The short answer
A compatible home battery can charge from the grid without solar panels. Its financial case depends on the complete tariff, losses, useful cycling and installed cost.
Define the job before choosing the capacity
For a battery-only proposal, identify the expensive periods you want to cover and the cheaper periods available for charging. Record how much demand actually falls into each.
Request an assessment for battery-only operation. A solar-and-battery estimate with the solar output casually removed is not automatically an adequate substitute.
Use an example with all units visible
Assume 10 kWh is bought for charging at 8p/kWh. It costs £0.80. At an assumed 90% round-trip efficiency, 9 kWh is delivered later. If all of it replaces imports at 28p/kWh, the avoided purchase is £2.52.
The illustrative gross difference is £1.72 for that cycle. It excludes equipment wear, standby consumption, installation, financing and other costs. These are invented example rates, not current supplier offers.
Check the rest of the bill
A tariff change can alter the price paid outside the cheap window and the standing charge. Compare total annual costs under both arrangements rather than multiplying a single good day by 365.
Check the supplier’s eligibility and operating conditions. Confirm that the intended system supports the required schedule and retains the settings you need.
Separate the backup decision
A request for outage protection adds design questions about isolation, supported circuits and reserve. It should be specified separately from daily tariff savings.
SolarIQ currently provides roof-based solar-and-battery estimates. For a battery-only project, use an installer assessment rather than interpreting those results as a dedicated battery-only forecast.
Before your assessment
Bring these questions with you.
- Demand during the expensive time windows.
- A whole-bill comparison of the two tariffs.
- The exact grid-charging and backup capabilities.
- A separate battery-only quotation.