Most popular questions

Choosing the right home battery is not easy and the amount of information often raises questions. We collect the most frequently asked questions below.
About our home batteries
When your solar panels generate energy, your home only uses the electricity you need at that moment. The surplus of solar energy is injected into the electricity network at that moment. At times when you need more electricity than you produce, you take so-called 'grey power' from the grid again.

By using a home battery you can store your surplus of generated renewable energy and use it at times when the sun is not shining enough. Your energy consumption is optimised, you become less dependent on external factors such as price increases for electricity and you turn your home into a green living environment.

An average family will have about consume 30% of the green electricity it produces via its solar panels. The other 70% is fed into the distribution network and is later taken back, but then it is impossible to check the origin of the electricity taken. Even when your family has a contract to buy green electricity, the electrons can come from anywhere: a nuclear power station, a gas power station, etc. This is why we call it 'grey' electricity. This is why we call it 'grey' electricity.

With a home battery you store your excess renewable energy yourselfresulting in a self-consumption of 60 to 80%. A world of difference.


Every situation is different and requires a customised calculation. The necessary amount of storage capacity of your home battery depends on your consumption profile, the strength of your inverter, the appliances you use and the locally available electricity production. To get a first estimation of this, you can use our product selector.

We advise you to have your specific situation examined by one of our certified partners. They will analyse your specific situation and elaborate a tailor-made proposal. A list of our partners can be found here.

Going off-grid, i.e. relying 100% on your own (stored) solar energy and therefore not drawing any electricity from the grid, is not possible. The AlphaESS home batteries are not designed for this.

In the event of a power outage, the system can be designed to supply a number of consumers or your entire home with power. In order to go completely off-grid in our climate, however, an alternative way of generating power would be required (for example: a diesel generator) and/or the battery pack would have to be very large. This is possible with the larger, commercial battery systems from AlphaESS.

There are several factors that make it difficult for a home battery to be completely self-sufficient: there are moments when there is not enough light for a long time, which makes it difficult to supply energy to consumers and to charge the battery. Also instantaneous peaks in consumption or production are not always easy to cope with. Under normal circumstances, you can (briefly) draw from the electricity grid or inject energy into it.

The AlphaESS home batteries are designed to allow a household to run as much as possible on its own renewable energy. On an annual basis, a self-consumption of 60 to 80% is possible. In the future, your AlphaESS home battery will even enable you to share power within local energy communities, contribute to grid balancing, and so on. You will then be able to play an important role in the energy transition!
A practical example:

A 1,000 Watt microwave oven running for one hour at maximum power will have consumed 1 kWh. The same is true for a 10 Watt LED bulb when lit for 100 hours. So a fully charged AlphaESS home battery of 11.4 kWh will be able to run the above mentioned microwave oven for 11.4 hours and the LED bulb will be able to burn for 1140 hours.

In the event of a power outage, the AlphaESS home battery will serve as an emergency power supply thanks to its built-in UPS (Uninterupted Power Supply). If a power outage occurs, the home battery can take over in less than 20 milliseconds. So you won't even notice the light flickering. Watch a demonstration here.

You can choose to connect a number of critical consumers in your home to the backup output of the AlphaESS home battery. This avoids problems with fridges, freezers, computers, etc. In some cases it is even possible to supply your entire house with emergency power.
AlphaESS home batteries are available in different sizes and are expandable. There are home batteries available with a storage capacity from 2.9 kWh, and you can go up to a maximum of 34.2 kWh. So there is an AlphaESS home battery for every situation.

As an indication, in 2019 an average Flemish family consumed 8.3 kWh per day.

With a solar panel installation of 2 to 3 kWp or more, it can already be interesting to install an AlphaESS home battery to increase your own consumption.

This is a theoretical possibility, but we certainly wouldn't recommend it. The best approach is to have more panels installed and to charge the car directly from the solar panels as much as possible. This is a form of smart charging. The surplus of your solar energy is stored in your home battery and can be used for domestic consumption when the sun goes down.

We also wrote an more extensive article.

Currently, each SMILE home battery already has 2 programmable contacts. These are fully operational in the SMILE B3, SMILE 5, and SMILE T10. With these outputs you can control certain consumers in a smart way. For example: when your home battery is fully charged and your solar panels produce more energy than you use at that moment, you can send the surplus of energy to the charging point of your car. The 'receiving' devices must of course be able to 'accept' this signal. So always discuss this functionality with your trusted installer. Contact us or one of our partners for more information.

In the future, more and more smart appliances will be marketed that can be controlled wirelessly. The AlphaESS home batteries are equipped for this.

This is not the purpose of a home battery. With a home battery that is properly tuned to your situation you will very often be able to get by for 24 hours, but this will not be the case during longer periods with little sun. This is not only the case in the winter of course. On a yearly basis you will be able to be independent from the electricity grid for 60 to 80%.

AlphaESS was founded in China in 2012. With strong, patented German technologies and its own smart energy management system, AlphaESS has the vision to make the use of green energy accessible to everyone. It is now a truly global leader in energy storage systems, with operations in more than 50 countries across South Africa, Europe, Australia and the Americas. More information about AlphaESS is available at this page.

The AlphaESS battery systems in the Benelux are imported from China, where they are manufactured. To compensate for the pressure on the climate caused by this transport, AlphaESS Belgium plants a climate tree for each imported battery system. Read here more about our climate trees.


Since August 2019, a Flemish premium has been provided for private individuals who have a home battery installed. Since April 1, 2021, this premium has changed. You can now count on a premium of €300/kWh, but the maximum amount of the subsidy per installation is a maximum of €2,550. In the coming years, the subsidy for home batteries will be systematically reduced to zero in 2025.

AlphaESS home batteries meet the technical conditions for the subsidy.

If you want to connect a home battery to an existing solar panel installation, you must have your installer check whether your existing inverter can be set to meet the 60% injection limit.

The latest update on government subsidies and legislation can always be found on our news page.

This depends very much on your specific situation. Factors that can strongly influence this are:

  • Do you already have solar panels?
  • What VAT rate can you have installed? 6% or 21%?
  • What do you currently pay for your electricity?
  • Are you entitled to subsidies and would you like to make use of them?
  • The difficulty of installing a home battery at your place
  • The quality of your home battery 

We have not only made numerous simulations with specialised software, but we also regularly study the results that are actually achieved in practice with the AlphaESS home batteries. We generally see payback periods of 8 to 10 years.

However, a home battery offers many more personal benefits, so just looking at payback time is not enough:

  • With a home battery you will be much less exposed to future increases in electricity prices. Not insignificant when you consider that electricity prices have been rising at an average rate of 6% per year for the past ten years!
  • You are doing your bit to reduce CO2 emissions and thus global warming. You become part of the solution.
  • Experience has taught us that the AlphaCloud monitoring platform gives people a very good insight into their energy consumption and allows them to take many small measures to reduce and optimise their energy use. The cheapest kWh is the one you don't use.
  • With an AlphaESS home battery you are prepared for a future where our energy will be green, produced decentrally, and shared.

Yes, the AlphaESS home batteries are all expandable. You can do this up to 3 years after purchase of your system, under the same factory warranty conditions. Later is of course also possible.

A battery system from AlphaESS is a total package. You don't have to buy any additional components (such as a separate battery inverter). This not only reduces the complexity of installation and use, but you will also have only one point of contact in the event of problems.


We'd like to explain this using our battery cycles. One cycle is the complete charging and discharging of a battery. In the AlphaCloud monitoring platform you can see graphically how much your battery has been charged or discharged on a given day. You'll see that you rarely get to a full cycle per day.

Studies have shown that in our climate and with a battery system that is properly adapted to your situation, about 280 cycles per year are needed. So in 20 years time you will need about 5,600 cycles. AlphaESS assures us that after 10,000 cycles the storage capacity of the home batteries will only drop by a maximum of 20%.

If in the future you were to use your home battery for other applications besides optimizing your own consumption (e.g. virtual power plants), the number of cycles you consume per year will increase slightly.

The systems from AlphaESS have been developed and tested to last 20 years. AlphaESS inverters come with a standard 5-year manufacturer's warranty. From 1 May 2021, the importer of AlphaESS Belgium will extend the warranty on the inverter to 10 years. AlphaESS also guarantees that the storage capacity of the home batteries will only decrease by a maximum of 20% after 10,000 cycles. You can read the full warranty conditions here read the full warranty conditions

When you purchase an AlphaESS home battery, you get free lifetime access to the AlphaCloud, AlphaESS' online and real-time monitoring platform. This can be done via a web browser or the app, which is available for both iOS and Android devices.

The app will allow you to extensively monitor the energy flows in your home. So you can easily follow what your solar panels produce, what your energy consumption is, how much energy is in your battery, and so on.

Read more about AlphaCloud here.

An internet connection is required to monitor your home battery usage in real time. If the connection is temporarily lost, the data is stored locally in your AlphaESS system at that time and will be uploaded to the AlphaCloud servers when your system comes back online.

AlphaESS home batteries are maintenance-free. The internet connection allows the system's software to receive regular updates.


AlphaESS works with certified partners for the ordering and installation of the home batteries. You cannot therefore order directly from AlphaESS. 

Are you interested in a battery, need advice or are you ready to request a quote? Then we recommend you contact your trusted installer. We have an extensive network of gCERTIFIED INSTALLERS We have a large network of installers across Flanders and Wallonia, who have been thoroughly trained to provide superior service.

No, the AlphaESS home batteries are only delivered and installed by certified AlphaESS partners. Our certified installers will be able to propose a system tailored to your needs.

Moreover, you can only apply for a subsidy if the home battery is installed by a certified electrical fitter and is subsequently inspected by an inspector.

The AlphaESS home batteries are compact systems, certainly in comparison with, for example, saline or lead-acid systems. The systems are placed against a wall and are 25cm deep. The height and width of your system depend on the type of AlphaESS home battery that is most suitable for your situation. There are also several possibilities to place a home battery in your area, since the modules can be combined above or next to each other. A Certified AlphaESS partner will work with you to determine the best location for your system.

The installation must be inspected by an independent body. You need this inspection report to register your home battery with your grid operator.

This registration must be done before you apply for a subsidy. Your fitter will advise and assist you in this process.

To ensure optimal operation of the AlphaESS home battery, we recommend that the system not be placed in an area where there is severe frost (temperatures below -10°C) or where it gets extremely hot (temperatures above 50°C).

To make installation easier, we recommend having the home battery set up as close to your fuse box and fixed internet connection as possible.

Usually this is not the case, but a Certified AlphaESS partner will certainly look into this for you before the system is installed.

After installation, an internet connection is required for registration and login of your system. A permanent and fixed internet connection to the AlphaESS home battery is required to make use of its full functionality.

The internet connection will allow the AlphaESS service team to push updates to your device, if necessary, and to detect and fix any malfunctions. An internet connection is therefore required in order to benefit from the full 5-year warranty on the inverter. warranty of 5 years on the inverter. From 1 May 2021, the AlphaESS Belgium importer will extend the manufacturer's warranty on the inverter to 10 years.

The SMILE 5 and SMILE T10 systems have a hybrid inverter. You can therefore connect solar panels directly to it (= DC coupling).

All AlphaESS home batteries can be connected to an existing PV system. We call this an AC coupling. An AlphaESS system is completely independent of your existing solar panel system and can therefore be installed at any time.

In Belgium, different grid connections are possible depending on how heavy your connection is and in which region you are connected. The most common connections are:

  • Single-phase 230 V
  • Three phase 3 x 230 V
  • Three phase 3 x 400 V + N

In some regions there is also a variant where no Neuter is available.

For each of these grid connections, a suitable AlphaESS home battery and connection method can be found. You can easily connect a single-phase battery system to a three-phase grid connection, but not all combinations are possible. Get advice from one of our certified partners

Yes, you can. When connecting, 3-phase EnFluRi meters are used. These meters will ensure that the required power of the battery will be compensated on the 3 phases.

An example:

Two consumers each need 500 Watt at a certain moment and are connected to phase 1 and phase 2, for example. The battery system is connected to phase 3, and there is currently no demand for energy on that phase. The AlphaESS system then measures how much electricity is needed in total over the 3 phases at that moment (in this case 1000 Watt). This electricity is made available on phase 3 because the home battery is connected to that phase.

Because there is no consumption on phase 3 at that moment, the 1,000 Watt on phase 3 is injected into the electricity grid. At the same time, the 500 Watts needed by the users on phase 1 and on phase 2 are withdrawn from the grid. The same amount of electricity that the users need is therefore injected on phase 3 (1,000 Watts) and withdrawn on phase 1 (500 Watts) and phase 2 (500 Watts). In this case, the electricity meter is stopped, so there is no additional electricity cost.

Our SMILE B3 and SMILE 5 are single-phase battery systems. You can easily connect them in a house where there is a three-phase PV inverter.


A Watt (W) expresses how much power is needed to run an electrical appliance. For example: a 10 W LED lamp or a 1000 W microwave oven.

1,000 Watt = 1 kilowatt (kW)

With a battery system it is the inverter that determines the power, i.e. how much energy can be put in or taken out of the battery at one moment. A Smile 5 has an inverter with a maximum capacity of 5.000 Watt (5 kW). So at one moment a maximum of 5.000 Watt (5 kW) can be charged or discharged.

A Smile 5 system that supplies 5,000 W can therefore simultaneously light up 500 LED lamps of 10 W:
5,000 W (battery power) / 10 W (LED lamp power) = 500 LED lamps.

A kilowatt hour (kWh) is an indicator of how much energy a particular appliance will use if operated for a full hour. A microwave oven of 1,000 W (1 kW) will use 1 kWh of energy in one hour:

1,000 W x 1 h = 1,000 Wh = 1 kWh

The storage capacity of a battery system is expressed in kWh. The total storage capacity depends on the type and number of battery modules you install. One Smile 5 battery module stores 5,7kWh. A Smile 5 system can be expanded to a maximum of 6 modules or 34,2 kWh.

The power of the inverter is expressed in kW, the storage capacity of the battery in kWh.

UPS stands for Uninterrupted Power Supply. It is an emergency power supply that ensures that the electricity supply will not be interrupted in case of a breakdown of the mains. 

The UPS (Uninterrupted Power Supply) output is built into the SMILE B3, 5 and T10 as standard.
This output is intended to connect to some essential consumers, such as a water pump or garage door.

If you do not want to connect just a few consumers but your entire house, you can choose a backup box. The backup box ensures that the entire electrical cabinet (and therefore the entire house) can be connected to the UPS output, with a limitation of 3x 32 Amps.

In the event of a power failure, the UPS or back-up box can only supply power to the (essential) users when energy is still stored in the battery system. AlphaCloud can be used to set the amount of capacity to be reserved from the battery system for use as emergency power. The battery will then not drop below the set percentage during daily use. This is known as capacity loss. The part reserved for emergency power must be subtracted from the full capacity of the battery system to calculate how much capacity you have left for daily use.

For example: It is set that the battery should not discharge below 30% for daily use (100%-30%= 70%). So only 70% is available for daily use in the above example. When the battery reaches 30% it will draw power from the grid to cover its energy consumption.

You can also choose not to set any limit for the UPS. In this way, the essential consumers will be powered when there is still energy in the battery, otherwise not. In this case, the full capacity of the battery will be used throughout the day. 


The useful storage capacity is also called the nominal capacity of a battery module. It represents how much energy a battery can deliver under specified conditions when fully charged.

A battery must always have some capacity left to be recharged. This is essential to be able to start the chemical reaction during charging. How deep you can discharge depends on the chemistry in the battery and to ensure a good battery life, it is best not to go to the limit. For example, a SMILE B3 battery module can be discharged up to 96% deep, which is very deep.

LFP stands for Lithium Iron Phosphate. Charging or discharging a battery is essentially an electrochemical process. Lithium iron phosphate indicates the chemical composition of the cathode of a battery cell. AlphaESS only uses LFP cells which are known for their thermal stability, technical quality and outstanding safety. Moreover, these cells are completely free of cobalt.


Not all (home) batteries have the same chemical composition. The chemistry of the battery determines its technical specifications and, consequently, its application. The chemistry of battery cells used in cars, for example, is not the same as that of the battery cells in a home battery.
Different functions are expected from these cells. The batteries of an electric car have to charge, discharge and be light. The battery of a mobile phone has to have a high specific energy (light) and usually does not have to last long. A home battery must above all be safe and have a long life.

Because safety is paramount for AlphaESS, only the extremely safe Lithium Iron Phosphate, also known as LiFePO4 or LFP, was chosen for these home batteries. This chemical composition makes the cells safe and non-flammable even in extreme conditions. This means that you can pierce the battery or cause a short circuit without any problem and it will not catch fire. The AlphaESS home battery is therefore extremely safe.

Lead batteries are cheaper but have some major disadvantages compared to lithium batteries. You can only discharge them halfway, which means that your battery capacity has to be twice as big. In addition, they are three to four times heavier and take up much more space. In recent years lithium-ion technology has undergone a gigantic evolution in terms of capacity and price, as a result of which the LCC (Life Cycle Cost) has become much more favourable than for lead-acid batteries.

AlphaESS only uses Lithium Iron Phosphate cells. These are much safer than the lithium batteries used in cars, for example. The chemical composition of the battery cells makes overheating due to so-called thermal runaway virtually impossible. This makes the cells safe and non-flammable even in extreme conditions. Lithium Iron Phosphate cells also have a very good life span. They are slightly heavier and less compact, but this is usually not a problem in a domestic situation. An additional advantage is that the Lithium Iron Phosphate cells do not contain any cobalt.

The disposal and recycling of batteries continues to place a heavy burden on the environment. Some lead-acid batteries are safely recycled to recover lead and other materials, but many lead-acid batteries still end up in landfills, especially in developing countries.

AlphaESS uses only Lithium Iron Phosphate (LFP) for its battery cells. Because the electrodes in LFP batteries are made from non-toxic materials, they pose a much smaller threat to the environment than lead-acid batteries. They can also be recycled to reuse the materials of the electrodes, wiring, and casings. Some of these materials can be used in new lithium batteries. At the moment there are already LiFePO4 batteries available that contain recycled materials.

Due to the long lifespan of LFP batteries, there are still a lot of batteries in use, so the recycling processes are obviously still in their infancy. As more lithium batteries reach the end of their useful life, recycling will naturally become more efficient and therefore cheaper as engineers continue to improve the processes to recover the materials.

To meet its obligations, AlphaESS has entered into a partnership with Bebat and Recupel.

Information packages

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