Octopus Outgoing is the practical route: it is the non-MCS option and paid a flat 12p/kWh as of July 2026 (cut from 15p on 1 March 2026), while EDF, E.ON Next, British Gas and OVO route you through an MCS or Flexi-Orb certificate a DIY grid-charged battery does not hold.
Grid-charge-and-export rarely profits: after round-trip losses and battery wear near 3p per kWh cycled the export margin lands close to zero, while self-consuming the unit is worth far more.
No solar means no Flux: a battery-only home cannot join Flux and defaults to Agile import arbitrage or a fixed cheap-window tariff.
Compare with one formula: value per kWh charged equals round-trip efficiency times avoided import price, minus the charge price, at about 90% efficiency.
Three separate rulebooks get blurred into one: Part P covers the socket, BS 7671 and product law cover the backfeed, and G98 covers grid notification. Only the first is a socket question.
Give the engineer the full pack up front: roof pitch, rafter size, span and spacing, covering, panel datasheet weight, mounting and postcode, to avoid a second visit.
Force charge is a permission chain: enable grid charge on the 02:00 to 05:00 row, set the target state of charge, and keep it coordinated with the Low Batt protection floor.
Beta export blinds your load reading: Selling First mode disables the CT coil, so you cannot see house consumption while exporting until the firmware fix ships.
Deye uses the same platform: set the same two windows through Time of Use, since a Deye may not expose Sunsynk’s one-click Flux button.
Deemed export stays at 50% of generation: solar PV up to 30kW keeps the 50% deemed rate even with a battery and a smart meter, because it is read off the generation meter.
Sort the decision into five outcomes: returned for fixes, offered as applied, capped on export, subject to works, or the requested arrangement declined.
