’s required operating and charging conditions.

The same principle applies to high-voltage installations. The MLP30000U’s 307.2V nominal configuration must be evaluated against the UPS’s specified DC input range and battery architecture.

Discharge current is equally important.

An existing UPS may demand more power during battery operation than a particular module can continuously supply. Engineers must therefore verify current ratings, wiring, protective devices, and the approved battery configuration.

For replacement projects, the UL Solutions guidance on UPS battery retrofits explains why replacement battery types and configurations must follow the UPS equipment’s applicable markings, listing, and instructions.

Verify BMS Communication and UPS Manufacturer Approval

A lithium-ion battery management system supervises battery operating conditions and can provide protection against conditions outside the intended operating limits.

In an integrated UPS installation, battery communication may be used to exchange operating data, report alarms, or coordinate charge and discharge behavior.

Common physical communication interfaces include CAN and RS485.

However, having the same communication interface does not guarantee that two devices understand the same messages.

Compatibility depends on the communication protocol, supported commands, control requirements, and system configuration.

For an existing UPS installation, verify that the complete battery arrangement is approved by the UPS manufacturer or has undergone an appropriate engineering and safety evaluation.

MANLY Battery supports OEM and ODM customization involving battery voltage, capacity, BMS current settings, connectors, wiring, and enclosures.

This allows customers to discuss a battery configuration around documented technical requirements rather than relying solely on a generic nominal-voltage match.

Understand the Difference Between a Battery Rack, UPS, and BESS

A battery rack, a UPS, and a battery energy storage system (BESS) perform related but different functions.

A battery rack contains battery modules and associated electrical and protective components. It stores energy for use by compatible equipment.

A UPS provides continuity of power to critical loads when the primary electrical supply is interrupted. It uses power conversion and control equipment together with an appropriate energy source.

A BESS combines energy storage with power conversion and controls for applications that may include backup power, energy management, or other operating functions.

For procurement purposes, this distinction matters because purchasing a battery rack does not automatically provide a complete UPS.

MANLY rack-mounted batteries can serve as energy-storage components in appropriately designed backup systems. The complete installation must provide the required power conversion, protection, controls, and compatibility with the connected equipment.

UL Solutions also explains these functional differences in its UPS versus ESS technical overview.

Data Center UPS Battery Safety, Monitoring, and Replacement

Reliable UPS battery operation depends on effective battery management, regular condition monitoring, planned maintenance, and appropriate system safety controls.

Even when a battery rarely discharges, its condition can change over time because of temperature, charging, aging, and other operating factors.

Battery Management and Remote Monitoring

Lithium-ion battery systems commonly incorporate a BMS to supervise cell voltage, temperature, current, and other operating conditions.

The system can provide protective responses when monitored parameters move outside their permitted operating limits.

For distributed installations, communication interfaces can also support remote monitoring through compatible equipment.

This matters in data centers because operators need to understand battery readiness before a power interruption occurs.

Useful monitoring information may include:

• Battery state of charge (SOC)
• Battery state of health (SOH)
• Cell or module voltage
• Battery temperature
• Charge and discharge current
• Alarm and protection status

For example, MANLY Battery’s 48V 50Ah telecom battery includes RS485/CAN communication and an integrated BMS.

These features provide a foundation for coordinated battery monitoring in compatible backup power installations.

Monitoring also supports maintenance decisions by helping operators identify changes in operating conditions before those changes affect the availability of backup power.

Inspections, Testing, and Replacement Planning

Battery maintenance should follow the chemistry, manufacturer instructions, and requirements of the complete UPS installation.

For VRLA systems, inspections and testing commonly include checks related to battery voltage, temperature, connection condition, internal resistance, and capacity performance.

Lithium-ion systems also require maintenance planning, although integrated electronic monitoring changes how some battery condition information is collected.

A well-managed data center UPS battery program should include:

• Routine review of battery status and alarms
• Inspection of connections and associated equipment
• Review of temperature and operating conditions
• Scheduled battery or system testing
• Documentation of maintenance and replacement history
• Planning for battery end-of-life replacement

IEEE 1188-2025 provides recommended practices for the maintenance, testing, and replacement of stationary VRLA batteries.

For lithium-ion batteries, operators should follow the applicable battery and UPS manufacturer maintenance procedures and the requirements of the installed system.

The goal is not simply to maximize calendar life. It is to maintain confidence that the UPS can deliver its required backup performance when called upon.

U.S. Safety Standards and Installation Requirements

In the United States, UPS battery projects must be evaluated against the standards and installation requirements applicable to the specific equipment and location.

Several standards are particularly relevant:

Not every standard applies to every UPS installation in the same way.

The applicable requirements depend on battery chemistry, system configuration, installation purpose, equipment listing, and the codes adopted by the local authority having jurisdiction.

For example, UL 1778 addresses UPS equipment, while UL 1973 concerns battery safety. Requirements involving UL 9540 and NFPA 855 must be evaluated according to the specific energy storage or UPS application.

The UL Solutions UPS safety guidance provides additional information about the interaction between equipment standards and U.S. installation codes.

For a MANLY Battery project, customers should request the applicable product-specific technical documentation and certification information during the purchasing process. This helps electrical designers and project stakeholders evaluate the proposed battery configuration against the intended installation requirements.

FAQ

How Long Can a Data Center UPS Battery Keep Servers Running?

A data center UPS battery can support servers for a few minutes or substantially longer, depending on the installed battery system and electrical load. Many facilities use UPS power to bridge the interval before backup generators take over. Others require additional runtime for controlled shutdown procedures.

To estimate the required capacity, start with the actual load in kilowatts, the target backup time, and the UPS manufacturer’s battery performance data. Battery discharge limits and system efficiency must also be included.

Can a Data Center UPS Operate Without a Backup Generator?

Yes. A data center UPS can provide temporary backup power without a generator, provided its battery system is sized for the intended load and operating duration.

In a server room without generator support, the UPS may be designed to maintain essential services during brief interruptions or allow equipment to shut down safely.

A facility requiring longer uninterrupted operation needs enough approved battery capacity or another suitable source of extended backup power. The design should reflect the site’s actual continuity requirements.

Why Can Two UPS Batteries With the Same kWh Rating Deliver Different Runtimes?

Two batteries with identical nominal energy ratings can deliver different runtimes because of their discharge characteristics, allowable current, voltage behavior, and operating limits.

A high-power UPS load can demand substantial current over a short period. The battery must maintain the required electrical output throughout that interval.

For this reason, buyers should evaluate manufacturer discharge curves and power ratings rather than comparing kWh alone. A properly specified data center UPS battery must satisfy both energy and power requirements.

Do Lithium-Ion UPS Batteries Need Monitoring If They Rarely Discharge?

Yes. Lithium-ion batteries require appropriate monitoring even when they spend most of their time in standby operation.

Temperature, cell voltage, charging conditions, and battery aging can influence readiness without frequent discharge cycles.

An integrated BMS supervises important battery operating parameters. In compatible installations, communication interfaces also allow operating information and alarms to be shared with monitoring equipment.

For data center operators, regular monitoring provides visibility into battery condition and supports maintenance planning before an actual power interruption.

What Information Should I Provide a Data Center UPS Battery Manufacturer Before Ordering?

Start with the UPS manufacturer and model, required DC voltage range, critical load, backup runtime, and installation environment.

Also provide the preferred battery chemistry, allowable dimensions, discharge current requirements, and any communication or monitoring specifications.

As a lithium battery manufacturer, MANLY Battery supports customized voltage, capacity, BMS configurations, connectors, and enclosures for suitable projects. Sharing the technical requirements early allows our team to discuss a battery solution aligned with the intended application and system integration requirements.

Conclusion

Data center UPS systems primarily rely on VRLA lead-acid and lithium-ion batteries to maintain critical electrical power during interruptions.

VRLA remains an established technology in existing infrastructure, while lithium-ion systems offer important opportunities for longer service life, compact installations, integrated monitoring, and lifecycle cost management.

The right data center UPS battery depends on the facility’s critical load, backup duration, electrical architecture, and maintenance strategy. Stored energy, discharge capability, and equipment compatibility must all be considered together.

MANLY Battery supports these requirements with high-voltage data center power systems and rack-mounted LiFePO4 batteries for telecommunications and distributed backup applications.

For a new installation or a battery system integration project, contact MANLY Battery to discuss your voltage, capacity, runtime, and customization requirements. Our team can help you explore a battery configuration suited to your project’s technical needs.

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