Power and Light · Guide

The Car as a Generator: 80 kWh of Backup Power from an EV with the PowerBridge Pro

How the RoamEnergy PowerBridge Pro turns my Tesla's 100 kWh pack into a 3,500 W / 7,500 W generator with no fuel: what it puts out, what it runs and for how long, the job site, the camper and the house, and the rules for connecting it safely.

Handle with care

Quick facts

What it isAn inverter that plugs into an EV's charge port and turns the pack into AC power; no fuel, no exhaust, no wiring for plug-in loads
OutputTwo 120 V outlets, up to 2,400 W each, 3,500 W combined; or 240 V at 7,500 W, 32 A, on a NEMA 14-50. One side at a time
My car100 kWh Tesla pack, about 80 kWh usable; my home battery bank is 15 kWh
RuntimeA house on the essentials (800 W average) about three and a half days; fridge and freezer alone, about 11 days
The house240 V single phase, no neutral: a transfer switch or interlock and possibly an autotransformer, installed by an electrician. Never a wall outlet
WhereRoamEnergy, free U.S. shipping, 30-day returns, 1-year warranty

This box has access to more than 80 kilowatt-hours of power. For reference, the battery bank wired into my house, the one on my home backup power page, is 15 kWh. The 80 is sitting in the driveway: a 100 kWh Tesla pack, call it 80 usable in the real world, and until now there was no way to get that power out of the car and into a fridge, a jackhammer or a camper. The RoamEnergy PowerBridge Pro is the missing piece. It plugs into the charge port and turns the biggest battery on the property into a generator with no fuel, no exhaust and no engine. I have had mine a little over a month, and I hate to say it: best purchase maybe ever. Just reality. The solar panels replaced going to the gas station, and I still have my truck. This page is what it is, what it puts out, what it runs and for how long, and what to know before you buy.

80 kWhusable in my TeslaA 100 kWh pack, about 80 realistic. My home battery bank is 15 kWh. The car is five of those.

3,500 Wfrom the two front outletsUp to 2,400 W from either outlet, 3,500 W combined, on ordinary 120 V plugs.

7,500 Wfrom the rear 240 V output32 amps, single phase, through a NEMA 14-50: a camper, a welder, a well, or the house through the right gear.

0 galof fuel to findThe outage shuts the gas stations down with the lights. A car charged from the array is full the morning the grid drops.

See the PowerBridge ProFree U.S. shipping, 30-day returns, 1-year warranty

What it is, and what comes out of it

An electric car is a battery with wheels, and a big one. A portable power station is a battery with an inverter, the part that turns DC into the AC your appliances use. The car has the battery but not the outlets. The PowerBridge is the inverter: it talks to the car through the charge port the way a charger does, pulls DC from the pack, and puts out pure sine wave AC on the front and 240 V on the back. No fuel, no exhaust, nothing to wire for the portable use. You charge the car, you plug in the box, you plug in the load.

Front: two 120 V outletsTwo NEMA 5-20 outlets, the 20 amp shape with one slot turned sideways; a normal plug fits. Up to 2,400 W from either one, 3,500 W combined. That is a fridge, a freezer, a space heater and a laptop at the same time, or the jackhammer on a job site that used to need the gas generator.

Back: 240 V, 7,500 W, 32 AA NEMA 14-50 on the rear cable, the same outlet an RV park or a welder uses. Single-phase 240 V with no neutral, which matters for the house (below). Plug a camper straight in, or run the big equipment the front outlets cannot start.

One side at a timeYou use the front outlets or the rear 240 V, not both at once. Pick the side for the job: front for the campsite and the outage, back for the camper, the shop and the house.

The screen and the appReal-time volts and amps on the display, with a minimum battery level you set so the car never gives up the charge you need to drive. The Bluetooth app on your phone shows status, sets the reserve and raises alerts; a USB-C port takes firmware updates.

Protection built inOver-current, short-circuit and thermal protection, pure sine wave output so electronics and motors see what the wall gives them. Quieter than a generator and no exhaust, so it runs beside the tent.

No installation for portable useNothing permanent and no rewiring for plug-in loads. RoamEnergy says normal portable use should not affect the vehicle warranty; check your maker's terms, as always.

Specs are RoamEnergy's published figures for the Pro Gen 2. The front outlets, the 240 V output, the one-side-at-a-time rule and the app are what I use; the house connection is covered below and is not something I have done yet.

Which cars, and how I plug in

Some newer EVs are starting to ship with this ability built in, which is the right direction. Mine is not one of them, and neither are most of the EVs on the road, which is the point of the box: it brings the feature to the older Teslas and to the long list of other brands that have a big pack and no outlet. RoamEnergy has tested it with Tesla and more than 30 EV brands, over 70 models, and publishes a compatibility list; if your car is not on it, they run a volunteer testing program. Check the list before you order, and note the one Tesla wrinkle my home backup page mentions: older Teslas may need the CCS retrofit before the port will talk to it.

What I do before I plug inCheck the car first: the app shows the state of charge and that it is ready, and I set the reserve so the pack stops at a level that still gets me to town. Then the box: turn it on, plug it into the charge port, plug in the load. That is the whole procedure.

Keep a reserveA generator that runs dry leaves you without power. A car that runs dry leaves you without power and without a car. The minimum battery setting is the most important number on the screen; I would never set it below what gets you to the nearest charger with margin.

Check the EV compatibility list at RoamEnergyTested with Tesla and 30-plus EV brands, 70-plus models; older Teslas may need the CCS retrofit

What I use it for

The reason this earns its place is that the biggest battery you own goes everywhere you go. Four jobs it does for me, and the loads they ask for.

The outage at homeFridge, chest freezer, the furnace blower on a propane furnace, the router and Starlink, phones, lights: 600 to 1,000 W on average with everything cycling, and the front outlets carry it on extension cords through a window. That is the first night and the first week covered from the driveway, before any wiring. My power outage gear page is the rest of that first night, and the blackout guide is the plan around it.

The job siteMy jackhammer used to mean dragging the gas generator out, filling it, starting it and listening to it. Now the truck brings the car, the car brings the box, and the front outlets run the hammer. Compressors, saws, chargers and work lights: anything with a plug that starts under 2,400 W, and the big 240 V tools off the back.

The camper and the campsiteA camper plugs into the 14-50 on the back the way it plugs into a park pedestal, and the car's 80 kWh is more than most campers would use in a week. For a tent, the front outlets run the cooler, the lights and the radios with no generator noise and no exhaust. The camping page is the rest of the kit.

The house, through the right gearWhere this thing will really earn its place: the rear 240 V into a generator inlet, through a transfer switch or interlock, and the car holds the house for days. I will cover my own connection when it is done. The rules for doing it safely are below, and they are not optional.

How long 80 kWh lasts

Runtime is the same math as any battery: watt-hours divided by the watts you are drawing. The car gives me about 80 kWh usable; knock off roughly ten percent for the conversion, and call it 70 kWh at the outlets. These are the hours at a steady draw, so an outage where the fridge cycles and the lights are off half the day lands at the low-watt end, and the job site with the hammer running is a few hours of hard use that barely dents the pack.

What is running	Draw	From 70 kWh at the outlets
Phones, lights, the router, a radio charger	100 W	About 700 hours, which is to say weeks
Fridge and chest freezer, cycling	250 W average	About 280 hours, 11 to 12 days
A house running the essentials: fridge, freezer, furnace blower, lights, Starlink	800 W average	About 88 hours, 3 and a half days
The front outlets flat out	3,500 W	About 20 hours
A camper with the air conditioner going	2,000 W average	About 35 hours
The 240 V output flat out	7,500 W	About 9 hours

Hours = usable watt-hours ÷ watts. Your fridge is not typical; a plug-in meter on it for a day beats this table, and my solar power basics page shows the arithmetic. The cold shortens every number on a car just as it does on a power station. Compare: the DELTA 3 Classic I carry into a room holds 1 kWh. The car holds eighty of those.

Get the PowerBridge ProAt RoamEnergy, with free U.S. shipping

Connecting it to the house: read this first

This is the part to read twice. The rear output is 240 V single phase with no neutral. A house panel in North America is split-phase 120/240 V, two hot legs and a neutral, and the 120 V circuits in the house run between one leg and that neutral. So the PowerBridge is not a drop-in replacement for a generator on a 14-50 inlet without one more piece: RoamEnergy says a split-phase autotransformer may be required depending on the setup, and that any panel, inlet, transfer switch or interlock connection needs proper transfer equipment installed by a licensed electrician. That is their rule and it is mine.

Never through a wall outletA cord from the box into a wall receptacle pushes power back up the line toward a crew working on it and can kill someone. The house connects through a transfer switch or an interlocked breaker that disconnects the grid first, or it does not connect at all.

The autotransformerThe box makes 240 V with no neutral. The autotransformer splits that into the two 120 V legs and the neutral a house panel expects, so the 120 V circuits work and nothing sees 240 that should see 120. Whether you need one depends on your inverter or panel setup; ask the electrician who does the inlet.

What my house will seeMy home runs through a hybrid inverter with a generator port, which is how the propane generator already connects; the car will come in the same way, as a third source. That plan is on the home backup page, and the write-up of the connection comes when it is done and tested.

The well pumpA 240 V well pump is the load that makes the rear output worth the wiring: about 1,000 W running with a 3,000 W start, inside the 7,500 W rating with room. Through an inlet and a transfer switch, the car runs the well for weeks.

Every part of a house connection that touches the service is an electrician's job and an inspection. Plug-in loads on the front outlets and the camper on the back need none of that.

The car, a power station, or a generator

Three ways to have power when the grid does not, and where each one wins. The honest answer is that they are layers, not rivals: I run all three.

Source	Stored energy	Output	Wins at	Costs you
PowerBridge Pro on the EV	About 80 kWh, the car's pack	3,500 W at 120 V; 7,500 W at 240 V	No fuel, no noise, no exhaust; goes where the car goes; the biggest battery you own	The car has to be home and charged; one output side at a time; the house connection needs an electrician
Portable power station and a panel	1 to 4 kWh per box	1,800 to 4,000 W	Carried in one hand, refills from the sun, nothing to wire	A night or two per box; the sun has to show up
Propane generator	A 100 lb tank is about 16 hours at half load	9,000 W and up	Runs the whole house for as long as the propane lasts; starts the biggest motors	Fuel to store, noise, exhaust, oil changes; it runs in the cold at the price of a tank

The portable stations are on my portable solar page, the generator and its fuel on the propane page, and the whole wired system, with the car as a planned third source, on the home backup power system.

Keeping the car full: the array is the gas station

A generator is only as good as the fuel you stored. The car is only as good as its state of charge, and the fix is the habit on my home backup page: charge from the array at noon, at the amps the panels can give, so the pack is near full on any given morning. That is what replaced the gas station for me, and it is what makes the car the outage battery instead of the outage problem. Before a storm, let it fill. In the outage, the charger goes to 6 to 10 A or off, so the house battery keeps the house and the car keeps what it has for the PowerBridge.

Before the stormCharge to full. Set the PowerBridge reserve in the app. Put the box, its rear cable and a heavy extension cord where you can reach them in the dark.

DuringFront outlets through a window for the fridge, freezer and the furnace blower; cords rated for the load, 12 gauge for anything over 1,500 W. Keep the car outside; the box makes no exhaust, but the car and the cords live better in the open.

AfterThe sun refills the car from the array, or the first open charger does. There is no tank to fill and no oil to change; wipe the connectors, coil the cable, put the box back in the truck.

What goes wrong

Running the pack to zeroSet the reserve. The car still has to drive, and a lithium pack left empty in the cold is a tow.

Backfeeding a wall outletNever. A transfer switch or an interlock, installed by an electrician, or plug-in loads only.

Expecting both sides at onceFront 120 V or rear 240 V. Plan the job for one side.

Treating 240 V no-neutral as house powerIt is not split-phase. The autotransformer and the electrician decide whether your panel can take it.

A light cord on a heavy loadA 16 gauge cord on a space heater gets hot and drops the voltage. 12 gauge for anything over 1,500 W, and short.

Buying before checking the carCheck RoamEnergy's compatibility list and, for older Teslas, the CCS retrofit. Ten minutes that saves a return.

Bottom line

Charge up, plug in, and you have days of power anywhere the car can drive. A gas generator asks you to store fuel, start it, listen to it and breathe it. The car was already sitting there with eighty kilowatt-hours in it. This box is how you get it out, and it is the most useful piece of preparedness gear I have added this year. More soon on the house connection. Prep hard, people.

Get the PowerBridge ProFree U.S. shipping and a 30-day return window; an extra year of warranty is offered at checkout

If a Tesla and 120 V is all you need, the PowerBridge Standard, Gen 1 is the lower-priced version for Tesla with up to 3,500 W at 120 V and no 240 V output; it is on my list beside the Pro at its own page. The Pro is the one for the camper, the shop and the house.

Questions this answers

Tap a question for the short answer.

Can I use my tesla to power my house

Yes, with the right hardware. The PowerBridge Pro plugs into the charge port and puts out up to 7,500 W at 240 V or 3,500 W at 120 V. Plug-in loads need nothing else; connecting to the house panel needs a generator inlet with a transfer switch or interlock, possibly a split-phase autotransformer because the output is 240 V with no neutral, and a licensed electrician. Never backfeed a wall outlet.

What is the roamenergy powerbridge pro

An inverter that connects to an EV's charge port and turns the car's battery into AC power: two 120 V outlets at up to 2,400 W each (3,500 W combined) on the front, and a 240 V, 7,500 W, 32 A output on a NEMA 14-50 on the back, one side at a time. Pure sine wave, a display and a Bluetooth app with an adjustable battery reserve, no fuel and no exhaust. I run one on my Tesla.

How much power does the powerbridge pro put out

Up to 3,500 W combined from the two front 120 V outlets (up to 2,400 W from either one), or up to 7,500 W at 240 V, 32 A, from the rear NEMA 14-50. You use the front or the back, not both at once.

How long can an ev run a house

Usable watt-hours divided by the watts you draw. My Tesla gives about 80 kWh usable, roughly 70 at the outlets after conversion: about three and a half days running the essentials at 800 W average, about 11 days running only a fridge and a freezer, and about 9 hours with the 240 V output flat out at 7,500 W.

Can the powerbridge connect to a house panel

Only through proper transfer equipment installed by a licensed electrician: a generator inlet with a transfer switch or an interlocked breaker. The output is 240 V single phase with no neutral, not split-phase 120/240, so RoamEnergy says a split-phase autotransformer may be required depending on the setup. I have not connected mine to the house yet; that write-up comes when it is done.

Which evs work with the powerbridge

RoamEnergy has tested it with Tesla and more than 30 EV brands, over 70 models, and publishes a compatibility list; cars not on it can go through their volunteer testing program. Older Teslas may need the CCS retrofit before the port will talk to it. Check the list before ordering.

What I use for this

Gear from my recommended list

Everything I recommend

Roam EnergyRoamEnergy PowerBridge Pro (Gen 2)The car as a generator: 7,500 W at 240 V from the EV's charge portPriced at roamenergy.tech

EcoFlowEcoFlow DELTA Pro 34,096 Wh, 4,000 W, 240 volts: the whole-house size$2,799~~$3,299~~optionsAbout, at us.ecoflow.com, checked today

Roam EnergyRoamEnergy PowerBridge Standard (Gen 1)120 V, up to 3,500 W, Tesla onlyPriced at roamenergy.tech

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