Battery Energy Storage Maintenance in Summer Conditions

Introduction

Battery Energy Storage Systems (BESS) are crucial in modern power systems, supporting load balancing, backup power, and integration of renewable energy sources. However, summer heat poses significant risks to battery performance, especially for 110-cell configurations using 2V lead-acid or VRLA cells. Proper maintenance during high-temperature months is critical to avoid degradation, capacity loss, or failures.

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Why Summer Maintenance Matters

• High ambient temperatures increase battery’s self-discharge rate.
• Electrolyte evaporation in vented lead-acid cells can accelerate.
• VRLA batteries are sensitive to overcharging at high temperatures.
• Thermal runaway risk increases above 30–35°C.
• Battery lifespan decreases rapidly without proper temperature control.

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Battery Configuration Overview (110 x 2V Cells)

• Nominal Voltage: 220V DC
• Common Uses: Substation DC systems, telecom backup, UPS banks
• Battery Types: Lead-acid (flooded or VRLA)
• PILOT CELL: Pilot cells are chosen in a group. This group may be of 10 or 20 in number. But in general 10 no group is maintained as a pilot cell. For the set of 10, no group, the cells are taken as cell no1 from the first group, cell no11 from the second group, etc (the cells are chosen no1, 11, 21,31,41,51, 61, 71, 81, and 91,101). Similarly, for the next month or for the next period, next succeeding cells are chosen (cell no 2, 12,22,32,42, 52, 62, 72, 82, 92,102). This method of selection continues till all the cells are covered under pilot cells

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Key Summer Maintenance Tips

🔧 1. Temperature Monitoring

• Keep battery room ambient temperature between 20°C to 25°C.
• Use temperature sensors across battery banks.
• Ensure HVAC systems are functioning efficiently.

💧 2. Electrolyte Level Checks (for Flooded Cells)

• Inspect electrolyte levels daily(Pilot Cells-1,11,21,31 on).
• Top up only with distilled water—never acid.
• Avoid overfilling, especially before peak heat hours.

⚡ 3. Equalization Charging

• Perform monthly equalization to balance cell voltages.
• Avoid scheduling during peak temperature hours.
• Monitor battery temperature rise during equalization closely.

🔋 4. Voltage & Specific Gravity Testing

• Record individual cell voltage and specific gravity.
• Flag and isolate cells with >0.05V deviation or SG difference.
• Use calibrated digital hydrometers or battery testers.

DETAILS OF Battery Set	Make, AH capacity and Type of Battery and other detail YOM, DOC etc..
Final SP Gravity /Voltage recorded ( Use Separate Table Data)	Sp. Gravity	Voltage	Level of Electrolyte
Physical status of Battery
Specific Complaint
ANY OTHER OBSERVATION

🔍 5. Visual Inspection

• Check for:
  • Swelling or cracks on the casing
  • Corroded terminals
  • Acid leakage signs
• Clean terminals and tighten loose connections.

🌬️ 6. Ventilation Check

• Ensure the battery room is well-ventilated.
• Use exhaust fans to dissipate hydrogen gas (especially for vented batteries).
• Prevent any gas accumulation in enclosed spaces.

📋 7. Record Keeping & Scheduling

• Maintain battery health logs.
• Record:
  • Cell voltages
  • SG readings
  • Water additions
  • Equalization dates
• Use maintenance software or DBMS systems to track historical data.

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Common Summer Issues & Remedies

Issue	Cause	Remedy
Excessive gassing	Overcharging, high ambient temp	Adjust float/boost voltage, enhance cooling
Reduced backup time	Capacity loss due to heat	Perform capacity test, replace weak cells
Acid corrosion	Inadequate cleaning, vent blockage	Neutralize and clean terminals, improve airflow
Uneven voltages	Sulfation, aging cells	Equalization charge, replace faulty cells

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Summer Safety Precautions

• Use insulated tools when working with terminals.
• Wear gloves, face shields, and acid-resistant aprons.
• Don’t charge or discharge batteries beyond rated specs.
• Label and restrict unauthorized access to battery rooms.

STANDARDS OF BATTERY SYSTEM

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Conclusion

Regular and meticulous summer maintenance of 110-cell (2V each) battery systems ensures safe operation, reduces risk of heat-induced failures, and extends service life. Prioritize temperature control, fluid checks, and voltage balancing to optimize battery performance under extreme conditions.