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  • 3 Models Considered
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    We purchase every product we review with our own funds — we never accept anything from product manufacturers.

    Shopping Guide for Best Caterpillar Portable Generators

    Last Updated April 2018

    In every season of the year, the chances of a big storm knocking out power to your home exists. And with a large enough storm, it could be a few hours, a few days, or even a few weeks before the restoration of electrical service.

    A portable generator can give you some peace of mind in the face of a devastating storm. You’ll be able to generate power that keeps appliances running and water flowing in your home until power returns.

    Portable generators also have a fun side. Take a portable generator to your favorite football team’s Sunday game, and you’ll be the hit of the tailgate party.

    You’ll be able to cook while running a big-screen TV with electrical fans blowing on a hot day or portable heaters running on a cold day.

    You might not even go into the stadium, you’ll be so comfortable!

    Electric-start generators begin running after you press a button. Many people prefer this starting method to a pull cord. Some generators have both types of starts.

    At BestReviews, we’ve compiled a shopping guide to help you find the perfect Caterpillar portable generator to meet your needs.

    Caterpillar is a trusted name in power equipment, and it sits near the top of the market in terms of portable power generators.

    We pride ourselves on the detailed research we’ve performed on Caterpillar generators, and we invite you to check out our product matrix above and the shopping guide below for more insightful information.


    The Caterpillar RP7500E portable generator’s ability to run for 10+ hours on one tank of fuel at a 50% load is one of its highlights. You won’t have to wake up in the middle of the night to refill this generator’s tank, unlike some other big generators. If you’re planning to charge electronic devices with this generator, you’ll appreciate its built-in voltage regulators. The RP7500E offers impressive power levels, too, with 7,500 running watts and 9,375 starting watts. It includes an electric start that provides reliability and ease of use, along with six outlets.

    How portable generators work

    If you know how combustion engines work, you have an idea of how portable generators work. A portable generator uses fuel – diesel, propane, or gasoline – to power a combustion engine.

    The engine turns an alternator that comes part-and-parcel with the portable generator. The alternator creates electricity, which the generator turns into something that will work with standard electrical outlets and extension cords.

    After you’ve started the generator, you can plug extension cords into the outlets on the side of the generator and use the power. You must keep the unit filled with fuel to keep it running. Importantly, you must run your generator outdoors, as the engine generates poisonous carbon monoxide exhaust.

    Portable generators run loudly. Most generators run at levels of 70 decibels or higher.


    Key features of portable generators

    When comparing portable generators, you'll want to pay attention to a few features in particular. These features allow the generator to meet your needs while operating as easily as possible.

    Fuel type

    Most portable generators run on diesel, gasoline, or propane fuel. Gas generators are the most common and the easiest to run; Caterpillar generators typically run on gas. But if you plan to use your generator a lot, propane will be cheaper, and diesel fuel stays fresher longer.


    Some generators will run on propane, while others run on gasoline or diesel.

    Run time

    Manufacturers estimate the amount of time a given generator can run on one tank of fuel. Potentially buyers should understand that the estimated run time listed uses a 50% load measurement. So if you run closer to the maximum wattage, you’ll experience a shorter run time than estimated.

    Running wattage

    A generator’s running wattage figure refers to the amount of power it provides as it operates. A higher number equals more power to run more appliances. Larger generators tend to offer greater wattage. Caterpillar portable generators offer running wattage between 3,500W and 15,000W.


    When running an extension cord from a generator, use one rated for outdoor use. The cord should be no longer than 100 feet for safest operation.

    Staff  | BestReviews


    Portable generators are box-like in shape. A metal frame surrounds and protects the engine parts. This frame also provides a hand grip for lifting and carrying the unit. Most Caterpillar portable generators measure 2 to 3.5 feet in length and 1.5 to 3 feet in height and width.

    Start method

    To start a portable generator’s engine, you either pull a starter rope (called a recoil) or press a starter button. Starter buttons are easier to use, but notably, the newest generators on the market have starter ropes that are also very easy to use.


    The Caterpillar RP5500 doesn’t yield top-end power, but it will perform well enough for a lot of home users – and at a great price, too. The unit is small and has two wheels, allowing you to roll it wherever needed, even if you're working in poor weather. It has plenty of built-in safety measures, including GFCI outlets that automatically shut off if the machine detects problems. The RP5500 offers 5,500 running watts and 6,875 starting watts with up to 15 hours of running time at 50% load. It has five outlets.

    Starting wattage

    A generator’s starting wattage figure refers to the amount of power the generator provides for a short time after the unit starts. This number is higher than the generator’s actual running wattage. It helps with running appliances that need a burst of power to start. A portable generator’s running wattage figure can give you a good feel for the long-term performance of the unit.

    Tank size

    Portable generators with large fuel tanks require fill-ups less often. You’ll love this feature when running the generator during poor weather conditions. But units with large tank sizes also weigh more, making them more difficult to move.


    Adding fuel stabilizer to a portable generator tank prevents the gasoline from degenerating. This keeps the fuel fresher for longer.


    Yes, these units are portable. But they still carry a lot of weight. Caterpillar portable generators typically weigh between 125 and 400 pounds. This means you’d need some help in lifting your generator in and out of a car or truck.


    Most portable generators, including Caterpillar units, have two sturdy wheels on one end. The wheels allow you to lift the other end and move the unit by rolling it. They also help you deal successfully with the heavy weight of the machine.

    Starting wattage, also called surge wattage, is the measurement of a generator’s peak wattage. Peak wattage only lasts for a short period of time after the initial start-up.


    Figuring out wattage needs

    Finding the right Caterpillar generator for your needs also involves figuring out your wattage needs.

    A generator’s “running wattage” figure represents its wattage output.

    So figure out what appliances you need to run during a power outage – or determine what you need to run at a tailgate – and proceed accordingly.


    Whether you need a portable generator for using power tools in a remote area, powering devices at a football tailgate, or keeping your home’s appliances running after a storm, the Caterpillar RP6500E is a great mid-sized option with a smart price tag. All of the controls sit on one side of the generator, making it easy to operate. This unit offers 6,500 running watts and 8,125 starting watts with six different outlets, providing the perfect level of power. It’ll run for 12 hours at 50% load on one tank of fuel. The electric start makes turning on the RP6500E a breeze, regardless of weather conditions.

    The wattage needs of common appliances are listed below.

    • Clothes dryer (Electric): 4,000 to 6,000 watts

    • Coffee Maker: 700 to 1,200 watts

    • Computer: 100 to 300 watts

    • Dishwasher: 1,200 to 2,000 watts

    • Freezer: 500 to 800 watts

    • Grill (Electric): 1,500 to 2,000 watts

    • Lamp: 10 to 60 watts

    • Laptop Charging: 40 to 100 watts

    • Microwave Oven: 625 to 1,000 watts

    • Portable Air Conditioner: 750 to 1,500 watts

    • Portable Electric Heater: 1,000 to 2,000 watts

    • Refrigerator: 500 to 800 watts

    • Smartphone Charging: 10 to 25 watts

    • Stove (Electric): 1,500 to 2,500 watts

    • Tablet Charging: 10 to 25 watts

    • TV: 100 to 400 watts

    • Washing Machine: 750 to 1,500 watts

    • Water Heater (Electric): 3,000 to 5,000 watts

    Research the appliances you have in your home to determine their exact wattage needs. (Keep in mind you won’t likely be running all of these items at once.) We recommending buying a generator that can take on your maximum wattage needs plus another 25 percent. That way, you’d likely be covered if you were to add appliances to your home after the purchase of the generator.

    Let your portable generator run every month or so, even if you don’t need it. This keeps the engine primed and ready for when you need it.


    Q. Why is my portable generator running so loudly and roughly?

    A. If you place a portable generator on uneven ground, it could shake slightly, causing noise. Make sure you’re using a fresh source of fuel in the generator. Check all of the unit’s fluid levels. If the fuel and fluids look correct, consider the air intake. Often times, a generator running roughly needs a new air filter.

    That said, it’s important to know that most generators put out noise when they run. The noise you’re hearing could be a normal part of its operation.

    Q. Should portable generators be grounded?

    A. Most portable generators do need to be grounded for safe operation. Read through your generator’s instructions for specific recommendations on grounding the unit. You may need to consult with an electrician to ground your portable generator properly.

    Q. What are some maintenance tasks I need to perform on my generator?

    A. As with most gas-powered engines, regular maintenance will increase the longevity of your unit. Generators need to have the oil filter, fuel filter, and air filter changed on a regular basis, usually after a certain number of hours of operation. Each individual generator runs slightly differently, so check the instruction manual for your unit for specific recommendations on maintenance.

    Q. Where should I place my portable generator?

    A. A portable generator creates exhaust as the engine runs, so it must be operated outdoors. This provides plenty of airflow to clear the exhaust. Some people will run a generator in a garage with the door open (never closed!) to encourage fresh airflow. Others build an enclosure on a patio that protects the generator from the elements while simultaneously allowing airflow.

    The team that worked on this review
    • Devangana
      Web Producer
    • Eliza
      Production Manager
    • Kyle
    • Melissa
      Senior Editor