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