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Which tariff should I use with solar and a battery, and should I switch in winter?

Short answer

With a battery, a time-of-use tariff lets you fill it cheaply overnight in winter and export solar at better rates in summer. Some owners switch seasonally: an overnight EV tariff such as Intelligent Octopus Go in winter, and an import-export tariff such as Flux in summer. Check exit fees and export conditions first.

Last checked 24 September 2026 · 1 source

In more detail

  • Intelligent Octopus Go: six hours of off-peak whole-home electricity 23:30-05:30 plus smart EV charging (8p/kWh from 1 Oct 2026; 8.4p before).
  • Octopus Flux: cheap 02:00-05:00, peak 16:00-19:00; battery schedule usually set by the owner.
  • Winter: little solar surplus, so value comes from charging the battery at the off-peak rate and avoiding peak import.
  • Summer: surplus solar; value from self-consumption and export at the better rates.
  • Switching is free on many tariffs but check fixed-term deals, export contract terms and whether the export rate is tied to import.

The facts, dated

  1. 01
    Intelligent Octopus Go off-peak window 23:30-05:30 — 6 hours

    market_data · GB · checked 24 September 2026 · Octopus Energy

  2. 02
    Intelligent Octopus Go smart charging rate from 1 Oct 2026 — 8 p/kWh

    market_data · GB · checked 24 September 2026 · Octopus Energy

What we saw in the field

[QA review 2026-09-24] C1-6 AGREES (Go winter/Flux summer; Flux needs solar+battery, Go needs an EV). C2-7 AGREES (IOG 8.0p from 1 Oct 2026). | Earlier notes: Agrees with Customer 1 (Go in winter, Flux in summer) and Customer 2 (IOG: winter charge at cheap rate, summer self-consume). Seasonal switching is rational given PVGIS winter/summer ratio (~1:4).

Sources

Last checked: 24 September 2026