Solar Batteries

More and more solar product suppliers are entering the energy storage market. Technology is advancing rapidly, especially as energy prices rise, and sales of home batteries will take off.

Until recently, home battery systems were used almost exclusively in off-grid applications to store generated solar energy. The rise of lithium batteries has generated huge interest from people looking to store excess solar energy, whether they are connected to the grid or not.

With a home battery storage system, it is possible to use this energy without solar power, or even go completely off the grid and become energy independent. In addition, more and more households have home batteries to further save on electricity bills.

Below we discuss the pros and cons of battery storage systems and point you in the right direction when choosing batteries for your home. There are several options available for both off-grid and on-grid situations.

Types of Solar Battery Systems

The variety of battery options and energy storage systems can be overwhelming for many people, and rapid technological developments have led to confusion about which types of batteries are best for residential use. Choosing from the various battery types and configurations available can be difficult.

Many people turn to installers, but many companies don't yet know the details of possible configurations, we can help you.

3 types of batteries

Roughly speaking, there are three types of batteries

• Lead Acid Batteries - Mainly used in automobiles. They are also used in traditional off-grid power systems.
• Lithium-Ion Batteries - Currently the most common battery type, they are also commonly found in consumer electronics due to their high energy density and long life. Progress in improving efficiency has been rapid.
• Flow battery - An electrochemical energy cell that generates energy by pumping metal ions dissolved in a liquid flowing through a membrane. The passage of ions from one liquid through the membrane to another produces an electric current, which can be collected by electrodes and used in electrical systems.

In recent years, lithium-ion batteries have replaced lead-acid batteries because they offer many advantages:

• They are lighter in weight
• They have a modular structure
• They are more efficient
• They live longer

Is solar battery storage cost-effective?

There is a lot of debate about whether battery systems are truly cost-effective. The relatively high purchase cost and low returns mean they are not a great investment. However, as the rate of solar integration into the grid continues to decrease, purchasing a battery system is becoming increasingly attractive.

In addition, the coming energy crisis may also make purchasing battery systems more attractive. However, for most people, financial gain is not decisive. Instead, they make choices based on principle and want to be able to live self-sufficiently without being reliant on the grid. Using a home battery can significantly increase your independence from the grid.

Benefits of Solar Batteries 

• Safety during power outages - With a home battery, you always have power available, even during a power outage or emergency.
• More efficient power consumption - While you typically only use "free" power during the periods when your solar panels are producing electricity, you can store excess power in a battery system so that it can be utilized when your solar panels are not producing electricity.
• Lower costs - You save money by using less energy from the grid.
• Environmentally Friendly - ​​By using the energy produced more efficiently, you can contribute to a cleaner environment. Additionally, you need less electricity from the grid, which is often generated by polluting coal and natural gas plants.
• Energy Independence - By storing energy you can rely on the capacity of the system and become more independent from the grid.
• Reduce peak load consumption - During peak times you can relieve pressure on the energy network and contribute to a more stable public electricity network.

Disadvantages of Solar Batteries 

• Complexity - Home batteries require hybrid inverters or additional monitoring equipment.
• Higher Initial Cost - There is a cost to purchasing a home battery and it doesn't bring much profit. (In principle, you buy more battery systems)
• Space - Home batteries take up more space than an inverter. It also needs to be installed in a safe location; an area that is well ventilated and out of direct sunlight.

Home batteries for solar panels and electric vehicle charging points

Many average homes can easily meet 50% or more of their electricity needs with solar power alone. This percentage can even be increased to 75% or higher by using timers or "smart" controllers to turn on high-energy-consuming appliances during the day so that they are powered directly by solar energy. These appliances include electric hot water systems, dishwashers, dryers, heating/cooling systems, car charging stations, and more.

After maximizing self-consumption, households can achieve almost complete energy independence through the use of home batteries. By using batteries of the right capacity, solar power can cover nearly the entire average daily electricity demand, including charging points for electric vehicles.

With current technology, it is easy to integrate electric vehicle charging stations into photovoltaic systems. The charging station can be easily connected to a hybrid inverter so it can be charged using the storage capacity of solar panels or household batteries.

What battery capacity do I need?

To calculate the correct capacity, it's important to understand the basics. Battery capacity is measured in kilowatt hours (kWh), and modern (lithium) battery systems are often modular and scalable, making it easy to find a battery that suits your needs.

Ampere hours (Ah) are the standard for older lead-acid batteries. This is largely obsolete now, as kilowatt-hours are the industry standard for modern lithium batteries.

The key question is how much electricity the average household consumes in a 24-hour period. Electricity is also measured in kilowatt hours. You can gain insight into your average consumption from your energy bill. The average household consumes around 20 kilowatt hours of electricity per day, but this can vary depending on the season.

Another important factor is electricity usage during peak hours in the evening and morning. Think about your kettle, espresso machine, steam shower and microwave, they all consume energy at the same time and therefore cause a spike in the power the battery must be able to provide.

Every home's situation is different and there's no one-size-fits-all solution, but these factors determine how much capacity a home battery should have. If you're considering purchasing a home battery, talk to your installer when making your choice.

Best Home Battery Brands: Buy Home Batteries

The largest solar inverter suppliers such as Growatt, Fimer, Huawei, SMA and LG-Chem also supply home storage systems. One popular option is the SMA Sunny Boy Storage inverter, which can be used to connect LG Chem batteries. Below we've taken a closer look at some home batteries to give you an idea of ​​your options.

FIMER REACT2-BATT

FIMER REACT2-BATT is a high-voltage lithium-ion battery with long life and storage capacity up to 12kWh. Modular solution can grow with the needs of any home, from 4 kWh to 12 kWh, and significantly reduce electricity costs Features:

- Lithium-ion battery cells for energy storage (minimum 4 kWh to 12 kWh)

- Industry leader in energy efficiency

- Suitable for new and existing solar installations

- Battery can be upgraded at any time during the life of the system.

- Flexible modular design

- Plug and play connection, easy and safe installation

- System monitoring via dedicated mobile app

- Modbus TCP/RTU Sunspec compliant

Growatt ARK HV (high voltage) battery system

The Het Growatt ARK battery system features a modular design that allows additional batteries to be stacked together. ARK HV home batteries are available in different capacities, ranging from 10.2 kWh to 25.6 kWh. Lithium iron phosphate batteries (LFP) do not contain cobalt and are therefore relatively cheap. The battery lasts for more than 6,000 charge cycles.

The battery has an IP65 protection rating and is suitable for wall and floor mounting. However, installation on the floor requires a separate base. Depending on the model, the batteries range in weight from 30kg for the lightest model to 310kg for the largest model.

Some of the advantages of this type of lithium iron phosphate battery compared to lead-acid and other batteries are: longer life, little maintenance required, safety, relatively light weight, improved discharge and more efficient charging.

ARK home batteries are also available in the LV (Low Voltage) range.

Huawei LUNA2000 home battery

Huawei's LUNA2000 home solar battery adopts an expandable modular design. The system consists of a power module and one or more battery modules. The battery module capacity is 5kWh and the discharge capacity is 2.5kWh. The heavier systems with capacities of 10 kWh and 15 kWh each have a discharge capacity of 5 kWh.

LUNA2000 battery modules are suitable for Huawei single-phase and three-phase inverters. Two batteries can be integrated in parallel in one solar panel installation. The maximum storage capacity per inverter is 30 kWh. The LUNA2000 battery uses lithium iron phosphate (LFP) batteries, which are safe and reliable. Defective battery modules are automatically isolated so that the system can continue to operate.

How much do home batteries cost for solar panels?

The cost of a home battery depends on the capacity of the battery in kilowatt hours (kWh), the characteristics and brand of the inverter used. A typical battery for solar storage costs around €700, while off-grid batteries with large storage capacities cost well over €10,000.

When purchasing a battery system, also consider the installation location in conjunction with the type of inverter used. That’s why you should always consult an installer to help you make the right choice.

Are solar cells worth investing in?

The payback period or return on investment (ROI) for most battery systems is approximately 7-10 years. With this in mind, it is significantly more cost-effective to use the solar energy produced more efficiently when it can be used immediately during the day. However, for most people, the independence and constant availability of power outweighs the cost.