What Type of Battery Is Used in A Solar-powered Street Light?

When transitioning to a solar streetlight system, a common concern among users pertains to the selection of an appropriate battery type. Users seek a battery that offers cost savings, longevity, and minimal maintenance requirements. Given the plethora of options available in the market, navigating through technical specifications can be challenging. Therefore, it is crucial to gain a comprehensive understanding of the various battery types, their specifications, and their intended applications before making an informed decision.

Notably, all batteries do not offer the same level of performance, and some pose operational hazards. It is essential to familiarize oneself with the available battery types in the market and acquire a clear understanding of their specifications and operational profiles.

Lead Acid Battery:

Many people choose this battery due to its affordability compared to other types. However, it has some drawbacks compared to Li-ion and LiFEPO4. It requires frequent maintenance, has a high risk of explosion, and poses environmental concerns due to the presence of lead. The battery's lifespan is typically between 3 to 4 years.

Another significant disadvantage of the lead-acid battery is that it requires a larger solar panel for charging. The solar panel needs to generate at least 12V to charge the battery. The battery's size requirement for solar light applications is not cost-effective, making them costly to manufacture and defeating the purpose of using inexpensive solar lights.

Lithium-ion (Li-ion) battery

The lithium-ion (Li-ion) battery is a compact and relatively expensive power source that requires 3.7 V for charging. This means that a smaller solar panel size is needed. The solar panel can still produce 3 V and charge the battery even on cloudy days. The battery has a life cycle of 4-5 years and requires no maintenance. However, it is not suitable for extreme weather conditions.

One specific type of lithium-ion battery is the ternary lithium-ion battery, which uses Ni-Co lithium manganate as the positive electrode and graphite as the negative electrode material. The battery operates at a 3.7V voltage platform, and its cycle life typically ranges from 500 to 800 charge cycles, depending on the manufacturer, model, and processes used. Below is an image of a ternary lithium-ion battery pack.

Lithium Iron Phosphate Battery:

The LiFePO4 battery is compact and more expensive compared to lead-acid and Li-ion batteries. It is one of the most advanced battery types available in the market. It requires 3.2V of power for charging, which means the required solar panel size will be smaller.