Batteries are the lifeline of any solar light. If the solar batteries are not working properly, it will directly affect the solar panels and the brightness of the lights. Although manufactures consider the battery lifespan as a major factor and design specifically to resist heat and cold cycles to make the solar batteries robust but within a span of time they stop working. It becomes important as an owner to know about these batteries as it will help them to get prolonged service for the price they have paid. Check if the batteries contain lithium in them as it has a lot of benefits in increasing the battery lifespan. These type of batteries are lighter and they have a higher DoD and longer lifespan when compared to lead acid batteries.
Now let us see what makes some solar batteries last longer even after having the same source of power. There are 3 factors generally which affect the lifespan of a solar battery. These are:
- Cycle life: Cycle life decides the lifespan of a solar battery. Like a gel battery can last for 500-5000 cycles, a flooded battery can last for 300-700 cycles whereas a lithium battery can reach up to 2000 cycles.
- Temperature: Solar batteries are impacted by its temperature. When we store a solar battery in a room with low temperature, it tends to decrease the capacity of the battery, but when we store it in a high temperature room, it increases its capacity. However, the battery’s life cycle will decrease gradually since chemical reactions are found to be higher in a battery when stored in high temperatures.
- Depth of Discharge: The depth of discharge (DoD) of a battery refers to the amount of a battery’s capacity that has been used. A higher DoD means we will be able to utilize more of our battery’s capacity. When we charge a battery every day, it starts degrading and slowly it loses the capacity to store energy. For example, a battery with a nominal capacity of 100 kWh at 60% DoD will have 40 kWh of charge remaining.
How to extend the lifespan of a solar battery?
Just like any other equipment, however good the quality is, one day it tends to lose the capacity if you do not maintain it properly. Below given are some points on how to maintain your solar batteries to give them an extended life:
- Minimize the number of batteries: Using more batteries will increase the connection and resistance which may lead to uneven charging, so try to control the number of batteries in the bank or limit it for up to 4 or less.
- Charge the batteries at certain intervals: If we leave solar batteries uncharged for a long time, they may get damaged; hence, it is always better to keep the charging source turn on so that the batteries charge continuously.
- Battery equalization: Uneven charging of batteries can cause sulphation on the plates and overcharging it can remove it through gassing. Battery equalization is the method of overcharging the solar batteries in a controlled manner. Modern solar batteries already use charge controllers to avoid overcharging.
- Use the right battery: Lithium batteries are the ones always recommended for a solar light. These batteries can last up to 8 years and they can even be replaced easily due to the waterproof plug and connectors.
While traditional solar street lights use lead acid batteries, modern solar street lights prefer using lithium-ion batteries or LiFePO4 batteries since they offer enhanced product life and are maintenance free. When compared to lead acid batteries, lithium batteries are more environment friendly and are way more compact and lightweight. Lithium batteries charge faster and this influences the life of the solar street light unit. Choosing the right type of solar battery and installing it in a climate-controlled environment can help in extending the life of the battery. Purchasing your solar lights from a reputed dealer can guarantee the quality of the components used.