Solar and Battery Payback Calculator
Works out the yearly saving from a solar and battery system and how many years it takes that saving to pay back the combined cost.
Enter your numbers
Example: 350000
Example: 250000
Example: 6000
Example: 8
Recent
Formula
How the calculation works
Enter the full installed cost of the panels and the separate cost of the battery you are considering.
Enter the units the system generates in a year and your electricity tariff per unit, which together set the yearly saving.
The tool multiplies generation by the tariff for the yearly saving, adds the panel and battery costs, and divides the total cost by the saving for the payback.
Common mistakes
- Crediting the battery with its own generation, since a battery stores power rather than making it and only shifts when you use it.
- Ignoring battery replacement, because a battery usually needs replacing well before the panels and that extra cost belongs in the payback.
When to use it
- Use it before adding a battery to a solar setup, since the battery often extends the payback even though it raises self-use.
- Use it to compare a solar-only quote with a solar-plus-battery one on the same generation and tariff.
Worked example
With panels at 350000 Taka, a battery at 250000 Taka, 6000 kWh of yearly generation and an 8 Taka tariff, the yearly saving is 48000 Taka and the payback is about 12.5 years.
Common questions
Does the payback account for battery replacement?
No, it uses the present costs only, so if the battery will need replacing before the panels, spread that future cost into the total to get a truer payback.
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