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270c5e R. Bishop 2025-04-02 18:59:11 1 
## **Central Battery Emergency Lighting Systems**
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A **Central Battery System (CBS)** provides emergency power from a single, centralized source to multiple emergency luminaires. This contrasts with self-contained systems, where each fitting has its own battery. Central systems are ideal for large buildings or complex installations where centralized monitoring, control, and battery maintenance are preferred.
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### **How Central Battery Systems Work**
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- The **central battery unit** powers all emergency lights via dedicated wiring.
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- Under normal conditions, the system monitors power and keeps the batteries charged.
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- On **mains failure**, the central battery activates and supplies power to all connected luminaires instantly.
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- Systems may supply **AC or DC** power depending on the luminaires used and system design.
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### **Types of Central Battery Systems**
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| **Type** | **Description** |
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|--------------|-----------------|
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| **AC/AC** | Outputs alternating current. Allows use of standard mains luminaires. Offers high light levels and greater flexibility. |
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| **AC/DC** | Outputs direct current. Requires DC-compatible emergency fittings. Common in purpose-built systems. |
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### **Applications**
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Central battery systems are especially suitable for large or high-occupancy buildings where consistent, reliable emergency lighting is essential:
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- Hospitals & healthcare environments
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- Universities & schools
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- Large office complexes
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- Shopping centres & commercial buildings
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- Warehouses & industrial sites
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### **Advantages of Central Battery Systems**
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- ✅ **Centralized Maintenance:** Easier to monitor and test a single battery bank rather than individual luminaires.
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- ✅ **Extended Battery Life:** Batteries typically last 5–10 years depending on the type (vs 3–5 years in self-contained).
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- ✅ **Higher Output:** Supports greater lighting performance and larger numbers of fittings.
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- ✅ **Improved Monitoring:** Many systems offer fault reporting, remote diagnostics, and testing automation.
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- ✅ **Cleaner Aesthetics:** Luminaires can be sleeker since they don’t require onboard batteries.
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### **Disadvantages**
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- ❌ **Higher Initial Cost:** Installation involves more infrastructure (cabling, central unit, space allocation).
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- ❌ **Single Point of Failure:** If the central battery fails, the entire system could be affected—redundancy is recommended.
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- ❌ **Complex Installation:** Requires specialist design and electrical planning.
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- ❌ **Space Requirements:** Battery rooms or cabinets may be needed to house central units safely.
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### **Maintenance & Testing Requirements**
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*(As per BS 5266-1 and BS EN 50171)*
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| **Check/Test** | **Frequency** | **Details** |
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|----------------------------|------------------|-------------|
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| **Visual Inspection** | Daily (manual systems) | Check control panels, LEDs, ventilation, and system status. |
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| **Functional Test** | Monthly | Simulate power failure to confirm emergency lights activate. |
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| **Full Duration Test** | Annually | Lights must remain illuminated for full rated time (usually 3 hours). |
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| **Battery Inspection** | Quarterly | Check voltage, connections, and signs of degradation. |
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| **Battery Replacement** | 5–10 years | Varies based on battery type and manufacturer. Replace proactively, not only on failure. |
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### **Battery Types & Lifespans**
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| **Battery Type** | **Typical Lifespan** |
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|------------------------------|----------------------|
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| Vented Lead-Acid | 5–10 years |
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| Sealed Lead-Acid (VRLA) | 5–7 years |
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| Nickel-Cadmium (NiCd) | 7–10 years |
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| Lithium-Ion (where used) | Up to 10+ years |
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> 🔋 Regular checks on charge/discharge cycles and ambient temperature help prolong battery life.
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### **Use Case Scenarios**
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| **Environment** | **Why CBS is Ideal** |
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|------------------------|----------------------|
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| Hospitals | Consistent lighting across wards and corridors. |
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| Shopping Centres | Centralized control over a large number of lights. |
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| Schools & Colleges | Simplifies routine testing across campus buildings. |
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| Multi-Storey Offices | Minimizes battery clutter across floors. |