Introduction

Valve-Regulated Lead-Acid (VRLA) batteries are widely used in backup power systems due to their sealed design and low maintenance requirements. However, to ensure reliable performance and long service life, regular inspection and systematic maintenance are essential. This guide summarizes the periodic maintenance steps, troubleshooting methods, and best practices for Dynasty VRLA battery systems.

Periodic Maintenance

1. Quarterly Maintenance (Every 3 Months)

• Keep the battery room clean, dry, and well-lit.
• Ensure fire safety equipment (e.g., fire extinguisher) is available.
• Maintain room temperature below 25°C.
• Visual inspection:
  • Batteries arranged properly
  • No signs of terminal damage or overheating
  • Covers intact and no obvious hot spots
• Measure and record:
  • Total charging voltage and ripple charging voltage
  • Ground faults using DC voltage check
  • Charging currents (both DC and AC floating currents)
  • Battery temperatures at the negative terminal
  • Individual cell voltages during float charging
  • Equalization voltage when applicable

2. Semi-Annual Maintenance (Every 6 Months)

• Repeat all quarterly checks.
• Perform a 100A load test to confirm cell health.
• Optionally, measure and record internal resistance or conductance.

3. Annual Maintenance (Every 12 Months)

• Perform semi-annual steps.
• Re-tighten all battery connectors according to manufacturer torque specifications.
• Ensure connector resistance does not exceed 20% deviation from initial installation values.

4. Bi-Annual Maintenance (Every 2 Years)

• Conduct a capacity test using the rated load of the system.
• If capacity drops below 85% of nominal, repeat capacity tests annually.
• Always perform equalization charging after testing.

Key Operational Considerations

Temperature and Battery Life

• Optimal operating temperature: 21°C – 28°C
• Every 10°C above 25°C reduces battery life by 50%.
• Avoid charging batteries at ambient temperatures above 50°C to prevent thermal runaway.
• If a cell temperature rises more than 10°C above ambient, stop charging and replace that battery.

Visual Inspections

• Cleanliness: Dust and moisture can create leakage paths → ground faults.
• Casing Damage: Cracks or leaks can dry out electrolyte → overheating or short circuits.
• Terminal Condition: Loose or corroded connectors cause heat buildup → possible melting or fire risk.

Float Charging Voltage

• Recommended: 2.25 – 2.30 V per cell @ 25°C
• Adjust for temperature:
  • -0.005 V/°C below 25°C
  • +0.005 V/°C above 25°C
• Overcharging leads to excessive gassing, corrosion, and electrolyte dry-out.
• Undercharging results in capacity loss and sulfation.

Ripple Voltage and Float Current

• Ripple voltage must be < 0.5% Vrms of float voltage.
• Excessive ripple → heating, gassing, and shortened life.
• Float current approximately doubles for every 10°C increase above 25°C.

Troubleshooting and Diagnostics

Common Issues

• Ground Faults: Detected by measuring voltage between battery terminals and ground.
• Shorted or Open Cells: Indicated by abnormal float voltages or zero float current.
• High Resistance Connections: Caused by loose terminals → voltage drops and overheating.

Testing Methods

• Momentary Load Test: High-rate (20–200A, typically 100A) discharge for 10 seconds; voltage must stay above 1.75 V/cell.
• Impedance Testing: Detects corrosion, electrolyte dry-out, or cell deterioration by measuring internal resistance.
• Capacity Testing: Replace batteries once capacity falls below 80% of rated value.

Conclusion

Proper preventive maintenance and regular diagnostics are critical to maximizing the reliability and service life of VRLA battery systems. By adhering to a structured maintenance schedule—quarterly, semi-annual, annual, and bi-annual—operators can minimize failures, detect early signs of degradation, and prevent costly downtime.