During an outage, vehicle-to-home (V2H) runs as a sequence, not a switch. Transfer equipment first disconnects the house from the grid; then the bidirectional charger converts the car’s DC battery power into AC for the home’s circuits; the car keeps supplying until it reaches a reserve level the owner set, or the grid returns. Our explainer, bidirectional charging explained, defines V2H alongside V2L and V2G — this article walks the outage sequence. One fact up front: no EVDANCE charger is bidirectional; all of ours charge one way.
Key Takeaways
- V2H in an outage is a sequence: detect, isolate the home from the grid, invert DC to AC, run selected circuits, stop at the reserve floor.
- Islanding — the isolation step — is what makes the arrangement safe and permissible; it is never optional.
- Usable backup is the battery above the owner’s reserve level, divided by the backup circuits’ real draw.
- No EVDANCE charger is bidirectional; V2H needs a bidirectional-capable car, charger and approved transfer equipment.
The Equipment Chain Behind the Sequence
| Element | Its job in the sequence | Confirmed from |
|---|---|---|
| The car | Supplies the energy; must support bidirectional discharge and be maker-approved for it | The car maker’s documentation for the exact model |
| Bidirectional charger | Charges the car normally; in an outage, inverts the battery’s DC output into household AC | The charger maker’s specification for the exact model |
| Transfer equipment | Separates the home from the grid during supply, reconnects it afterwards | The system design, local rules and the utility’s requirements |
| Backup circuits | The selected circuits the system is designed to carry — typically lights, refrigeration, communications | The load list agreed at design time with the electrician |
The Sequence, Step by Step
- The grid fails. The system detects the loss of supply; nothing is powered yet.
- The home is isolated. The transfer equipment disconnects the house from the grid. This step makes the arrangement safe and permissible: the car must never feed power into lines crews may be working on. It is called islanding.
- The charger reverses. With the home isolated, the bidirectional charger draws DC from the car and inverts it to AC at household voltage and frequency.
- Selected circuits run. Power flows to the backup circuits chosen at design time — not automatically to the whole house.
- The reserve floor is watched. The system tracks the car’s state of charge against the reserve level the owner set, so the car keeps enough for driving. At the floor, supply stops.
- The grid returns. The transfer equipment reconnects the home, discharge ends, and the car can charge again on its normal schedule.
The Limits to Plan Around
Three limits shape every V2H design. First, usable backup energy is only the part of the battery above the reserve floor — duration is the owner’s own arithmetic: usable energy divided by the backup circuits’ real draw. Second, the car must be home and plugged in when the outage starts; a car at the office backs up nothing. Third, every step involving the home’s wiring and the grid connection is approval territory: the interconnection is confirmed with the utility, the installation is designed and signed off by a licensed electrician, and the car’s bidirectional use — including any battery warranty conditions — is governed by the car maker’s document. Sending power to the grid itself, rather than to the home behind the meter, is V2G — a different arrangement with its own programmes and approvals.
Where EVDANCE Fits Today
EVDANCE builds one-way chargers, and none of them can discharge a car into a home — if a seller suggests otherwise, the product pages are the check. For daily charging, the practical choice for most homes today is a smart unidirectional wallbox such as the EV-ACT5006T: up to 48 A, NACS connector, 25 ft cable, IP65/IP66, ETL, FCC and CE as listed. Buyers planning V2H for later should settle the car, charger and utility questions in writing first, then size the everyday charger around them — our residential charging page and contact page are the starting points.
Frequently Asked Questions
Can any EV power a home this way?
No. The car must support bidirectional discharge, the maker must allow that use for the exact model, and a compatible bidirectional charger plus transfer equipment must be installed.
Does V2H switch on automatically in a blackout?
Only in a system designed for it: the car connected, the transfer equipment installed, and the sequence enabled. The isolation step is automatic in such systems because it has to be — a home must never be connected to the grid and the car at the same time.
Will V2H run my whole house?
Usually it is designed around selected circuits, not the whole house. Which circuits are backed up is a load decision made at design time with the electrician, and it sets how long the car’s usable energy lasts.
Related Reading
- Bidirectional Charging Explained: V2L, V2H and V2G
- When Will Vehicle-to-Home Be Available?
- Is Bidirectional Charging Worth It?
