Article reviewed by Jesús Andrade, an electronics engineer with an MBA from ESIC. He combines 20 years’ experience developing emergency lighting and risk-prevention devices with a strong background in business management. Andrade is currently CTO at SVE Worldwide, a company specialising in industrial risk-prevention solutions.
Rechargeable batteries for cordless lamps store the energy needed to use a light without keeping it permanently connected to the mains. This can be particularly useful during a power cut.
What makes a rechargeable lamp or a light with an emergency function different from a conventional lamp? Alongside design, installation and intended use, one of the main factors shaping these characteristics is the battery.
In a rechargeable cordless lamp:
- The design needs to accommodate the battery, which can have a significant impact on the overall size of the lamp depending on its dimensions, weight and capacity.
- It is important to distinguish between a luminaire that forms part of an emergency lighting installation and a rechargeable lamp that can provide additional lighting during a power cut. The former is designed to switch on automatically when the mains supply fails and, when it forms part of a regulated installation, must meet specific requirements. The latter is normally charged from the mains and can then be used without remaining connected to it.
- In terms of everyday use, a battery powered lamp can be moved between different locations because it does not need to remain permanently connected to the mains to provide light.
The battery therefore influences many of the characteristics of a lamp, but what types of batteries are available, and which are most commonly used in rechargeable lamps for the home?
Contents
Types of rechargeable batteries for cordless lamps
What batteries do we use in LILAK rechargeable cordless lamps?
Frequently asked questions about rechargeable batteries for battery-powered lamps
Conclusion: choose a battery based on its application
What is a battery?
An electrical battery is a device made up of one or more electrochemical cells. It stores energy in chemical form and converts it into electrical energy when it discharges. In rechargeable batteries, this process can be reversed by connecting the battery to a suitable power source.
Batteries are used in a huge range of applications, from wristwatches and mobile phones to vehicles and energy storage systems. We use countless battery-powered devices in our everyday lives, and lighting is no exception.
Types of rechargeable batteries for cordless lamps
There are many different types of battery available today. One of the main differences between them is their chemical composition, which affects characteristics such as voltage, the amount of energy they can store, weight, lifespan and charging speed.
Battery technology is constantly evolving. Although some technologies have been in use for decades, improvements in materials, construction and electronic protection systems continue to make them suitable for new products and applications.
There is no single battery technology that is best for every device. The right choice depends on its intended use and factors such as the required runtime, available space, weight, safety, cost and lifespan.
Here are some of the most common types.
Lead-acid batteries
Lead-acid batteries are mainly used as starter batteries in vehicles, although they are also found in other applications.
They consist of lead plates immersed in a sulphuric acid electrolyte. They are one of the oldest rechargeable battery technologies and still operate according to the same basic electrochemical principle, although their construction has evolved considerably over time.
Their advantages include relatively low cost, reliability and the ability to supply high currents. However, they are relatively heavy and store less energy in relation to their weight, so they are generally not the most suitable option for a battery powered lamp.
Nickel-metal hydride batteries
Nickel-metal hydride batteries, commonly known as NiMH batteries, are used in rechargeable cells, electronic equipment, medical devices and some hybrid vehicles.
They can withstand many charge and discharge cycles and generally cope well with regular use. However, they typically have a lower energy density and higher self-discharge rate than many lithium-ion batteries. This means they can lose some of their charge even when stored and not being used.
Lithium-ion batteries
Where are lithium-ion batteries most commonly found? If you are reading this article on a laptop or regularly use a power bank to charge your phone, there is a good chance you are already using one.
These batteries, also known as Li-ion batteries, are widely used in portable electronics because they can store a relatively large amount of energy for their weight and volume. They also offer relatively low self-discharge and a good lifespan when charged and used within the conditions specified by the manufacturer.
They are also sensitive to conditions such as overcharging, excessive discharge and unsuitable temperatures. Products containing lithium-ion batteries therefore need protection and management systems suited to the battery configuration.
In battery packs containing several cells, these functions can be handled by a battery management system, or BMS.
Lithium-polymer batteries
Lithium-polymer batteries, commonly known as LiPo batteries, belong to the lithium-ion battery family.
They are often produced in laminated formats, allowing batteries to be thin, lightweight and manufactured in a wider range of shapes and sizes. This makes them easier to integrate into mobile phones and other compact devices.
Like other lithium-ion batteries, they require suitable charging and protection systems.
Lithium iron phosphate batteries
Lithium iron phosphate batteries, known as LiFePO₄ or LFP batteries, are another type of lithium-ion battery.
They generally have a lower energy density than some other lithium chemistries used in electronic devices. This means they may require more space or be heavier to store the same amount of energy.
However, this technology is valued for its thermal stability, safety and potential for a long service life when properly integrated and managed. These characteristics can make it suitable for products where reliability and durability are more important than achieving the smallest possible size.
| Battery type | Main advantage | Main limitation | Use in cordless lamps |
| 🔋 Lead-acid | Reliable and affordable | Heavy and bulky | ❌ Less suitable for battery operated lamps |
| ♻️ Nickel-metal hydride (NiMH) | Good resistance to charge cycles | Higher self-discharge and lower energy density | ⚠️ Suitable, but less common today |
| ⚡ Lithium-ion (Li-ion) | Lightweight with high energy density | Requires suitable charging and protection systems | ✅ Widely used in portable devices |
| 📱 Lithium-polymer (LiPo) | Enables thin and compact designs | Requires appropriate protection and management | ✅ Suitable where space is limited |
| 🛡️ Lithium iron phosphate (LiFePO₄) | Stability, safety and long service life | Can take up more space and add weight | ✅ Suitable when reliability and durability are priorities |
What batteries do we use in LILAK rechargeable cordless lamps?
At LILAK, we use lithium iron phosphate batteries in our rechargeable cordless lamps with emergency functionality for the home.
Our choice is based on the balance this technology offers between stability, safety, lifespan and suitability for the requirements of the product.
Our aim is to develop efficient, reliable and durable devices. For this reason, we believe the characteristics of LiFePO₄ batteries are well suited to the intended household use of LILAK lamps.
Frequently asked questions about rechargeable batteries for battery-powered lamps
How long does the battery in a cordless lamp last?
Runtime depends on several factors, including the amount of energy the battery can store, the lamp’s power consumption, the selected brightness level, temperature and the condition of the battery itself.
For this reason, runtime can vary between different models and even when using the same lamp. In general, higher brightness settings consume more energy and provide a shorter runtime. The specific runtime should always be checked in the product specifications.
If a rechargeable lamp is going to be stored for a long period, it is also worth checking the manufacturer’s recommendations regarding the appropriate charge level and how often the battery should be recharged.
What is the best battery for a rechargeable lamp?
There is no single battery technology that is best for every rechargeable lamp.
The choice depends on the balance required between runtime, safety, weight, dimensions, lifespan and cost. A battery that works well in a small, lightweight lamp may not be the best option for another model designed to provide longer runtime or act as back-up lighting during a power cut.
Can the battery in a battery powered lamp be replaced?
Whether the battery can be replaced depends on whether the lamp has been designed to allow battery replacement.
Some products make it easier to access and replace certain components. In others, the battery is integrated into the product and should be replaced by the manufacturer or a suitable service technician.
Before attempting to replace a battery, check the product instructions to confirm whether it is designed to be replaced by the user.
Conclusion: choose a battery based on its application
Batteries store energy in chemical form and supply it as electricity when a device needs it. Today, they are used in applications as varied as vehicles, consumer electronics, portable lighting and energy storage systems.
Each application requires a battery with specific characteristics. This is why different battery technologies can be found in a car, a watch or a rechargeable lamp.
When choosing rechargeable batteries for cordless lamps, factors such as weight, available space, safety, stored energy and expected lifespan all need to be considered. It is also important for the battery, charging system and protection electronics to be properly designed to work together.
There is no single battery technology that is suitable for every lamp. The choice should reflect the intended use and the balance the manufacturer is looking to achieve between runtime, size, safety and durability.