- Wattage (Gas): 4,500 W / 3,650 W
- THD: < 3%
- Noise Level: 69 dBA
- Fuel Type: Dual Fuel (gasoline/propane)
- RV Ready: No
- Run Time@ 25% load: 25 h
- Run Time@ 50% load: Unspecified
- Weight: 119 lbs
Table Of Contents
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The Firman WH03662OF has a 120V output and great power and versatility thanks to its dual-fuel technology. If it is powered by gasoline, the device has a running power of 3,650W and a starting power of 4,500W. If it’s powered by propane, it gives 3300 watts at full power and 4100 watts when starting up. Also, since it can work in parallel (but doesn’t come with a parallel kit), this power can be increased by connecting it to another unit that works with it. The noise level of the inverter generator is 69 dBA, which is less than background music. It has a simple pull-start mechanism and a simple and elegant electric starter (battery included). With a fuel capacity of 6 gallons, the WH03662OF can run on gasoline for up to 25 hours (using about 0.24 GPH) or on propane for up to 19 hours (using about 0.25 GPH) on a 20 lb tank. As the WH03662OF makes a clean sine wave with a Total Harmonic Distortion (THD) of less than 3%, you can safely plug sensitive electronics into the AC outlets.
The following 4 AC outlets are on the control panel: Duplex 120V 20A (5-20R); 120V 30A (L5-30R) receptacle; 120V 50A (14-50R) receptacle.It also has 3 DC outlets: two 5V USB ports (USB-A) that make it easy to charge devices like cell phones and tablets, and a 12V 8A receptacle that looks like a cigarette lighter and lets you easily charge your batteries.Since it has a 14-50R outlet, this Firman unit is ready for an RV with a 50-amp service if you have an RV with 50-amp service.With the L5-30P to TT-30R adaptor that comes with it, the L5-30R plug can also be used to connect a simple RV.Note that the 14-50R outlet usually works with 120/240V.But this unit doesn’t give off 240V.This outlet is here for your convenience, but only 120V appliances should be plugged into it.Also, since the generator can only run at a maximum of 3650 watts, you won’t be able to use all 50 amps from the outlet.
The status and activity of the WH03662OF can be easily checked on the control panel, which has a meter that shows voltage, frequency, and lifetime hours.On top of this, there are some lights that let you know right away if the oil level is too low, if the generator is overloaded, or if it is ready.The inverter generator has a built-in fuel gauge that makes it quick, easy, and convenient to check how much gas it has.When it comes to safety, this product has a circuit breaker for overheating and an automatic shut-off for low oil, so you can use it without any worries.The WH03662OF also has Firman’s CO Alert carbon monoxide shutdown, which turns off the engine when harmful levels of carbon monoxide build up around the generator or when a CO Alert fault happens.It’s a nice extra safety measure, but don’t forget to take your generator outside at all times.The Firman WH03662OF comes with standard paperwork and an owner’s manual that will help you get the device up and running quickly.It also comes with a tool kit, oil, an RV adapter, battery charging cables, a propane hose, and a funnel.
The Firman WH03662OF has a standard, open frame that measures L24.5 x W24.1 x H23 in, This frame gives it support and lets it be raised above the ground.The design shown is great for the outdoors and other rough places.Even though the generator is technically considered to “be portable,” it will be very hard to move it by hand because it weighs 119 pounds (in the sense that it is movable).But its wheels (diameter: 9″) and folding handle, which make it easy to move once it’s on the ground, make up for the fact that it’s not easy to move.
The following charts show how some of the most important features of the Firman-WH03662OF compare to other generators with the same power output.
**Fuel efficiency is give in relative percentage, 0 being the lowest and 1 being the highest value. Please see below specification table for actual value.
|Yes, cable not included
|Dual Fuel (gasoline/propane)
|208 cc OHV 4-stroke
|AC: 120V 60 Hz, DC: 12V
|Running amps (@120/240V)
|Peak amps (@120/240V)
|Run time @50% load
|Run time @25% load
|Automatic Voltage Regulator
|1x Duplex 120V 20A (5-20R); 1x 120V 30A (L5-30R); 1x 120V 50A (14-50R)
|2x 5V USB port (USB-A); 1x 12V 8A (cigarette lighter style)
|Low oil, overload and output ready
|Steel, 6 gal
|Approx. dimen. (L x W x H)
|24.5 x 24.1 x 23 in
|Noise (lower limit)
|CARB, EPA, ANSI/PGMA G300-2018
|Low oil and overload protection, CO monitoring
|Oil, funnel, tool kit, propane hose, RV adapter, battery charging cables, battery, and wheel kit
- We compared more than 500 portable generators at 50% load. We found that there is “skewed right” distribution for the difference between 50% load and 25% load and the median comes at 1.43. With this number we converter all the 25% load runtime to 50% load. Same with the propane efficiency, where median is 1.38.
- For some generators where propane runtime was not given, we used NIST 1994 GGE (Gasoline Gallon Equivalent) formula: 5.66 lbs. of propane = 1 gal of gasoline. All propane runtime is for 20 lbs. propane tank (4.7 gallons).
- Unlike many other sites, we actually tried to find out information about each of the above requirements. However, we are human and are therefore capable of the odd oversight or mistake. Please let us know if you spot any missing or erroneous values so that we can fix them.
About the Manufacturer
Firman Power Equipment is a business with a recent but reputable history in the power equipment sector.It was founded in 1999.The Arizona-based business provides a vast array of goods, including power tools, automotive equipment, storage items, work clothing, but its assortment of generators of different shapes, sizes, and outputs stands out above the rest.Interestingly, Firman serves as a de facto distributor of China National Machinery Industry Corporation’s goods in the US and is a fully owned subsidiary of that business.
There is a warranty on the Firman WH03662OF for up to 3 years.This warranty may not cover all parts of the generator or may only cover certain parts.Check out Firman’s warranty policies if you want to know more about the warranty on a Firman generator.You can also call their customer service line at 1-844-FIRMAN1 (844-347-6261).