What is a home battery?
A home battery is a large rechargeable battery for your home that stores electricity so you can use it later. The power comes from your solar panels or from the grid, and the battery releases it again the moment you need it.
What does a home battery in your house do?
A home battery in your house shifts power from the moment it's available to the moment you use it. Solar panels generate most during the middle of the day, while you use the most power in the evening.
Without storage, according to Milieu Centraal you use an average of around 30 percent of your solar power yourself and the rest goes to the grid. A home battery captures that surplus and delivers it back to your household later.
The battery charges when more power comes in than your home needs and discharges when you use more than is being generated. When it's full, the surplus still goes to the grid. When it's empty, you simply draw power from your energy supplier again. This switching happens automatically, without you having to do anything.
What components make up a home battery?
A home battery consists of five components that together form one system:
- Battery modules: blocks of battery cells where the energy is stored, in most home batteries these are lithium iron phosphate cells, abbreviated LFP or LiFePO4.
- Battery management system (BMS): monitors the cells and keeps temperature, voltage and charge level within safe limits.
- Inverter: converts the direct current from the battery cells and solar panels into the alternating current of your power sockets, and vice versa.
- Energy meter: often a P1 meter on the smart meter in your meter cupboard, which measures how much power your home is using or feeding back at any given moment.
- Software: based on that measurement, it decides when the battery charges and discharges, and you usually control it through an app.
Only when these components work together can the battery respond to your usage on its own. Want to know how a home battery works once all these components come together? We'll walk you through it step by step in a separate explainer.
What do you use home energy storage for?
You use home energy storage for three things: making the most of your own solar power later, saving cheap power from the grid, and keeping your devices running during a power outage. Which use matters most depends on your situation and on the model.
1. Store solar energy for the evening
Storing solar energy for the evening is the best-known use of a home battery. The surplus your panels generate during the day gets used after sunset for cooking, lighting and the dishwasher. Without a battery, that surplus goes straight to the grid.
2. Storing cheap grid power in a home battery
Storing cheap grid power in a home battery is possible if you have a dynamic energy contract. With such a contract, the electricity price changes by the hour, depending on the market price. The battery then charges during low-price hours and supplies power when it's expensive. You don't need solar panels for this.
3. Home battery as backup power during an outage
A home battery as backup power during an outage only works with models that have a separate backup power output. If the grid goes down, such a battery switches over and the devices you connect to that output, like a freezer or your wifi router, keep working. A battery without such an output does not supply power to your home during an outage.
What is a plug-in home battery?
A plug-in home battery is a home battery that you connect to a power socket with a plug, without needing an installer. The battery supplies its power to your home installation via that circuit.
A fixed home battery, on the other hand, is connected in the meter cupboard by an installer, usually on its own circuit. Plug-in systems are often modular: you start with one battery and expand later with extra modules.
With the heavier models, you only get the full output with a separate circuit or a fixed connection installed by an electrician. Also keep an eye on what else is on the same circuit, because heavy appliances on that circuit can overload the wiring together with the battery. You can see which models are available in the overview of plug-in home batteries.
What are the pros and cons of a home battery?
The pros and cons of a home battery are closely balanced: you get more out of your own power, but you pay a hefty investment for it. Here they are at a glance.
Benefits of a home battery
The benefits of a home battery mainly come down to having more control over your own power:
- More of your own solar power: you use a larger share of what your panels generate yourself, instead of feeding it back to the grid.
- Less dependent on the grid: in the evening and at night your home partly runs on stored power.
- Respond to electricity prices: with a dynamic contract you charge during cheap hours and use power during expensive hours.
- Less feed-in: you supply less power to the grid, which matters now that many energy providers charge feed-in costs.
- Expandable: many systems are modular, so you can add capacity as your consumption grows.
- Power during outages: models with a backup power output keep important appliances running when the grid goes down.
How much of those benefits you notice depends on how much electricity you generate, when you use it, and which energy contract you have.
Downsides of a home battery
The downsides of a home battery lie mainly in the costs and the limits of storage:
- High purchase price: a home battery is a hefty investment, and whether you'll earn it back isn't certain.
- Not self-sufficient: in summer you generate more than the battery can store, and in winter too little to fill it, so you'll still need a grid connection.
- Environmental impact: making a battery takes a lot of energy and raw materials.
- Placement: the battery needs a well-ventilated spot, away from walkways and escape routes.
- Wear: the storage capacity slowly decreases after many charge cycles.
Whether the benefits outweigh the costs varies from household to household. You can read how to work that out for your own situation in the article about the payback time of a home battery.
Why are more and more households choosing a home battery?
More and more households are choosing a home battery, because fed-back solar power earns less than it used to. The net metering scheme ends on 1 January 2027.
After that, for electricity you feed back you'll only get a payment from your energy supplier, and that's usually lower than what you pay for electricity from the grid. On top of that, many energy suppliers charge feed-in costs, which means feeding back can already cost you money.
With a dynamic energy contract, the electricity price varies by the hour. A battery makes those differences useful. Plug-in models that you connect yourself have also made the step to a home battery smaller.
Wondering if a home battery is right for you?
Curious whether a home battery is right for you? It helps to see the models side by side. In the overview of all home batteries you'll find the home batteries TechPunt carries, and on every product page you can see how much storage and power a model offers.
TechPunt sells plug-in home batteries from Zendure and Anker SOLIX and ships them from its own warehouse in Barneveld.
