Gas + Manual start
Dual fuel + Electric start
Zoom on the Firman WH03662OF
In a nutshell, the Firman WH03662OF is a portable inverter generator mostly geared towards:
- RV travellers wishing to enhance their freedom and nomad lifestyle
- People occasionally participating in sporting competitions, open-air performances and outdoor festivals
- Homeowners in need of an emergency backup power for their essentials
- Tailgating and campground aficionados with the desire of enjoying power anywhere they go
The following sections will present you in detail its power characteristics, the different outlets it offers, its overall portability, the extra features it benefits from, and any relevant emission compliance details.
Power & Run Time
Thanks to its dual-fuel technology, the Firman WH03662OF delivers 120V and offers power and versatility. When gasoline-powered, it benefits from a running wattage of 3,650W and a peak wattage of 4,500W. When propane-powered, it has 3,300 rated watts and 4,100 peak watts. In addition, the device is parallel capable (parallel kit not included) and thus, can be linked to a similar or compatible unit for added power.
Enjoying a noise rating of 69 dBA (less noisy than an office), this inverter generator can be started thanks to a simple traditional pull-start mechanism, but also to a simple and elegant electric starter (battery included).
Regarding its running time, the WH03662OF, with a 6 gallons fuel capacity can operate for up to 25 hours with a full tank of gasoline (fuel consumption around 0.24 GPH). When using propane, it can run for up to 19 hours (on a 20 lbs tank - propane consumption around 0.25 GPH).
Sensitive electronics can be safely plugged in the AC outlets, as the WH03662OF produces a clean sine wave, with a <3% Total Harmonic Distortion (THD).
The control panel provides the upcoming 4 AC outlets:
In addition, it provides 3 DC outlets: there's two 5V USB ports (USB-A) allowing you to conveniently charge electronics such as mobile phones and tablets and a 12V 8A (cigarette lighter style) receptacle with which you may charge your batteries with ease.
If you own an RV with a 50-amp service, you can consider this Firman unit as RV-ready, as it features a 14-50R outlet. Its L5-30R receptacle can also be used for a simple RV connection with the included L5-30P to TT-30R adaptor.
Important note: The 14-50R outlet is normally 120/240V. However, this unit does not produce 240V. This outlet is here for your convenience, but should only be used to power 120V appliances. In addition, since the generator provides a maximum of 3650 running watts, it will not be possible to draw the full 50 amps from the outlet.
The design of the Firman WH03662OF is a typical, open frame, with the dimensions of L24.5 x W24.1 x H23 in, offering support and stability and enabling the possibility of raising it above ground level. This type of design is ideal for tough environments and heavy outdoor use.
While the generator is considered to be technically 'portable' (in the sense that you can move it), manually lifting and transporting it may be challenging, due to its high weight of 119 lbs. Nevertheless, thanks to its set of wheels (⌀9") and its folding handle (a decent solution to its lack of maneuverability), the generator can be easily moved, once placed the ground.
The control panel of the WH03662OF includes a convenient meter showing you voltage, frequency and lifetime hours, helpful for the monitoring of its status and activity.
In addition to this info, the light indicators show you if the generator is ready, the generator is overloaded and the oil level is too low.
The inverter generator includes a built-in fuel gauge, a quick, easy and convenient method of checking the device’s gas level.
From a security standpoint, the product offers an automatic low oil shut-off and an overload protection (circuit breaker), allowing you to use it with a peace of mind.
The WH03662OF also benefits from Firman’s CO Alert carbon monoxide shutdown, which automatically shuts down the engine when harmful levels of carbon monoxide accumulate around the generator or a CO Alert fault occurs.
Besides the classic documentation and an owner's manual (opens in a new tab) to get you promptly started, the Firman WH03662OF also comes with some accessories: propane hose, oil, battery charging cables, RV adapter, tool kit and funnel are included.
The Firman WH03662OF is EPA-approved and CARB-compliant. Therefore, its sale and purchase are permitted in all of the 50 states, including California.
Moreover, it features a spark arrestor and thus, may be used in forested areas.
The unit also meets the ANSI/PGMA G300-2018 safety and performance requirements.
The Firman WH03662OF versus other generators
The following charts are provided to give you an idea of how some of the key specs of the Firman WH03662OF compare to inverter generators of similar power (between 3500 and 4500 W).
- At a weight of 119 pounds, the Firman WH03662OF places in the expected weight range of the inverter generators in the 3500-4500 rated wattage range. In terms of weight, one of the champions in their power range is the WEN GN400i, standing at just 66.1 lbs.
- If compared to generators capable of producing a similar running wattage, this inverter generator with a lowest emitted noise of 69 dBA can be considered somewhat noisy. If you’d prefer a less noisy device, one of the most quiet devices, which share the same power range with this one, is the Westinghouse iGen4500DF, whose lowest noise levels reach just 52 dBA.
- The WH03662OF provides one of the highest run time among similarly powerful inverters, reaching up to 25 hours at 25% load.
- While the run time is an important parameter, it is dependent on the fuel tank’s capacity and thus, doesn’t say much on its own unless we consider fuel consumption as well. This inverter generator is somewhat less fuel efficient than devices of comparable output: its estimated fuel consumption reaches 0.24 GPH at a 25% load. If you are concerned with gasoline efficiency, having a fuel consumption of just 0.16 GPH, the Champion 200988 is a device you could look out for.
As you can see from this interactive chart, when compared to other 3500-4500W dual fuel inverter generators, the Firman WH03662OF 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
- In the expected price range
- Dual Fuel
- CO Alert technology
- Several accessories included
- RV adapter included
- Electric start
- Parallel capable
- High run time
- Decent weight (119 lbs)
- No 240V output
- No remote start
- On the noisy side (69 dBA)
- Low fuel efficiency
Features and Specifications
|Parallel capable||Yes, cable not included|
|Fuel||Dual Fuel (gasoline/propane)|
|Engine||208 cc OHV 4-stroke|
|Starting system||Recoil, Electric|
|Voltage||AC: 120V 60 Hz, DC: 12V|
|Running watts||3,650 W||3,300 W|
|Starting watts||4,500 W||4,100 W|
|Running amps||30.4 amps||27.5 amps|
|Peak amps||37.5 amps||34.2 amps|
|Run time @50% load||Unknown||Unknown|
|Run time @25% load||25 h||19 h|
|Automatic Voltage Regulation||Inverter|
|AC outlets|| |
|DC outlets||2x 5V USB port (USB-A) |
1x 12V 8A (cigarette lighter style)
|Indicators||Low oil, overload and output ready|
|Fuel tank||Steel, 6 gal|
|Approx. dimensions (L x W x H)||24.5 x 24.1 x 23 in|
|Noise (lower limit)||69 dBA|
|Compliance||CARB, EPA, ANSI/PGMA G300-2018|
|Security||Low oil and overload protection, CO monitoring|
|Accessories included||Oil, funnel, tool kit, propane hose, RV adapter, battery charging cables, battery, and wheel kit|
|Country of origin||China|
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.
About FIRMAN Power Equipment
Founded in 1999, Firman Power Equipment is a company with a short, but established history in the power equipment industry. Based in Arizona, the company offers an immense range of products, including power tools, automotive equipment, storage utilities, work wear, but most importantly, a wide selection of generators of all sizes, designs and outputs. Interestingly, Firman is a wholly owned subsidiary of the China National Machinery Industry Corporation - a somewhat well renowned company in China and acts as a de facto distributor of their products in the US.
The Firman WH03662OF 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 Firman generators, please consult Firman's warranty policies (opens in a new tab). Alternatively, you can also contact their Customer Support: 1-844-FIRMAN1 (844-347-6261).
Questions & Answers
What can it power?
|Item||Running Watts||Starting Watts|
|At home||AC (10,000 BTU)||1500||2200|
|Refrigerator (energy star)||192||1192|
|Total||2917 W||3917 W|
|For camping||RV AC (11,000 BTU)||1010||1600|
|Set of 5 LED light bulbs||55||55|
|Cell phone charger||20||20|
|Total||2915 W||3505 W|
|Electric fence (25 miles)||250||250|
|Total||2910 W||4010 W|
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