
Generating solar power is one thing ā maximising its use is another. Discover how to optimise battery capacity, charging strategy, and system choice for the best return.
With solar panels alone ā without a home battery ā the average household uses only 25ā35% of its self-generated electricity directly. The rest is exported to the grid, and with the net metering scheme ending on 1 January 2027, this is becoming an increasingly significant financial loss.
A home battery raises this percentage to an average of 70ā85% self-consumption. But not every combination is equally optimal. The smartest choices are made by understanding how solar panels and a battery work together ā and how to match the capacity to your specific situation.
A frequently asked question is: how much battery capacity do I need for a given panel output? As a rule of thumb, your battery capacity should ideally cover 50ā75% of your average daily solar panel yield:
| Solar panels | Annual production (avg.) | Recommended battery |
|---|---|---|
| 8 panels (2.4 kWp) | approx. 2,000 kWh/year | 3 ā 5 kWh |
| 12 panels (3.6 kWp) | approx. 3,100 kWh/year | 5 ā 8 kWh |
| 16 panels (4.8 kWp) | approx. 4,100 kWh/year | 7 ā 12 kWh |
A battery that is too small wastes a lot of solar power; a battery that is too large does not charge sufficiently in winter and has a longer payback period. The optimal size lies in between ā and is season-dependent.
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The charging strategy has a major impact on the return of your combination. There are three basic modes that modern home batteries support:
The battery charges from solar surplus and discharges as soon as the household consumes more than the panels produce. This is the most commonly used mode and optimal for those who want to reduce their own energy bill. Self-consumption efficiency: 70ā85% with a correctly dimensioned system.
With a dynamic energy contract, the battery also charges from the grid when the electricity price is extremely low or negative. This increases the number of optimal charging moments ā even outside sunny periods. Additional savings compared to pure self-consumption mode: ā¬100 ā ā¬250 per year for an average household.
The orientation and any shading of your solar panels has a direct impact on the battery's charging pattern:
The choice of system (AC or DC coupling, hybrid or retrofit) determines how much of your solar power actually ends up in the battery. DC-coupled systems have a higher round-trip efficiency (94ā98% vs 85ā90% for AC). For new builds or complete system replacements, a hybrid system ā where inverter and battery are integrated ā is the most efficient choice.
For existing installations, AC coupling (plug-and-play systems such as Anker Solarbank 2) is the fastest and most cost-effective route to higher self-consumption, despite slightly lower efficiency.
The perfect combination of solar panels and a home battery does not exist as a one-size-fits-all answer ā it depends on your consumption pattern, roof orientation, the size of your panel installation, and your energy contract. Those who align everything properly achieve 80% or more self-consumption and recoup the battery in 4ā6 years.
At HES, we guide you in dimensioning your ideal system. Schedule a free consultation and receive a personalised calculation based on your situation.
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