If you already own an electric car, you may have a large battery sitting on your driveway that could be doing far more than storing driving range. Vehicle-to-home (V2H) technology lets that battery power your house — which raises an obvious question: do you need a separate home battery at all?
The honest answer depends on two things. First, whether you own (or plan to own) a V2H-compatible EV. Second, whether your car will reliably be home and plugged in when you need stored energy. If both answers are yes, V2H can be significantly cheaper than buying a dedicated battery system. If either answer is no, a home battery offers advantages that V2H cannot match.
Key Takeaways
- V2H uses your EV’s existing battery, so the main incremental cost is the bidirectional charger (from around £530)
- A dedicated home battery costs £1,800–£9,500 installed but is available regardless of whether the car is home
- Octopus Power Pack V2H and V2G can save up to £620 a year; a home battery typically saves £300–£700 a year
- V2H makes most financial sense if you already own a compatible EV and can plug in reliably
- Home battery is better if you want resilience during power cuts or have solar panels to charge from during the day
What each technology actually does
Before comparing on cost, it helps to understand what each system is doing differently.
| Feature | V2H | Home battery |
|---|---|---|
| How energy is stored | EV traction battery | Dedicated wall or floor unit |
| Available when car is away | No | Yes |
| Requires bidirectional charger | Yes | No (standard inverter) |
| Compatible with solar | Yes (via smart charger) | Yes |
| Grid export capable (V2G) | Yes, with G99 approval | Some models, with G99 |
| Installation complexity | High — G99 may be needed for V2G | Medium |
The critical difference is availability. A home battery is always on site, always charged (assuming grid or solar supply), and always ready to discharge. Your EV is only available when it is plugged in at home. For households where the car is often away — long commutes, frequent overnight trips, multiple drivers — this limitation is significant.
Cost comparison: upfront and ongoing
This is where V2H wins its clearest argument, provided you already own a compatible EV.
| System | Approx. unit cost | Approx. total installed | Notes |
|---|---|---|---|
| V2H bidirectional charger (AC) | £530–£707 | £930–£1,300 | NexBlue Point 2 or Zaptec Go 2; no battery purchase |
| V2H bidirectional charger (DC) | ~£6,100 | £7,600–£9,100+ | Wallbox Quasar 2; pre-reg UK only May 2026 |
| Home battery — 5kWh (e.g. GivEnergy) | — | £1,800–£3,500 | Budget-level residential storage |
| Home battery — Tesla Powerwall 3 (13.5kWh) | — | £7,500–£9,500 | Premium, larger capacity |
Figures vary — verify current pricing before budgeting. Prices shift with supplier promotions, installation complexity, and equipment availability.
If you already own a BYD Dolphin or Nissan Leaf, the only incremental spend for V2H is the bidirectional charger. An AC unit (NexBlue Point 2) costs roughly £530 with installation under £1,100 total. At that price, it competes with even the cheapest home battery systems on pure hardware cost.
If you need to buy both a compatible EV and a bidirectional charger, the picture changes. A new BYD Dolphin plus an AC bidirectional charger is a very different conversation from “charger only.”
Annual savings: V2H vs home battery
V2H scenario (Octopus Power Pack): A driver with a BYD Dolphin paired with a Zaptec Pro on the Octopus Power Pack tariff saves up to £620 a year compared with a standard flexible tariff. This is delivered as free EV charging. The saving assumes 7,500 annual miles at 0.306 kWh per mile and reliable plug-in on 20 nights per month.
Home battery scenario (Intelligent Octopus Go): A 5kWh battery charged overnight at 5.49p per kilowatt-hour on Intelligent Octopus Go, then discharged during peak hours at 24–28p per kilowatt-hour, can save approximately £300–£500 a year. A larger 13.5kWh system extends this further. With solar panels generating excess energy during the day, a home battery’s savings increase to £500–£900 a year, as stored generation can replace grid import rather than being exported at lower rates.
On headline savings, the Power Pack V2G model edges ahead at its best-case figure. But note that the Power Pack’s £620 figure is against a standard flexible tariff — if you compare it against a home battery owner who is already on Intelligent Octopus Go (now 5.49p overnight), the gap narrows meaningfully.
Figures vary — verify current tariff rates before modelling your own scenario.
Which is right for you?
| Your situation | Recommended option |
|---|---|
| Already own a BYD Dolphin or Nissan Leaf, drive ~7,500 miles/year, can plug in 20 nights/month | V2H or V2G — low incremental cost, strong savings |
| Have solar panels, want to store excess generation regardless of car’s location | Home battery — available around the clock |
| Want backup power during outages without relying on car being home | Home battery — permanently on site |
| Buying an EV anyway and want to minimise total tech spending | V2H charger — skip the separate battery if car is compatible |
| Drive long distances or regularly park away from home overnight | Home battery — V2H not available when car is absent |
| Budget is primary concern, already own compatible EV | AC bidirectional charger — significantly cheaper than most home batteries |
The honest verdict
V2H is the better financial choice if you already own a compatible EV and can reliably plug it in. The incremental cost is low, the potential saving is solid, and you avoid the expense of a separate battery system. The technology is still maturing — compatible vehicle options remain limited in 2026 — but if you fall into the eligible group, the maths generally works.
Home battery is better if resilience, solar storage, or always-on capability is your priority. A dedicated battery does not care whether your car is home. It charges from solar during the day and discharges during the evening peak, regardless of where you parked. For households with solar panels, a home battery often delivers the better financial return on that specific investment.
The two technologies are not mutually exclusive long-term. Many households will eventually have both: a V2H-capable EV providing large-capacity backup and V2G income, alongside a smaller home battery for solar integration and daytime flexibility. In 2026, most households are choosing one or the other based on their existing assets.
Check which EVs can replace your home battery with V2H — see our guide to the best EVs for V2H.
Frequently Asked Questions
Is V2H cheaper than a home battery?
If you already own a compatible EV, V2H can be significantly cheaper — you only need a bidirectional charger from around £530, rather than buying a separate battery system costing £1,800–£9,500 installed. If you need to buy both an EV and a bidirectional charger to access V2H, the cost advantage narrows considerably and a home battery may be simpler.
Does a V2H system work during a power cut?
Yes, with the right setup. The bidirectional charger must support an islanding function — this disconnects your home from the grid during an outage and allows your EV’s battery to power your circuits safely. Not all bidirectional chargers include islanding, so check the specification before buying. Your car also needs to be plugged in for this to work, which is a key limitation compared with a permanently installed home battery.
How much can a home battery save per year in the UK?
A home battery typically saves UK households around £300–£700 per year on smart tariffs such as Intelligent Octopus Go, depending on capacity and usage patterns. Adding solar panels can push savings to £500–£900 per year, as excess generation is stored and used later rather than exported at lower rates. Figures vary — verify current tariff rates and system costs before modelling your savings.