Capacity check · 20 kWh
Home battery 20 kWh: who is this the right size for?
20 kWh is a large size, intended for households that use a lot of electricity — think heat pump, electric vehicle or a large household with many solar panels. Below you can see when 20 kWh makes sense and when a smaller size is enough.
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- Heat pump and/or EV
- For households with heavy electrification and high usage.
- Maximum daily buffer
- Keep more of your own power for evening and night.
- Often needs three-phase
- Expect a larger setup — check upfront whether you will use the capacity.
Who is 20 kWh right for?
20 kWh is usually only worthwhile if your usage is well above average and you want to keep plenty of your own solar energy for evening and night.
- Large household or lots of electrical equipment
- Annual usage around 6,000 kWh or more
- Heat pump and/or electric vehicle you want to (partly) charge with solar power
- Roughly 18 solar panels or more
- Often a three-phase connection in the consumer unit
Worked example: heavy user with heat pump and EV
An indicative example for a household with around 7,000 kWh usage per year, a heat pump, an electric vehicle and 20 solar panels. Guide figures only — not a guarantee.
- Annual usage
- ± 7,000 kWh
- Solar panels
- 20 (± 8,000 kWh generation)
- Usable capacity per day
- ± 18 kWh
- Extra loads
- heat pump + electric vehicle
- Connection
- usually three-phase
With 20 kWh you have enough left on a sunny day to run heavy loads such as the heat pump partly on your own power in the evening and at night. For an average household, much of this would stay unused.
Is 20 kWh too small, right or too large?
Too small if…
If you charge an electric vehicle at home and run a heat pump, 10 kWh is often empty early in the evening. In that case, 20 kWh helps you keep more of your own power.
Right if…
With high usage (± 6,000 kWh or more), a heat pump or EV and a sizeable solar panel system, you will actually use the 20 kWh — then the large size is justified.
Too large if…
Do you have average family usage without a heat pump or EV? Then much of 20 kWh stays unused and 10 kWh (or a middle size) is usually more logical.
What does a 20 kWh setup look like?
20 kWh is assembled from six to eight or more modules, or from multiple units side by side. Combined with a heat pump and home EV charging, a three-phase connection with higher charge/discharge power is often recommended. Allow for more space and weight, and for the capacity of your consumer unit. Because this is a substantial system, it pays to determine upfront whether you will really use the capacity — otherwise a smaller, expandable setup is wiser.
Example batteries around 20 kWh
BYD Battery-Box
Fijnmazig uit te breiden met kleine modules, van compact tot ruime capaciteit.
Growatt (APX / ARK)
Schaalt van klein tot groot; ook 3-fase varianten beschikbaar voor hoger verbruik.
Pylontech
Vaak gecombineerd met een losse omvormer; populair bij maatwerk-installaties.
Sessy
Nederlandse thuisbatterij; meerdere units zijn aan elkaar te koppelen.
Tesla Powerwall
Grote vaste capaciteit per unit; meerdere units zijn koppelbaar voor extra capaciteit.
Voorbeelden ter illustratie. Modules, vermogen en beschikbaarheid verschillen per leverancier en jaar. thuisaccuKWH.nl verkoopt geen specifiek merk - de check kijkt naar de juiste capaciteit voor jouw situatie.
Go large in one go, or grow over time?
Is the heat pump or electric vehicle only coming later? With a modular system you can start with a smaller size and add capacity up to 20 kWh later. That way you do not pay upfront for capacity you are not yet using.
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Frequently asked questions about 20 kWh
Do I need a three-phase connection for 20 kWh?
Many larger home batteries around 20 kWh work best on a three-phase connection, especially combined with a heat pump and a charge point. Whether it is needed in your consumer unit depends on the system and your other loads — that is something to check during advice.
Is 20 kWh enough for a heat pump and electric vehicle?
20 kWh can cover a substantial share of the daily usage of a heat pump and home EV charging, especially on sunny days. In winter, with little sun and high heating demand, you will still partly depend on the grid.
When is 20 kWh too large?
With average family usage without a heat pump or electric vehicle, much of 20 kWh stays unused. Then a smaller size such as 10 kWh is usually the better balance between capacity and utilisation.
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