Batteries play a crucial role in the modern world, quietly providing backup power for critical systems such as Substation protection auxiliary power supply, Data Centers, Emergency lighting, and Uninterrupted Power Supplies (UPS). Proper battery maintenance is essential to maintaining their reliability.
Battery capacity may be degraded over a period of time due to the below mentioned reasons:
- Over charging
- Shorting due to misplaced busbar or any other conductor
- Self discharge due to internal resistance & chemical reaction
- Sulfation on battery terminals
- Grid corrosion on battery terminals
- Capacity loss due to Ageing
- Internal Heating
Due to this degradation, periodical Battery Capacity (Discharge) testing becomes necessary to ensure the optimum power backup from Battery Banks for the desired duration. Let’s dive into battery discharge testing—the backbone of effective battery care—guided by the recommendations from three key IEEE standards: IEEE 450, IEEE 1188, and IEEE 1106.
1. IEEE 450: Vented Lead-Acid (VLA) Batteries
IEEE 450 focuses on vented lead-acid batteries commonly used in standby power applications. These batteries have a rich history and continue to be prevalent in various industries. Constant Current or Constant Power load pattern is recommended for acceptance or performance test in this standard.
Maintenance and Testing Recommendations
- Regular inspections: Battery systems operating under normal float charge conditions should receive a general inspection at least once per month
- In-depth inspections: More detailed assessments should occur quarterly and annually
- Replacement Criteria: When a battery exhibits signs of degradation (a decrease of 10% from the last test) or falls below 90% of the manufacturer’s rated capacity, annual capacity testing is recommended. Replacement is advised when capacity drops below 80%
2. IEEE 1188: Valve-Regulated Lead-Acid (VRLA) Batteries
IEEE 1188 addresses VRLA batteries used in stationary applications. These sealed batteries are common in UPS systems and other critical installations.
Maintenance and Testing Recommendations
- Similar to IEEE 450, regular inspections are crucial
- When capacity drops below 80%, consider battery replacement
3. IEEE 1106: Vented Nickel-Cadmium Batteries
IEEE 1106 focuses on vented nickel-cadmium batteries. These batteries possess unique characteristics and are often used in critical applications. In this standard installation design, maintenance, and testing procedures are outlined. Cell and battery replacement guidance with the help of modified performance tests is provided in this standard.
Comparison between Battery Discharge Methods
| Parameter | Salt Water Method | Manual Resistor Load Bank | Electronic Load Bank |
| Discharge resistance | Salt Water Solution | Rheostat or resistors | High Precision resistors |
| Difficulty level to maintain constant current | Difficult due to changing resistance | Moderate | Easy and Automatic |
| Total Discharge Time Error | High | Moderate | Low |
| Trip Timer | Not available | Yes | Yes |
| Manual Error | Time error due to periodic changing of water concentrations, Current error due to location of clamp | Voltmeter & Ammeter reading | Less |
| Report Generation | Manual | Manual | Automatic via PC/Laptop |
| Cost | Low | Medium | High |
| Cell voltage monitoring | Manual via Multimeter | Manual via Multimeter | Automatic |
Conclusion
In this blog, we covered the standards set by IEEE for battery discharge testing. Also from the table above it is clear that electronic load bank offers an advantage over other types of load banks. SCOPE offers an electronic battery loading unit under the brand name BLUe. For Information related to battery testing products offered by SCOPE – https://scopetnm.com/test-and-measurements/dc-test-equipment/battery-loading-unit
For more information about the subject and advanced transformer turns ratio meter inquiry please write to us at marketing@scopetnm.com
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