Which emergency light battery is best?

Emergency light batteries, as the name suggests, are batteries that provide power for emergency lighting devices. There are many types of emergency light batteries on the market, including lead-acid batteries, nickel-cadmium batteries, nickel-metal hydride batteries, lithium batteries, etc. Among these batteries, which one is the best?

When choosing products such as emergency light batteries, in addition to the quality and safety of the product, you should also consider the life cycle cost of the product, including subsequent  maintenance costs, to avoid frequent replacement in the future that consumes more manpower, material resources, and financial resources . Next, let’s talk about the characteristics of these emergency light batteries.

Lead-acid batteries are mainly used in central battery systems . This is also one of the earliest emergency lighting systems. It has certain advantages for installation sites with complex terrain, because all its accessories are connected to one power supply, and subsequent maintenance of the battery will be more convenient, but it also means that once a single point of failure occurs, it will affect the entire system; at the same time, the installation of a centralized battery system will be relatively complicated, because the connection between the battery and the lamp requires a long cable, and its cost will increase. Centralized battery systems can easily create high-temperature environments. The increase in temperature has a certain impact on the life of lead-acid batteries. The theoretical optimal temperature of lead-acid batteries is 20°C-25°C. Every time the theoretical data changes by 10°C, the lifespan will be reduced 20 %-50%, therefore the battery indoor temperature needs to be controlled through external conditions, which also means an increase in other costs.

Nickel-cadmium batteries and nickel-metal hydride batteries contain toxic heavy metals such as nickel-cadmium, which have a certain impact on the human and the environment. However, due to their small size and high energy density, they were widely used on the market.Nickel-cadmium batteries and nickel-metal hydride batteries were not gradually replaced until the appearance and development of lithium batteries.

Lithium batteries currently often used in emergency lights are ternary lithium and lithium iron phosphate cylindrical batteries. Lithium iron phosphate batteries are not only cheaper than ternary lithium batteries, but also much safer than ternary lithium batteries. For details, you can check《Why are LiFePO4 batteries safer?》. Compared with other batteries, lithium iron phosphate batteries are relatively new to the market, but they have obvious advantages in terms of stability, sustainability, and service life.

Next, let’s know the advantages of lithium iron phosphate batteries compared with alternatives such as nickel-cadmium batteries and nickel-metal hydride batteries:

1. Lithium iron phosphate batteries have a low self-discharge rate. All rechargeable batteries lose charge over time, lithium iron phosphate batteries have a monthly self-discharge rate of 2%-5%; nickel-cadmium batteries have a monthly self-discharge rate of 15%-30%; nickel-metal hydride batteries have a monthly self-discharge rate of 25 %-30%;
2. Lithium iron phosphate batteries have high charging efficiency. During the charging process of the battery, energy will be lost in the form of heat. The charging efficiency of lithium iron phosphate batteries is 95 %.When the capacity of nickel-cadmium batteries reaches 70 %, heat will be generated, and the charging efficiency will be reduced to 85 %. Emergency light batteries in use need to be continuously charged to reach 100% battery capacity , which means that the nickel-cadmium battery will continue to generate a large amount of heat.
3. Lithium iron phosphate batteries have a long life. The service life of lithium iron phosphate batteries is usually 8-10 years; the service life of nickel-cadmium batteries and nickel-metal hydride batteries is usually 3-4 years.
4. Lithium iron phosphate batteries have a wide operating temperature range. Lithium iron phosphate batteries perform well in ambient temperatures of -20°C and 60°C, while the high temperature tolerances of nickel-cadmium batteries and nickel-metal hydride batteries are 55°C and 50°C respectively , and cannot provide the electric charge required for emergency lamp illumination at ambient temperatures below 0°C.
5. Lithium iron phosphate batteries are environmentally friendly. Lithium iron phosphate batteries do not contain heavy metals and can be recycled; nickel-cadmium batteries and nickel-metal hydride batteries contain toxic heavy metals, which are more harmful to the environment and human.
6. Lithium iron phosphate batteries are the future trend. Lithium iron phosphate batteries are becoming more and more popular due to their stability, safety, economy and high efficiency. The batteries are widely used in UPS, AGV/AMR, medical equipment, starting power supplies, emergency lights, energy storage and other fields.

To sum up, emergency lights using lithium iron phosphate batteries are the safest and most cost-effective. Users can obtain maximum benefits at the lowest cost throughout the product life cycle.

As a professional emergency light battery manufacturer, you are always welcome to contact us at sales@plb.com.cn. We look forward to discussing the emergency light battery solution that is most suitable for your facility.