An inverter takes DC power (battery or solar, for example) and
converts it into AC "household" power for running electronic equipment and appliances.
2) How is an inverter different than a UPS?
A UPS typically includes the battery and battery charger in one stand-alone unit. However, there are UPS systems that use external batteries, and Power Stream makes inverters with battery chargers, so the differences blur as features proliferate.
3) Why are they called inverters?
Originally converters were large rotating electromechanical devices. Essentially they combined a synchronous ac motor with a commutator so that the commutator reversed its connections to the AC line exactly twice per cycle. The result is AC-IN DC-OUT. If you invert the connections to a converter you put DC-IN and get AC-OUT. Hence an inverter is an inverted converter.
4) What are square wave inverters?
These are old-fashioned inverters, the cheapest to make, but the hardest to use. They just flip the voltage from plus to minus creating a square waveform. They are not very efficient because the square wave has a lot of power in higher harmonics that cannot be used by many appliances. The modified sine wave is designed to minimize the power in the harmonics while still being cheap to make.
5) Why do buzzing noise come from stereos when using a modified sine wave inverter?
Some inexpensive stereos use power supplies that cannot eliminate common-mode noise. These would require a sine wave inverter to operate noise-free.
6) Can I use my inverter in parallel with the generator or grid power?
Definitely not! If you have a generator on board or a grid connection you must install a Master switch. The switch is available with various applications, but its main function is to switch automatically and safely between grid, generator and inverter power.
7) Can I run a computer on the inverter?
Yes, you can. All sine wave inverters can easily and safely supply power to a computer. In fact the output voltage from an inverter is often better than that from the electricity grid.
8) Can I run a microwave on an inverter?
Yes. You can connect any model of microwave to your inverter, but keep in mind that a 800 watt microwave consumes 1200 to 1300 watt from the 230V system, so you must make sure you choose the correct size inverter.
9) Are there any appliances that cannot be run on an inverter?
In general you can connect almost any appliance to an inverter, with a few practical exceptions. While the inverter can easily supply a heavy load like an electric heater, the battery capacity is often too low to maintain the supply for any great length of time. The same applies to air conditioning units. As long as the battery capacity is high enough you can use a large inverter to run a washing machine, a large single cooking element or a small two-ring electric cooker.
10) How much power does an inverter consume?
If you connect a 850W coffee machine to a sine wave inverter, consumption will be 850W divided by the voltage of the electrical system (12V) = 70 Amperes. Add another 8% (100%-92% =8%) to this total for the inverter consumption. The total power consumption is then 70 Amperes + 6 Amperes = 76 Amperes. Of course a coffee machine is only in use for about 10 minutes so the actual Ampere consumption is relatively low (76 x 10 min = 13Ah).
11) What size inverter should I buy?
Determine Continuous Load and Starting (Peak) Load: You need to determine how much power your tool or appliance (or combination of them that you would use at the same time) requires to start up (starting load), and also the continued running requirements (continuous load).
What is meant by the terms "continuous-2000 watts" and "peak surge-4000 watts" is that some appliances or tools, such as ones with a motor, require an initial surge of power to start up ("starting load" or "peak load"). Once started, the tool or appliance requires less power to continue to operate ("continuous load")
Helpful formulas: To Convert AMPS to WATTS:
Multiply: AMPS * AC (voltage) * η (efficiency of Inverter) = WATTS This formula yields a close approximation of the continuous load of the appliance To calculate approximate Startup Load:
Multiply: WATTS * 2 = Starting Load This formula yields a close approximation of the starting load of the appliance, though some may require an even greater starting load.
NOTE: Induction motors such as air conditioners, refrigerators, freezers and pumps may have a start up surge of 3 to 7 times the continuous rating.
Most often the start up load of the appliance or power tool determines whether an inverter has the capability to power it.
12) Do I need Modified Sine Wave, or Pure Sine Wave?
Advantages of Pure Sine Wave inverters over modified sine wave inverters:
a) Output voltage waveform is pure sine wave with very low harmonic distortion and clean power like utility-supplied electricity.
b) Inductive loads like microwave ovens and motors run faster, quieter and cooler.
c) Reduces audible and electrical noise in fans, fluorescent lights, audio amplifiers, TV, Game consoles, Fax, and answering machines.
d) Prevents crashes in computers, and glitches and noise in monitors.
e) Reliably powers the following devices that will normally not work with modified sine wave inverters:
-> Laser printers, photocopiers, magneto-optical hard drives
-> Certain laptop computers (you should check with your manufacturer)
-> Some new furnaces and pellet stoves with microprocessor control
-> Sewing machines with speed/microprocessor control
-> Medical equipment such as oxygen concentrators
-> The difference between them is the Pure Sine Wave inverter produces a better and cleaner current. They are also considerably more expensive. You might find it practical to get a small Pure Sine Wave inverter for any "special need" you may have, and also a larger Modified Sine Wave inverter for the rest of your applications.
13) How far can I keep my inverter from my batteries?
Keep the cables between your inverter and batteries as short as possible. This will help your batteries perform their best and keep the inverter's signal clean. The cables that come with the inverter are "rated" or good for up to six ft. If you plan on going over six ft., drop down to a larger gauge cable. Please call us if you are still unsure. This is pretty important stuff that should NOT be overlooked. If the cables between your battery and inverter get hot while under heavy load, then you should use heavier cables.
14) What is the Low Voltage Alarm & Shutdown?
The low voltage alarm will sound when the DC source falls below a certain level and the automatic shutdown will power off the inverter. This is done to save your batteries; you can restart your inverter once grid power is available.
15) Is my inverter weatherproof?
No. Treat your inverter like you would your TV. You wouldn't put your TV outside in the rain, please don t leave your inverter there either. Be aware of lighting storms. If struck, your inverter would go into a permanent overload state and may even smoke it. If using in a marine environment, try to keep it tucked away underneath, in a dryer area.
Inverters