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, saving you more money, reducing your carbon footprint still further, and ensuring you are in charge of how you power your home without having to rely too much on the national grid. Ultimately, they’re a huge asset to your solar panel system.
As solar storage maximises output of clean, renewable energy, it further reduces reliance on national grid electricity. 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. That’s right, you can retrofit a solar battery if you didn’t opt for one when you initially invested in panels.
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? Does a solar battery’s longevity make it a worthwhile investment?
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 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, but it gives you flexibility too. When your panels aren’t producing enough electricity to meet your needs, you can then switch to mains electricity seamlessly to ensure you’re still able to stay powered up at home. This is also beneficial in the event of a power outage, as you have the ability to switch between the two here as well.
Solar panels only generate electricity during daylight. This is when homes typically need less power because the occupants aren’t at home. Without battery storage, this energy would automatically be diverted back to the grid and wasted.
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.
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Solar Battery Costs And Lifespan
When you’re considering investing in a solar battery, your thoughts will turn at some point to how long it might last. A solar battery is rarely, if ever, a one-off purchase as it’s unlikely to last much longer than half the life expectancy of your solar panels – meaning you’ll probably need at least two during your solar system’s life, if not more depending on the quality of the battery and type you opt for.
Lifespan varies widely according to the solar battery’s type – usually from 5 to 15 years. This compares with the typical 25 to 30-year lifespan of solar panels.
Modern solar batteries cost around £3,500 to £10,000, depending on the size required for your solar panel system and its specs. However, solar panel storage as part of a home solar system typically saves around £800 a year on energy costs, meaning they could potentially pay for themselves during their lifespan.
Solar battery longevity is gradually increasing alongside advances in battery technology (including improvements in depth of discharge) and extended solar battery warranties.
What Determines Solar Battery Lifespan?
Various factors influence the longevity of a solar battery. These include:
- Battery usage and energy storage.
- 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 overtime.
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 systems will notice a dip in performance, eventually to the point where it can no longer store and release enough energy to meet energy needs or provide backup power reliably.
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.
The more a solar battery is used, the shorter the lifespan of a solar battery, it’s as simple as that.
Depth of Discharge
Depth of discharge (DoD) refers to the maximum amount of battery capacity that can be used without risking damage to the battery from a full discharge.
The percentage of energy the battery releases affects how long solar batteries last. With most solar batteries, depth of discharge and battery cycle life are linked together closely, and a longer lifespan is linked to a better depth of discharge.
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 is 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, battery systems achieving 100% depth of discharge are becoming increasingly more common, meaning they only need ‘refilling’ with solar electricity, if you like, when the battery is completely empty, yet this may still not be the most efficient use of your battery.
Battery Type and Lifespan
The most common battery type available for solar batteries today tends to be lithium ion batteries. They’re the most efficient, have the best lifespan and depth of discharge, and most top solar battery manufacturers are opting for this today, so they’re more easily accessible.
However, it’s worth noting that lithium ion batteries cost more than what was once the industry standard – lead acid batteries – but prices are coming down continuously as more and more customers invest in this technology over lead acid options.
A lead acid battery was once the most popular option simply because it was the most readily available and affordable. As the prices of their better-performing lithium ion counterparts continue to fall, lead acid batteries are mostly seen as budget options that won’t perform exceptionally, but will certainly do the job.
It’s also worth mentioning that an emerging battery type is something that many solar battery manufacturers are looking into, but isn’t yet readily available: saltwater batteries. Saltwater batteries are known for their potentially longer lifespans, reduced fire risk, and more easily recycled components, but they are currently prohibitively expensive for many households as lithium ion batteries remain the most cost effective option when you consider its lifespan, initial cost, and savings.
Generally, when looking for a long lifespan solar battery, you ought to consider lithium ion batteries.
How long do solar batteries last?
Lithium-ion batteries (typically lithium iron phosphate) are the most common type of solar batteries installed by homeowners and businesses today. They are lightweight and longer lasting, with a lithium ion battery typically lasting around 10 to 15 years – around half the average lifespan of solar panels and twice as long as its biggest rival, the lead-acid battery.
Lead-acid batteries, with a typical lifespan of 3 to 7 years, also tend to need more extensive maintenance. Other types of solar batteries include nickel-based batteries and flow batteries, but neither are commonly used with domestic solar panels.
Saltwater batteries fall somewhere between the two currently in terms of lifespan, lasting around 7-10 years on average, but as tech develops many experts are predicting that a saltwater solar battery could last 15+ years comfortably – but it isn’t there yet.
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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 extend your solar battery’s lifespan. These include:
- Installing your battery in the right location.
- Battery maintenance.
- Ensuring correct battery charge and discharge.
Battery Location
Batteries exposed to extremely high temperatures may overheat, which shortens its lifetime. Very cold temperatures also negatively impact how long a solar battery lasts because it has to work harder and at a higher voltage to charge. A solar battery will last longer in an environment that can be regulated for temperature.
The best 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 under-stairs cupboard or utility room for convenience. A loft or a garage can also be a suitable location to avoid extreme heat or cold.
Batteries need good ventilation, wherever they’re installed. This helps them run smoothly and lessens the risk of overheating and affecting the battery’s health.
If you install a solar battery outside your home, it needs to be protected from rain, moisture and wind. Be careful if outside solar batteries are to be part of off grid energy systems, though, as extreme weather can seriously affect their performance and you might be left without power at all.
Maintenance of Solar Batteries
Regular maintenance ensures peak performance of residential solar batteries, extends its life, and avoids costly repairs. Looking after your battery includes:
- Regular cleaning to remove dust and debris (especially if installed outside).
- 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. Lithium ion solar batteries, for instance, require little or no maintenance. Other battery types will benefit from an annual inspection by a professional.
Corrosion can be a major concern with lead acid batteries. 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 – unless the DoD is 100%.
When only some of the stored electricity is used, the solar battery lasts longer and performs better. Battery manufacturers specify the correct depth of discharge to avoid extracting full battery capacity – be mindful of this when using your solar battery.
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 as a major part of your solar power system. |
| 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 additional 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 a 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 being 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, whereas a solar battery costs substantially more.
This makes sense, however, as solar batteries are an optional extra to a solar system, whereas solar inverters are necessary in every setup.
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 and allowing you to make efficient use of excess solar energy being produced.
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, meaning you’ll get the most from your system.
Get in touch for a free quote.
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