Grid-Fee Smart Charging schedules the customer's EV into the cheapest hours of the available charging window, where "cheapest" includes both the wholesale spot electricity price and the distribution network's time-of-use grid fees. This is the standard smart-charging mode Gridio applies once a customer has set a charge-by deadline.

Overview

In many European markets, the customer's bill for a kWh of charging energy is the sum of:

• the spot/market price — the wholesale price of electricity at that hour, varying continuously through the day, and
• the grid fee — a per-kWh charge from the distribution operator, structured in time-of-use bands (e.g. peak / off-peak / night).

Optimising on spot price alone leaves money on the table: the cheapest spot hour can fall inside a peak grid-fee band and end up more expensive in total than a slightly higher spot hour at off-peak. Grid-Fee Smart Charging sums the two components per hour and selects the lowest total-cost hours.

The result: the vehicle still reaches the configured target State of Charge by the configured deadline; the bill is lower than spot-price-only optimisation would deliver in any market with non-trivial time-of-use grid fees.

How it works

For each vehicle with a charge-by deadline, the charging engine runs every 30 seconds:

1. Determines the available charging window. From the configured charge_from time (or right now) to the configured charge_by time. For per-location windows the location-specific schedule overrides the vehicle-level one — see Per-location charging windows.
2. Computes total cost per hour across the window.
   • Spot price per hour, from the local market data Gridio integrates with.
   • Grid fee per hour, derived from the location's configured energy tariff: each hour is mapped to a price level (peak / off-peak / night / …) via the tariff's intervals, and each level carries a per-kWh fee.
3. Sums spot + fee to get the total cost a kWh would carry at that hour on the customer's bill.
4. Computes time-to-full for the vehicle from current State of Charge, target SoC, max charge power, and battery capacity.
5. Selects the cheapest hours adding up to time-to-full, ensuring the vehicle reaches the target by the deadline. Optionally subject to:
   • Guaranteed max price — hours where the total cost exceeds this ceiling are skipped. If the deadline cannot be met without breaching the ceiling, the engine prefers meeting the deadline and logs a warning.
   • Guaranteed minimum SoC — until this SoC is reached, the max-price ceiling is ignored. Useful for "always at least 40 % by morning, then bargain-hunt above that".
6. Issues start / stop commands at the hour boundaries to follow the plan. Each subsequent cycle re-evaluates against the latest SoC, latest spot prices, and latest grid-fee bracket; if charging progresses faster than expected, later hours are dropped from the plan.

When no energy tariff is configured for the location, the engine falls back to spot-price-only optimisation. Behaviour is otherwise identical.

Requirements

Vehicle

Location