What is solar battery storage & how much does it cost?

While solar battery storage is optional, it’s a wise investment if you want to be able to store your solar panel’s excess energy once the sun goes down. It’s not a particularly expensive addition to a solar energy system and its inclusion can save you money in the long run and even give you the ability to sell excess energy back to the grid.

What is a solar battery?

Solar batteries connect to your solar panel system and store any excess energy that you haven’t used, keeping you online even when the grid is down. If you install a solar energy system without a battery, you’ll have to use any energy you generate immediately or sell it back to the grid. Plus, you’ll be missing out on the environmental benefits of the continuous use of renewable energy to power your home as opposed to external energy sources powered by fossil fuels.

Why do we use Lithium-ion batteries

Lithium-ion batteries are the most used battery in domestic solar energy systems, and here’s why:

Low cost: They have become the most cost-effective solution for home energy storage with the increase in electric vehicle production, bringing the price down by 97% over 30 years.
Low maintenance: Even the most affordable Lithium-ion batteries will last for over 6000 charges when paired with a good battery management system.
High battery energy density: They can hold more energy than a lead acid battery.
High depth of discharge or efficiency: They can store more energy before they need to recharge.
Long lifespan: At Wickes Solar, we guarantee that our Lithium-ion batteries will last for at least 12 years. Keeping you online for over a decade.

Do I need solar battery storage?

While battery storage is not a necessity, it’s a no-brainer. Unfortunately, you won’t be able to use solar- generated energy in the evening without a battery, and as you can see from this chart, that’s when you’ll likely use it the most.

How much does a solar battery cost?

The cost of your solar battery is determined by several factors, including the quality and brand. However, the average price continues to drop over the years so you’ll likely be looking at between £400-£500 per kWh.

When you tally up the cost of each replacement battery over your system’s lifetime, the price will likely be closer to £900 per kWh. But as we’ve already mentioned, you shouldn’t need to replace your battery before 12 years have passed.

Don’t forget, you can also save money by investing in a solar battery; With the average home saving around £665 a year on their energy bills. Also, signing up for an SEG (Smart Export Guarantee) will allow you to charge your battery cost-effectively and then sell the excess energy back to the grid at peak times.

What should I consider when choosing a solar battery?

We always recommend a battery storage add-on for our systems, but we do advise that you consider a few factors before you take the leap:

Energy usage: If you use most of your energy when the sun is down, you’ll benefit greatly from a solar battery. Solar panels work at peak level during the daytime, so while you’re out and about, your battery can store this generated energy for you to use when you need.
Cost: It’s always worth considering if your lifestyle will make the initial cost of a solar battery worthwhile. For instance, if you work away a lot, you may not reap the rewards compared to someone who spends a lot of time at home.
Space: One of the many benefits of solar batteries is that they are compact in size and able to be stored in colder environments, including a garage or loft. If you don’t have this type of space readily available, there’s always the option of a freestanding waterproof cabinet to shelter the battery outside your home. Some batteries are also available in ‘stackable’ systems that’ll help you save space.

Will I need more than one solar battery?

There’s no need to buy more batteries than your system can charge. If you do decide that you want more storage space, you’ll have the choice of buying one or two larger batteries or lots of little ones. We recommend several smaller batteries as if one needs replacing, the cost will be much less than it would to replace a large battery.

How long does a solar battery last?

Lithium-ion batteries generally last between 5 and 15 years with battery management making all the difference. On average, they’ll have 6000 lifecycles, meaning they’ll last for 10 years with just 3,650 charges. As your battery will often charge more than once a day, over 10 years you’re more likely to get 6000 charges.

Will battery storage work with my existing panels?

Battery storage can be retrofitted to most solar energy systems, but you’ll need to consider what your inverter is able to charge.

Can I use solar battery storage to power my entire home?

In theory, yes, but most domestic installations don’t consist of enough panels to provide energy for an entire night. You likely won’t have the room to house the number of solar panels you’d need to provide a battery with enough energy for an entire night. However, an SEG will allow you to charge your batteries at night; You just need to remember that it would still take 8 hours to generate enough energy to run the average family home, and most nighttime tariffs are only 4 hours.

Can you have batteries with no solar panels?

With battery-only systems becoming increasingly popular, many energy companies offer a selection of cheap SEGs. This means that your battery is charged overnight when energy costs are low, allowing you to use this power at peak hours without paying a premium. While this is beneficial, we still recommend installing solar panels as this process becomes even cheaper when you can generate energy yourself.

How do I maintain a solar battery storage system?

Fortunately, Lithium-ion storage systems don’t require much maintenance, but as the chemicals inside get older they’ll naturally start to degrade. There are a few things you can do to prolong the life of your battery:

Don’t over or undercharge: Battery management software will take care of this, but it’s important to check the monitoring app regularly.
Monthly visual checks: All the cables and connections need to be regularly checked to ensure they’re in working order and free from corrosion or oxide. Make sure you turn the power off before cleaning!
Keep your battery at the right temperature: The optimum temperature for solar batteries to work is between 10 and 30 degrees Celsius. While they can function at temperatures as low as - 20, your panels will need to work harder to achieve the same results in these conditions. Thankfully, temperatures as extreme as these are uncommon in the UK.
Don’t overload your battery: If you draw too much power from a battery too quickly by plugging in several appliances at once, you can overload it. However, your battery management system should stop this from happening.
Replace your battery when necessary: At Wickes Solar powered by Solar Fast, we offer a 12-year guarantee on our batteries, Meaning you won’t have to lift a finger for over a decade.
Store your battery properly: It’s really crucial that you store your battery somewhere dry, whether in your home or in a purpose-built shelter outside.

What sort of problems can arise with solar battery storage?

You may have heard of the term ‘thermal runaway’; A phrase often connected to issues that could arise with battery storage. The risk of thermal runaway, the ejection of gas, shrapnel and/or particulates, is just 0.0001% so there’s no need to worry. In general, batteries are completely safe if they’re kept in cool, dry conditions. But, as a rule of thumb, we do encourage you to check for the following issues on occasion:

Damage to the battery: This will be internal, so to check for damage, simply ensure it's not overcharging or discharging to 0% when it shouldn’t be.
Extreme weather: Ensure your battery is kept in a location that maintains a constant temperature so that extreme highs and lows don’t affect its performance.
Problems with battery management: If your management software is draining the battery too fast, this can cause major issues in the long run. While an unusual problem, it may be caused by software faults or the app and your converter trying to control the battery at the same time.
Parasitic Draw: Leaving devices on standby mode and not turning them off can lead to your battery being discharged. Good energy management can prevent this.
System problems: If your battery isn’t working at all, begin identifying the issue by checking other areas of the solar system before looking into battery repairs or a replacement.