Battery is an integral part of solar power systems. A good battery helps to store the energy for a long time that is produced by the solar panel. It can provide constant and uninterrupted level of power throughout the night. As many people are becoming aware of the benefits of utilizing solar energy, there are a few things to know which will allow them to get most out of their purchase. Although the parts of solar power system are not complicated to understand, since there are varieties of options available in the market, knowing the differences and advantages/disadvantages of every type will help you to choose the best one. In this blog, we will learn about different types of batteries used for solar power storage.
Types of batteries:
As discussed, there are various types of batteries available; hence, it becomes important to learn the specifics of at least the common ones so that customers do not end up spending for a battery which actually does not match their situation or needs.
Lead Acid Batteries: Known to be the first rechargeable battery which is a best option for different situations. They can be charged fast, have an extended life cycle with highest capacity and relatively less wastage of energy. However, if any form of conductor is put in their terminals, they can discharge the stored energy very quickly.
Lithium Ion Batteries: Lithium Ion Batteries have gained similar popularity as Lead acid Battery. Li-Ion batteries need low maintenance and has low self-discharge rate. It can outperform other types of batteries due to high energy density and long cycle life of lithium phosphate batteries. Li-Ion batteries have become the best option for storing solar energy compared to other types of batteries.
Absorbed Glass Mat (AGM) Batteries: This is another type of battery which became popular in the late 1980s as a sealed lead acid battery. The sulphuric acid is absorbed by a very fine fiberglass mat, making the battery spill-proof. AGM batteries can work very well in a low temperature and it has a low self-discharge. One of the main advantages of using this type of battery is that they are capable of delivering high currents on demand, it has low internal resistance, a long life expectancy, even when deep cycled and it can get charged 5 times faster than with flooded technology.
Gel Cell Batteries: Gel Cell Batteries have similar advantages compared to flooded lead acid batteries as it is easier to transport, but the only drawback is the gelled electrolyte in this type of battery is very viscous. Gel Cell batteries are extremely robust, versatile and they are safe to be installed in places even where ventilation is limited.
Nickel based batteries: Nickel based batteries, also known as Nickel Cadmium, Nickel hydride and Nickel Iron Batteries are used in AA and AAA sizes. Some of the specific types of these batteries are made for storing more energy, but compared to Li-Ion or lead acid batteries, Nickel based batteries have some disadvantages which is making them a less popular option for solar storage. They have lower cycle life, high self-discharge rate, lower energy density and memory effect of NiCad battery.
LiFePO4 (Lithium Phosphate) Batteries: This most advanced variant of lithium-ion battery is based on premium battery technology. They are well known to withstand extreme weather conditions and since they are very compact in size, we do not require large solar panels to run it. Safety and reliability are guaranteed because of the high-quality cells used to manufacture these batteries. Charging happens at a faster rate and with LiFePO4 batteries, solar lights can sustain their brightness for a longer time even when the charge is less.
Factors to consider when buying a battery for solar panels:
When buying a battery for solar panel, it is necessary to consider 3 points to make sure that you are actually buying the right product according to your needs.
Storage capacity of a solar battery: Calculating the capacity of the battery is necessary to know how much storage capacity will be required for your home to run the solar appliances. To understand this, you should multiply the volts (V) x the amp hours (storage capacity) and divide by 100. The result will tell you how many hours a fully charged battery can store the energy.
Life expectancy: Life expectancy of a solar battery plays a very important role. The efficiency of a battery depends on the number of life cycle, meaning the number of times the battery can be charged and discharged before it stops working. Like every battery when it loses 20% of the original capacity, it will slowly reduce the working capability and become inefficient.
Appropriate charge controller: A charger controller is an important part in any solar energy system with batteries. The controller helps in controlling the speed at which the batteries are charged and protects them from overcharging and getting damaged.
Traditional solar street lights majorly use lead acid batteries to store the converted solar energy, but modern solar street lights prefer to have either lithium ion or LiFePO4 (lithium iron phosphate) batteries due to their multiple advantages. Because of their lightweight nature, lithium batteries are proven to be the right choice for solar street lights that can be installed on poles or attached to walls. These compact batteries are integrated and consolidated into the solar street light designs now, making the installation and maintenance uncomplicated.
Both lithium ion as well as LiFePO4 batteries charge faster and have good storage capacity. This stored energy can help to illuminate the lights during overcast weather days where the panels do not receive sufficient sunlight to charge the batteries. Lithium batteries have a longer lifespan and can be easily replaced in case of any damage. A good battery with excellent durability and backup capability can directly influence the total life of a solar street light unit.