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June 4, 2024

How Long Does a Solar Battery Last?

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Houses with solar panels

Solar batteries play a vital role in cutting energy costs. They store free electricity generated by solar panels so you can use it at the times you need it.

As solar battery storage maximises output of clean, renewable energy, it further reduces reliance on the national grid. When you use less mains electricity, you make more cost savings, while also lessening your carbon footprint.

For these reasons, many homeowners consider incorporating a battery when installing a solar panel system, while others may opt for battery storage later.

Although more affordable than solar panels, a solar battery is still a significant investment in green energy. Batteries don’t last as long as solar panels and will inevitably have to be replaced at some point, but when can you expect that to happen with your battery? 

This post explains how long you can expect your solar battery to last. We’ll also explore the advantages of solar battery storage, how you can prolong battery lifespan, and how to tell when your battery needs replacing.

Benefits of Solar Battery Storage 

Thousands of homeowners have added a battery to their solar panel system to optimise energy management and cut electricity bills by up to 90%. Surplus energy generated by solar panels is stored in the battery and distributed when needed. 

Deep-cycle solar batteries are the long-distance runners of the battery world. Most solar batteries work on a deep cycle, discharging 80% or more of stored energy before recharging is necessary.

Solar batteries hold large amounts of electricity compared with normal batteries, and they produce power that can be used over longer periods of time.

They also monitor household energy use so they know when your home needs more power than the solar panels are providing. This means less reliance on expensive mains electricity, especially at times of peak demand.

Solar panels only generate electricity during daylight. This is when homes typically need less power. Without battery storage, this energy would automatically be diverted back to the grid.

Solar batteries store this energy during the hours of daylight and release it when your household needs more power, typically during the evening. You can also use solar battery storage during a power cut.

Solar Battery Costs and Lifespan

When you’re considering investing in a solar battery, two crucial deciding factors are what it costs and how long it will last.

A solar battery is rarely if ever a one-off purchase. It’s unlikely to last much longer than half the life expectancy of your solar panels. 

Solar battery lifespan varies widely – usually from5 to 15 years. This compares with the typical 25 to 30-year lifespan of solar panels.

Solar batteries cost around £3,500 to £10,000, depending on the size of your solar panel system. However, solar panel battery storage typically saves around £800 a year on energy costs. 

Solar battery longevity is gradually increasing alongside advances in battery technology, including improvements in depth of discharge (more on this later).

What Determines Solar Battery Lifespan?

Various factors influence the longevity of a solar battery. These include: 

  • How often you use your battery. 
  • The battery’s depth of discharge.
  • Type of solar battery.

 

Battery Use

The life of a solar battery is mainly determined by its use cycles. As with laptops and mobile phones, the more a solar battery is charged and discharged, the less time the charge lasts. 

The charging and discharging process is known as the charge cycle. It measures:

  • Power input needed to top up the battery.
  • Power output before the battery is drained.

 

After a certain number of cycles, solar battery performance will have degraded to the point where it can no longer store and release enough energy.

This is inevitable and the reason solar battery life expectancy varies. For example, a battery with the standard, grid-tied solar energy system gets less use than a battery with an off-grid system. On-grid systems therefore last longer.

Depth of Discharge

Depth of discharge (DoD) refers to the maximum amount of battery capacity that can be used without risking damage from full discharge.

The percentage of energy the battery releases affects its lifespan. With most solar batteries, depth of discharge and battery cycle life are linked.

Cyclic life is the number of charge-discharge cycles a battery can sustain and depends on how much of the battery’s capacity is used.The higher the depth of discharge, the more energy you can use from the battery’s total capacity before it needs recharging.

If a battery is frequently discharged at a lower depth of discharge, it will have more useful cycles than if it’s drained to the battery’s maximum DoD.

For instance, if you have a 5kWh battery with 80% DoD, it should only discharge 4kWh before being recharged. However, batteries achieving 100% depth of discharge are becoming increasingly common.

Types of Solar Batteries

Lithium-ion batteries are the most common type of solar batteries installed by homeowners and businesses.They typically last around 10 to 12 years – around half the average lifespan of solar panels and twice as long as its closest rival, the lead-acid battery.

Lead-acid batteries, with a typical lifespan of three to seven years, also need more extensive maintenance. Other types of solar batteries include nickel-based batteries and flow batteries. Neither are commonly used with domestic solar panels.

Can I Make My Solar Battery Last Longer?

All types of batteries degrade over time, gradually storing less energy, with lower power output. However, there are ways to help make your solar battery last as long as possible. These include:

  • Installing your battery in the right location.
  • Maintaining your battery.
  • Ensuring correct battery charge and discharge.

Battery Location

A battery exposed to extremely high temperatures may overheat, which shortens its lifetime.  Very cold temperatures also negatively impact a battery because it has to work harder and at a higher voltage to charge. 

The optimal location for a solar battery is in a temperate environment – neither too hot nor too cold. This is why they’re usually installed inside a property, typically in an understairs cupboard or utility room for convenience. A loft or a garage can also be a suitable location.

Batteries need good ventilation, wherever they’re installed. This helps them run smoothly and lessens the risk of overheating.

If you install a solar battery outside your home, it needs to be protected from rain, moisture and wind. 

Battery Maintenance 

Regular maintenance ensures peak performance of a solar battery, extends its life, and avoids costly repairs. Looking after your battery includes:

  • Regular cleaning to remove dust and debris.
  • Checking your battery for signs of corrosion or physical damage.
  • Keeping the battery software updated.

 

Some types of solar batteries need more upkeep than others. A lithium-ion battery, for instance, requires little or no maintenance. Other types benefit from an annual inspection by a professional.

Corrosion can be a major concern with a lead-acid battery. Check the terminal connections regularly and remove any rust buildup.

Battery Charge and Discharge

Although a solar battery should be charged fully, in most cases it will wear out faster and have a shorter lifespan if it’s frequently discharged completely.  

When only some of the stored electricity is used, it will last longer and perform better. Battery manufacturers specify the correct depth of discharge to avoid extracting full battery capacity.

Signs Your Solar Battery Needs Replacing

If your solar battery is failing to meet your energy needs, various indications may point to the need to replace it.

Decreased Storage Capacity

A noticeable decrease in storage capacity is one of the more obvious signs your solar battery is nearing the end of its life. Repeated charge and discharge cycles over time result in battery capacity degrading. If the battery isn’t holding as much energy as it used to, even on sunny days, it’s likely time for a replacement.

Reduced Performance

Solar battery performance declines over time. The battery’s charge won’t last as long if the battery is taking longer to charge or is discharging faster than normal. If this happens, you may no longer be able to rely on your battery when you need it most.

Battery Damage

A damaged battery can pose safety risks as well as compromise your solar energy system. Signs of corrosion, leakage or bulging could mean your battery needs replacing. 

Increased Maintenance

With age, batteries become more prone to malfunction, requiring more maintenance. If components of your solar battery system need repairing or replacing frequently, the battery could be nearing the end of its lifespan. 

Outdated Technology

Solar battery technology is constantly improving. If your battery is using outdated technology, it might be time to consider upgrading to a newer model with longer lifespan, better efficiency, and more storage capacity.

How Long Do Solar Panels Last?

Photovoltaic (PV) solar panels harness energy from the sun and convert it into free electricity to power homes.

Solar panels cost on average around £7,000 and should last 25 years or longer.  But one key component of the system may need replacing after about 12 years. This is the solar inverter. 

Solar panels produce direct current (DC) electricity. A solar inverter is essential to convert this into the alternating current (AC) that’s compatible with household electrical circuits.

Solar inverter costs average around £800. As we’ve seen, replacing the solar battery costs substantially more.

Effective Home Solar Batteries

As your solar battery warranty nears expiration, it might be time to consider whether the battery is still meeting your energy needs.

Whether you need a battery upgrade or are thinking about installing a new solar panel system, solar energy specialists Effective Home can help.

We supply and install quality solar batteries with a 10-year warranty and solar panels with a 25-year warranty.

Get in touch for a free quote.

Build Your Solar Quote Today

Justine Effective
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