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Home Battery Size Calculator
Useful battery capacity for your solar system.
7.4 kWh
Recommended usable capacity
8.2 kWh
Nominal capacity (for DoD)
7.4 kWh
Evening/night use per day
15.9 kWh
Average PV surplus per day
Runs entirely in your browser. Nothing is sent anywhere.
How it works
- 1Enter your values.
- 2See the result update instantly as you type.
- 3Change any value to compare scenarios.
About this tool
Home Battery Size Calculator: Useful battery capacity for your solar system. Type your numbers and the result is calculated instantly — no button to press, nothing to install. All math runs locally in your browser, so the values you enter are never sent anywhere.
Example
| Input | |
|---|---|
| Electricity use per year (kWh) | 4,500 |
| Share used in the evening/night (%) | 60 |
| PV yield per year (kWh) | 7,600 |
| Usable depth of discharge (%) | 90 |
| Result | |
| Recommended usable capacity | 7.4 kWh |
| Nominal capacity (for DoD) | 8.2 kWh |
| Evening/night use per day | 7.4 kWh |
| Average PV surplus per day | 15.9 kWh |
How do I use the Home Battery Size Calculator?
Enter your values. See the result update instantly as you type. Change any value to compare scenarios.
Is the Home Battery Size Calculator free?
Yes. It is completely free with no sign-up, no usage limits and no watermark.
Is my data sent to a server?
No. Everything is calculated locally in your browser. Nothing you enter is uploaded, logged or stored.
Does it work on my phone?
Yes. It works in any modern browser on Android, iPhone, iPad, Windows, Mac and Linux — no app needed.