As an EV enthusiast, there are only a few things that can really make or break your day. Electricity is one of these. The ability to access energy when you need it is essential for powering your Tesla effectively and efficiently.

A common scenario: with the arrival of a storm, the power goes out. The nearest available Level 2 charging station that hasn’t been knocked out is a dozen miles away. When you get there, you see a line of cars and realize you’ve wasted your battery getting there. In emergency situations, dinner can be heated on a gas burner, but a horse-drawn Tesla is out of the question today.

In fact, there can be many scenarios when you need to charge an EV from a generator, from a plan to visit a remote campsite to emergency situations. Charging the Tesla with a generator is only available for certain models, which you can read about below.

Best Choice
Generac G0071540 GP3300i Portable Inverter Generator
Flexible Charging for Your Electric Vehicle
A Portable Inverter Generator has a charging capacity similar to that of a traditional generator. But it has an inverter built in to make charging easier and more efficient than ever before. So whether you're charging a Tesla or a Chevy Bolt, you'll get the most charging done.
Read Verified Customer Reviews

A portable generator is a great option for those who need portable power that they can count on. But it’s important to know that not all generators are capable of charging your Tesla.

The good news? You don’t have to be an expert to get the most out of this truly amazing piece of equipment. Here’s what you need to know about charging the Tesla from a generator.

Jump to the comparison chart.

So what kinds of generators can you find on the market? And which will work for your EV?

Not all generators are capable of charging your electric car.

1 Charging Cycle — It’s not for charging a Tesla

The charging cycle is the most basic way to charge a generator. It is an AC motor that charges a battery bank.

2 Battery Charger / Converter — It’s not for charging a Tesla

Charging by battery is the quietest, cheapest but slowest way to charge. It can be used with a solar power system for off-grid living. It’s not good for EV charging.

3 Specialty Generators — It’s not easy

There is charging support for large power requirements, such as charging a gas turbine generator. There are charging sources that can do this. Some charging generators can be adapted to work with alternative fuel sources. You’re not going to find one of these in your neighbor’s garage.

4 Inverter — It’ll charge your Tesla or an EV, but…

The charging source that’s used in most modern portable generators today, inverter charging is also the most efficient charging method. Inverters can be used to convert a charging cycle generator or an AC power outlet into a charging station for your battery bank or deep-cycle battery needs. The problem with inverter charging generators is they’re usually the most expensive charging options, and they’re also the noisiest charging sources…

What specs should a generator have in order to charge a Tesla?

True Sine Wave (TSW) — is an important factor in the generator needed to charge the Tesla.

A true sine wave is a smooth waveform of electrical output. An alternating current that is made by a TSW inverter, like the best choice of inverter, has this kind of waveform. A modified or square sine wave inverter does not have this kind of waveform.

All EV charging stations should be powered by TSW sources. Jump to the comparison chart.

Requirements to charge a Tesla

If you don’t want to deal with sine waves, you will only see tried & true Tesla-friendly generator models in this review.

What is important to us when choosing a Tesla gas generator?

When comparing the two options, keep in mind the following four criteria:

We selected 5 tested models according to these parameters basedon our customers’ experience. More about that further on. Jump to the comparison chart.

Common outlet types of generators

In non-inverter generators the variety of sockets is wider (there you can find L5-30 and L14-30), but they’re not what we want. Tesla gas generators, suitable for us, most often have the NEMA socket 5-20 (compatible with the usual plug-in 5-15). Less common are L5-20 and TT-30.

NEMA 5-20s are rated up to 20 amps, 120 volts, and 2400 watts. They will power your Tesla for a couple of miles, which means they can be a reliable power source if you need to get to the nearest power station. However, these outlets are not suitable if you need a power source that lasts a few days.

Tesla vehicles come with special sockets. They are compatible with NEMA outlets thanks to Mobile Connectors. Older Tesla models had 14-50 and 5-15 connections, while newer cars are limited to Gen 2 and NEMA 5-15 outlets (it’s compatible with NЕMA 5-20).

All of the portable generators to charge Teslas in this review have a 5-20 socket, and some of them have other additional sockets.

Charging speed forecast

How long will the Tesla Model 3 run after one hour of charging from a particular socket? This is shown by the mph parameter.

mph20%→80% battery
Nema 5-201015+ h
Nema L5-201015+ h
Nema TT-30179+ h

How long does it take to charge a Tesla from a generator? To charge the battery to 60%, you will have to use the recommended generator for at least 15 hours. Other calculations can be done with this charge time calculator. Below is a detailed table of the different generators for charging a Tesla or EV, considering also the charging speed.

Comparison of Tesla and EV portable generators

ImageProduct 
Best Choice
Generac G0071540 GP3300i
Generac G0071540 GP3300i — Best Choice with the overall best performance
  • L5-20, 5-20R Duplex
  • Lightweight and portable
  • USB ports for charging electronic devices
  • Has a mode that saves fuel

Check Price
READ OUR REVIEW
Also Great
Generac GP2500i Inverter review
Generac GP2500i Inverter
  • 5-20R Duplex
  • Can connect in parallel with another Generac GP2500i generator
  • Shuts down automatically when oil level is low
  • Has USB ports to charge electronic devices directly

Check Price
READ OUR REVIEW
Also Great
Honda 663520 EU2200i 2,200 Watt review
Honda 663520 EU2200i 2,200 Watt
  • 5-20R Duplex
  • CO detector
  • Lightweight and portable
  • Smartphone app for monitoring generator status

Check Price
READ OUR REVIEW
Also Great
Champion Power Equipment 200986 4500-Watt review
Champion Power Equipment 200986 4500-Watt
  • TT-30R, 5-20R Duplex
  • Produces high power
  • Starts quickly in cold weather
  • Three-year warranty with lifetime technical support

Check Price
READ OUR REVIEW
Also Great
WEN 56203i Super Quiet 2000W review
WEN 56203i Super Quiet 2000W
  • 5-20R Duplex
  • Fuel efficient
  • Two-year warranty
  • Lightweight

Check Price
READ OUR REVIEW

Specs comparison of the generators

Generac G0071540 GP3300i Generac GP2500i Inverter Honda 663520 EU2200i Champion Power Equipment WEN 56203i
Output starting/running 2.5—3.3 kW 2.2—2.5 kW 1.8—2.2 kW 3.5—4.5 kW 1.7—2.0 kW
Weight 59.5 lbs 48 lbs 53.57 lbs 95.7 lbs 39 lbs
Tank volume 1.06 gallon 1.0 gallon 0.95 gallon 1.6 gallon 1.0 gallon
NEMA Outlets L5-20
5-20R Duplex
5-20R Duplex 5-20R Duplex TT-30R
5-20R Duplex
5-20R Duplex
Time to charge a Tesla Model 3 from 20 to 80% 15+ hrs 15+ hrs 18+ hrs 9+ hrs 19+ hrs

As a Tesla or other EV brand owner, you might find yourself in situations where you can’t connect to the grid to charge your vehicle. This may happen on camping trips or during power outages caused by natural disasters. A portable gas-powered generator can save the day and give you enough charge to get home or to the next EV charger. If you are planning to get one, this review will help you select the most reliable gas generator for a Tesla. Jump to the comparison chart.

Limit inbound power for proper charging

Start charging by setting a limit on the consumption of your electric car. This is done in the interface. Start with the minimum values, then increase to 20A (or more depending on the portable generator model) within a few minutes.

Product #1. Generac G0071540 GP3300i — Best choice with the overall best performance

The Generac G00 inverter generator is compact and very portable. It uses Quiet Inverter Power technology to reduce noise during operation and to provide optimal performance.

There is the economy mode that helps to conserve fuel by automatically adjusting the engine speed, which also reduces the noise produced.

The Generac is lightweight at 59.4 pounds, allowing it to be carried around easily by its handle. Apart from charging an electric car, it can also juice up mobile devices like smartphones and tablets through its USB ports. The status lights warn when something is wrong, for instance, the oil level is low or there is an overload on the generator.

Performance

The Generac is rated for 3300 watts starting and 2500 watts running, and provides clean and stable power suitable for charging an electric car. However, changing the oil is a chore, as the large side panel has to be removed with a screwdriver first.

Recommended?

This is the best choice as it balances performance, price, and weight very well.

Pros

Lightweight and portable

USB ports for charging electronic devices

Has a mode that saves fuel

Quiet operation

Status lights show the condition of the generator

Cons

Customer support is spotty

Changing oil could be a chore

Product #2. Generac GP2500i Inverter — Great features but with lower output

It has a bright orange and black plastic exterior. It has a simple startup procedure. It has a simple startup procedure.

The generator weighs 48 pounds and has a built-in handle. It does not take up much space.

This generator also has an economy mode for saving on fuel and LED indicators for when it needs attention or other statuses like low oil level or that the generator is ready to charge the car.

The Generac GP2500i Inverter has a safety feature that shuts down the engine automatically when the oil is too low to prevent damage. The outlets are covered for protection from the environment. The fully enclosed design of the generator reduces the amount of noise produced during operation.

The Generac GP2500i can connect in parallel with another Generac GP2500i to output more power.

Performance

The Generac is rated for 2500 watts starting and 2200 watts. The process of changing the oil is, however, needlessly complicated.

Recommended?

This generator has many practical features and good enough power output. It is easily recommended.

Pros

Can connect in parallel with another Generac GP2500i generator

Not heavy

Shuts down automatically when oil level is low

Has USB ports to charge electronic devices directly

Comes with fuel saver model

Works noiselessly

Cons

People report that customer support is not good

Adding or changing oil is complicated

Product #3. Honda 663520 EU2200i 2200-Watt — Generator with CO-Detection and Smartphone app

It has a bold red and black appearance. The Honda 663520 works on quietly that you can’t hear it over a normal conversation. It is also fuel-efficient, lasting up to 8 hours on 0.95 gallons of fuel.

It weighs only 53.57 pounds and comes with a built-in handle. It has a feature called CO detector that monitors the level of carbon monoxide and shuts down when the level is dangerously high. There are also indicator lights for oil alert, overload alarm, and eco throttle to ensure the generator works optimally.

Performance

The maximum power output of the Honda 663520 EU2200i is 2200 Watts, and 1800 Watts loaded. It is easy to disassemble for maintenance. It can be turned off via Bluetooth and monitored with a smartphone app that offers oil change reminders.

Recommended?

With the rated output so low, it will take longer to charge up your car battery. However, the three-year warranty offered by the manufacturer increases confidence in the product.

Pros

CO detector

Lightweight and portable

Fuel efficient

Quiet operation

Easy to maintain

Smartphone app for monitoring generator status

Three-year warranty

Cons

Does not produce as much power

Product #4. Champion Power Equipment 200986 4500-Watt — Most powerful but heavy and costly

The main difference from other models is the presence of an additional TT-30R socket. This is a popular socket among RV adepts, and it will help you get more power from the 30A socket for the Level 2 charger. It is easy to use with the NEMA 14-50 adapter to connect the Tesla Mobile Connector.

The Champion generator is very efficient, as it can run for up to 14 hours on only 2.3 gallons of fuel. The total weight is 95.7 pounds.

There is an intelligauge feature on the control panel for monitoring the voltage, frequency, and hours of operation, while the economy mode will monitor fuel consumption in real time.

There are two wheels at one end of the generator for easy movement. It also has cold-start technology that allows it to start quickly during cold weather.

Champion Power is offering a three-year warranty with free lifetime technical support.

Performance

The Champion Power generator has rated capacity of 4500 Watts starting rating and 3500 Watts loaded. More power can be gotten by combining two generators using the optional parallel kit. However, its heavy weight renders it less portable than the rest of the generators on the list.

The Champion Power will charge your electric vehicle faster but the high price and heavy weight make it hard to recommend.

Pros

TT-30R socket with 30A

Produces high power

Fuel-efficient

Three-year warranty with lifetime technical support

Starts quickly in cold weather

Cons

High cost

Quite heavy

Product #5. WEN 56203i Super Quiet 2000Watt — Ultra lightweight but less powerful

The WEN 56203i is just 39 pounds, making it easy to transport or lift with its built-in handle. It produces low sound when in operation.

The generator uses up all the fuel in the carburetor before shutting down, which prevents damages to it. There is also an eco-mode feature that automatically adjusts fuel consumption to save on fuel costs.

There is a two-year warranty from the manufacturer covering the generator.

Performance

The WEN generator produces 2200 Watts starting rating and 1700 Watts loaded, which means it will take the longest to charge your electric vehicle. However, you can link up two WEN generators in parallel to increase the power output, with the help of the Parallel Connection Kit that is sold separately.

The WEN generator is the least recommended despite its lightweight because it will take so long to charge your electric vehicle. However, it can work in a pinch.

Pros

Fuel efficient

Two-year warranty

Lightweight

Cons

Low power output

What did we look at when selecting the best generator models for Tesla?

In addition to power, charging time of the Tesla from a generator and technical specifications, we consider other factors.

#1 — Fuel Consumption and Running Time

The most efficient charging sources available today, inverters consume about 8 % of their overall power output charging your Tesla battery via a charger. The least efficient charging sources available today, charging cycle generators consume about 20% of their overall power output charging batteries. That’s why we focus on efficient inverter generators when choosing.

#2 — Noise Levels

Yes, true sine wave generators can be noisier than others. However, the noise level is determined by the design feature and the power limit.

#3 — Charging Costs

If you want to charge off your generator as much as possible, inverter charging generators are the most cost effective charging sources available today. Since a portable generator is often considered in the sense of a temporary solution, such use will not significantly harm your budget. The fuel consumption is proportional to the allowable peak power of the generator. 

#4 — Parallel Operation

Some portable generators for Tesla allow you to connect multiple devices because they have several outlets. Obviously, the power when plugging in another device will reduce the power capabilities of your electric vehicle charging station. 

#5 —  Warranty

Warranties range from 90 days up to 5 years on portable charging generators. Inverter charging generators have shorter warranties than charging cycle charging generators because their AC to DC charging inverters tend to wear out over time. If you’re charging your battery bank or charging station very little during an emergency situation it’s not a problem.

FAQ

How do I charge my Tesla with a portable generator?

Yes, you can charge your Tesla with some generators. You will need a properly grounded inverter that produces a clean sine wave. You will also need a high power generator. A minimum of 2000 watts is recommended when trying to charge your Tesla with a generator.

What power settings should I set in the Tesla when charging from a portable generator?

The alternator needs time to warm up. Accordingly, set the amperage to minimum with the dashboard monitor. Don’t add amps too quickly, or you risk damaging the alternator. Instead, slowly work your way up to 20–30 amps and then up to the alternator’s maximum output.

Can I use a generator to regularly charge my Tesla?

It is impractical and certainly not recommended to do so. You should not rely on a generator even as a backup plan to charge your electric vehicle. Using a generator makes the entire process of driving a Tesla less environmentally friendly than driving a conventional gasoline-powered car.

Vehicles that run on gasoline convert it directly into kinetic energy, which is not the case with power generators. Specifically, a generator first uses gasoline to produce kinetic energy and convert it into electricity, which charges your Tesla. This energy is then converted back into kinetic energy as you drive your electric car. This is a very inefficient process of turning fuel into kinetic energy that moves your car.

The idea of combining an alternator and batteries in cars to increase the driving distance has existed for a long time. But since then, batteries have been improved, and there is no longer such a need for them to be supported by an alternator.

Is it possible to connect a Level-2 EV charger to a portable generator?

Depending on the power of the portable generator, it will support L1 and/or L2 devices. In our comparison you will find generators that support high power connection over the TT-30R socket, which will be suitable for the Level-2 charging.

Since I will use the generator only occasionally, do I need to do maintenance on it?

Yes, maintenance is necessary so that you can use it when you need to do so. If left abandoned until there is an emergency, the generator might have problems starting. Be sure to run the generator once a quarter to make sure it is working well. Check the oil level regularly. Keep a maintenance schedule. Many generators will strain their coils when they run to the last drop of oil. If you need to store the generator for some time, add a stabilizer to the fuel in the tank or drain the remaining fuel. Keep the generator protected from rain or moisture.

Can I connect the Tesla Mobile Connector to a gasoline generator for charging?

Tesla vehicles may be charged using a pure sine wave inverter and a grounding solution, as long as the generator is an inverter that provides a pure sine wave and has some sort of grounding solution.

Can I charge my vehicle on the road?

You should never charge your electric vehicle while you drive, as it is not safe. You would be breaching the warranty of a Tesla car, as the manufacturer explicitly warns against doing so. Further, it’s simply not possible to charge your EV while in motion, at least not without significant alterations to your EV — which would void your warranty and possible cause serious damage.

How long can a generator run continuously on one tank of gasoline?

Based on the manufacturers’ instructions, with 50% of the load connected, we can expect the portable generators reviewed here to give us about 9–10 hours of continuous and stable power supply on a full tank. But when charging an electric car, the load is usually higher and this reduces the continuous power supply to 5 hours on one tank.

Can I parallel two generators to charge my electric car?

Yes, you can, if specified by the manufacturer. However, make sure you follow the generator manufacturer’s instructions. For example, Generac states you can only parallel two generators of the same model.

Is it possible to charge an electric car with a power extension cord?

When charging your electric car, don’t use a household multi-socket extension lead. Go with a reputable seller or the manufacturer when purchasing a charging cable that follows US safety standards. Use these basic recommendations for EV drivers and read more about comparison items here.

How much power for a generator do I need to charge a Tesla?

You’ll need a generator with at least 1,500 watts, otherwise you’ll be far from being able to charge the electric car. It would be more ideal if you have a 3,000 watt generator with a true sine wave and an EV determines that it is properly grounded.

I’ve heard of cases where the Tesla didn’t take a charge from the generator, why?

The alternator for your Tesla should produce an unchanged pure sine wave. All Tesla’s come with built-in protection that prevents charging from unstable power sources. Charging with an alternator that outputs anything other than a pure sine wave can cause a destructive voltage spike and damage your vehicle.

Here we have selected sine wave generator swith that charge electric cars and that include Teslas.

Which generators can I use to charge my electric vehicle?

When selecting a generator that you will use to charge your car, make sure it is the type that produces a clean sine wave. Tesla, for example, detects when the sine wave is dirty and simply won’t charge. The generators above produce a clean sine wave.

How do I prepare to charge my car with a generator?

It is important to ensure the generator is grounded properly. Again, a Tesla won’t charge if the grounding is not done properly. Many generators use the frame for grounding. This info can be found in the owner’s manual of each model. Always start charging with a low charge rate and gradually adjust to about 20–30 amps.

Our Top Pick

While it is not recommended to charge an electric vehicle with generators frequently, emergencies do happen that leave little or no choice. It is important to select the best generator and keep it well-maintained so that it does not disappoint you nor damage the car.

While the Generac G0071540 GP3300i Portable Inverter Generator is our best choice, any of the generators above will get the job done. They are trusted, as they have great buyers’ reviews.

Mike Becker
About Mike Becker Linked In
Mike is a seasoned engineer with 10+ years of experience in charging systems. He bought a Tesla Model S in 2014 and has been in love with EVs ever since. He runs a small EVSE installation business in Florida and blogs about what he loves.