The useful starting point
There is no single best battery for every home. Compare complete installation proposals against the job you need the system to do.
Give the battery a job before choosing a brand
Start with one priority: use more of your solar generation, shift cheaper grid energy, provide specified backup, or support future changes to your home. Several goals can coexist, but they may compete for capacity. A large backup reserve leaves less storage for everyday tariff savings.
Write down the energy you want to shift, the loads that must run together and how long you need them. That is a more useful brief than a request for the brand with the largest headline capacity.
Two different approaches worth understanding
| Product approach | What it helps you examine | Guide |
|---|---|---|
| Tesla Powerwall 3 | A 13.5 kWh unit with an integrated solar inverter; confirm the commissioned output and backup scope | Powerwall 3 buying guide |
| Sigenergy SigenStor | A controller and modular battery arrangement; identify the exact modules, usable energy and expansion limits | SigenStor buying guide |
This is a deliberately focused research shortlist, not a ranking of the entire market or a hands-on test. Other systems may fit your home and budget. Ask the installer to explain why its selected hardware matches your demand and support needs.
Put these five lines beside every quote
- Usable energy: state the commissioned capacity after relevant system limits.
- Power: separate continuous charge and discharge from short peak figures.
- Backup: list included hardware and supported circuits, not simply “backup ready”.
- Whole-system cost: include installation, electrical work, access and VAT treatment.
- Support: identify who handles a failed module, lost connection or faulty inverter.
Ask for warranties in writing. Years alone do not describe throughput limits, retained-capacity promises, connectivity conditions or whether labour and travel are covered.
Stress-test the sales example
Ask what happens if the tariff gap narrows, annual cycling falls or some energy must stay in reserve. A proposal that only looks attractive on its sunniest or most favourable tariff day deserves more investigation.
Our battery scenario tool lets you vary those assumptions. It includes round-trip losses and the cost of charging energy. It does not simulate a product’s control software or establish a property-specific design.
Once the shortlist is clear, use the detailed product comparison as a template for questions rather than treating a single specification as the answer.
Published information supports your research. Your installer should confirm the exact product, suitability, scope and terms for your property.
Suggest a correction ↗Your next useful step
Put the information to work.
Take the questions that matter to your project, explore the numbers and decide what to ask next.
