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Gas + Manual start
Dual fuel + Electric start
Zoom on the Firman WH03662OF
In summary, the Firman WH03662OF is a portable inverter generator especially useful for:
- 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
- Camping and tailgating hobbyists looking for a portable power source
In the following paragraphs, we shall explore the power characteristics, available outlets, portability, and any additional features of the device, along with its emission compliance information.
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. Moreover, since it is parallel capable (parallel kit not included), its power may be increased if linked to a second compatible unit.
The inverter generator is rated for a noise of 69 dBA (less noisy than an office). Its starting mechanisms include a conventional pull-start mechanism and a simple and elegant electric starter (battery included).
The running time of the WH03662OF, with its 6 gallons fuel capacity, can reach up to 25 hours on a full tank of gasoline (fuel consumption around 0.24 GPH). With propane, it can reach 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 features the upcoming 4 AC outlets:
In addition, it provides 3 DC outlets: there's two 5V USB ports (USB-A) with which you may charge electronics, for example mobile phones or tablets, conveniently and a 12V 8A (cigarette lighter style) receptacle with which charging your batteries is made easy.
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 Firman WH03662OF has a conventional, open frame design, of the following dimensions: L24.5 x W24.1 x H23 in, which offers support and allows it to be raised above ground level. This type of design is ideal for tough environments and heavy outdoor use.
Even though this device may be technically portable (as in movable), manipulation and transportation without special equipment can be a challenge, as it weighs 119 pounds. 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 WH03662OF's control center features a convenient meter showing you voltage, frequency and lifetime hours to aid you with the monitoring of its status and activity.
In addition to this info, when the generator is on overload, its oil levels are insufficient and the generator is ready, you will be informed by the featured light indicators.
A built-in fuel gauge allows for a quick, easy and convenient check of the fuel level of the inverter generator.
As far as security is concerned, the generator can be used with a peace of mind, as it features an automatic low oil shut-off and an overload protection (circuit breaker).
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.
Apart from the typical documentation and an owner's manual (opens in a new tab), which lets you start it right away, the Firman WH03662OF also is packed along with the following accessories: propane hose, battery charging cables, RV adapter, oil, funnel and tool kit.
The Firman WH03662OF is EPA-approved and CARB-compliant. It can therefore be sold and purchased in all 50 states, including California.
Moreover, it features a spark arrestor and therefore, can 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).
- As its dry weight is 119 pounds, the Firman WH03662OF is one of the heavier of the inverters which can generate 3500 to 4500 running watts. If you are concerned by weight, one of the champions in the above-mentioned power range is the WEN GN400i, with a dry weight of just 66.1 pounds.
- This inverter generator, with its lowest possible noise rated at 69 dBA falls into the more noisy category, compared to other devices of a similar running wattage. If noise emissions are important to you, one of the least noisy generators of this power range is the Westinghouse iGen4500DF with only 52 dBA.
- With a run time of up to 25 hours at 25% load, the WH03662OF has one of the highest run times, compared to its similarly powerful peers.
- Even though run times are undoubtedly important, they are dependent on the fuel capacity to a large extent. For a more wholesome picture, we must take into consideration the fuel consumption of the generator. In fact, this inverter generator is not among the most fuel efficient, within the aforementioned wattage range : its estimated gasoline consumption at 25% load is around 0.24 GPH. If fuel consumption is your top priority, we suggest to check out the Champion 200988, which has a fuel consumption of only 0.16 GPH and thus, is one of the most efficient devices in our database.
As you can see from this interactive chart, when compared to other 3500-4500W dual fuel inverter generators, the Firman WH03662OF is on the expensive side of the price range.
While certainly not the cheapest of its kind, purchasing it would most likely also mean enjoying the reliability of a high-end product.
The bottom line
- CO Alert technology
- Several accessories included
- RV adapter included
- Electric start
- Parallel capable
- Dual Fuel
- High run time
- On the expensive side
- No 240V output
- No remote start
- On the heavy side (119 lbs)
- 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|
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||Refrigerator (energy star)||192||1192|
|Cell phone charger||20||20|
|Total||2912 W||3912 W|
|For camping||Radiant heater||1300||1300|
|RV AC (11,000 BTU)||1010||1600|
|Cell phone charger||20||20|
|Total||2910 W||3500 W|
|Total||2910 W||4010 W|
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