Choosing the Right Solar Battery for You

Solar power is a leading source of renewable energy for homes and businesses across the UK, providing clean electricity directly from the sun. However, with the sun only providing maximum light for a few hours a day, solar batteries are an essential component of solar power systems. Solar batteries store excess energy for later use, allowing you to make use of your panels even when the sun isn't shining.

With so many options on the market, its difficult to decide which solar battery is right for you and your system. In this article, we'll walk you through the key considerations to help you make an informed decision.

Capacity and Power

A battery's capacity refers to the total amount of electricity that it can store, measured in kilowatt-hours (kWh). Power is the amount of electricity a battery can deliver at once, measured in kilowatts (kW). Running multiple appliances simultaneously requires a battery with both high capacity and high power.

Depth of Discharge (DoD)

The depth of discharge refers to how much of a battery's capacity can be used before it needs recharging. Most manufacturers recommend not to use 100% of a battery's capacity in order to extend its lifespan. For example, a battery with an 85% DoD can use up to 85% of its stored electricity before it needs to be recharged.

Most lithium-ion batteries have a DoD of 80%, which is deemed a good level.

Round-Trip Efficiency

Round-trip efficiency is a measure of how much energy you can use from a battery compared to the amount of energy it took to store. A high round-trip efficiency means that more energy is available for use. For example, if a battery has a 90% round-trip efficiency, it means that 90% of the energy used to charge it can be utilised.

Lifespan and Warranty

Most solar batteries will perform well until they are around 15 years of age. The lifespan of a solar battery is typically measured in cycles, with each cycle representing one full charge and discharge. When browsing the battery's warranty terms, you'll want to look for something that will cover a significant number of cycles or upwards of 10 years.

Cost and Value

Upfront cost will be an important consideration, as you'll have to keep yourself within budget. However, you shouldn't opt for a battery purely because it's the cheapest option. Consider the long-term value of a battery in terms of its efficiency, lifespan, and maintenance costs. A more expensive option will usually perform better when it comes to these factors. This will subsequently lead the battery to offer better value over its lifespan.

Installation and Compatibility

Ensure that the solar battery you choose is compatible with your existing solar panel system and your installer is familiar with the model. Some batteries require specific inverters or additional equipment, which will add to the installation cost.

Here are two of the best solar battery options on the market today:

1. Tesla Powerwall 3

The Tesla Powerwall 3 boasts an integrated inverter, which allows for direct DC coupling with solar panels. This enhances the system's efficiency, as the battery will automatically convert the DC currents produced by the panels into AC current, which power household appliances. Most solar batteries have separate inverters, which increases the risk of electricity loss during the conversion process.

As a result of direct conversions, the Tesla Powerwall has an impressive 97.5% storage efficiency. You'll be able to use more of the electricity you generate, decreasing your reliance on the grid.

[For more information about the Tesla Powerwall 3, check out our benefits guide.]

2. Fox ESS Battery

As well as being highly reliable, the Fox ESS battery is completely scalable. You can upgrade it post-install to accommodate future energy needs. Its lithium-ion cells ensure longevity and durability, meaning the battery will be part of your setup for many years to come.

Despite this, it remains an affordable option, presenting great short-term value as well as great long-term value.

The battery is built for modern usage, allowing users to monitor the amount of electricity it has stored in real time using a mobile phone. This will help you manage your usage and conserve energy for when you need it most.

[EPC, MCS Certified solar battery installer, Essex and the South East]

Choosing the right solar battery involves balancing several factors to meet your energy needs, budget, and environmental goals. It's always best to consult with a renewable energy expert before making the decision, as they will be able to guide you towards the perfect system for your requirements.

Investing in a solar battery is hugely recommended, whether you're investing in a solar panel installation or already have a system in place. Not only will it help you conserve energy for use during solar downtimes, it will also allow you to make use of the Smart Export Guarantee (SEG) scheme. This allows you to make money by selling excess energy back to the grid.