V2L, V2H and V2G explained

V2L powers portable loads. V2H can supply a home. V2G can export through the grid connection. All use energy from an EV battery, but they are not interchangeable features. Check the exact vehicle, charger, installation and local programme before treating any “bidirectional-ready” claim as a working system.

What is vehicle-to-load?

Vehicle-to-load, or V2L, lets the traction battery power external electrical equipment. The car may provide a built-in socket or a manufacturer-approved adapter connected to the charge port. It behaves more like a portable power source than a grid-connected charger.

Typical uses include tools, lights, computers or camping equipment within the output rating. The vehicle documentation states maximum power, earthing arrangement, environmental limits and whether certain loads are unsuitable.

V2L is the simplest of the three concepts because it does not normally synchronise with the public grid. It still needs correct cables and dry, undamaged connections. Starting currents from motors and heating loads can exceed an appliance’s nameplate power.

What is vehicle-to-home?

Vehicle-to-home, or V2H, uses the EV battery to supply loads in a house. A compatible system can support selected circuits during an outage or shift household consumption away from expensive times. It is a fixed electrical installation, not an extension-lead trick.

The system must control how the home separates from or interacts with the grid. It must also respect the vehicle’s discharge limit, reserve for driving, charger power, phase arrangement and local grid rules. Some products supply a backup panel rather than every circuit.

V2H availability is sold as a complete ecosystem in many cases. A car may support bidirectional power in one market but not another. Firmware, connector standard, charger model and installer commissioning can all decide whether it works.

What is vehicle-to-grid?

Vehicle-to-grid, or V2G, allows controlled export from the EV through the electricity connection. An aggregator, utility or energy service can request discharge or adjust charging to support the grid or respond to prices. The owner needs a compatible commercial arrangement, not only hardware.

The IEA distinguishes V2G from unidirectional smart charging, often called V1G. V1G can move or reduce charging demand without sending battery energy back. This simpler flexibility can already lower peak load and follow renewable generation.

V2G adds power electronics, communications, metering, grid-code compliance, market access and battery controls. Revenue claims depend on programme terms, availability requirements, electricity prices and cycling. Do not assume a result from another country applies to your home.

How does ISO 15118-20 fit in?

ISO 15118 covers communication between an EV and charging equipment. ISO 15118-20 defines messages and sequences that include bidirectional power transfer. It is an enabling standard, not a promise that every product carrying “ISO 15118” supports V2G.

Products may implement different parts or generations of the standard. Certification, connector support and real interoperability testing matter. The IEA notes that commercial V2G offers still tend to rely on specific combinations of vehicle, charger and utility programme.

Ask vendors to identify the supported standard part, direction of power, compatible vehicle list, country, grid approval and commissioning process. “Future ready” without those details is a roadmap, not a feature.

How much of the battery can the house use?

The answer depends on the vehicle and system settings. Owners usually need a minimum reserve for driving. The system may also hold energy for battery protection or emergency operation. A 70 kWh usable battery set to keep 40% has at most 42 kWh above that reserve before conversion losses:

70 kWh × 60% = 42 kWh

That does not mean 42 kWh will reach home loads. Inverter and wiring losses apply, and the system may stop at another limit. Backup duration also depends on power. A 2 kW average household load consumes energy much more slowly than a 10 kW collection of heating and cooking loads.

Use an energy budget for duration and a power budget for what can run at once.

Does bidirectional charging wear out the battery?

Extra energy throughput can add cycles, but degradation depends on depth of discharge, state of charge, temperature, rate, chemistry and control strategy. A shallow grid-service cycle is not identical to repeatedly emptying the battery.

The vehicle’s battery-management system must enforce safe state-of-charge and temperature limits. Commercial terms should explain warranty treatment and who controls the reserve. If these points are unclear, do not value promised grid income as guaranteed profit.

Smart charging without export may deliver much of the household benefit with less hardware. For example, it can charge from midday solar or avoid an evening peak while keeping all stored energy for driving.

Which option is useful today?

Choose V2L when you need approved portable power and the vehicle explicitly provides it. Consider V2H when backup or time-shifting has clear value and a complete, locally approved package exists. Consider V2G only with a named programme, compatible equipment and understandable contract.

For everyone else, a well-designed smart wallbox remains useful. It can schedule, follow available power and coordinate with solar without promising energy export that the rest of the system cannot yet deliver.