CBS – Centralised Battery Systems

CBS

Centralised Battery Emergency Lighting System
> Central Battery emergency lighting system
> Connect up to 24 fluorescent light fittings
> 20% emergency lighting for one or three hours
> Maintained operation
> Reduced maintenance costs

The Central Battery System (CBS) provides a centralised battery pack (48V) connected to satellite emergency luminaries. A maximum of 24 emergency luminaries may be connected to the central battery pack thereby reducing installation cost.

Maintenance costs are dramatically reduced as battery replacement does not require individual luminaire access, traditionally a problem, as batteries usually require replacement every three years. Each emergency luminaire contains an emergency module (TL48_EM) to enable maintained operation. The modules are specifically designed to protect associated electronic ballasts from open circuit (no lamp) conditions. Also, the emergency modules are polarity insensitive thereby simplifying wiring. A typical installation will be a dedicated central battery supply for each floor (storey) supplying all emergency lighting for that floor (exit, anti-panic and stair-well lighting). A standby facility is included to preserve battery power in the event of extended mains failures.

The industry standard emergency lighting system consists of a battery pack and an emergency control unit built into the luminaire. The luminaire is then fed by an extra permanent live connection to charge the batteries and detect power failures. The extra connection enables the luminaire to be used for both normal and emergency lighting (so-called maintained operation). This option is preferred to motor generator sets because they will be activated when the power supply failure is restricted to a particular circuit or floor (SABS 0114-2). The emergency luminaires may be installed in shopping malls, airport departure halls, banking halls, restaurants, sports stadiums, warehouses, etc.

Periodic luminaire maintenance requires re-lamping and, if necessary, reflector cleaning. It is generally accepted that emergency luminaire batteries be replaced every three years assuming that the batteries were mounted in the coolest part of the luminaire. The battery replacement could coincide with the re-lamping exercise thereby defraying costs but replacing batteries is usually considerably more time consuming than replacing lamps often because no consideration was given before mounting the batteries initially.

GENERAL DESCRIPTION
The Central Battery System (CBS) consists of a base station and inverter modules. The base station houses the batteries, battery charger and supervisory circuitry. It is housed in an attractive enclosure that is ideally positioned for easy access, usually on every floor of multi storey buildings. The base station provides 48V dc during a power failure to the emergency lighting luminaires via 2mm dia. Surfix cable. The inverter modules are fitted into each emergency luminaire and can be configured to provide maintained or non-maintained emergency lighting.

Base station
The base station requires a permanent 230Vac mains connection in order to charge the batteries and to detect power failures. Four 12V 7Ahr sealed lead-acid batteries are housed within the base station. The battery charger is capable of charging the batteries within 24 hours, in accordance with SABS/IEC 1464 part 22, provide over-voltage and low-voltage protection as well as other necessary requirements. In the event of a power failure the output voltage (48V dc) is supplied to the emergency light fittings.

Inverter Modules
The inverter modules are fitted within the emergency luminaires. They connect the lamp to the ballast under normal conditions so that the luminaire can be used for normal lighting (maintained operation). In the event of a power failure the lamp is energised by the inverter. A special sense circuit is included to prevent emergency operation during normal lighting thereby protecting the electronic ballast (if used) from open circuit (no lamp) conditions. Each inverter module draws less than 150 mA so that a maximum of 24 emergency luminaires can be connected to each base station (24 x 150 mA = 4.5 A) thereby ensuring a minimum emergency lighting duration of one hour. The low current draw and volt drop tolerance of the inverter modules permits cable runs of 100 m using 2 mm dia. Surfix.

Luminaire Requirements
Any four pin fluorescent lamp from 7 to 65 Watts can be used. This includes linear T12, T8, T5 and compact fluorescent types.

Maintained Mode
For maintained mode (where the luminaire is also used for both normal and emergency lighting) the luminaire must house both the electronic ballast and the inverter module. The electronic ballast must be provided with a switched live feed (230Vac) to provide normal lighting. The inverter module must be supplied by the 48V dc feed from the base station. The emergency lamp will be connected to the electronic ballast via the inverter module. In the event of a power failure the 48Vdc feed from the base station will be energised and the emergency lamp will be powered from the inverter module.

Non-Maintained Mode
For non-maintained mode (where the luminaire is only used for emergency lighting) the luminaire need only house the inverter module, i.e., no electronic ballast and switched live feeds are required. The only feed to the luminaire will be the 48Vdc feed from the base station.

Cosine Developments CBS centralised battery systems