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Eastwood 300W Pure Sine Wave Power Inverter is rated 3.0 out of 5 by 1.
Rated 3 out of 5 by from A conveniently packaged little inverter Before I started to use the 300 W Pure Sine Inverter, I called Eastwood about the comment in the instructions about using a fuse, "Use only 12 Volt batteries with this inverter and install a properly rated fuse between the positive output and the inverter." I mentioned that they did not suggest a type or rating of fuse. Though I insisted that it was proper for them to say what would be needed to protect the inverter, they refused, saying they could not because of liability reasons. I found this amazing because other makers of similar products do suggest a fuse rating. I guess Eastwood thinks the people who buy their products are not as smart as those who buy products from other suppliers. Now, having been an electrical engineer, I do understand the issues involved. Fuses can be used in two ways: To protect the wiring to a device, or to protect the device itself. In the case of the wiring recommended in the instructions, 6 AWG, that wire can handle 80 amperes at the typical 330 circular mils/Amp the National Electrical Code uses. At 12 Volts, that represents 960 Watts, which is more than the inverter will draw. At the surge rating of 600 Watts and the efficiency listed in the instructions (90%), the inverter will draw 55.6 Amperes. So, should I fuse it to protect the wire (which, incidentally, will stand much more than 80 Amperes for the time it takes a fuse to blow -- 6 AWG wire is rated at 101 Amperes for chassis wiring and melts at over 600 Amperes), or protect the inverter? I asked the Eastwood Technical Assistance Service Department, 1-800-544-5118, about what I should do to protect the inverter, but they could not answer my question. Frustrated, I took the 300 W Pure Sine Inverter out of its box and powered it up in my office with the 12 Volt output from a computer power supply (which is current-limited, so it needs no fuse). It worked just fine and lit up two 100 W incandescent light bulbs just as if they were connected to the power company. After a short while, though, I noticed the smell of hot varnish and realized that the coils and circuit board had not been thoroughly baked during manufacture -- probably as a cost-cutting measure. I also noticed I was beginning to get a headache from it. I moved the power supply and the Pure Sine Inverter out to the shop and ran them there. After running the Pure Sine Inverter several days there was still an odor of uncured varnish, though it was much weaker. Since it's cold out in the shop, I covered the Inverter with a cardboard box and monitored the air inlet temperature with an electronic thermometer, as shown in the picture. I have thus been able to run it in an ambient between 45 deg.F. and 79 deg.F. The inverter has continued to function, except for one time when I returned from a several hour absence. The inverter's AC output was off, the green LED was off, the red LED was on, and the inverter warning beeper was making its warning sound. I cycled the inverter's power and the AC output came back on. It has continued to work since then without interruption. With a load of 200 Watt in a 60 - 65 degree Fahrenheit environment, the Inverter's cooling fan comes on periodically and then shuts off. Since it's small, it's fairly noisy. With a load of 260 W, the fan comes on continuously in a 45 degree Fahrenheit environment. Now, after three weeks of running the inverter with a 260 Watt load during the day and no load during the night, I can only barely detect the varnish smell that was so strong earlier. One of the first things I noticed when I took it out to the shop was that it not only audibly noisy under load, it is electrically noisy as well. Out here in the sticks, we have weak FM signals and when I turned the Inverter on out in the shop, the music on the FM radio (which is supposed to be immune to interference) was drowned out by noise. The noise was minimal with no load, but was very pronounced with a 200 Watt load. I was able, by readjusting the radio's antenna, to minimize the noise so I could still listen to the radio. I don't know what this will do to radio reception in a vehicle, nor how it might affect the other electronics in modern vehicles. I plan on putting it in my Kenworth truck and having it running while I'm driving down the road to provide 120 VAC power, so I guess I'll find out. At this time, I do not have access to an oscilloscope to check what the output waveform really looks like. I hope to have that access in the future and will see how pure the Pure Sine Wave really is. So, if you have an opportunity to run the inverter to burn off the hot varnish smell (and maybe put it in your car's trunk, something a big truck doesn't have) it seems like it will do the job of supplying 300 Watts of 120 VAC power just fine.
Date published: 2017-12-08
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Eastwood 300W Pure Sine Wave Power Inverter

Item #31463 Brand: Eastwood

300W Pure Sine Wave Power Inverter

In stock

Only $74.99

Sale $55.97



The Eastwood 300W Automotive Power Inverter is a heavy-duty professional grade piece of equipment designed to bring 120 volt power to any automobile or truck. Features a true sine wave output that is capable of efficiently running a wide variety of devices.

  • 300W continuous power 600W Peak Power
  • Pure Sine Wave
  • 2 120v AC Outlet
  • 1 USB Plug 5v DC 2.1Amps
  • 12VDC Input
  • 120VAC output
  • ETL Listed

Perfect for camping, the job site, and everywhere in between.This unit must be wired into the electrical system. Not for use in 24v electrical systems.

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About Eastwood 300W Pure Sine Wave Power Inverter

Pure Sine Wave Verses Modified Sine Wave

All power inverters convert DC power (which is power stored in batteries) to AC power, which is the power supplied by the electric company and fed to your home. Electronic devices need AC power to operate, but power inverters generally output power in two forms, modified sine wave vs. pure sine wave.

  • • Pure sine is a direct replica of the power in your house, and it’s what all 110 Volt electronic devices are made to run on (i.e. anything with a 2 or 3 prong plug).

  • • The more sensitive the device, the less likely it will work well on a Modified Sine. For example induction plates for cooking won’t run on Modified sine.

  • • Newer devices such as camera batteries, air purifiers, computers, tablets, LED TV’s, power tools, etc. may be damaged over time when used on a modified sine wave.

  • • Pure sine is more efficient. The best example is with boiling 1 cup of water in a microwave: on a pure sine it takes 1 minute, on a modified sine it takes 2. Using less energy means you can use more devices, or save money by installing less solar or batteries.

  • • The biggest benefit is not having to replace sensitive gadgets on a semi-regular basis: Laptop Battery $140; Laptop Charger $80; Milk Frother $100; AA Rechargeable Batts $15

Pure sine wave power flows in even, arching waves, whereas modified sine wave power flows to your devices in chunky, square waves. The square waves are giving power to your device “all or nothing,” so to speak. Your device will run properly, or not. The power is coming through in a less seamless fashion. Gaining power that is flowing in modified sine waves does not come through as clean and efficient—it doesn’t flow to the device as “pure.” The devices will get the power they need to operate, but when it comes to devices like fans, TV’s, radios and lights, they will tend to buzz, as they are running a bit “hotter,” due to the way power flows to them.


One 300w Inverter


Continuous Power: 300w
Surge Power: 600w
Input Voltage Range: 9.5-16v DC
Output Voltage: 120v
Output Frequency: 60Hz
Output Wave Form: Pure Sine Wave (THD<3%)
Efficiency: 90%
USB Output: 5v DC Max 1A
Input Over-Voltage Shutdown: 16v DC ± 0.5v
Input Under-Voltage Shutdown: 9.5v DC ± 0.5v
Input Under-Voltage Alarm: 9.8v DC ± 0.3v
Over-Temperature Protection: 65°C ± 5°C
Overload Protection: Yes
Overload Backup Fuse: Yes
No-Load Currents: 0.9A
Dimension (L x W x H): 185 x 140 x 74mm
Weight: 1.33Kg
Working Temperature: 0°C - 40°C
Storage Temperature: -10°C - 45°C
Intelligent Cooling: Cooling fan will operate with loads over 100w
Recommended Minimum Cable Size @ 10’: 6 AWG


Click here for product instructions


Always read instructions before using this product and wear proper safety equipment during use.

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1 Year


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