Pure Lead Battery FAQs

No, there isn’t a standard for how a pure lead battery is made. There are differences in grid design (thickness, structure) and paste density that will directly impact performance, lifespan, and high-rate discharge capability. These design factors vary by manufacturer and application focus. Each manufacturer will determine how to best achieve it.

Pure lead batteries use very high-purity lead (typically >99%), with minimal alloying elements to improve mechanical strength and corrosion resistance.

The ideal operating temperature is around 25°C (77°F). Pure lead batteries will suffer a reduced impact on service life due to temperature compared to standard lead acid batteries.

While not strictly mandatory, climate control is highly recommended to ensure optimal performance and maximize service life regardless of the technology chosen.

This will depend on the depth of discharge, but VRLA batteries typically provide 400–800 cycles.

No. The sizing methodology remains the same.

 
What changes is the battery's operating profile. In systems without emergency generation, batteries no longer operate primarily under float service conditions and instead are subjected to a more cyclic operating profile.

 
This operating condition reduces the service life of batteries designed for float applications and should be considered when selecting the most appropriate battery technology for the application.

The number of battery cells is determined by the UPS electrical design and the DC voltage specified by the UPS manufacturer.

 
When the UPS manufacturer allows a voltage range, the system designer has greater flexibility to optimize the battery bank by selecting the combination of system voltage and battery capacity that best meets the application's runtime requirements, helping reduce costs while improving overall system efficiency.

IEEE standards do not specify a mandatory percentage of spare batteries.

 
However, for critical applications, it is considered a best practice to maintain spare batteries equivalent to approximately 0.5% to 1% of the total batteries installed.

 
These spare batteries should remain on float charge using an independent charger and can be used during preventive maintenance or scheduled battery replacements.

Battery sizing calculations should consider the battery bank's actual operating temperature. When the ambient temperature is below the battery's reference temperature, the required nominal battery capacity increases.

 
When the operating temperature is above the reference temperature, the required battery capacity decreases; however, battery aging accelerates.

 
Whenever possible, designers should use the temperature correction factors provided by the battery manufacturer. If manufacturer-specific data is unavailable, the correction factors presented in IEEE 485 may be used as a conservative design approach.

Design Life represents the theoretical life expectancy of a battery when operated under the ideal conditions specified by the manufacturer, including:

• Float operation
• Controlled ambient temperature
• Proper float voltage
• Minimal discharge events
• Proper maintenance

 
Service Life, on the other hand, represents the actual operating life achieved in the field and depends on real-world operating conditions, including ambient temperature, number of cycles, depth of discharge, recharge quality, equalization practices, and environmental conditions.

The primary factors include:

• Elevated operating temperatures
• Frequent deep discharges
• Incomplete recharging
• Improper equalization charging
• Excessive ripple current
• Overvoltage or undervoltage
• Contaminated environments
• Inadequate ventilation

  The more severe these operating conditions are, the shorter the battery's service life will be.

Temperature is the single most significant factor affecting the service life of VRLA batteries. As a general rule of thumb, an average increase of 18°F (10°C) above the battery's reference operating temperature can reduce battery service life by approximately 50%.

 
Low temperatures also affect battery performance by reducing the available discharge capacity and may promote sulfation when automatic temperature compensation of the charging voltage is not provided.

Lifespan of VRLA batteries in UPS applications will vary greatly depending on the selected technology.

• Standard VRLA has a life expectancy of 3-5 years
• Pure Lead 5-8 years
• Advanced Pure Lead 8-10 years

Achieving a long service life depends on maintaining proper temperature, correct float voltage, regular maintenance, and avoiding deep discharges or overcharging. A proactive maintenance strategy is required, including periodic inspections, testing, and timely replacement of weak units to maintain overall system performance and reliability.

Cable and protection device sizing should consider:

• Maximum application current
• Required discharge time
• System voltage
• Interrupting capacity
• Voltage drop
• Applicable standards (IEEE 485, IEEE 1187, NBR 5410, and IEC 60364)

 
It is also recommended to:

• Use cables of equal length for parallel battery strings to ensure proper current sharing.
• Periodically verify connection torque.
• Perform thermographic inspections to identify potential hot spots before failures occur.

According to the C&D Technologies maintenance guidelines:

• Perform a capacity test every two years.
• Whenever possible, use the same discharge rate employed during the acceptance test.
• Once the measured capacity reaches 85% of its rated capacity, perform capacity testing annually.
• Before testing, perform a refresh charge (equalization charge) for 12 to 24 hours.

Yes. However, IEEE 1188 recommends performing a risk assessment before conducting the test.

 
In critical applications, when the battery already shows clear signs of degradation, it may be more appropriate to replace the battery bank proactively rather than subject it to a discharge test.

Capacity testing should continue until the battery reaches its End of Life (EOL).

 
As the battery approaches this stage, operators should evaluate the operational risks before deciding whether to perform another capacity test or proactively replace the battery bank.

A properly designed and installed battery bank should include:

• An ambient temperature that complies with the battery manufacturer's specifications
• Adequate ventilation
• Connections tightened to the manufacturer's specified torque values
• Properly sized cables
• Balanced current sharing between parallel battery strings
• Correctly specified protective devices
• Complete installation documentation to support future inspections and maintenance activities

 
Following these best practices helps maximize battery reliability, safety, and service life while ensuring the UPS system performs as expected in critical applications.

The battery system installation may be subject to local, state and national building, fire and electrical codes. There are also guides as published by the IEEE. Relevant codes and guides may include, among others, the following:

• National Electric Code (NEC) Section 480 – Storage Batteries
• Uniform Building Code (UBC) Article 307
• Uniform Fire Code (UFC) Article 64
• IEEE – 1187 “Recommended Practice for Installation of Valve Regulated Lead Acid Batteries”
• IEEE – 484 “Recommended Practice for Installation Design and Installation of Vented Lead Acid Batteries for Stationary Applications”
• OSHA 1926.403

Key indicators include:

• Reduced battery capacity
• Increased internal resistance
• Reduced conductance
• Voltage deviations between battery blocks or cells
• Elevated operating temperature
• Reduced runtime
• Bulging, leaks, or physical deformation
• Terminal corrosion
• Increased float current

 
More important than any single measurement is tracking how these parameters change over time. Trend analysis provides the most reliable indication of battery health.

The following records should be maintained:

• Complete battery bank identification
• Electrical configuration
• Routine inspection records
• Capacity test results
• Failure history
• Battery replacements
• Calibration records for test instruments
• Historical trends for temperature, voltage, internal resistance, and capacity

 
Maintaining these records supports proactive maintenance planning and improves overall system reliability.

The battery system maintenance may be subject to local, state and national codes depending on the application. These codes and guides may include, among others, the following:

• IEEE – 1188 “Recommended Practice for Maintenance and Testing of Valve Regulated Lead Acid Batteries”
• IEEE – 450 “Recommended Practice for Maintenance and Testing of Vented Lead Acid Batteries for Stationary Applications”

To determine the best battery size for your system, you must consider the expected load, runtime requirements, temperature, and system voltage. A detailed calculation or system design review is always recommended to ensure every system is a perfect fit for your needs.

For the best combination of power and longevity, high-rate pure lead batteries such as the Pure Lead Plus and Pure Lead Max are typically recommended due to their energy density, compact footprint, and long life in demanding UPS applications.

• Pure Lead Plus – Standard 5-year warranty
• Pure Lead Max – Standard 8-year warranty

While both require backup power for emergencies, how it is delivered will vary greatly.

• Telecom Application: Medium-rate discharge (e.g., C10 rates), focusing on longer, sustained backup.
• UPS Application: High-rate discharge, delivering large amounts of power in a short time. Key differences between the batteries include: -- Grid design (geometry and thickness) -- Paste density -- Discharge profile optimization

The primary references are:

• IEEE Std 485 — Recommended Practice for Sizing Lead-Acid Batteries for Stationary Applications.
• IEEE Std 1188 — Recommended Practice for Maintenance, Testing, and Replacement of Valve-Regulated Lead-Acid (VRLA) Batteries for Stationary Applications.
• IEEE Std 1187 — Recommended Practice for Installation Design and Installation of Valve-Regulated Lead-Acid (VRLA) Batteries for Stationary Applications.

 
These standards provide industry-recognized guidance for the design, installation, inspection, testing, and maintenance of battery banks used in mission-critical applications.

Battery sizing calculations should consider the battery bank's actual operating temperature. When the ambient temperature is below the battery's reference temperature, the required nominal battery capacity increases.

 
When the operating temperature is above the reference temperature, the required battery capacity decreases; however, battery aging accelerates.

 
Whenever possible, designers should use the temperature correction factors provided by the battery manufacturer. If manufacturer-specific data is unavailable, the correction factors presented in IEEE 485 may be used as a conservative design approach.

Temperature is the single most significant factor affecting the service life of VRLA batteries. As a general rule of thumb, an average increase of 18°F (10°C) above the battery's reference operating temperature can reduce battery service life by approximately 50%.

 
Low temperatures also affect battery performance by reducing the available discharge capacity and may promote sulfation when automatic temperature compensation of the charging voltage is not provided.

Sulfation is typically caused by undercharging, prolonged discharge, or improper storage. In most cases, it is not fully reversible and leads to permanent capacity loss.

Indirectly, yes. Poor connections can lead to increased resistance and improper charging, which may accelerate sulfation.

Both are valid diagnostic methods. Conductance testing is commonly preferred for quick and reliable field assessments.

Yes, it remains one of the most reliable methods to validate actual battery capacity and system performance. Typically, once a year or according to industry standards and site criticality. Excessive testing should be avoided to prevent unnecessary battery stress.

If needed, an equalization charge may be performed if the UPS allows it, but only under controlled conditions and according to the manufacturer’s recommendations. How long to run it for will depend on system conditions and should follow our guidelines to avoid overcharging.

Proper commissioning includes verifying installation, measuring baseline values (voltage, temperature, impedance), and documenting these parameters. Recording this data is highly recommended for warranty validation and future comparisons.