Open frame inverter generators might look like normal portable generators, but the addition of an inverter system makes it quieter, and it provides cleaner power. For this review, I answer a few questions about the noise level, fuel capacity, run time and application of the Generac GP3500iO open frame inverter generator (model number 7128).
What is the noise level of the Generac GP3500iO?
We do not know the answer to this question because Generac does not provide decibel levels for their generators like other manufacturers. The only noise level claim they make in the spec sheet is that the Generac GP3500iO is 50% quieter when compared to the Generac GP3300. Of course, that still does not give us a decibel rating.
Another example is the Generac GP2200i portable inverter generator (read review here) which has a closed design: as a result it is quieter than the open frame design of the GP3500iO. Therefore, the GP2200i is a better choice for camping and hunting when compared to the GP3500iO.
What is the fuel and oil capacity of the engine?
This open frame inverter generator is powered by a 212cc OHV gasoline engine. Its fuel tank has a 2.37-gallon (9L) capacity while its oil capacity is 0.6 qt (10W-30/SAE 30). A bottle of engine oil and an oil funnel is included with the generator.
A fuel shut off is integrated into the engine dial knob. The engine is protected against running without oil by a low oil shutdown function. It seems like a small hour meter is built into the control panel.
This generator has neither an electric starter switch nor a remote key fob. It only has a recoil pull start handle.
What are the estimated run times of the Generac GP3500iO?
This inverter generator might run for up to 8 hours at 50% load on a full gas tank (2.37 gallons). The estimated run time at 25% load is almost 11 hours. You might press the economy mode switch to decrease engine speed and noise and increase fuel efficiency while under very low power loads.
Which devices can the Generac GP3500iO run?
This open frame inverter generator produces 3000 running watts and up to 3500 peak starting watts.
Devices and appliances with an electric motor needs more watts when starting up compared to running continuously.
For example, a 15000 BTU RV air conditioner might need only 1800 watts when running but a lot more when starting its motor. The total wattage required should take into account the peak power draw of a device.
The refrigerator/freezer is the prime example of a household appliance that draws more power when starting up. The running watts for a refrigerator is only around 700.
The job site has quite a few examples of electric tools that need extra starting watts such as the air compressor, circular saw, belt sander and hand drill.
You should check each device for the actual power requirements before making your calculations. Remember that amps multiplied by volts equals watts.
Can it run household appliances during a power outage?
Yes, the inverter system provides clean power with less than 3% total harmonic distortion (THD). It has the following outlets available:
- 120V 20A 5-20R Duplex
- 120V 30A L5-30R Twist Lock
- 5V DC 1A/2.1A USB
Let us do a quick calculation on what you might run during a power failure.
First of all, you need to run the refrigerator, so that is 700 running watts.
Furthermore, you might want to watch something on the LED/LCD television, hence another 120 watts. We almost forgot the lights, thus 600 watts more.
In addition, you might use either the microwave oven, toaster or coffee maker at around 1500 watts.
Add it all up and you get a minimum running watts requirement of at least 2920. That is within the 3000-watt rated power of the GP3500iO. The inverter generator still has 500 extra starting watts available should the refrigerator/freezer motor turn on again. Of course, this is merely an example of what this generator might run during a power outage.
The Generac GP3500iO might be too small to run a window AC unit that requires more than 3500 starting watts. In reality, you will need a much more powerful portable inverter generator to run an entire household during a power failure.
Is the Generac GP3500iO capable of parallel connections?
Yes, this 3500-watt open frame inverter generator is parallel ready with parallel outlets on its control panel. You can connect this generator in parallel with another GP3500iO. The inverter parallel kit (model 7668-0) is not included, but it is sold separately.
Please note that you cannot connect this generator in parallel with a different Generac model such as the GP2200i. You can only use the exact same model and wattage generator for parallel connections.
Generac GP3500iO vs. Honda Inverter Generator
Honda does not have a portable open frame inverter generator on the market, so it is almost impossible to make a real comparison.
Even so, a comparison might be made with the Honda EU3000iS which has a fully enclosed design. The Honda has less peak starting watts at 3000 and only 2800 running watts. It does not have USB outlets. However, it has both a recoil pull starter and an electric starter.
Finally, the big difference between these Generac and Honda inverter generators is the retail price. The Generac GP3500iO costs more than 50% less than the Honda EU3000iS. Your wallet or credit card might have the final vote when it comes down to which inverter generator to buy.
Verdict
At the end of the day the Generac GP3500iO might weigh less than an enclosed design inverter generator, but it is probably not as quiet due to its open frame design. Then again, an open frame inverter generator is quieter compared to an ordinary portable generator of similar size and wattage.
Therefore, the key benefits of the Generac GP3500iO are its inverter system, lightweight dimensions, generally quiet operation and competitive retail price (check price on Amazon).