Inverter FAQs

Why do I need a power inverter?

Inverters change DC current to AC current. Most common appliances run on AC current. A home outlets produce if connected to the grid (if you pay a power bill your a part of the grid) an AC pure sine wave on a 15 or 20 amp breaker.

Solar panels create DC power that is useful to change to AC power with an inverter and maybe store excess power in battery banks  (it’s up to you).

Car, truck, golf cart and boat batteries all give DC. Hook an inverter up to any and you got AC power. Or for smaller use you can get an inverter that plugs into your lighter socket for plug and play inverter action.

Great video about how DC to AC power inverters work.

 

 

Where are power inverters usefull?

Power inverters vary in their uses from industrial and home grade devices that power entire states, or small countries, all the way to versions that power only simple electronics in a portable manner. The principle remains the same no matter what size the power inverter happens to be. Electrical companies use the largest inverters in massive industrial complexes to generate their own power supply.

Wind generators and solar.

Electrical power generation methods create a either alternating or direct current. The typical versions in many electrical companies involve a power turbine that generates alternating current due to the spinning motion of the copper wires. However, modern green technology will generally create direct current due to the nature in which electrons are allowed to move. Solar cell technology is a prime example of this.

Alternating current is easier to transport through cables over long distances than direct current. The electricity itself is still the same concept. It is the method of delivering that electrical current that changes to that it is in a specified frequency and power scale in accordance with individual power related needs.

The largest power inverters power cities and states. However, the smallest of these can have something as simple as a twelve-volt battery attached to it and will generate a safe and reliable form of alternating current as a portable or emergency power supply that can run many smaller types of electronic equipment.

What is the difference between alternating and direct current?

This form of electricity is generally lower in voltage but it has a continuous stream of steady power. Direct current is normally found in batteries both internal and external. Many home based appliances such as television sets have internal battery systems that convert the alternating current into a lower powered and safer version of direct current for the sensitive circuits that the electricity will run through. Higher electrical levels can short out or even set those circuits on fire and are a serious safety hazard. This is why power inverters were made to switch current types back and forth, or even shift them in scale from the same type to a higher voltage of that type.

Alternating current has negative and positive alternating cycles, thus granting this form of electricity delivery its name. This is useful for equipment that requires a surging style of power as well as transferring electrical current across large distances through conductive metal wires. However, this can be a dangerous form of electrical power to use in sensitive electronics.

Residential power inverters and vehicle power inverters

These are the ones that are used for inversion of green technology power generation methods such as solar cells, which generate direct current so that this can tie into the homes power grid. This type of power inverter is called a grid-tie, or grid-inversion, inverter.

However, the simplest use of all for a power inverter is through the addition of a simply 12 or 24 volt DC car battery. Many individuals will even leave their vehicle running while the inverter is attached so that the battery continues to cycle. With this as an emergency or portable power supply the owner of the inverter can power simple electronics such as radios and televisions. The amount of electronic equipment that can be run and the length of time they can be run, called run time, will vary on the voltage of the battery and the capacity of the inverter.

 

How much equipment can I run off of a portable power inverter and for how long?

The general rule of thumb for determining the run time for any given amount of electronics is to combine the amps from all the batteries you will be running in parallel. Normally you will only be using one unless you wish to maintain a larger power base for more equipment or to extend run time. Divide the number gathered by twelve and keep that number on hand for further use.

Acquire the amp numbers for each of the devices you intend to use and add them all together. Many suggest adding another half an amp to the total for the inverter itself, but a full amp is best to be certain the manufacturers were not off slightly in their estimates for each device.

Take this new number and divide that into the original number this resultant number is the run time in hours for how long your equipment can run on that power supply.

If you are unable to determine the amperage on any given appliance then take the wattage and divide it by one hundred-twenty. This will equal the amperage. If this is done for each device then the formula will work.

Similarly to the run time formula the amount of total wattage, or amperage, will need to be determined to make certain the inverter you purchase will have the necessary amount of output to meet your needs. There are two factors to take into account when determining this step continuous power and starting load

The continuous power requirement is how much wattage the device requires to continually run. The starting load, also known as peak load, is the initial start up requirement for the device. Generally the start up cost is twice the continuous cost in power. However, it should be noted that this is not always the case and each device should be read carefully to determine the true values for each.

At any rate to determine the amount of power required for a device it is best to base it off of the peak amount. Add the peak wattage, or amperage if you prefer, of each device together and the total is the amount of required power your inverter must generate to allow for the usage of these devices.

The savvy power inverter purchaser will buy one that is capable of generating at least twice the amount of what they think they will need. This allows for other equipment to be added later.

 

Pure sine wave or modified sine wave inverters?

There are generally two types of inverters on the market for residential use. These are pure sine wave and modified sine wave inverters. The differences between the two are quite substantial in overall usefulness and cost.

They are 'pure'. This means a cleaner running system that allows most equipment that would run on standard electrical power outlets to be powered by the inverter. This purity of this sine wave allows for a lower harmonic distortion factor similar to the standard power outlet.

With a pure sine wave power inverter sensitive electronics will run better overall with more efficient processes and less audible noise. There are some types of electronics that will not work at all with a modified sine wave and this much more expensive version is the only true answer to your power needs.

Modified sine wave power inverters are generally much cheaper in cost than the pure sine wave inverters. However, the price drop comes with a cost in efficiency and noise reduction. They will reliably run equipment that isn't as sensitive as some high-end electronics but they may generate an electrical hum or distort sounds in some manner.

There are a few types of electronics that a modified sine wave power inverter cannot run effectively. Generally any highly technical piece of electronic computer should be checked with the manufacturer to determine if a modified sine wave will work for you. Laptops, laser printers, optical hard drives, and a great deal of medical equipment such as oxygen concentrators will not work properly with this type of power inverter.

General rules of thumb to maintain a solid power connection

No matter what type of power inverter you purchase there are a few tips that can greatly enhance the usefulness and efficiency of the device. These tips vary slightly with the size of the inverter in terms of output.

Special: small wattage inverters

  • The manufacturers of these inverter types, they are generally 400 watts and below typically come with a cigarette lighter attachment for quick usage. These typically will not be able to draw more than 150-180 watts of power at a time though. To use the full capacity of the inverter you will have to perform the same direct cabling as the larger inverters.

 

Large wattage inverters

  • The manufacturers of larger wattage inverters, 500 watts and above rarely include a cigarette lighter adapting technology due to the higher energy requirements of the device. If they do provide this capacity it will be no different than with the small wattage inverter.
  • Large wattage inverters, and full capacity use of small wattage inverters, require the addition of heavy-duty power cables that are attached directly to the battery. Hard wiring it directly to the batter can do this. The owner's manual for the inverter will detail the exact necessary requirements for a given inverter. However the short rule is to always use the thickest cable of the shortest length possible for the battery-to-inverter connection. This is where the highest voltage of electrical current will be traveling.
  • Battery jumper cables can work in a pinch, but are generally a bit long for the purposes involved. There may be a loss in efficiency and power using them. If the inverter has a way to connect them, then this is a viable solution. Check to be certain that the gauge of wire is at least to the minimum standard for the wattage of the inverter, however.
  • Generally speaking a 1500-watt or less inverter will work fine with something along the lines of a # 4 gauge wire. Many retail outlets sell this type of wire in home and garden sections. Most power inverter suppliers will carry them as well. Some will even have eyelets and ring connectors to make the connection between battery and inverter a breeze.
  • An inverter with a higher wattage than 1500 would be best served by something more along the lines of a #1/0 gauge as the amount of current going through them will be substantial. A lesser wire may not be capable of handling the load efficiently.
  • No matter which type of cabling used the shortest possible length is recommended.

    Important safety tips:
  • It should go without saying that the most important tip is to be certain to use rubber-insulated wire. Anyone foolish enough to use non-insulated wire will find the very real possibility of a tragedy on their hands when they, their family pet, or a child accidentally steps on or grabs the wire.
  • Keep the inverter and cabling away from any flammable materials. This includes the engine compartment of a vehicle. There are gas fumes, oil residue, and various other products that can ignite whenever the occasional spark is produced from an inverter. The amount of heat generated by the inverter while running dictates that it should be used in a well-ventilated area as well.
  • Keep it out of reach of children and small animals when in use. Even as little as 110 volts of power can be lethal for a grown adult. Children and animals will be far more susceptible.
  • Keep the inverter in a flat, dry, location when in use. This is to help insure maximum efficiency ad well as to prevent it from sliding off onto the floor, ground, or a flammable pile of oily rags if such is available.