Pure Sine Wave Inverter Reviews

Beginner's guide to sine wave inverters

Dependence on electronic devices that use AC power clearly shows the complications linked to the unexpected power loss from the electrical grid. In places where the electrical setup is not fully developed, power losses can cause big problems that can result into a major disaster.

Therefore, there is a dire need for reliable sine wave inverters for use in such places.

Conventionally, there are two ways in which electrical power is transmitted. Direct current originates from a constant voltage source and works best for device level or short range transmission.

Alternating current, famously known as AC power, is comprised of a sinusoidal voltage. In alternating current, there is a continuously changing voltage (and current) that can be used to employ magnetic components.

Electrical power that is transmitted over long distances is normally done in AC power. This is because of the fact that the voltage can be stepped up or boosted with the use of step up transformers to avoid power loss.

The adoption of AC power has created a trend where most devices become accustomed to alternating current power from an outlet into DC power for use by the device via an electrical inverter. However, AC power is not constantly available and the need for flexibility has given batteries an advantage in portable power.

Thus, inverters are required in places where there is need for portable alternating current power.

Direct current voltage from a solar panel or battery is fed to the inverter as input and changes it to an output of alternating current. The size and quality of an inverter are critical for the effective conversion of the DC power to useable AC power.

The working of an inverter is based on the principle of a circuit powered by a DC source used to power an AC device and with four switches. The switches are connected in a way that when switch 1 and 4 close, switch 2 and 3 will open and vice versa. This means that the load will have an AC although it is connected to a DC source.

When one pair of switches is open, current flows through the right side of the AC device. Similarly, when the second pair of switches is open, current flows through the left side of the AC device. Therefore, the device experiences an alternating current.

However, the device will not experience a sine wave. The sudden switching will result in a square wave that can damage an electrical device. To prevent this, the wave needs to be smoothed out.

To smoothen the wave, you require some components like diodes, MOSFETs, and IGBTs (Insulated Gate Bipolar Transistor). MOSFETs and IGBTs are the two main types of switches used in power electronics.

MOSFET is designed to handle relatively huge amounts of current and voltages while an IGBT is used in extremely high voltage applications. What an IGBT does is that it divides the circuit cycle into smaller segments that make the wave smooth and so the electrical component will experience a sine wave alternating current.

In general, IGBTs are perfect for high voltage and low-frequency uses while the MOSFETs are best suited for low voltage and high-frequency applications.

It is, however, important to point out that IGBTs have a major disadvantage. They usually have an unavoidable current tail when they turn off. Normally, the gate transistor current cannot dissipate immediately when the IGBT turns off. This causes a lot of power loss every time this happens. This problem is as a result of the IGBT design and cannot be rectified.

Uses of inverters

-They are integrated into variable frequency drivers to control the speed and direction of AC motors.
-They are used within HVAC systems for industrial and commercial purposes.
-Used in solar power systems
-Inverters can be used in centrifugal fans, mixers, pumps, conveyors, and extruders.
-They can be used as Uninterruptible Power Supply (UPS).
However, you should note that an inverter is not a UPS. Inverters are just a component of the originally made UPSs. A UPS includes an inverter, battery, and battery charger in one stand-alone unit.

The main categories of sine wave inverters include;
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Pure Sine Wave inverters

They are also called true sine wave inverters.
They are expensive since they involve a more sophisticated design to stimulate the smooth output of standard mains power. A pure sine wave inverter allows you to run a wide range of appliances away from the mains power with a lot of ease.

It is the best power inverter for use with sensitive devices like laser jet printers and audio equipment. This die to the fact that they provide cleaner and high-quality energy. These inverters are also proven to lengthen the lifetime of your electrical devices.

Benefits of using Pure Sine Wave Inverter

Most equipment currently in the market are made to be used with sine waves.
Some appliances will not produce full output if they do not use sine wave power.
Medical equipment may not function at all unless a pure sine wave inverter is used.
Using this type of inverter gives you the freedom to use a variety of electrical devices and appliances.


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Modified Sine Wave inverter

It converts DC to AC by making the voltage go straight up and down, thus creating a blocky signal.

It is cheaper and runs basic electronics like fans, heat element devices like heaters, and 240V lights. However, they are not fit for running such equipment as phones, televisions, and microwaves because of their square-shaped output wave. They are also noisy and rough. By saying so I’m not discouraging you from buying them. I’m only being honest with you.

Appliances that won’t run on a modified sine wave inverter

A few laptop computers
X-10 automation systems
Digital clocks with radios
Medical equipment like oxygen concentrators
Appliances with speed controls like sewing machines
Anything with a silicon-controlled rectifier like those used in washing machine controls.
Some fluorescent lights with electronic ballasts.

If you just want to run none ballast lights, kettle, heater, etc., a modified sine inverter is fit for your needs.
Cons of using a modified sine wave inverter.

Power surge

In modified sine wave inverters, peak voltages vary with the battery voltage. Without regulation of the power supply, it can cause electric devices to behave abnormally due to the power surges.

Power wastage

Equipment used to convert DC to AC lose power during the conversion process. This simply means that if the converter is 70 percent efficient, then 30 percent of the power is lost. The power loss is in the form of heat. With the reduced efficiency of a modified sine wave inverter, power wastage is high.

When buying an inverter, consider doubling the draw you’ll be placing on it. This is because the power rating of any device is based on continuous power. When an electronic device is starting up, there is a current surge. The power surge is twice that of the rated continuous power.

Choosing an inverter with a high-power output will allow the inverter to work within its capacity, lowering the chances of damaging the electrical appliances or worse still, blowing power fuses in the event of a power surge.

With so many companies manufacturing sine wave inverters, I know how difficult it can be for you as a beginner to choose where to buy your inverter. However, presenting these questions to the manufacturer can give you a hint on whether it is best for your needs. It is always better if you know as much about them so that you buy the best.

1.What do you specialize in? Commercial, residential, or industrial sine wave inverters?

That way, you will know whether the manufacturer has the inverter that you want.

2.Do you manufacture the inverters in the house or you do outsourcing?

Manufacturers that outsource products usually cannot ensure quality control. Only companies that make their products can account for the products and therefore, it is advisable to buy from them.

3.Are the sine wave inverters customizable?

In the future, your power inverter needs may change. That is why you need to buy your inverter from a company that can customize them.

4.Are your inverters certified by NEBS?

Certification from Network Equipment Building System (NEBS) proves that the inverter can work even in adverse conditions like heavy moisture and places with airborne contaminants.

5.Do you give warranties to the inverters?

Look for a manufacturer that offers a great warranty and with minimal terms and conditions that you can read easily. That way, you can tell if there is anything mentioned there that could make the warranty void.

6.Do the inverters have an OEM maintenance plan?

In many cases, this plan is free for a small period and costs more than third-party maintenance plans.
After using the free portion of your plan, you can then decide whether it is the best option for you.

Choose from whatever answers the manufacturer will give you. However, the cost should never be a consideration factor while buying sine wave inverters. Based on your power needs, you should choose the types and number of appliances it should power.

A more expensive sine wave inverter comes with overload and control features. The extra features are very useful in preventing system overload problems and potential battery damage.

Important:

Induction motors like pumps, freezers, air conditioners, and refrigerators may have a start-up surge of up to seven times their continuous power rating. So be careful to choose the best inverter if you will use it for such devices.
240V of electricity can be destructive. Therefore, the improper use of a sine wave inverter can lead to personal injury, property damage, or even loss of life.

While using your inverter with the right devices, ensure that you get the right size battery. Batteries have varying maximum draw currents that can be sustained without damaging the cells of the battery.

You can find the maximum current that an inverter will draw from a battery by checking the specifications of your inverter and therefore decide the right battery to purchase. In case you have uncertainties, contact the retailer or customer service department of the manufacturer.

Approximating battery requirements

To decide the battery capacity that you need,
1.Judge the number of watts consumed by every appliance that gets power from the sine wave inverter. You should find the watt rating labeled on the product. When it is only the current draw given, multiply it by 115. This will help you get the power consumption in watts.
2.Estimate the duration which each appliance will be operating daily.
3.Analyze the number of watt-hours required for each appliance.
4.Sum the number of watt-hours required for all the appliances. Multiply this sum by the amount of time between charges.
5.Divide the sum of watt hours of alternating current load between charges by ten to get the battery ampere-hours used between the charges.

When making the determination of the size your battery, do not be tempted not to double the draw from the inverter. It is always better to have more capacity as this will result in increased reserve capacity, will be better handling significant loads, and the battery will not be discharged very quickly.

You can also decide to reduce battery size. This only happens when conserving energy. Energy conservation is done by removing or minimizing the use of some loads. It is also done by recharging more often.

The life of the battery is unswervingly dependent on how intensely it is discharged. The more intense the discharge, the shorter the lifespan.

Once you get the right battery for use, link the inverter to the battery, plug in your AC devices into the inverter then boom! You’ve got portable power whenever and wherever you need it. You can now operate electric lights, power tools, kitchen appliances just to name a few.

However, when connecting an inverter to a battery, use the thickest wire available and the shortest practical length. Aluminum is cheaper and lighter. However, it gives a much higher resistance for a given gauge and is more difficult to connect to.

If you are an expert in such things or know one, and you also need the advantages that aluminum gives, go ahead. If not, use copper. It is by far the best conductor.

The battery needs to be constantly recharged since the inverter draws power from it. Recharging can be done by running a car motor, generator, solar panel, wind turbine. You can also decide to use a battery charger plugged into an AC outlet. Whichever suits you best.

However, never use an inverter to directly recharge a battery through appliances. Always use the charger provided with that appliance.

It is recommended to recharge your batteries before complete charge is halfway depleted. By doing so you are increasing the lifespan of your batteries than recharging them than recharging them once they are fully discharged. More so, this ensures that the devices attached to the inverter won't shut down unexpectedly from power loss.
However, it is possible to recover from a shutdown caused by a completely discharged battery.

Recharging your battery from low voltage:

-Recharge your battery and turnoff all appliances.
-Restart your appliances once the low charge light turns off, and when the ON light of the inverter illuminates.
When restarting the appliances, turn them on separately after the inverter has started. Thus, the inverter does not have to convey the initial current for all appliances coincidentally and aids in preventing an overload shutdown.

What’s the best place to install an inverter?

As a technician, do not install an inverter in a partition with some degree of airflow. Also, do not obstruct or cover the ventilation openings. Overheating may result from such.

An inverter should be put in a place that has the following features:

1. Dry

Select a dry location. Water or other fluids should not splash or drip on the inverter. The inverter should not be exposed to splashing water snow or water.

2. Cool

The place should be cool enough. Average air temperature should range from 32 °F (0 °C) to 104 °F (40 °C) — in this range, it becomes better as it gets cooler.

3. Ventilated

The inverter needs air circulation to maintain the ideal operating temperature and provide the best performance. If the inverter unit has insufficient ventilation, it may develop problems as a result of overheating or even shut down. It is, therefore, critical to provide as much ventilation in the unit as possible.

It is recommended that other objects should be 3 inches (76 mm) at the very least, away from the openings of the ventilation chamber for optimum performance. The air emitted through the fissures should have a path as well to have circulation far from the inverter.

4. Safe

Never set up the inverter in a similar section as the batteries or in any partition containing liquids that are flammable like petrol.

5. Close to the battery compartment

Long direct current cables should be very big. Consequently, they should be very short. However, avoid installing the inverter unit near the battery compartment. This is because there may be explosive hydrogen gas that is emitted from the batteries.

6. Protection from the acid of the battery and gases

Be careful not to let battery acid trickle on the inverter when adding acid to the batteries or checking their specific gravity. Avoid mounting the unit in a place that is susceptible to battery gas exposure. These battery gases have a corrosive effect. Consequently, excessive exposure will reduce the life of the inverter.

7. Orientation of the Inverter

The inverter must be fixed on a horizontal surface that is flat with the front panel. This is necessary in order to meet the requirements set aside by regulatory authorities.

It is important to note that Sine Wave Inverters should not be utilized together with systems of life support in ICUs or other tools or devices unless there is a 24/7 inspection of the inverters and their components. This is because, in moments of failure or malfunctioning, people may lose lives.

Troubleshooting an inverter

This section offers you tips to detect and find the solutions to most issues that can affect the sine wave inverters. It identifies the problem, the possible cause of that problem, and how to resolve it.
Prior to contacting your dealer, kindly take a look at these guidelines. However, if you are not able to dodge the issue, call or book an appointment with your dealer or customer service of the manufacturer.

1.No output voltage and no indicator beams

Possible causes:
a.There might be no input power available to the inverter.
To resolve this, have a look at the DC connection to the inverter for connections that may be loose, an open DC disconnect, or frayed wiring
b.DC fuse may be open (external).
Contact a technician who is qualified so that he or she can have a look and have the fuse replaced.

2.No voltage output and fault light of the inverter is illuminated

Possible cause:
a.The inverter may be overloaded.
In such a case, you need to disconnect all appliances connected to the inverter, then reset it.
b.Battery voltage could extremely high.
The always inverter restarts once the battery voltage goes below a stipulated level as indicated by the manufacturer.
c.Excessive heat.
You should let the inverter cool down. It will restart automatically thereafter.

3.No output voltage and low battery illuminates.

Possible cause:
a.Battery voltage is too low.
Its remedy is recharging the battery and roughly exceeding 12.6V, and it will restart automatically.
b.Poor DC wiring can cause this.
Disconnect the DC wiring, then use correct wiring and make sure to tighten all connections.

4.The output voltage is present. However, the inverter’s light is on and the Low Battery light is lightened.

The possible cause is that the battery voltage is too low. To solve this problem, disconnect all appliances and recharge the battery.

5.The fan does not run.

This could be caused by the apparatuses inside the inverter not being warm. However, there is no physical remedy for this. Give it time. The fan is able to run automatically when needed to cool down the components of the inverter.

6.The fan runs always.

Possible causes:
a.The appliances consume a lot of power.
No physical intervention is required. After some time, the fan should rotate at speeds that are lower and automatically stop once the inverter’s temperature reduces.
b.The temperature is high.
Don’t intervene in any way. The fan will rotate at lower speeds and stop when the temperature falls.

7.The remote switch is on but the inverter's ON light is off.

The most possible cause of this is that the cable connection is loose or faulty. Check the cable and the connection to ensure everything is in order.

8.Battery usage time is too short.

Possible causes:
a.Electrical power consumption is too large.
You should replace the battery with a larger capacity one.
b.The battery could be damaged.
Consider replacing it.
c.Battery charging could not be enough.
Consider charging the battery or replacing it.
d.It could be attenuation of a wire.
In such a case, you should shorten the length of the wire or even use a thicker one.

Safety measures when working with batteries.

1.Carry out all the instructions provided by the battery manufacturer or the equipment manufacturer where the battery is installed. This will help to minimalize risk of explosion.
2.Ensure that the area surrounding the battery is ventilated properly.
3.Avoid sparks or flames from reaching anywhere close to the batteries or engine. They can cause a fire that may be fatal.
4.Take caution not to drop any metallic object on the battery. This could lead to a battery short circuit or a short circuit of other electrical parts. It can also produce sparks that can cause an explosion.
5.Batteries usually produce explosive gases under normal working conditions. Make sure to follow all the instructions as required before installing or using the inverter.

Important precautions

1.Before you install and use the inverter, read all the recommended guidelines provided by the manufacturer of the inverter or any caution marks on the batteries and inverter.
2.Do not make use of the inverter in the event that it has had a sharp blow, has been dropped, or even damaged.
3.Avoid disassembling the inverter because it does not have user-serviceable parts and trying to service it by yourself could lead to fire or electrical shock.
4.To minimize electrical shock risks, have both the DC and AC power disconnected from the inverter prior to dealing with any circuits connected to it.
5.Ensure that the inverter is away from water, snow spray and rain..
6.Keep the openings of the ventilation clear to minimize risk of overheating.
Gauging on the size, number, and type of your electrical appliances, you should be able to decide the best sine wave inverter to use. Buying from the manufacturer as compared to retailers is greatly advised. That way you will be able to get efficient assistance when need be and when replacements are required, you can get exact parts to that of your original inverter.

Conclusion

In conclusion, if you are intending to run multiple appliances, getting an inverter is the best option that you will have. Many companies and some medical facilities have implemented the use of inverters. When installed correctly and given proper care and maintenance, they can prove to be reliable for a long time.