Battery inverters

A battery inverter is an important element in a photovoltaic system with battery storage. It enables direct current (DC) from solar cells to be converted into household alternating current (AC), which can then be stored or consumed directly.

How it works:

• Charging: Excess electricity is converted into direct current by the inverter and stored in the battery.
• Discharging: If the solar yield is lower or there is a power outage, the inverter uses the electricity from the battery and converts it into alternating current.
• Grid stability: Modern devices can stabilize the power grid, by feeding or feeding in power when necessary.

Battery retrofitting:

The subsequent installation of a battery storage system in an existing solar system is possible if the following requirements are met:

• Compatible inverter: The existing inverter must be suitable for integrating a battery inverter, the battery must be compatible.
• Sufficient capacity: The size of the battery must be adapted to the electricity needs of the household.
• Expert installation: The installation should be carried out by a certified specialist company.

Advantages of battery retrofitting:

• Increased self-consumption: Significantly increase the self-consumption rate of solar power.
• Independence: Less dependence on the public power grid.
• Cost savings: Reduce electricity costs through lower grid consumption.
• Emergency power supply: Solar power is available in the event of power outages.
• Sustainability: Contribution to the energy transition and climate protection.

In summary:

A battery inverter enables the use of solar power even at night and during power outages. Retrofitting a battery into an existing solar system can increase the self-consumption rate, improve independence from the power grid and save costs. It is important to check the economic viability, get expert advice and take advantage of possible funding programs.

Battery inverters can be categorized according to various criteria:

1. Function:

• Grid-connected battery inverters: The most common variant. They enable excess solar power to be fed into the grid and grid power to be purchased when needed.
• Off-grid battery inverters: Supply independent systems without a mains connection. They regulate the energy flow between the solar system, battery and consumers.
• Hybrid battery inverters: Combine the functions of grid-connected and off-grid battery inverters.

2. Technology:

• PWM battery inverter: Pulse width modulation (PWM) is a simple and inexpensive technology, but it is less efficient.
• MPPT battery inverter: Maximum Power Point Tracking (MPPT) optimizes the performance of the solar system and increases the efficiency.
• Sinusoidal battery inverters: Generate pure sine wave current, which is important for sensitive devices such as computers and hi-fi systems.

3. Output power:

• Small battery inverter: Suitable for small solar systems and homes with low power requirements.
• Medium-sized battery inverters: Covers the needs of larger residential buildings and small commercial businesses.
• Large system battery inverter: Specially developed for large solar systems and commercial operations with high power requirements.

4. Other features:

• Emergency power function: Enables power supply during power outages.
• Parallel connection: Enables the expansion of performance by connecting several devices.
• Smart functions: Integrated WLAN interface, energy management and monitoring functions.

Choosing the right battery inverter:

Choosing the right battery inverter depends on various factors, e.g. E.g.:

• Size and type of solar system
• Electricity requirements of the household or business
• Budget
• Required functions

It is important to seek advice from a specialist before purchasing. to find the optimal battery inverter for your individual needs.

The size of a battery inverter you need depends on several factors:

1. Power consumption:

• Analyze your annual electricity consumption (kWh) based on your electricity bills.
• Estimate your future electricity needs, e.g. B. by purchasing new equipment.

2. Size of the solar system:

• The output of the solar system (kWp) determines the amount of electricity that can be generated.
• A battery inverter should be able to process the entire output of the solar system.

3. Degree of self-sufficiency:

• What proportion of your electricity needs would you like to cover with solar power?
• A higher level of self-sufficiency requires a larger battery inverter and storage.

4. Daily and seasonal requirements:

• Keep in mind your electricity consumption fluctuates throughout the day and year.
• A battery inverter should be large enough to cover peak loads.

5. Storage capacity:

• The size of the battery storage (kWh) determines the amount of solar power that can be stored.
• Larger storage enables greater self-sufficiency, but also increases costs.

Sizing a battery inverter requires an individual consideration of your needs and circumstances. Expert advice and online calculators will help you choose the right size.

Prices for battery inverters vary greatly depending on performance, technology, brand and dealer.

• Performance: Higher performance = higher price
• Technology: MPPT technology is usually more expensive than PWM
• Brand: Well-known brands are often more expensive than no-name products
• Additional functions: Smart functions and emergency power supply increase the price

Save costs:

• Compare offers: Obtain prices from different dealers
• Use funding: Find out about funding programs in your region
• Buy a larger system: Battery inverters for larger systems are usually cheaper per kW
• Self-assembly: Save assembly costs, if you are skilled in craftsmanship

Recommendation:

• Set a budget and create a cost calculation.
• Inform yourself about different models and compare prices.
• Get advice from a specialist and make an offer.

In summary:

Prices for battery inverters vary greatly. With careful planning and price comparison, you can find the battery inverter that suits your needs and budget.

The choice of battery for your battery inverter depends on various factors, including the technology of the battery inverter, the required storage capacity and your budget.

Basically:

• Battery inverters only work with DC batteries.
• The nominal voltage of the battery must match the voltage of the battery inverter.
• Pay attention to the compatibility list of the battery inverter manufacturer.

Common battery technologies:

• Lead-acid batteries: Cheapest variant, but shorter lifespan and lower cycle stability.
• Lead-gel batteries: Improved lead-acid batteries with longer service life and lower gas emissions.
• AGM batteries: Maintenance-free lead batteries with high cycle stability and good deep discharge compatibility.
• Lithium-ion batteries: State-of-the-art technology with high energy density, long service life and high cycle stability.

Other criteria:

• Storage capacity: The required storage capacity depends on your electricity needs and your level of self-sufficiency.
• Charging and discharging current: The battery inverter must be compatible with the charging and discharging currents of the battery.
• Temperature range: The battery must be able to be operated within the temperature range of the place of use.
• Safety: Pay attention to safety certificates and battery protection measures.

Recommendation:

• Get advice from an expert to choose the right battery for your battery inverter.
• Please note the technical data and compatibility information from the battery inverter manufacturer.
• Invest in a high quality battery to ensure long life and reliable performance.

In summary:

Various batteries are compatible with battery inverters. Choosing the right battery depends on your needs, budget and the technical requirements of the battery inverter. Get advice from a specialist to find the optimal battery for your solar system.

The installation of a battery inverter should be carried out by a professional as it requires complex electrical work.

Before installation:

1. Planning: Make sure you have chosen the right BWR for your solar system and your needs.
2. Preparation: Obtain all necessary permits and select a suitable installation location.
3. Safety Precautions: Turn off the power and take safety precautions to avoid electric shock.

Installation steps:

1. Mounting: Mount the battery inverter in a suitable location, e.g. B. on a wall or on a stand.
2. Cabling: Connect the battery inverter to the existing solar system and the battery storage. Pay attention to the correct polarity and cable thickness.
3. Commissioning: Configure the battery inverter according to the manufacturer's instructions and put it into operation.
4. Tests: Perform tests to ensure that the battery inverter is functioning properly.

Recommendations:

• Have a certified electrician carry out the installation.
• Observe all safety regulations.
• Read the battery inverter installation instructions carefully.
• Use only suitable tools and materials.
• Take out insurance in the event of damage.

Battery inverters are an important part of solar power systems with battery storage. They convert the direct current from the solar modules into grid-compliant alternating current and control the charging process of the battery.

Unfortunately, various problems can occur with battery inverters:

Technical problems:

• Defective components: As with any electronic device, components in battery inverters can also fail. This can lead to malfunctions, reduced performance or, in the worst case, a total failure.
• Overheating: Under high loads or insufficient cooling, the battery inverter can overheat. This can shorten the lifespan of the device and, in extreme cases, even lead to a fire.
• Compatibility Issues: Not all battery inverters are compatible with all battery types. When selecting the inverter, it is important to ensure that it is suitable for the battery used.

Network problems:

• Power outages: In the event of a power outage, the battery inverter usually switches off. This can result in a loss of power if the battery is not sufficiently sized.
• Grid fluctuations: Fluctuations in the grid voltage can disrupt the battery inverter and lead to malfunctions.
• Island operation: In the event of a grid failure, the battery inverter must be able to guarantee the power supply in island operation. Not all devices are suitable for this.

General Problems:

• Ageing: Battery inverters are subject to a natural aging process.> Over time, the performance and efficiency of the device may decrease.
• Maintenance: Like any technical device, a battery inverter also needs to be maintained regularly. This includes cleaning the device, checking the connections and updating the firmware.
• Cost: Battery inverters can be relatively expensive. When purchasing a device, you should therefore take into account the costs of purchasing, installing and maintaining it.

It is important to note that the problems mentioned do not have to occur with all battery inverters. The quality and reliability of a device depend heavily on the manufacturer and model.

When choosing a battery inverter, it is therefore important to seek advice from a specialist and to rely on products from renowned manufacturers.

To extend the life of your battery inverter and avoid problems, there are a few things you can do:

Optimal environment:

• Temperature: Avoid extreme temperatures, both hot and cold. Store the battery inverter in a cool, dry place and protect it from direct sunlight. Ideally the ambient temperature is between 10°C and 30°C.
• Ventilation: Make sure that the battery inverter is sufficiently ventilated. Avoid installing in narrow spaces or closets. Dust and moisture can affect the performance and lifespan of the device.

Proper Usage:

• Load: Avoid permanently overloading the battery inverter. Only operate devices whose total output does not exceed the rated output of the inverter.
• Deep discharge: Avoid deep discharge of the battery. Deep discharge protection should be integrated into the battery inverter or installed additionally.
• Maintenance: Observe the manufacturer's maintenance intervals. Clean dust from the battery inverter regularly and check that the connections are tight. If necessary, have the device serviced by a specialist.

General information:

• High-quality products: Invest in a battery inverter from a renowned manufacturer. High-quality components and careful workmanship contribute to a longer service life.
• Professional Installation: Have the battery inverter installed by a qualified electrician. Professional installation minimizes the risk of errors and damage.
• Regular checks: Regularly monitor the battery inverter for error messages and malfunctions. This allows you to identify and resolve problems early.

Additional tips:

• Use a surge protector: A surge protector protects the battery inverter from damage caused by sudden voltage peaks in the grid.
• Update the firmware: Make sure the battery inverter firmware is up to date. Updates may contain bug fixes and performance improvements.

By following these tips, you can significantly extend the life of your battery inverter and improve the reliability of your solar power system.

Battery inverters are electrical devices that work with high voltages and currents. Therefore, it is important to follow some safety precautions when handling these devices to avoid accidents and injuries.

Before installation:

• Expert installation: Have the battery inverter installed by a qualified electrician. Installation should be carried out in accordance with the manufacturer's instructions and local regulations.
• Suitable location: Choose a suitable location for the battery inverter. The location must be dry, well ventilated and protected from direct sunlight.
• Grounding: Make sure> that the battery inverter is properly grounded. This is to protect against electric shocks.

During operation:

• Switch off before work: Always switch off the battery inverter before carrying out any work on it. This also applies to maintenance work and troubleshooting.
• Avoid contact with water: Water can cause short circuits and electric shocks. Therefore, avoid contact of the battery inverter with water or other liquids.
• No metallic objects: Do not place any metallic objects on or near the battery inverter. This can lead to short circuits.
• Protection against damage: Protect the battery inverter from shocks and vibrations. Damage to the device can lead to malfunctions and safety risks.

In case of an error:

• Immediate switch-off: Switch off the battery inverter immediately if you notice a fault.
• No unauthorized repairs: Do not attempt to repair the battery inverter yourself. Contact a qualified electrician.
• Fuse perimeter: Set up a fuse perimeter around the battery inverter if a fault has occurred. Only enter the area when the battery inverter is completely switched off and grounded.

Additional notes:

• Read the operating instructions: Read the operating instructions of the battery inverter carefully and observe all safety instructions.
• Wear suitable protective clothing: When working with the battery inverter, wear suitable protective clothing, e.g. B. insulated gloves and safety shoes.
• First Aid: Familiarize yourself with first aid procedures for electric shock.

By following these safety precautions, you can protect yourself and avoid accidents when handling battery inverters.

The battery inverter plays a central role in photovoltaic systems with battery storage. It converts the direct current from the solar modules into grid-compliant alternating current and controls the charging process of the battery.

However, battery inverters are not the only way to use solar power. There are various alternatives that can be considered depending on individual needs and requirements:

1. DC-coupled systems:

• DC coupling: In DC-coupled systems, the direct current from the solar modules is fed directly into the battery. A special DC regulator ensures that the battery is not overcharged. If necessary, the electricity is then converted by the battery into grid-compliant alternating current and delivered to the house network.
• Advantages: DC-coupled systems are more efficient than AC-coupled systems because there are no conversion losses from direct current to alternating current. They are also cheaper to purchase because no battery inverter is required.
• Disadvantages: DC-coupled systems are not as flexible as AC-coupled systems. You can e.g. B. cannot be operated with power supply. In addition, the selection of compatible components is limited.

2. Island systems:

• Isolated operation: Island systems are off-grid photovoltaic systems. The solar power generated is stored in batteries and used directly in the house when needed. A battery inverter is necessary to convert the direct current from the batteries into grid-compliant alternating current.
• Advantages: Island systems are independent of the public power grid. They can therefore also be used in remote areas where there is no grid connection.
• Disadvantages: Island systems are generally more expensive than grid-connected systems. In addition, the dimensioning of the battery and the battery inverter is very important to ensure reliable operation.

3. Powerhubs:

• Intelligent power distribution: Powerhubs are intelligent power distribution devices that distribute solar power directly to consumers in the house. A battery storage can be optionally integrated. Powerhubs can be used with grid-connected and off-grid photovoltaic systems.
• Advantages: Power hubs offer a high level of flexibility when using solar power. You can optimize your own consumption and control the grid feed-in.
• Disadvantages: Power hubs are comparatively new on the market and therefore more expensive than conventional systems. In addition, the selection of compatible components is limited.

4. Virtual power plants:

• Marketing of surplus electricity: Virtual power plants bundle solar power from several small systems and market it on the electricity exchange. This means that even small system operators can benefit from the high electricity prices.
• Advantages: Virtual power plants contribute to the energy transition and promote the integration of renewable energies into the power grid.
• Disadvantages: Participation in a virtual power plant usually requires a special electricity meter and registration with the network operator. In addition, profitability depends on current electricity prices.

Which alternative is the best depends on the individual needs and requirements. Important factors in the decision include: B. own consumption, grid feed-in, budgeting and technical conditions.

It is advisable to seek advice from a specialist in order to find the optimal solution for your own photovoltaic system.