A battery does not create energy — it moves it in time. Everything about its payback comes down to how much value that shift is worth on your particular meter.
The three levers of a real payback
Most simulations quote a single figure and hide the assumptions behind it. In practice, savings come from three separate mechanisms, and their weight differs from one household to the next.
- Self-consumption : every kilowatt-hour you store at midday and use at night is a kilowatt-hour you no longer buy at the evening price.
- Peak shaving : capacity tariffs bill your highest quarter-hour of the month. Flattening that single peak often saves more than it looks.
- Injection value : when the grid pays little — or nothing — for what you export, storing is worth strictly more than injecting.
Sizing beats over-sizing
A pack larger than your night-time consumption spends most of the year half empty. The right capacity is the one that is cycled almost every day: it is the number of cycles, not the number of kilowatt-hours, that turns into money.
A battery that cycles daily at 80% pays back faster than a bigger one that cycles at 40%.
This is also why modularity matters. Starting at the capacity you actually cycle today, and adding a module when your usage grows, keeps the whole system on the efficient side of that curve.
See the OXOVOLT range
