Overview 

Life safety in buildings includes more than safety from fire. Although fire safety has been the long standing focus of NFPA 101, its widely know title, Life Safety Code, and its technical requirements respond to a wider range of concers, including, for example, crowd-safety. Code requirements that contribute to the safe movement of people during fire emergencies might also assist in responding to many other hazards that require decisions about where people can be safely located.Emergency UFO LED High Bay Light Battery Backup

UL 924 is UL’s Standard for Safety of Emergency Lighting and Power Equipment. UL tests and certifies exit signs, emergency lights, and combo emergency exit signs to meet functionality, reliability, and visibility standards.

And now, Lightide Manufactory Co., Ltd. (LMC) mainly focuses on quality led lighting manufacturing. So we also use emergency batteries for led lighting, such as led garage & canopy lighting, led high bay and led wall packs lighting. But sometimes peoples are confused about how to choose emergency battery and it is difficult to decide a suitable emergency battery. Here let’s see how to choose it for emergency backup led lighting. 

Lightide DLC_CE Listed LED Vapor Tight Lights

Types of Batteries

Batteries can be sorted into 3 categories: lithium-ion (Li) battery (LIB), alkaline battery and nickel–metal hydride (Ni-MH) battery. Now we usually use rechargeable Lithium-ion, Li-FePO4 and Ni-MH battery for emergency backup led lighting. 

Lithium-ion Batteries (LIB)

Lithium-ion batteries (LIB) are common in consumer electronics. They are one of the most popular types of rechargeable battery for portable electronics, with one of the best energy densities, no memory effect, and only a slow loss of charge when not in use. Beyond consumer electronics, LIBs are also growing in popularity for military, electric vehicle, and aerospace applications. Research is yielding a stream of improvements to traditional LIB technology, focusing on energy density, durability, cost, and intrinsic safety.

Comment: Very high specific energy,  limited specific power. Market share has stabilized.

EMERGENCY Lithium-ion battery for led lights

Lithium iron phosphate (LiFePO4 ) battery

The lithium iron phosphate battery (LiFePO4 battery) or LFP battery, is a type of rechargeable battery, specifically a lithium-ion battery, using LiFeP4 as the cathode material, and a graphitic carbon electrode with a metallic backing as the anode. The LiFePO4 battery uses lithium-ion-derived chemistry and shares many advantages and disadvantages with other lithium-ion battery chemistries. However, there are significant differences. LFP chemistry offers a longer cycle life than other lithium-ion approaches.

Comment: Flat discharge voltage, high power low capacity, very safe and elevated self-discharge.

Emergency Li-Fe PO4 battery for led Wallpack light

Nickel–Metal Hydride (Ni-MH) batteries

A nickel–metal hydride cell, abbreviated NiMH or Ni-MH, is a type of rechargeable battery. It is very similar to the nickel-cadmium cell (Ni-Cd). NiMH uses positive electrodes of nickel oxyhydroxide (Ni-OOH), like the Ni-Cd, but the negative electrode uses a hydrogen-absorbing alloy instead of cadmium. A NiMH battery can have two to three times the capacity of an equivalent size Ni-Cd, and their energy density approaches that of a lithium-ion cell.

Comment: Has higher capacity, less maintenance. 

Emergency Ni-MH battery for led CANOPY light

Emergency Battery Comparison 

BatteryLithium-ionLi-Fe P04Ni-MH
Specific Energy150–200Wh/kg90–120Wh/kg60–120Wh/kg
Volume ComparisonSmallBigBig
Weight ComparisonLightHeavyHeavy
CostCheapExpensiveExpensive
Cycle Durability400-1200 cycles1000-2000 cycles>500 cycles

How to choose Emergency battery for led lighting?

From the above descriptions, we know the difference between these batteries. So next we here recommend a simple method to choose a suitable battery for our emergency backup led lighting step by step.

1. UL 924 Listed Emergency battery 

As you shop around online for emergency lights, you might notice that certain products are proudly advertised as either UL Listed or meets all UL 924 guidelines. This is not merely filler content being added to spruce up the product and sound technical. To be a UL Emergency Light is to meet or exceed the high standards set forth by the Underwriter’s Laboratories (UL), the most trusted not-for-profit testing and compliance agency in North America.  All  the emergency lighting led fixtures Lightide made passed UL924.

UL_Logo

2. Emergency battery type choice

Firstly, Existing battery-operated emergency lights shall be use only reliable types of rechargeable batteries provided with suitable facilities for maintaining them in properly charged condition. Batteries used in such emergency lighing or units shall be approved for their intended use and shall comply with NFPA 70.

Please check the circumstance temperature of the battery. If it is used for emergency backup led lighting below room temperature 35ºC,  Lithium battery should be the best option. If the room temperature is 45~55 oC, we also may choose Li-Fe PO4 battery.  When the room temperature is more than 55 oC, a Ni-MH battery should be a better choice..

NFPA 101 Compliant

3. Decide Emergency Time 

As per NFPA 101, emergency illumination shall be provided for a minimum of 1½ hours in the event of failure of normal lighting.  Of course, it also can be up to the customer’ requirement.  Lightide’ DLC QPL emergency led canopy lights, the emergency work time is 1.5 hrs (90 minutes) at least to 3 hrs (180 minutes).

Battery-backup-90-minutes

4. Emergency Power

Based on NFPA101, emergency lighting facilities shall be arranged to provide initial illumination that is not less than an average of 1 ft-candle (10.8 lux) and, at any point, not less than 0.1 ft-candle (1.1 lux), measured along the path of egress at floor level. The maximum-to-minimum illumination shall not exceed a ratio of 40 to 1.

So we may decide the emergency power value based on the fixtures qty and installed height. You may review led high bay light is 150 watts with 15~30 watts emergency power backup.  

led-garage-canpy-emergency-light

Periodic Testing and Maintenance of Emergency backup LED Lighting

Testing of required emergency lighting systems shall be permitted to be conducted as follows. Lightide usually will install a push button switch on the surface of emergency fixture for testing.

(1) Self-testing/self-diagnostic emergency battery-operated emergency lighting equipment shall be provided.
(2) Not less than once every 30 days, self-testing/self-diagnostic battery-operated emergency lighting equipment shall automatically perform a test with a duration of a minimum 30 seconds and a diagnostic routine.
(3) Self-testing/self-diagnostic battery-operated emergency lighting equipment shall indicate failures by a status indicator.
(4) A visual inspection shall be performed at internvals not exceeding 30 days.
(5) Functional testing shall be conducted annually for a minimum of 1½ hours.
(6) Self-testing/self-diagnostic battery-operated emergency lighting equipment shall be fully operational for the duration of the 1½-hour test.
(7) Written records of visual inspections and test shall be kept by the owner for inspection by the authority having jurisdiction.

Please contact us for more detail. 

 

Lightide Manufactory Co., Ltd. 

2020-02 updated

Any questions, please tell us. We would like to help you.