Understanding how long solar batteries last is important when planning and budgeting for a solar system. Generally a solar battery will last about 15 to 17 years depending on the battery type, climate and usage conditions. The lifespan of a solar battery that is exposed to high temperatures or extreme usage may be reduced to 12 to 14 years. In this article we will explain what a solar battery is and how they work, factors that affect the lifespan of solar batteries and how to prolong solar battery life.
How Do Solar Batteries Work?
A solar battery is a device that interfaces with a solar panel system to store surplus energy to be used later. Solar panels convert sunlight into energy to be used in the home through solar photovoltaic panels. This energy, known as direct current (DC) electricity, is fed into the inverter to be converted to alternate current (AC) electricity which can be used in the home. This electricity can only be used when the sunlight is out and solar panels are working unless the system has a solar battery installed.
When a solar system has a solar battery added, a switchboard redirects excess energy produced by the solar panels to the battery. The energy which was converted to DC electricity is converted back to AC to be stored in the battery. The battery converts the DC to AC electricity to be used in the night time or on cloudy days when there is little to no sunlight. It is then stored there for later use when the sun is no longer shining. An AC coupled storage system will be stored on the AC side of the inverter, while a DC coupled system will be stored on the DC side.
What Factors Impact Solar Battery Lifespan?
While solar batteries may have a lifespan of about 17 years, they can also degrade quickly and only last for as little as 12 years. The discrepancy between a long and short lasting solar battery lifespan is influenced by a number of factors. These include:
How often you use the solar battery
How often a solar battery is used impacts its lifespan. When batteries are being used they charge and discharge which is the process of how they store and release energy. Solar batteries charging is when energy is stored from the solar panels and discharging is when that energy is released to the home. The charging and discharging cycle of a solar battery, known as the cycle life, significantly affects its lifespan. The more often a solar battery charges and discharges the less time the charge lasts. After a certain amount of cycles, solar batteries will not be able to store or discharge enough energy and will need to be replaced.
Solar battery type
The type of solar battery significantly impacts how long a solar battery will last as some batteries have a better charge cycle than others due to their chemistry and design. The main types of solar batteries used today are lithium ion, lead acid, flow and nickel cadmium.
- Lithium ion is the best choice of solar battery for longevity and, in good conditions, will last, commonly referred to as LFP. On average lithium ion solar batteries have about 2,000 to 10,000 charge cycles before they degrade. These batteries can hold a larger amount of energy than other solar batteries and are highly efficient.
- Lead acid batteries only have a charge cycle life of about 1,500 to 3,000 cycles, depending on environmental conditions and usage patterns. Although lead acid batteries are generally less expensive, they do have the lowest lifespan of all the solar batteries.
- Flow batteries have the largest lifespan of all the solar batteries with capacity of 10,000 to 15,000 charge cycles. However, they are not suitable for residential uses and only used in large scale applications.
- Nickel cadmium is used in some solar systems but has a very limited lifespan of only 500 to 1,000 charge and discharge cycles.
Environment
The environment a solar battery is stored in affects the lifespan. If a solar battery is stored outside and subjected to the elements, it will deteriorate quicker than a battery stored in a controlled environment. Garages and storage rooms are the typical place for solar batteries to be installed and usually provide the amount of protection from the elements they need to maintain longevity. The Ingress Protection (IP) rating grades the resistance of an enclosure to the intrusion of dust and liquids. This rating is crucial for outdoor installations where solar batteries are exposed to the elements.
Depth of discharge
Depth of discharge refers to the percentage of the battery that has been used after being fully charged. The depth of discharge has a significant impact on battery life. Higher depth of discharges in batteries lead to faster degradation, while shallower discharges extend the battery life. That is because each deep discharge cycle puts stress on the internal components of the battery which leads to reduced cycle numbers before battery replacement is required.
Maintenance
Regular maintenance is essential to keep a solar battery as efficient as possible and extend its lifespan. Maintenance and monitoring will identify any problems with the battery before they escalate. During maintenance a professional will check the battery cycles and ensure temperature management.
Installation
Solar battery installation will impact how long they last. When a solar battery is professionally installed by a solar expert, they will ensure the battery is connected properly to ensure longevity. Incorrect installation can lead to electrical hazards, system failures, and reduced efficiency, while a certified installer ensures adherence to safety regulations and maximises the solar battery lifespan.
Do Solar Batteries Have Warranties?
Most solar batteries come with a manufacturer’s warranty which promises the solar battery will work for a certain number of years, cycles, or total energy throughput. Because of their expected longevity period, different batteries will have different warranty times. A lithium ion solar battery will usually have a warranty period of about 10 years, while a lead acid solar battery may be less at just 3 to 5 years.
Typically, warranties for solar batteries cover the product warranty, cycle warranty, throughput warranty, and end of warranty capacity guarantee.
- Product warranty: This is also known as a warranty against defects and covers manufacturing faults and performance failures due to defects. Most solar battery product warranties are for 10 years.
- Cycle warranty: This covers the number of charge and discharge cycles a battery can perform. Usually solar batteries have about 6,000 cycles which is approximately 16 years of use if used once a day. Warranties usually finish when the cycle count or years are reached, whichever comes first.
- Throughput warranty: This warranty covers the total amount of energy in kWh or MWh a solar battery can process over its lifetime.
- End of warranty capacity guarantee: Most manufacturers will have a guarantee that the solar battery will retain a percentage of its original capacity by the end of the warranty period. A 70% capacity after 10 years is the most common.
There are also installation and extended warranties that can be offered by some retailers. The installation on workmanship warranty is separate from the battery and covers issues caused during installation. The extended warranty can be purchased by retailers for an extra fee. They can be good but make sure they cover more than the original warranty covers.
Signs A Solar Battery is Degrading
When a solar battery degrades it loses its ability to store and distribute energy as well. There are a number of signs to look out for to determine if your solar battery is on the decline and it might be time to consider replacement. These are:
- Reduced capacity and energy storage: A decrease in the amount of energy a battery can hold is the first sign of battery decline. If a solar battery is on full charge but drains quickly, the internal cells may be degrading. When a battery has reduced capacity like that it will struggle to convert solar energy as efficiently, resulting in shorter operating periods.
- More frequent recharging: When capacity declines, the solar battery will need to be recharged more frequently. Even on sunny days, the battery will take longer to charge and discharge quicker which is a sign of degradation.
- Decrease in performance: The solar battery does not perform as well particularly in periods of high demand, like during power outages. Often solar batteries are an excellent source of backup power supplying energy when the power is out. When the solar battery shows a marked reduction in the duration or intensity of power output during these times, it is a sign of reduced capacity and performance.
- Visible physical damage: Physical damage like cracks, or corrosion around the terminals is an obvious sign of battery degradation. Lead acid batteries may show signs of corrosion or bulging sides and lithium ion batteries can sometimes develop swelling which indicates internal pressure buildup. Regular inspections and maintenance is essential to detect any physical damage early.
How To Prolong Solar Battery Life
There are a number of ways to prolong solar battery life and get the most out of your solar battery. These are:
- Avoid deep discharges: Deep discharging is when more than 80% of a battery’s capacity is used before recharging. When you deep discharge a battery regularly, it can lead to a reduction of capacity and the ability to hold a charge. Pay attention to the manufacturer’s recommendation for the depth of discharge (doD) as each battery type will be different. A lithium ion battery might have a recommended DoD of 80% to 90% while a lead acid may be 50%. Going beyond the recommended figures will significantly shorten solar battery life.
- Temperature management: Extreme temperatures can affect solar battery life so it is important to make sure the ambient temperature where the solar battery is located is managed. Temperatures above 30°C to 35°C may cause the electrolyte in the battery to degrade faster, while temperatures below 0°C can lower battery efficiency. Provide adequate ventilation where the battery is located and regularly check the operating temperature.
- Regular maintenance: To ensure longevity, have solar batteries professionally inspected and maintained once a year. While a professional solar expert can inspect the batteries, homeowners can also do visual inspections to make sure there are no visible signs of damage and check performance periodically.
Solar batteries are an important component of a solar system, allowing you to maximise usage of your solar panels and the energy they produce. However, understanding how long a solar battery will last is essential when it comes to deciding whether to invest in a battery. In this article we have explained how long solar batteries last and what impacts solar battery lifespan. As well as choosing the right type of battery, installation and professional inspections are essential. The team at Tasmanian Safer Solar are experts in solar batteries for any further information on how long a solar battery might last.
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