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Generac GP3500iO - 3000/3500W Open Frame Inverter Generator

The Generac GP3500iO (7128) is a compact and lightweight open frame inverter generator with a rated wattage of 3,000 W and a starting wattage of 3,500 W.

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Description

Portable generators are a welcome addition to many activities at home, at work, and away. In an emergency, portable generators can provide critical backup power. They make camping and tailgating more comfortable. And contractors appreciate the flexibility portable power brings to the jobsite. (source: Generac (opens in a new tab))

Zoom on the Generac GP3500iO

In a nutshell, the Generac GP3500iO is a compact and lightweight portable inverter generator mostly geared towards:

  • RV travellers who wish to upgrade their experience to another level
  • Occasional participants of outdoor events, competitions, concerts and festivals
  • DIYers who wish to improve their efficiency with tools
  • Homeowners who want to be able to use the most necessary devices in their household, even during a blackout
  • Tailgating and campground aficionados with the desire of enjoying power anywhere they go

In the following paragraphs, we shall explore the power characteristics, available outlets, portability, and any additional features of the device, along with its emission compliance information.

Power & Run Time

The Generac GP3500iO in use

The Generac GP3500iO

The Generac GP3500iO houses a 212 cc Generac OHV 4-stroke engine, which provides 120V, consumes gasoline and delivers a running wattage of 3,000W along with a peak wattage of 3,500W. Additionally, as the generator is parallel capable (GP3500iO Parallel Kit not included), it can be linked to a second unit for more power.

This inverter generator gets running thanks to a conventional pull-start mechanism. It features Generac's PowerDial™, an easy-to-use dial with three operation settings.

Thanks to a fuel capacity of 2.37 gallons, the GP3500iO can operate for up to 11 hours with a full tank (fuel consumption around 0.22 GPH).

Delicate electronics can be plugged in an AC outlets safely, as the GP3500iO generates a clean sine wave, reaching a <3% Total Harmonic Distortion (THD).

Outlets

The control panel features the upcoming 3 AC outlets:

Duplex 120V 20A (5-20R)
120V 30A (L5-30R) receptacle

In addition, it provides 2 DC outlets: there's two 5V USB ports with which you may charge electronics, for example mobile phones or tablets, conveniently.

This Generac generator features an L5-30R receptacle, enabling an easy RV connection via an L5-30P to TT-30R adaptor. However, it is still not quite RV ready.

Portability

With its dimensions of L19.3 x W16.9 x H16.4 in, the conventional, open frame design of the Generac GP3500iO offers stability and allows the generator to be raised above ground level. The generator is designed for ideal use outdoors and in rough environments.

The GP3500iO's dry weight of 74.3 lbs lets you use its power anywhere needed. Moreover, its open frame design makes it incredibly easy to grab the frame in order to change its location.

Features

Panel of the Generac GP3500iO

The GP3500iO's control panel

A digital data center, one of the features of the GP3500iO's control panel, gives you information on the lifetime run hours, and thus, is helpful for the monitoring of its activity and status.

In addition to this info, when the generator is overloaded, the oil level is too low and the generator is ready, you will be informed by the featured light indicators.

From a security standpoint, the product offers an overload protection (circuit breaker) and an automatic low oil shut-off, allowing you to use it with a peace of mind.

Along the basic documentation and an owner's manual (opens in a new tab), useful for starting the generator right away, the Generac GP3500iO's package also includes these accessories: funnel, tool kit and oil.

Emissions

The Generac GP3500iO is CARB-compliant. Thus, selling and purchasing this generator is allowed in each of the 50 states, including California.

Moreover, it features a spark arrestor and thus, may be used in forested areas.

Product Videos

The Generac GP3500iO versus other generators

The following charts are provided to give you an idea of how some of the key specs of the Generac GP3500iO compare to inverter generators of similar power (between 2500 and 3500 W).

  • In terms of its dry weight, the Generac GP3500iO stands at only 74.3 lbs, meaning that is one of the lighter inverters of the 2500-3500 rated wattage category If weight matters to you, one of the champions in this power range is the Pulsar PGD40iSCO with only 46 pounds.
  • As for its autonomy, the GP3500iO, with an autonomy of up to 11 hours at a 25% load, is placed on the low end among the generators of its kind. If autonomy is your priority, one of the devices of a similar power output with the highest run time is the Champion 200914, reaching up to 22 hours.
  • Even though run times are undoubtedly important, they are dependent on the fuel capacity to a large extent. For a more wholesome picture, we must take into consideration the fuel consumption of the generator. This inverter generator is rather wasteful, compared to other devices within the aforementioned output range, when it comes to gasoline consumption, as it reaches roughly 0.22 GPH at a 25% load. If you wish to further improve in the area of fuel efficiency, the Energizer eZV3500P, which boasts with a gas consumption of only 0.13 GPH, may be the right generator for you.

Price comparison

As you can see from these interactive charts, when compared to other 2500-3500W inverter generators, the Generac GP3500iO is on the average side of the price range.

Therefore, this generator nicely fits in the expected budget for this kind of product.

The bottom line

STRENGTHS:
  • In the expected price range
  • Several accessories included
  • Parallel capable
  • Inverter
  • Lightweight (74.3 lbs)
WEAKNESSES:
  • No electric start
  • Relatively low run time
  • Low fuel efficiency

Do you own the Generac GP3500iO and agree (or disagree) with these strengths and weaknesses?

Let us know and write your own review.

Features and Specifications

General
InverterYes
Parallel capableYes, cable not included
RV readyNo
FuelGasoline
Engine212 cc Generac OHV 4-stroke
Starting systemRecoil
Warranty3 years
Power
VoltageAC: 120V 60 Hz, DC: 5V
Running watts3,000 W
Starting watts3,500 W
Running amps25 amps
Peak amps29.2 amps
Run time @50% load8 h
Run time @25% load11 h
Features
GFCI outletsNo
Covered outletsNo
Automatic Voltage RegulationInverter
AC outlets
  • 1x Duplex 120V 20A (5-20R)
  • 1x 120V 30A (L5-30R)
DC outlets2x 5V USB port
Data centerLifetime run hours
IndicatorsLow oil, overload and output ready
Fuel tank2.37 gal
Fuel gaugeNo
Misc
Weight74.3 lbs
Approx. dimensions (L x W x H)19.3 x 16.9 x 16.4 in
Noise (lower limit)Unknown
THD< 3%
ComplianceCARB
SecurityLow oil and overload protection
Spark arrestorYes
NeutralFloating
Accessories includedOil, funnel, and tool kit
Other model numbers7128
UPC696471072020

Unlike many websites, we did our best to research each of the specs above. That being said, we are not immune to making the occasional mistake or omission. Should you notice any missing or incorrect values, don't hesitate to suggest improvements so we can address the issue.

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About Generac

Generac Power Systems is an American based generator and power equipment manufacturer, founded in 1959. As its name suggests, the main focus of Generac are power generators, and other related electric equipment, such as switches, paralleling systems and small engines. The company has several manufacturing facilities based in the US, thus, their products are engineered and built in the USA. However, their components can be a mix of domestic and foreign parts.

Warranty Information

The Generac GP3500iO is covered under a warranty for up to 3 years. This warranty may be limited and may not cover all parts of the generator.
For more information about the warranty of Generac generators, please consult Generac's warranty policies (opens in a new tab). Alternatively, you can also contact their Customer Support: 1-888-GENERAC (888-436-3722).

Questions & Answers

What can it power?
Examples of items that can be simultaneously powered.
The examples below are based on a maximum load of 80% and estimated wattages. For a more accurate estimation, use our generator sizer.
ItemRunning WattsStarting Watts
At homeRefrigerator (energy star)1921192
Hair dryer18001900
Blender400850
Total2392 W3392 W
For campingRadiant heater13001300
RV refrigerator180600
Toaster oven800800
Radio100100
Total2380 W2800 W
For workGrinder14002500
Reciprocating saw730960
Drain cleaner250250
Total2380 W3480 W
What is the noise rating of the GP3500iO?

Due to the lack of standardization in noise emission measurement, Generac does not provide their units' noise levels.

Does it have an eco mode? (Asked March 19th, 2020)

There is an economy switch that can be put to "ON" when running appliances or equipment that are resistive loads (non-motor starting), such as TVs, lights, laptops, etc.

I want a fuel shut off valve where do I find it (Asked September 24, 2020)

The "OFF" position of the PowerDial Switch stops the engine and shuts off fuel flow.

This unit is a inverter generator ,why do you say it isn't for RV . Is it good for Small 24 ft. Travel trailer? 1 small roof air conditioner? And tv outlets few other things ? (Asked March 20, 2021)

We did not say it's not for RV. We said it's not RV-Ready, since it does not have a TT-30R outlet. This does not mean that the unit is not suitable for an RV. You may read our definition of RV-Ready and use our wattage calculator to estimate your appliances power needs.

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Generac GP3500iO
9 Total Score
2 reviews
Add your review
Price
9.5
Value
9.5
Quality
8.5
Performance
8.5

User Reviews

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  1. 4.15
    Price
    90
    Value
    100
    Quality
    70
    Performance
    70

    For the price. Runs close to a honda. Quality is good not perfect.

    + PROS:
    • Large watt inverter for great price. Hour meter is convenient. Fuel gauge on top is useful.
    - CONS:
    • Some parts rattle at certain rpms.
    Helpful(0) Unhelpful(0)You have already voted this
  2. 4.9
    Price
    100
    Value
    90
    Quality
    100
    Performance
    100

    Great generator

    + PROS:
    • Had this generator for over a year. Here hurricanes hits yearly and electricity is out from 1 to 7 days...so far It starts up with ease all the time for me. Easy to maintain. I have a large fridge and 3 other items connected. Runs smoth and no issues. Happy with my generac.
    - CONS:
    • So far no cons that i can see or gone through.
    Helpful(0) Unhelpful(0)You have already voted this

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