Emergency, How to Light

How to Light: How often should I change emergency lighting batteries?

How often should I change emergency lighting batteries? 

This question has been answered by Jonathan Bell – commercial director of Liteplan 

In short, emergency lighting batteries should be changed when they no longer reach their rated duration. Whether you have standalone emergency, or a more sophisticated self-testing system, full duration tests are only carried out once a year. There is therefore a danger that the capacity of the batteries will fall below the required three hours (UK) in between these test dates, so this is a very sensible question.

BS EN 5266-1:2016 recommends that in all cases, the manufacturer’s instructions should be followed, so it is best to check what they recommend for their particular products. Also, it is extremely important that the correct battery type is used with the control gear that will be charging it. In other words, each battery is charged differently. Therefore, replacing an NiCd battery with an NiMH version for example, can cause major problems and the batteries may not last for more than a year following the change. The control gear will show what battery should be used.

Another point to consider is the temperature of the battery in question. There are four main types of battery used in emergency lighting. They vary in upper temperature tolerance and their life will be dramatically affected following long excursions over these rated temperatures. The typical temperature tolerances for each chemistry are as follows:

Valve Regulated Lead Acid (VRLA) – Rated up to 25°C

Nickel Metal Hydride (NiMH) – Rated up to 50°C

Nickel Cadmium (NiCd) – Rated up to 55°C

Lithium Iron Phosphate (LiFePO4)  – Rated up to 60°C

Emergency lighting batteries should have a minimum design life of four years, however in some cases, they will last well beyond this. Some of the more cautious facilities companies, when dealing with sensitive buildings, will change batteries every four years. This can be a waste as in some cases they will last double this period. I therefore refer back to the statement that batteries should be changed when they no longer reach their rated duration. The manufacturer of the emergency control gear/batteries will be able to provide you with information on their expected lifetime.  

As technology moves forward, we are finding more and more companies using LiFePO4 batteries for emergency lighting. Not only do they consume far less power, but tests have shown that they can last up to double the life of traditional types, which will save you a lot of effort.


  • The Emergency Lighting Conference will return to the Escape Zone at LuxLive 2018 this November 14th & 15th. As well as offering a run through of current obligations to ensure compliance with emergency lighting standards, the conference will also examine the common pitfalls that can often put you in breach of emergency lighting and fire regulations. You can find out more and register to attend by clicking HERE.