Bidirectional EV Chargers: V2H, V2G & Solar Terms (UK Guide)

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EV Charging and Solar Glossary: Essential Terms Explained 


As electric vehicles (EVs), solar panels, and battery storage systems become increasingly connected, understanding how these technologies interact is critical, especially for UK solar professionals and energy-conscious homeowners.

From Vehicle-to-Home (V2H) to bidirectional EV charging, this guide explains essential terminology, how it all works, and why these terms matter in the context of modern UK solar installations.


Why EV and Solar Integration Is a Game-Changer in the UK

EVs aren’t just transport - they’re mobile energy storage. Paired with rooftop solar PV, battery energy storage systems (BESS), and smart inverters, EVs can help manage household or commercial energy use, reduce costs, and improve grid resilience.

What this means for UK homeowners:

  • Lower energy bills via time-of-use or solar-optimised charging
  • Better use of on-site solar power
  • Energy independence and backup during outages
  • Eligibility for smart tariffs and export payments


EV and Solar Integration: Key Terms Explained

Below is a glossary of the most important EV terms UK installers and energy users should understand.


➤ (EV) Electric Vehicle

A general term for vehicles powered partly or fully by electricity.

  • BEVs (Battery Electric Vehicles): Fully electric, no petrol/diesel.
  • PHEVs (Plug-in Hybrids): Combines electric motor and combustion engine.


➤ V2H – Vehicle to Home

Vehicle to Home allows an EV to supply electricity to a home, acting as a backup during power outages or peak times. It improves energy independence and can lower electricity bills.

For example, a home with solar panels can charge the EV during the day and use its stored energy to power the home at night.


➤ V2G – Vehicle to Grid

Vehicle to Grid allows an EV to send electricity back to the national grid, helping balance supply and demand. It supports grid stability during peak times and may offer financial rewards through smart tariffs. While not yet widespread in the UK, this technology is expected to grow as energy flexibility markets expand.


➤ V2B – Vehicle to Building

V2B enables an EV to supply power to larger buildings such as offices or apartment blocks. It works similarly to V2H but at a larger scale, reducing grid reliance, lowering costs, and providing backup. When multiple EVs are connected, an energy management system can discharge them during peak hours - a process known as load shifting.


➤ V2X – Vehicle to Everything

V2X is a broad term covering V2H, V2G, V2B, and other ways an EV supplies energy to external systems. It reflects the shift in how EVs are viewed, not just as transport, but as mobile, flexible energy storage. V2X plays a key role in smart grid and smart home integration, helping EVs support homes, buildings, and infrastructure in real time.


➤ Bidirectional Charging

A charger/inverter setup that allows electricity to flow both into and out of the EV. Essential for enabling V2H and V2G. Not all EVs support it, as compatibility depends on both the vehicle and the charger or inverter.


➤ DC vs AC Charging

  • AC Charging: Common in homes. The vehicle’s onboard converter turns AC into DC to charge the battery. This is slower and less efficient, especially for sending energy back to the home or grid.
  • DC Charging: Used for public fast charging and in systems designed for V2H/V2G. The power conversion happens outside the vehicle, enabling faster, more efficient two-way energy flow.

The Haier Smart Cube system includes a built-in bidirectional DC EV charger, ready for V2G and V2H integration.


➤ Smart Charging

Smart charging automatically adjusts EV charging based on electricity tariffs, solar generation, and grid demand. It includes features like load balancing, scheduled charging, and energy monitoring, helping reduce costs and increase solar self-use. For example, charging an EV overnight on off-peak tariffs and using the stored energy during the day.


➤ Dynamic Tariff Optimisation

A function that schedules EV charging and discharging based on real-time electricity pricing. This is useful under UK time-of-use tariffs and will grow in value as energy markets become more dynamic.


➤ Backup Mode / UPS Function

Backup mode (or uninterruptible power supply function) switches to stored energy when the grid fails. In systems with a compatible inverter or bidirectional charger, the EV or home battery can power key circuits, providing resilience for critical loads.


➤ SOC – State of Charge

SOC is the battery's current energy level, expressed as a percentage. It is used to help systems decide when to charge, discharge, or export energy for optimal performance.


➤ EMS – Energy Management System

The ‘brain’ of an integrated solar-battery-EV system. It controls how solar panels, batteries, EV chargers, and the grid work together. It helps optimise energy use based on tariffs, solar production, and household demand. Coordinates usage, prioritises savings, and enables smart export and backup. 


EV Charging Connectors Overview

Understanding EV connector types is essential for ensuring system compatibility, particularly when planning V2G or V2H-capable installations.

Connector Type Charging Type Use Case Max Power Output Notes
Type 2 AC (Slow/Fast) Standard for UK homes and networks 3.7 to 22 kW Most common in the UK; locking mechanism included
CCS DC (Rapid) Commercial rapid charging 10 to 150 kW Standard on most UK EVs; supports bidirectional flow; charger output varies
CHAdeMO DC (Rapid) Favoured by Japanese carmakers 50 to 100 kW Supports V2G but being phased out in the UK
Type 1 AC (Slow/Fast) Mainly seen in early-generation car imports 3.7 to 7 kW Rare in the UK; no locking mechanism
EV Charging and Solar Glossary: Key Terms for UK Installers & HomeownersEV Charging and Solar Glossary: Key Terms for UK Installers & Homeowners

Types of EV Connectors -  Source: EVA England

Most UK homes are limited to 7.4 kW on single phase, making Type 2 the most practical and cost-effective choice for home charging. For bidirectional features like V2H or V2G, only CCS connectors are currently suitable. 

CCS bidirectional use is still in the early stages and is more commonly seen in commercial settings.


Why This Matters to UK Installers and Wholesalers

With the rise of smart energy systems, solar installers are increasingly expected to deliver EV-ready PV systems. Understanding terms like V2H, V2G, and EMS ensures better system design and adds value for customers.

For those looking to offer integrated solutions, a system like the Haier Smart Cube offers a complete energy hub with EV integration and smart EMS control and is distributed exclusively in the UK by Alternergy, a leading solar wholesaler and distributor.

Sungrow delivers EV chargers that complement these setups, offering efficient and reliable charging for a wide range of electric vehicles, suitable for both residential and commercial installations.

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Frequently Asked Questions
What is bidirectional EV charging and how does it work?

Bidirectional charging allows energy to flow both into and out of an electric vehicle (EV). This enables functions like Vehicle-to-Home (V2H) and Vehicle-to-Grid (V2G), turning EVs into flexible energy assets.

Do all EVs support V2G or bidirectional charging?

No, only some EVs and chargers support bidirectional charging. Compatibility depends on the vehicle model and the charger’s capabilities (e.g. CCS Combo or CHAdeMO).

Do I need a special charger for V2G or V2H?

Yes. Bidirectional charging requires a compatible charger and inverter that supports energy export functions like V2G or V2H.

What is the difference between V2G, V2H, and V2B?

V2G sends power from an EV to the grid, V2H powers a home, and V2B supplies a commercial building. Each use case has different hardware and benefits.

What is V2V and V2L?

V2V allows EV-to-EV charging. V2L (Vehicle-to-Load) powers devices directly from an EV, such as laptops or appliances, typically via a standard socket. In essence, V2L is about powering everyday external equipment, while V2V is about sharing battery energy between electric vehicles. Both are part of the growing field of bidirectional EV technology, but each serves a distinct purpose.

Is bidirectional charging available in the UK?

Yes, but it’s limited to specific chargers and EVs. Pilot projects and early adopters are already using V2G and V2H systems in the UK.

Is V2G available in the UK right now?

Yes, but currently limited to pilot schemes and select hardware, with wider rollout expected by 2026–2028.

Is V2H available in the UK?

Yes, although it's less common than V2G. V2H is gaining interest as more EVs and chargers support home energy backup functionality.

Is bidirectional charging worth it in 2025?

For many UK homeowners and businesses, bidirectional charging offers energy savings, backup power, and potential income, making it a smart investment in 2025. Alternergy supplies bidirectional EV chargers from leading brands like Haier and Sungrow designed for both residential and commercial use.

How can I earn money by exporting EV battery energy in the UK?

EV owners may earn money through the Smart Export Guarantee (SEG) or future V2G programmes by sending stored energy back to the grid.

Can I charge my EV from solar panels?

Yes. With a solar-compatible EV charger or hybrid inverter, you can charge your EV using power from your rooftop solar PV system.

How does solar panel integration work with EV charging?

Solar energy is used to charge the EV during the day, and smart energy systems can optimise this based on generation, pricing, and battery state of charge.

What are the three types of EV charging?

EV charging is typically classified as Level 1 (slow), Level 2 (fast AC), and Level 3 (rapid DC), depending on speed and power source.

What are Type 1, Type 2, and Type 3 (DC Fast Charging) EV Chargers?

Type 1 (5-pin) is a single-phase AC connector used in older or imported EVs. Type 2 (7-pin) is the UK standard for AC charging, supporting both single- and three-phase setups. Type 3 refers to CCS, which combines the 7-pin Type 2 with 2 DC pins for fast charging, now standard for Level 3 charging in the UK.

Is DC charging faster than AC, and which connectors are used?

Yes, DC (Direct Current) charging is significantly faster than AC (Alternating Current) charging because it bypasses the vehicle's onboard converter and sends power directly to the battery. In the UK, AC charging typically uses Type 2 connectors (up to 22 kW) for home or workplace use, while DC fast charging uses CCS Combo connectors, which are now the UK standard. CHAdeMO is also used for DC charging but is being phased out. Alternergy supplies solar-compatible EV chargers from leading brands like Haier and Sungrow, trusted by UK installers and designed for both residential and commercial use.