Electric cars are starting to work like giant power banks for your house. Here is how it works, in plain words, and how to work out how long your car could run your home in a power cut.
Yes, some EVs can power a home, but only when the car, the charger and the home wiring all support two-way power. Backup time is simple maths:
Power cuts, high fuel prices and cheaper EVs have made "your car as a home battery" a hot topic. Recently, Tesla said new Model 3 and Model Y buyers in the US can use home backup with a Powerwall 3, and reports say it can keep a house running for over two days. Features like this change by model and country, so treat it as a sign of where things are going.
Other carmakers already offer similar features. Several EVs sold around the world, including in India, can power plug-in appliances directly. Check your own car's manual before you rely on it.
These terms are everywhere in EV news. They all describe the car sending power out instead of only taking it in.
| Term | Means | What it does |
|---|---|---|
| V2L | Vehicle-to-load | Plug an appliance into the car, like a big power bank |
| V2H | Vehicle-to-home | Car feeds your house panel during a power cut |
| V2G | Vehicle-to-grid | Car sends power back to the utility grid |
You can read more about the grid side on Wikipedia's vehicle-to-grid page, and about the cars themselves on electric vehicle.
An EV battery stores DC power, but your home runs on AC. A bidirectional charger contains an inverter that converts between the two. During a power cut, the home is disconnected from the grid so the car's power stays inside your house. Our AC vs. DC guide explains why that conversion is needed.
Everything here depends on telling these apart. A kilowatt-hour (kWh) is an amount of energy, like litres of fuel in a tank. A kilowatt (kW) is how fast you use it, like how quickly you burn that fuel.
Our electrical power guide covers this in more detail.
Follow three easy steps.
A 60 kWh EV, keeping a 20% reserve, with 90% conversion efficiency:
Usable = 60 × 0.80 × 0.90 = 43.2 kWh
Running essentials of 1 kW (fridge, fans, lights, Wi-Fi, TV):
Hours = 43.2 / 1 = 43.2 hours (about 1.8 days)
Notice how fast the hours drop when you add big loads. Keeping to essentials is the secret to long backup. For a quick estimate with your own numbers, use our Battery Life calculator.
Every kWh you give your house is a kWh you can't drive on. If your EV covers about 6 km per kWh (a common figure, but check yours):
A normal home day of about 10 kWh:
10 kWh × 6 km/kWh = 60 km of range
So one day of backup costs roughly one short commute.
The charger's kW rating is a hard limit. If your running loads add up to more, the system will cut out or refuse to start.
Air conditioner 1.5 kW + fridge 0.2 kW + lights and fans 0.3 kW + water heater 2 kW:
Total = 1.5 + 0.2 + 0.3 + 2.0 = 4.0 kW
That fits within a 7.4 kW charger with room to spare. See how current and cable size work in our Wire Gauge calculator.
Safety first. Never connect a car to your home wiring yourself. Feeding power into home wiring without the right equipment can send power back into the grid and seriously hurt line workers. Always use certified equipment installed by a licensed electrician.
Try each one before you open the answer.
Usable = 40 × 0.8 × 0.9 = 28.8 kWh. Hours = 28.8 / 0.8 = 36 hours.
15 × 6 = 90 km.
7.4 − 4.5 = 2.9 kW.
V2H means the car's battery sends electricity back to your house, usually during a power cut. It needs a car, a charger and home wiring that all support two-way power flow.
V2L (vehicle-to-load) powers plug-in appliances directly from the car. V2H powers your whole home through your electrical panel. V2G (vehicle-to-grid) sends power back to the utility grid.
Divide the battery energy you can safely use by your load. A 60 kWh car with about 43 kWh available runs a 1 kW load for roughly 43 hours.
Occasional backup use is a small amount of extra cycling, but heavy daily use adds wear. Check your car's warranty terms for bidirectional charging.
No. The car, the charger and the home installation must all support it, and availability depends on the model and your country. Check your manual or ask the manufacturer.
Product details are based on news reports from early October 2026, including The Cool Down and pv magazine USA. Features, models and availability change, so always check the manufacturer for current details. The calculations on this page use example figures, so replace them with your own car and home numbers.
Work out how long a battery can run your own load.
Open the Battery Life Calculator