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. (Read full specs)

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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 few words, the Generac GP3500iO is a compact and lightweight portable inverter generator perfectly suited for:

  • RV travellers looking for even more independence
  • People occasionally participating in outdoor fairs, festivals or events
  • Amateur DIY lovers
  • Homeowners who want to be able to use the most necessary devices in their household, even during a blackout
  • Camping and tailgating hobbyists looking for a portable power source

Over the following sections, you'll uncover its power characteristics, the selection of outlets it offers, its overall portability, and the supplementary features it includes.

Power & Run Time

The Generac GP3500iO in use

The Generac GP3500iO

Running on gasoline, the Generac GP3500iO operates with a 212 cc Generac OHV 4-stroke engine, delivering 120V, with a running wattage of 3,000W and a peak wattage of 3,500W. In addition, the device is parallel capable (GP3500iO Parallel Kit not included) and thus, can be linked to a similar or compatible unit for added power.

This inverter generator gets running thanks to a classic hand-operated recoil starting mechanism. It features Generac's PowerDial™, an easy-to-use dial with three operation settings.

The GP3500iO's fuel tank, boasting 2.37 gallons, allows it to operate for up to 11 hours with a full tank (with an estimated fuel consumption of 0.22 GPH).

As the GP3500iO produces a clean sine wave, with a <3% Total Harmonic Distortion (THD), sensitive electronics may be plugged in the AC outlets safely.

Outlets

The control panel features the upcoming 3 AC outlets:

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

Moreover, it boasts 2 DC outlets: there's two 5V USB ports enabling convenient charging of devices like mobile phones and tablets.

Despite not meeting the 'RV Ready' criteria, this Generac generator grants the advantage of simple RV compatibility via its L5-30R receptacle, enabling you to conveniently power your RV by using an L5-30P to TT-30R adaptor.

Portability

At L19.3 x W16.9 x H16.4 in, the traditional open frame structure of the Generac GP3500iO ensures stability while facilitating convenient maintenance access to components and promoting air cooling. The device has been designed for tough environments and demanding outdoor use.

With a dry weight of 74.3 lbs, the GP3500iO can easily follow you wherever your power needs are. In addition, it is even easier to grab and move the generator around thanks to its open frame design.

Features

Panel of the Generac GP3500iO

The GP3500iO's control panel

To help you monitor the GP3500iO's status and activity, its control panel is equipped with a digital data center, giving you information on the lifetime run hours.

In addition to this info, the generator's light indicators provide visual feedback when its oil levels are insufficient, the generator is ready and the generator is on overload.

As for its security measures, the device features an overload protection (circuit breaker) and an automatic low oil shut-off, letting you use it with a peace of mind.

Apart from the typical documentation and an owner's manual (opens in a new tab), which lets you start it right away, the Generac GP3500iO also is packed along with the following accessories: funnel, tool kit and oil.

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).

  • Regarding its weight, the Generac GP3500iO only weighs in at 74.3 pounds, which means it's one of the lighter inverter generators in the 2500-3500 rated wattage range. If weight is an important consideration for you, the Pulsar PGD40iSCO stands out as one of the top contenders in this power category, with a dry weight of 46 pounds.
  • Regarding its autonomy, the GP3500iO can run for up to 11 hours at a 25% load, aligning it with the lower performers in its type and power range. Concerning the run times, one of the several devices with a comparable output, offering the highest autonomy, is the Champion 200977, which is able to run for up to 22 hours.
  • Run time is a key metric, but it's dependent on the generator's fuel capacity. Therefore, discussing fuel efficiency is necessary to get the full picture. Compared to its peers, this inverter generator is not exactly fuel-efficient, compared to similarly powerful devices, with an estimated fuel consumption of 0.22 GPH at a 25% load. If gasoline efficiency is at the top of your list, you may want to have a look at the Energizer eZV3500P, which has great fuel efficiency, with a gas consumption of only 0.13 gallons per hour.

The bottom line

STRENGTHS:
  • 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 sizing calculator.
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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