Inverter generators are known for being more energy efficient and for generating less noise pollution.
The Champion 3100 watt inverter generator is one of the leading models on the market and is a slightly bigger, and more powerful, upgrade of the smaller 73536i.
This upgraded version offers the same features as its predecessor, aside from offering a bigger engine and peak watt output, as well as a new style of handles and rolling wheels.
The 75521i’s crowning glory is its ultra-quiet operation - 58 dBA is perfect for RVs, tailgating, your next work or DIY project or to use as backup power for your home, featuring 3100 starting watts and 2800 running watts with up to 8 hours run time on a 25% load.
Champion Power has tailored the 75521i to provide clean, safe power for smaller electronics and gadgets such as smartphones, computers, and other small tools.
This makes it the perfect generator for camping and other outdoor settings where you need to power some lighting, a few larger appliances, and some smaller, more sensitive, electronic devices.
Overall this generator provides energy efficiency and ultra-quiet, clean, power.
Champion Power Equipment
Item Dimensions LxWxH
22.4 x 17.3 x 18.3 inches
171 Cubic Centimeters
Design and build
Measuring 22.4 x 17.3 x 18.3 inches, this updated version of the 3100 inverter generator is slightly more compact than the earlier model, yet doesn’t compromise on power output.
However, at 94.8 pounds it’s still pretty hefty in terms of weight, which is where the foldable pull handle and wheels come in especially handy.
This makes it easy to maneuver and transport, and makes it especially convenient if you’re sharing the generator with a few families whilst camping.
All the buttons are located on the front on an easy-to-access “quick-touch” panel where you can reach all of the buttons and controls with minimal effort.
As expected from Champion, the yellow and black plastic casing is robust and durable, making it perfect for outdoor use.
Engine and output
The 75531i generator is powered by a 171cc engine and generates 3100 starting watts of power and up to 2800 running watts.
It can provide continuous power for up to 8 hours when the gas tank is filled to its full capacity of 1.59 gallons.
The four-stroke engine is built for durability and reliability, while the single cylinder ensures quick starting up and cooling down of the engine.
The 75531i doesn’t come with a supply of oil, however, Champion does recommend its own-brand 10W-30 oil.
To access the 0.63-quart oil reservoir simply remove the back casing of the generator.
Champion have also provided a dipstick for checking the oil level, and a funnel to make adding oil easier and to reduce the risk of spillage.
The generator also features a low-oil shut-off sensor to ensure maximum safety when in use.
Efficiency and cleanliness
Using the generator in economy mode allows the engine to cut power output when there are fewer loads, meaning you save fuel for when you really need it.
When powering heavier loads, simply use the generator in its regular mode to provide adequate fuel.
This is far more energy-efficient than conventional generators that run continuously on one speed and therefore burn the same amount of fuel even if the load is far smaller.
Due to the more efficient use of power in this inverter generator, you’ll make financial savings over time as you'll be using less fuel, and you’ll also reduce the wear and tear on the engine, meaning it’s likely to last longer.
The advanced inverter technology is also more environmentally friendly, as the 75521i has two 120V 20A household outlets with clean electricity (less than 3% THD) and produces true sine wave output so you can safely power even the most sensitive gadgets.
Noise pollution is kept to a minimum with the 75521i thanks to the economy mode, which saves power when smaller loads are in use, meaning noise pollution is also reduced.
Producing just 58 decibels from a distance of 7 meters, this generator is extremely quiet in comparison to non-inverter variations, however, it’s worth bearing in mind that manufacturers may not take noise readings when the generator is running on full load, meaning it could be louder than this in reality.
It’s also worth considering that because of its maximum power output, and due to the larger engine size than earlier models, this inverter generator will be louder than smaller models, but this is compensated by its engine size and power output.
The noise of the 75521i will generally depend on how many loads are running at any given time.
More loads equal more power, and, as a result, a higher noise level, while the opposite will be true for smaller loads.
The Champion 3100 watt inverter generator is super easy to operate, regardless of your experience with generators.
The front panel is easy to access and straightforward to understand, and you also have two 120V outlets for the AC load and 20A circuit breaker for the below outlets.
To the left, you’ll find the 5-30R duplex outlet, and you’ll use this 30A outlet mainly to supply power to your RV if you have one.
The other outlet on the panel is used for DC loads, and you should always run the engine at full-power when using these.
While there’s no voltage meter on the 75531i generator, this isn’t necessary in our opinion, as you simply switch the generator on or off and the engine does the rest of the hard work for you.
Like most common generators, this one uses a standard manual recoil mechanism for starting up the engine.
The pull cord is easy to access thanks to its being located just underneath the control panel, and a manual start, as opposed to an electric one, limits the weight and minimizes maintenance requirements.
Most of the time, a single pull should get the engine up and running if it’s cold, whereas a warm engine will take a little more attention and perseverance.
Upkeep is pretty minimal with the Champion 3100 inverter, thanks to the manual start and the four-stroke, single-cylinder engine.
You can perform general servicing yourself by following manual guidelines for oil changes, cleaning, and checking spark plugs, or you may want to seek professional servicing to ensure your generator is running at its best.
Your generator’s gas tank and fuel filter will need semi-regular cleaning and typically once you’ve had the generator for about 2 years, you’re likely to need a new fuel line.
What we like about the Champion 75531i
- Quick Touch Panel for accessing all your controls in one spot,
- Ultra-Quiet Operation thanks to Economy Mode
- 3100 starting watts and 2800 running watts with up to 8 hours run time
- Clean power for sensitive electronics and smaller devices
- Smart Economy Mode – Reduces electrical load providing quieter operation, extended engine life, and better fuel economy
- Champion Support – 3-year limited warranty and free lifetime technical support
- Handle and wheels for easy transporting
- low oil shut-off sensor for maximum safety
What we dislike about the Champion 75531i
- Even though it’s pretty compact (for its engine size) it’s quite heavy, so the handles and wheels are essential.
- There’s no gas drain, which would be handy for draining the tank before storage.
If you’re looking for a powerful inverter generator that combines energy efficiency with a robust engine and significant power output, look no further than the Champion 3100 watt 75531i.
With Champion’s Smart Economy Mode, you’ll save fuel, and as a result, money, as the engine will run at a reduced output when running smaller loads, which also limits noise pollution and reduces strain on the engine.
With clean power output, you can operate the most sensitive electronics, such as smartphones and other small devices, as well as larger appliances such as refrigerators or powering up your RV.
Speaking of which, this generator is perfect for camping. Whilst it’s a little on the heavy side, which does make it harder to handle, the wheels and fold-down handle are extremely convenient and make transporting this generator far easier.
On the whole, it’s also easy to operate with a simple mechanical start-up for maximum reliability. The low-oil indicator ensures maximum safety, whilst the quick-touch panel keeps all the buttons in one place to make accessing the controls that little bit easier.
This generator isn’t the smallest or most compact inverter generator on the market, and as a result, it isn’t the quietest in the world, either.
However, considering its size and power output, it bridges that gap between achieving enough power capacity to run larger loads, whilst also maximizing your energy efficiency.
With Champion, you’re guaranteed durability and reliability, which is why their 3-year limited warranty provides even greater reason to purchase and means you get substantial bang for your buck.