How long do solar batteries last – 3 decisive factors

The run time and lifespan of solar batteries determine the effectiveness and sustainability of solar power systems. The answer to how long do solar batteries last can be broken down into two parts: battery run time and battery lifespan.

The run time of a solar battery determines how long it can provide power to devices or appliances without needing to be recharged, while the lifespan determines how long the battery can function efficiently and reliably.

In this article, we will explain the calculation for how long do fully charge solar batteries last, the lifespan of solar battery and how to extend the run time and lifespan.

The main factors determine how long solar batteries last

The run time refers to the duration for which the solar battery can provide power to the connected devices or appliances without needing a recharge.

To ensure a constant and stable supply during emergency, there are 3 main factors that affect the duration of solar battery should be taken in account before the purchase.

Battery Capacity

Battery capacity refers to the amount of electrical charge that a battery can store and deliver to a device or system. It is typically measured in ampere-hours (Ah) or milliampere-hours (mAh), and represents the amount of current that can be drawn from the battery over a specified period of time.

Battery capacity is an important factor when choosing a battery for a particular application, as it determines how long the battery will last before it needs to be recharged or replaced.

Here is an article about how to estimate how long a solar battery will last based on a fix battery’s capacity: How long will a 200ah battery last – amp hours explained

Type of battery and Depth of discharge

The depth of discharge (DOD%) refers to the amount of energy that has been drained from a battery compared to its maximum capacity，which determines how many energy in the battery is usable and the run time.

Different battery types have different recommended maximum depths of discharge. For example, lead-acid batteries can typically be discharged to a maximum of 50%, while lithium-ion batteries can typically be discharged to 80% or more.

Overall power consumption

The overall power consumption of a solar battery system is also a crucial factor in the length of running time of solar battery.

A system with high power consumption will drain the battery faster, shortening its running duration. Therefore, it's essential to ensure that the system's power consumption is within the battery's capacity.

To more accurately calculate the total power consumed by the system and how long the battery, the inverter no-load power and inverter efficiency should also be included:

Overall Power Consumption = Power required by load / Efficiency of inverter + No-load power consumption of an inverter
Power consumption of loads = Loads voltage x Loads current / Efficiency of inverter

Formula of how long will a solar battery last

To calculate how long a solar battery will last, we use the following formulas:

Battery Power Capacity (Wh) = Battery Capacity (Ah) x Battery Voltage (V) x DOD%
Power consumption of loads = Loads voltage x Loads current / Efficiency of inverter
Battery run time = Battery capacity (Wh) / System power consumption (W)

How to extend the run time of a solar battery

Use battery-saving mode

A properly designed solar system can help you charge the battery faster and more efficiently. As the brain of the solar system, an inverter charger not only can regulate the charging current and voltage, prevent overcharging and undercharging, but also store excess solar energy during the day and use it at night.

Set the working mode of the inverter and the power supply priority of the solar system, you can avoid the point of the battery being consumed prematurely, thus extending the working time of the battery and leaving the power in the use of the power supply is not sufficient.

Use energy-efficient appliances

Using energy-efficient appliances can help you reduce your energy consumption and extend the runtime of your battery on a charge. This can include using LED lights instead of traditional bulbs, turning off appliances when not in use, and using appliances with a low energy rating.

Improve the efficiency of the solar panels

Proper placement of solar panels is critical to getting the most out of them. Make sure that they are placed in a spot where they receive maximum sunlight throughout the day. Using high-efficiency solar panels can help you generate more power from the same amount of sunlight. This can help you charge your battery faster and extend its runtime.

What is life expectancy of a solar battery

The life expectancy of a solar battery depends on several factors such as the type of battery, how often it's used and how well it's maintained. Generally speaking, the life expectancy of a solar battery can range from 5 to 15 years.

Lead-acid batteries are a common type of solar battery and typically have a lifespan of 5-10 years. Lithium-ion batteries, on the other hand, are becoming more popular due to their longer lifespan of 10-15 years.

Ultimately, the life expectancy of a solar battery will depend on the specific circumstances of its usage and maintenance.

Factors that affect solar battery lifespan

There are several factors that can affect the lifespan of a solar battery. Here are some of the most significant ones:

How to maintain a solar battery and increase its lifespan

Here we provide you 8 tips for maintaining solar batteries and extending their lifespan.

Avoid overcharging or undercharging the batteries

Storing a battery at full charge or complete discharge for an extended period can damage the battery and reduce its lifespan. The ideal level for storage is around 50% charge. In this case, battery management system can save you some time watching the battery level.

Regularly check battery water levels and use only distilled water

It is important to regularly check the water level in flooded lead-acid batteries and top them up with distilled water as necessary. This helps to prevent the battery plates from becoming exposed and damaged, which can shorten their lifespan.

Avoid extreme the temperature of the batteries

Keeping the batteries at a moderate temperature range of between 20-25°C is recommended. This can be achieved by installing them in a well-ventilated area, away from direct sunlight or other heat sources.

Use the right charger

Always use the charger recommended by the manufacturer for your specific device. Different devices have different charging requirements, and using the wrong charger can result in overcharging or undercharging.

Restrict battery count

Reduce the battery count in the bank. More batteries mean more connections, leading to increased resistance, resulting in uneven charging. Limit the bank to 16 batteries or fewer, if possible.

Use a surge protector

Protect your device and battery from damage due to power surges by using a surge protector.

Equalize the batteries periodically

Equalization is a beneficial method to overcharge batteries in a controlled manner. As batteries' individual cells can be inconsistently charged during normal cycling, sulfation may accumulate on the plates. Equalization returns all cells to full charge, removing sulfation through gassing, which also stirs the electrolyte to prevent stratification. Check your battery manufacturer's instructions and your inverter or charge controller manual for equalization guidance.

Remove sulfation buildup on the battery plates

A battery desulfator can help extend the lifespan of a battery by removing sulfation buildup on the battery plates. Sulfation is a common cause of battery failure, and using a desulfator can help prevent it, resulting in a longer battery lifespan.

Allow gassing or boiling

Gassing or "boiling" is a necessary part of proper battery charging and should occur regularly, ideally daily. The process begins at around 14.1Vdc (for a 12V system), 28.2Vdc (24V), or 56.4Vdc (48V) and produces hydrogen and water. Proper ventilation is critical to prevent hydrogen buildup and potential hazards. Think Hindenburg.

By following these tips, solar power system owners can extend the lifespan of their batteries and ensure that their system continues to operate efficiently.