CAT Portable Generators – Compare INV1250 vs INV2000 vs RP3600 vs RP12000 & More

Last Updated on April 21, 2023 by Rod Olivares

Caterpillar has been one of the leading manufacturers of industrial and commercial equipment for decades.

CAT has designed and manufactured a wide variety of portable generators to fit just about every need.

If you are in the market for a CAT generator, this article should help give you everything you need to know about the best CAT portable generators on the market.

Let’s take a look at the best Cat generators ranked by their running watts.

CAT Generator	Running Watts	Starting Watts	Weight	Run Time @ 50% Load
INV1250	1000 Watts	1250 Watts	33.1 lbs	7.9 Hours
INV2000	1800 Watts	2250 Watts	57.3 lbs	6 Hours
INV4000	3200 Watts	4000 Watts	103.6 lbs	8 Hours
RP3600	3600 Watts	4500 Watts	123.22 lbs	13.5 Hours
RP5500	5500 Watts	6875 Watts	177.73 lbs	15 Hours
RP6500	6500 Watts	8125 Watts	200.23 lbs	12 Hours
RP7500	7500 Watts	9375 Watts	205.73 lbs	11 Hours
RP12000	12000 Watts	15000 Watts	395 lbs	11.7 Hours

1. CAT INV1250

First up on our list is the CAT INV1250 inverter generator. This inverter is a simple, take anywhere generator that provides you with the wattage needed to power a single tool or appliance.

This generator works great for camping, using a tool away from a power source, or even to keep a small TV going during a power outage.

Power

Don’t let the INV1250’s small frame fool you, this little generator sports a 60cc engine capable of putting out 1,000 running watts and 1,250 starting watts.

This is going to be plenty for the use of a single tool or small appliance. This power range is perfect for outdoor recreation, mobile hospitality, and tailgating.

Outlet Selection

Even though INV1250 is small, you still have a nice selection of outlets to make full use of the 1,000 running watts.

Choose from the included 1 5-20R Duplex outlet, 1 5V 2.1A USB outlet, 1 5V 1.0A outlet, and 1 12V DC 8.3A outlet. This variety makes it easy to plug in small electronics for quick use or charging.

Fuel Capacity & Run Time

With a 0.8 gallon fuel tank, you can still get nearly 8 hours of run time from this little inverter at 50% load.

This makes it an excellent choice when tailgating or camping to keep the party going all day (or night) long.

Stand Out Features

The standout features of this inverter are going to be the 4 different outlets packed into such a small inverter. You will also get the availability or running two of these generators with the built in parallel outlets to double the power of your inverters.

IMHO: In My Humble Opinion
If you are needing a small, 1000 watt generator, the CAT INV1250 is going to allow you to plug in just about anything you may need to charge or power on your next camping trip or tailgating party. This inverter was built to power small electronics, tools and appliances and will be a great tool to add to your collection for small emergency needs.

2. CAT INV2000 Generator

If you are needing just a little more power for your tools or home back up power needs, the INV2000 will offer nearly double the power of the INV1250, making it perfect for residential use.

Power

The CAT INV2000 generator is going to feature a 79.7cc OHV engine that will rate this generator at 1,800 running watts and 2,250 starting watts.

This power level is perfect for high power tools, running multiple smaller tools, providing home backup power support for smaller appliances, and powering your next tailgating party.

Outlet Selection

This generator is going to offer you greater protection for your outlets in the form of plastic, snap-in outlet covers.

These covers help to provide protection against moisture, debris, and dirt that can damage your outlet and generator.

Take your pick from 2 5-20R GFCI outlets, 1 5V 2.1A USB outlet, 1 5V 1.0A outlet, and 1 12V DC 8.3A outlet.

Fuel Capacity & Run Time

The INV2000 is going to get a 1 gallon fuel tank that will allow for up to 6 hours of run time at 50% load.

Of course, with less use you can extend this run time and if you are using your generator at full load, these times will decrease.

Stand Out Features

The features on this generator are pretty standard for an inverter.

You will get the benefit of it being quiet enough to meet National Park Service campground requirements and being OSHA compliant for safety compliant worksite use.

IMHO: In My Humble Opinion
If you are looking for an easy to transport, 2000 watt generator, the INV2000 is a superb choice. The outlet selection, easy to carry handle, and covered outlets make this generator stand out from the competition and provide easy use from just about anyone. Parallel capabilities would have been nice, but I would still highly recommend this generator for this power range.

3. CAT INV4000

At nearly twice the wattage capacity as the INV2000, the INV4000 generator is the next best step up when it comes to CAT generators.

Perfect for campsites, worksites, and residential, this generator is the total package when it comes to mid-level power generators.

Power

With a 212cc OHV engine, the CAT INV4000 generator is able to put out 3,200 running watts and 4,000 starting watts. CAT lists this generator as a suitable generator for RV, Tailgating, Camping, Outdoor Recreation, Mobile Hospitality, Emergency Backup Power, and DIY Projects.

Outlet Selection

Covered outlets make an appearance on the INV4000 which make this generator a great choice for any type of climate.

Choose from 1 5-20R GFCI Duplex outlet, 1 L14-30R (Twist Lock) outlet, 1 5V 2.1A USB outlet, 1 5V 1.0A USB outlet, and 1 12V DC 8.3A outlet.

Fuel Capacity & Run Time

The 2.1 gallon tank on the INV4000 is going to allow you to enjoy up to 8 hours of use at 50% load.

This will ensure that you get just about a full work days use from your generator as long as you are not using it at full capacity.

Stand Out Features

With the size and weight of this generator making it impossible to carry by yourself, CAT has designed a folding, double hinged handle that pair with the never flat wheels to make for quick and easy transportation of your generator.

You can also enjoy an electric push button start to make using the generator much easier. A Smart Display allows you to easily read out the remaining run time, power and fuel levels volts, and hertz.

IMHO: In My Humble Opinion
The INV4000 generator is a great all around mid level generator that is both easy to transport and easy to use. The push button start makes it much more convenient to use than a traditional pull cord and the outlet selection allows you to plug in just about any tool or appliance you may need for your home, job site, or RV. This generator would be a great solution for those who enjoy camping, tailgating, or who need a solution for their job site or home back up.

4. CAT RP3600

As I make my way down this list, the CAT RP3600 is a great segway into the larger generators meant for heavier duty machinery.

This does not mean that they cannot still be used for light duty use, but when you are needing something to take on the rough conditions of a job site, you are going to need the right tool for the job.

Power

The CATRP3600 is outfitted with a 212cc Caterpillar engine that allows for it to be rated at 3,600 running watts and 4,500 starting watts. You can expect this generator to be perfect for home back up power and job site applications.

Outlet Selection

This generator is going to offer 5 different outlets with all of them being protected by plastic outlet covers for protection from dirt, debris, and moisture. Take your pick from 4 20A 120V outlets and 1 30A 120V TT-30 outlet for some of your larger appliances or tools.

Fuel Capacity & Run Time

You can expect this generator to provide you with up to 13.5 hours of run time when used at 50% load thanks to the 4.5 gallon fuel tank. There is also a built in dial gauge on this generator to keep you informed of your fuel levels.

Stand Out Features

Besides being able to power an average RV AC unit, this generator is EPA compliant and features a couple of great amenities. A digital meter gauge allows you to keep up with hours, volts, and hertz while using the generator. You will also notice a small LED light mounted in the bottom right hand corner of the control panel to allow for easy readings when using the generator in dark conditions.

IMHO: In My Humble Opinion
The CAT RP3600 generator is a great generator for those who need an easy to transport, durable power solution both on and off the job site. Built to withstand any type of climate, this generator, in my opinion, would be a great option for both homeowners and job site supervisors.

5. CAT RP5500

Stepping it up a notch is the CAT RP5500, a similar generator to the RP3600, but with some much needed extra power.

The 3600 provided great power for light duty use, but the 5500 is going to allow you to use either larger tools/appliances, or more of them if needed.

Power

CAT has dropped in a 300cc Caterpillar engine into this generator to allow for up to 5,500 running watts and 6,875 starting watts to ensure you have enough power for your next power outage or job site.

While this type of wattage may be a little overkill for home backup power, depending on the house and appliances, it may be ideal for your situation.

Outlet Selection

Looking at the RP5500, the control panel looks quite similar to the RP3600.

Taking a closer look, you will notice that there is actually an upgrade in the outlets.

You will now get 4 20A 120V GFCI outlets and 1 30A 120/240V TT-30 outlet. This upgrade allows you to run bigger tools and appliances without worry.

Fuel Capacity & Run Time

The CAT RP5500 generator is going to utilize a 7.9 gallon fuel tank that will allow you to enjoy up to 15 hours of run time at 50% load.

This should be more than enough to get your through your work day or power your a/c or furnace through the night.

Stand Out Features

While this generator isn’t going to feature any stand out options, the 15 hour run time is going to be one of the major selling points.

Many generators in this power level are not able to sustain this type of runtime.

IMHO: In My Humble Opinion
This generator is definitely going to be geared to those who are needing a long lasting generator that is maintenance free throughout the day. With a mid-level power range, multiple outlets to choose from, and a 15 hour run time, this generator is going to be a job site’s best friend.

6. CAT RP6500

For larger job sites or RV use, the RP6500 generator is going to accommodate larger tools and appliances to ensure that even your largest appliances can be powered alongside your smaller appliances.

Power

With a large 420cc CAT engine on the RP6500, you can expect a rating of 6,500 running watts and 8,125 starting watts from this generator.

This is going to be best suited for RVs and commercial use since most home backup needs will not reach the 6,500 running watts.

Outlet Selection

Of course with more power comes more outlet selections. This outlet is going to be outfitted with the same 4 20A 120V GFCI outlets and 1 30A 120/240V TT-30 outlet as the RP5500 but you will get an additional 30A 120V L5-30 outlet as well to help power some of your larger tools or appliances.

Fuel Capacity & Run Time

You can enjoy up to 12 hours of run time on the RP6500 thanks to the 7.9 gallon fuel tank.

This should give you more than enough use throughout the workday without having to worry about filling the tank back up.

Stand Out Features

As generators get higher in wattage capacities, they become less riddled with standout features as they are more than often used for commercial use only.

This generator is a good example of having great features such as covered outlets, digital meter, and electric start, but nothing too fancy that would make someone base a purchasing decision off of.

IMHO: In My Humble Opinion
There is not one thing that I could find that I did not like about this generator. As a commercial use generator, it has just about all of the features one could ask for to ensure you have everything you could need. With a 12 hour run time, electric start, and being EPA compliant, it will be hard finding a better generator in its power class.

7. CAT RP7500

A step above the RP6500, but in the same family, is the RP7500. The RP7500 follows the same framework as the 3600-6500 generators did, but with upgraded hardware.

There is nothing groundbreaking with the RP7500 when compared to the 6500, but it is worth mentioning due to its power capabilities.

Power

Caterpillar has equipped the RP7500 with a 420cc engine that is powerful enough to push the ratings of this generator to 7,500 running watts and 9,375 starting watts.

This type of power range will limit this generator to be used for either RV, food truck, or job site use only. While you could still use it for home backup power if needed, this is not going to be the sole purpose of this generator.

Outlet Selection

When it comes to outlet selection on the RP7500E, you will notice that it is exactly the 6500.

That is due to the outlets being able to handle the same appliances with the additional power that the 7500 has.

Fuel Capacity & Run Time

The RP7500 generator is going to feature a7.9 gallon fuel tank that will allow for an 11 hour run time.

This can be increased by using less of a load and decreased when using more than 50% load.

Stand Out Features

Much like the 6500, the 7500 is not going to change the world with any of its features.

The digital gauge and covered outlets are a plus, much like the integrated handle and wheels, however, many of the CAT generators are going to come equipped with these.

IMHO: In My Humble Opinion
If you liked all of the features of the 6500 but needed a little more power, the 7500 is going to give you exactly what you need. The last rung in the RP series, the RP7500 is going to give you the most wattage in this small, easy to transport setup. This generator will most likely be best suited for job sites, RVs, or those who absolutely need high wattage capacities around the house.

8. CAT RP12000

Last but certainly not least is the powerful CAT RP12000 generator.

As a high wattage generator, this unit is going to be best suited for those who are using tools that require the largest of portable generators to get the job done.

Power

With a 670cc v-twin OHV engine, you can expect this generator to be capable of 12,000 running watts and 15,000 starting watts.

It will come equipped with a pressurized oil system to ensure your engine gets oil where it needs it the most. You will also get to take advantage of electric start for quick and easy use.

Outlet Selection

There is no shortage of outlets on this generator, as a matter of fact, you can choose from 8 different outlets to use every bit of your 12,000 running watts.

Choose from 1 DC 12V 8.3A outlet, 4 20A 120V GFCI household outlets, 2 30A 120V L5-30 outlets, 1 30A 120/240V L14-30 outlet, and 1 50A 120/240V L4-50 outlet.

This hand picked selection makes this generator ready for just about anything, including being plugged straight up to your RV.

Fuel Capacity & Run Time

When dealing with these larger generators, you are going to get a larger fuel tank to support the larger engines. This particular generator is going to feature a 13.2 gallon fuel tank to allow you to get nearly 12 hours of run time at 50% load.

Stand Out Features

A couple of features that make this generator a little better is the utilization of covered outlets, LED lights on the control panel, an idle control switch, and a digital meter.

IMHO: In My Humble Opinion
If you are in the market for a generator that is going to give you all of the wattage that you could ever need, look no further than the CAT RP12000E. This generator has all of the basic necessities without any bells and whistles that could make the generator harder to use than it needs to be. This is going to be a perfect fit for construction crews, full home backup power, or complete RV use.

Frequently Asked Questions

Final Words on CAT

Now that I have walked through some of the best CAT portable generators, you should be able to make a better decision on which may be a perfect fit for your application.

When it comes to Caterpillar generators, you can never go wrong as they produce high quality products that are built to last.

As with any generator, you are going to want to ensure that you familiarize yourself with the user manual and maintenance guide to make sure your CAT generator last for years to come.

Each CAT generator comes with a 2 year warranty that can be extended an extra year if your generator is registered within the first 30 days.

Are you currently using a portable generator? If so, what size, and what appliances are you running with it?

Please consider sharing this post with anyone you know who might be in the market for a CAT generator!