Your EV Is a Giant Battery. So Why Can’t It Run Your House?

The pitch writes itself.

A new Kia EV9 carries 99.8 kWh of battery.^[5] A Tesla Powerwall 3 carries 13.5.^[2] The Powerwall costs $13,000 to $20,000 to install.^[13] The car came with its outlet for free.

So why would anyone buy a home battery?

Because a battery has two numbers, and the pitch only quotes one. The tank, in kilowatt-hours, is how long you can go. The tap, in kilowatts, is how much you can run at once.

Every EV sold in the US with vehicle-to-load, or V2L, has an enormous tank and a narrow tap. Hyundai’s and Kia’s cars deliver 120 V at under 16 amps,^[6] which is 1.9 kW: one ordinary kitchen outlet. Nissan’s new LEAF gives 1,500 W through an adapter on its charge port.^[8]

A Powerwall 3 delivers 11.5 kW, and starts motors drawing 185 A.^[2]

Think of the outlet as a doorway 1,920 W wide.

Anything that runs under that walks through.

But motors and compressors need a shove to start: two to three times their running draw, for a moment. The doorway has to be wide enough for the shove, on top of everything else already running.

The carmakers say the same thing in their own words. Kia’s manual: “Do not use high power electrical appliances such as an air conditioner, washing machine or dryer.”^[6]

And, in a line worth reading twice: “Do not use appliances that require a continuous power supply, such as medical equipment.”^[6]

The car will cut the outlet when the pack reaches the discharge limit you set, when it overheats, or if someone turns the car off. For a CPAP or an oxygen concentrator, that is the argument for a battery that does nothing else. Our medical-equipment planner sizes one.

Two more lines the chart cannot show. A well pump is 240 V, so no car outlet in the first group can touch it, and nor can any 120 V transfer switch.

And every one of these outlets is outside, or in the back seat. The fridge is reached by an extension cord through a door, in whatever weather caused the outage.

Here the car wins, by a mile.

The table runs each tank down from full on each basket. We keep 20% of the car’s pack back so it can still drive, and count 85% of every battery’s energy as reaching the appliance after the inverter.

The last column is the 30 kWh a day Tesla and Ford plan on, close to the US average of 29.6 kWh.^[12]

There are four ways to get stored power into a house.

“Is the car cheaper” only has an answer once you say which two you are comparing. Prices below are today’s: the stations’ from the makers’ stores as our price monitor last read them, the installed systems’ from Tesla’s and GM’s own pages.

Compare like with like and the car does win twice. Against the extension-cord path it is nearly free, because the battery was paid for with the car.

And against a wall battery, letting a truck feed the panel is the cheaper whole-home system. Tesla puts Powershare Home Backup at about $1,950 of hardware and $2,000 to $4,000 of installation.^[1] GM lists its charger-and-kit bundle at $8,998, $6,748 on promotion until November 2, 2026, before installation.^[3] Either delivers a tank several Powerwalls deep.

Home batteries also lost their 30% federal credit for anything installed after December 31, 2025,^[17] which widens that gap.

It loses the comparison people actually make, between a car they do not own and a battery they might buy. The cheapest car on the first chart starts at $29,990.^[8] A power station with 240 V and a UPS mode starts around $2,599.

V2L is a very good reason to pick one EV over another. It is not a reason to buy an EV.

Put the two charts together and the question dissolves.

Everything the car lacks, the station has: 240 V for the well pump, a surge that starts the sump pump, a switchover measured in milliseconds for the CPAP, and a place in the house.

Everything the station lacks, the car has, which is energy.

So plug one into the other.

An EcoFlow TITAN 5000 holds 5.0 kWh.^[15] A 1.9 kW cord fills it from empty in about 2.6 hours before charging losses, and an IONIQ 5 keeping its 20% reserve has enough for about 10 fills.

The station runs the house, quietly and automatically, on its 7.2 kW tap. The car tops it up during the day, and still drives to work. That is about 4 days of the winter basket, furnace fan included, from a car whose own outlet could only carry it on the edge of tripping.

It is also the version that works for a renter, a household with one car that commutes, or anyone whose panel an electrician has not touched. The station plugs into the wall between outages and recharges from the grid, and the car becomes a reserve rather than the plan. Add a panel or two and the car is not even needed for a short outage; our system builder pairs them.

• You own an EV with V2L, heat with gas, and outages are rare and short. Buy the adapter and a 12-gauge outdoor cord, and nothing else. Run the fridge, the router and a lamp. Set the discharge limit so the car can still drive.
• You have a sump pump, a well pump, a CPAP, or outages that last days. The car can’t start the pump, can’t reach 240 V, and the manual tells you not to run medical gear from it. Buy a station with a UPS mode and 240 V, have an electrician fit an inlet, and treat the car as its charger.
• You drive a Cybertruck, a Silverado EV or another of GM’s twelve V2H-capable EVs, or you are ordering a Model 3 or Y. The installed vehicle-to-home kit is the cheapest whole-home backup you can buy, by a wide margin, as long as the truck is home when the lights go out. Price the installation first; the hardware is the smaller half.
• You don’t have an EV and want backup. Nothing here argues for buying a car. A station covers an apartment or a gas-heated house; an expandable system or a wall battery covers a 240 V house. Our home backup guide and calculator start from your own appliances.

Car figures are the makers’ own, read on October 19, 2026: battery sizes from Hyundai’s, Kia’s and Nissan’s specification pages, outlet ratings from Tesla’s Powershare page, Chevrolet’s Silverado EV page and Kia’s owner’s manual (the “under 16 amps” line, which at 120 V is 1.9 kW).

Tesla and GM do not publish pack sizes. Where a maker says “over three days at 30 kWh a day” we use 90 kWh as a floor and mark it.

Prices for installed systems are Tesla’s and GM’s pages on the same day; the power stations’ are the catalogue prices this site’s monitor last read. Appliance draws are planning figures from this site’s appliance library, which records the source of each; starting watts follow the generator makers’ two-to-three-times rule. Runtimes assume 85% of rated energy reaches the appliance and that a car keeps 20% to drive.

The photographs are generated illustrations, labelled as such in their captions and in each file’s metadata; no real product, place or person is shown.

1. [1]Tesla, “Powershare: vehicle to home and grid”, read October 19, 2026.
2. [2]Tesla, “Powerwall 3 specifications”, read October 19, 2026.
3. [3]GM Energy, “GM Energy V2H Bundle: price, V2H-capable vehicles, promotion through November 2”, read October 19, 2026.
4. [4]GM Energy, “GM Energy V2H Enablement Kit: Home Hub, inverter and dark-start battery, 200 A service”, read October 19, 2026.
5. [5]Kia Media, “2026 Kia EV9 specifications: 76.1 and 99.8 kWh packs”, read October 19, 2026.
6. [6]Kia, “Owner’s manual, Vehicle to Load: “Only use electrical appliances under 16 amps”; no heaters, air conditioners or medical equipment”, read October 19, 2026.
7. [7]Hyundai USA, “2027 IONIQ 5: Vehicle-to-Load 120 V outlets; 63 and 84 kWh packs; trims from $35,250”, read October 19, 2026.
8. [8]Nissan USA, “2026 Nissan LEAF press kit: 75 kWh, V2L 1,500 W with adapter”, read October 19, 2026.
9. [9]Chevrolet, “Silverado EV: up to 11 outlets and 10.2 kW of offboard power”, read October 19, 2026.
10. [10]The Drive, “The electric Ford F-150 can power your entire house for three days on a single charge”, May 19, 2021.
11. [11]Electrek, “Ford reveals new F-150 Lightning EREV plans, kills off EV version”, December 15, 2025.
12. [12]U.S. Energy Information Administration, “How much electricity does an American home use?”, read October 19, 2026.
13. [13]PowerOutage.us, “Tesla Powerwall cost analysis”, read October 19, 2026.
14. [14]ThePricer, “How much does it cost to install a manual transfer switch?”, July 2026.
15. [15]Power Station Arena, “Home backup guide: the ladder from extension cords to a smart panel”, 2026.
16. [16]Electrical Safety Foundation International, “Generator safety: never backfeed through an outlet”, read October 19, 2026.
17. [17]Solar Energy Industries Association, “The clean energy provisions in the “One Big Beautiful Bill”: Section 25D ends December 31, 2025”, read October 19, 2026.
18. [18]Lectron, “How to use the V2L feature of the Hyundai IONIQ 5 with an adapter (15 A, 120 V, NEMA 5-15)”, read October 19, 2026.