How Long Do Solar Batteries Last? What Factors Influence Their Lifespan?

Solar batteries store extra energy generated by solar panels for future use to ensure a continuous power supply during non-sunshine hours. They provide consistent backup power during outages and enhance energy independence, thereby reducing the reliance on the grid. Solar batteries can last between 5 and 25 years depending on various factors such as type, uses, environment, etc.

Understanding the lifespan of solar batteries helps you to plan for maintenance, and replacements to ensure the long-term efficiency and reliability of the solar power systems. To learn the proper methods of how to extend the solar battery’s lifespan, it is important to gain knowledge about the influencing factors such as usage, depth of discharge, types, environmental conditions, and maintenance.

How Long Do Solar Batteries Last? (Average Lifespan of Solar Batteries)

The average lifespan of a solar battery is between 5 and 25 years, which varies according to the type and usage patterns.

In comparison, solar panel systems have longevity between 25 and 30 years with a lower degradation rate of 0.5% to 1%. As a result, solar batteries do not have a longer life than solar panels since they degrade faster.

Factors Influencing Lifespan of Solar Batteries

Solar Batteries are determined by certain factors such as the usage, depth of discharge, different types, environment, and maintenance:

Battery Usage

There are higher chances of the batteries to degrade at a faster rate at a certain time if you use your solar power system more frequently every day. This is due to the heavy dependence on the solar energy systems.

Depth Of Discharge

Depth of Discharge (DoD) is a metric that represents the amount of energy drained from the battery before its next recharge. You need to keep in mind that deeper DoD results in a shorter lifespan of the battery. For example, a 100 Ah lithium-ion battery capacity has 60% DoD if 60 Ah is discharged.

DoD is important to maintain the battery’s health for the following reasons:

• Long life of a battery: Lower DoD means less stress and a lower degradation rate since it is important for maintaining the battery’s longevity.
• Cycle Life: The term “Cycle Life” refers to the number of times a battery has charged and discharged before its performance starts declining. A majority of manufacturers specify cycle life as a part of the product specifications to ensure checking this factor while buying a new solar battery.
• Performance: The battery performance is optimal only by ensuring the proper management of DoD, which helps to maintain efficiency and increase the battery’s lifespan.

Different types of batteries have fluctuating depths of discharge capacity and cycle life. For instance, lead-acid batteries have lower DoDs than Lithium-ion Batteries and are more likely to last longer with more cycles than other variants.

Exceeding the recommended DoD impacts solar battery’s lifespan in the following ways:

• Accelerated Degradation: Higher DoD can lead to faster wear and tear, thereby reducing the cycle life of a battery and its longer lifespan.
• Minimized Efficiency: Frequent discharges at a deeper level can reduce efficiency over a certain time.
• Manufacturer Recommendations: Several battery manufacturers recommended a specific DoD for the battery’s optimal performance. For instance, if a battery manufacturer recommends 60% DoD for a 10 kWh battery, you shouldn’t use more than 6 kWh. Avoiding these recommendations can lead to failure in solar batteries at an early stage.

Various Types of Solar Battery

Different types of solar batteries have differing lifespans. For instance, Lithium-ion batteries are the most commonly used solar battery type and have a lifespan of up to 15 years.

Lead-acid batteries have a shorter lifespan that lasts between 3 and 7 years, whereas flow batteries last more than 20 years.

These are the technological characteristics contributing to important differences in the lifespan between these battery types:

• Cycling Availability: Lithium-ion batteries have an outstanding cycle life of upto 5,000 cycles, whereas lead-acid batteries have a cycle life of 300 to 500 cycles. However, flow batteries have unlimited battery cycle life due to the lack of phase-to-phase chemical reactions, which means that the lifespan is longer with the avoidance of any degrading materials.
• Depth of Discharge (DoD): Lithium-ion batteries can resist longer discharges without undergoing any damage, while lead-acid batteries can perform at their best level when withstanding low-level discharges. Flow batteries are not affected by the depth of discharge, which makes them suitable for various applications.
• Temperature Sensitivity: Lead acid batteries are highly sensitive to extreme temperatures to increase their lifespan. In comparison, lithium-ion batteries can deliver their best performance when operating at a higher temperature range.

Despite a shorter lifespan, Lithium-ion batteries are preferred over flow batteries due to the following reasons:

• Increased Density: The lithium-ion batteries can store additional energy in a small space, thereby making them a perfect choice for portable electronic devices.
• Efficiency: The energy loss is minimized due to higher charging and discharging cycles.
• Advanced Technology: Highly advanced research and growth have made these types of batteries long-lasting and available in a budget-friendly price range.

The Environment

Higher temperatures boost chemical reactions inside the battery which increases the solar battery’s performance and storage capacity. This leads to the faster degradation of battery components, reducing its overall lifespan. Whereas, colder temperatures can increase the internal resistance of the battery, and it becomes challenging for charging which results in lower battery capacity and efficiency.

It is important to be aware of the charging temperatures that a solar battery can withstand. Certain types of solar batteries are more sensitive to temperature variations when compared to other variants such as:

• Lithium-ion batteries can be charged from 32 °F to 113 °F and discharged from –4 °F to 140 °F, having high sensitivity to temperature changes.
• Lead-acid batteries get affected by huge changes in temperature and the charging and discharging are allowed from -4 °F to 122 °F.
• Lithium Iron Phosphate (LFP) Batteries are highly stable and less sensitive to temperature changes when compared to lithium-ion batteries.

The optimal storage conditions for different types of solar batteries include:

• Lithium-ion Batteries: Stored in a cool and dry place away from sunlight and other heat sources at a temperature of 15ºC to 20ºC.
• Lead Acid Batteries: Reserved in a well-ventilated area at a temperature of 15ºC to 20ºC.
• Lithium Iron Phosphate (LFP) Batteries: Stored in places to avoid the buildup of gas at a temperature of 20ºC to 25ºC.
• Flow Batteries: Stored and operated in a controlled environment with minimum fluctuations in temperature allowed between 10ºC and 40ºC.

Maintenance

Proper maintenance is essential for solar batteries to ensure longevity and performance, and here are the best practices to be followed:

1. Frequent inspection and cleaning: You need to clean your solar battery regularly to avoid the accumulation of dirt and debris.

2. Prevent corrosion: During regular cleaning, check for corrosion on the terminals, which is a frequent problem that can cause performance losses.

3. Check tight connections: Since loose connections can cause inefficiencies in your system, it is important to regularly check and tighten the wirings to prevent performance losses.

4. Charge Level Monitoring: For a standalone solar battery system, ensure a full charge every three weeks once to maintain its health and maximize its longevity. Modern solar power systems have monitoring software to indicate if a battery is 100% charged. Also, avoid overcharging and discharging, which can damage the battery.

5. Coating Metal Components: It is essential to protect the metal components from corrosive elements by applying a sealant or grease only on the metal parts to resist high temperatures.

Modern technology can assist in monitoring the battery performance and health in the following ways:

1. Solar Monitoring Systems presents real-time analytics related to solar energy generation and battery operation. The few best modules include Enphase Enlighten, SunPower Monitoring, mySolarEdge, and the Tesla app.

2. Battery Management Systems (BMS) are essential to keep track of and control battery performance which includes sensors, controllers, and communication components such as voltage, current, temperature, and the amount of charge. The system processes the input of the battery it receives into an algorithm that predicts possible problems in advance.

3. Web and app-based platform services are offered by several solar monitoring systems to allow tracking of their system and receiving alerts and notifications about performance and technical issues.

How Can You Extend a Solar Battery’s Life Span?

These are the basic ways how homeowners can extend a solar battery’s lifespan to ensure its efficient operation for possible longer periods:

1. Determine the number of batteries required: It is important to minimize the number of batteries in the bank. The increased batteries equals more connections and each connection enhances resistance, which can cause unbalanced charging. If possible limit your bank upto 16 batteries or less.

2. Use larger interconnecting cables: You need to use larger battery interconnecting cables, that reduce power loss and facilitate even charging. For a 12V and 24V system, it is recommended to use a 4/0 cable and a 2/0 cable for a 48V system.

3. Limit the Depth of Discharge (DoD): Avoid your batting from getting discharged completely. For example, lead acid batteries have 50% DoD, and lithium-ion batteries upto 80%.

4. Temperature Control: Place your battery in such an environment where the temperature is controlled. In other words, store a battery at dry places with neutral temperatures.

5. Proper Size of Battery Bank: Ensure that your battery bank is properly sized according to your energy needs. If the battery bank is undersized, it leads to frequent discharges at a deeper level, thereby reducing your battery’s capacity to last.

6. Use distilled water for cleaning: It is recommended to use distilled water to clean the battery. However, to remove corrosion completely from the battery terminals, you should mix baking soda and distilled water to obtain the best results. Although corrosion is a natural process, it is important to clean your battery terminals every four to six months for long-lasting performance.