A power inverter changes direct current (DC) power from a battery, usually 12V, 24V or more, into conventional mains alternating current (AC) power at 230V or more. This simply means that a power inverter changes the voltage of a battery to one that looks exactly like the voltage your generator will provide or like the one EEDC or PHCN will provide in their absence or in a bid to reduce cost.
You can use one to operate all kinds of devices eg.
Just connect the inverter to a battery, and plug your AC devices into the inverter and you’ve got portable power whenever and wherever you need it. The inverter draws its power from a 12V, 24V battery or higher voltage which is dependent on configuration (preferably deep-cycle), or several batteries wired in parallel. The battery will need to be recharged as the power is drawn out of it by the inverter.
The battery can be recharged by solar panels, or wind turbine. Or you can use a battery charger plugged into an AC outlet to recharge the battery.
There are 2 types of inverters available for use in consumer applications. These are:
The name pure sine wave inverters come from the wave form of its output. They have pure sine wave form output. This is identical or to replicate as close as possible to general mains. As most electronic products are designed to be powered by mains, pure sine wave inverters are suitable for all applications, especially motorised devices where it is proven that pure sine wave power will lengthen the product’s lifetime and run much quieter.
Pure sine wave inverters are more expensive than modified sine wave inverters because they involve a much more sophisticated design in order to simulate the smooth output of standard mains power.
Again modified sine wave inverters are named after their output waveform. The output of the modified sine wave inverter cycles through positive, ground and negative voltage to give a similar output waveform to pure sine wave. Modified sine wave inverters are a much cheaper alternative to pure sine wave inverters as they don’t require the complicated system needed to smooth and render the output waveform. The only down side with a modified sine wave is that it introduces harmonic distortion to inductive and audio equipment. This is caused by the harsh clipping in the on and off phase changing in voltage. However, modified sine wave inverters are suitable for heat element devices (kettle, heater, etc) and devices that have an external or built-in adaptor (laptop, TV, etc).
Modified sine wave works well for most devices, and is the most common type of inverter on the market, as well as the most economical.
If you mostly want to run lights (none ballast), TV, kettle, heater, etc, a modified sine wave inverter is suitable for your needs.
Pure sine wave inverters (also known as true sine wave) are more suited for sensitive electrical devices such as laser printers, inductive devices (ballast, compressor, AC motor), variable speed control devices and audio equipment.
A very simple way to use an inverter for emergency power (such as during a power outage), is to use a battery that is already precharged by a solar panel or by the inverter itself during power-in, and an extension cord running into the house, where you can then plug in electrical appliances.
The output power you require depends on the power (Watts) of devices that you want to run. The power information of most devices can usually can be found on a specification label on the product or packaging, if you have any uncertainty please contact the retailer or customer service department of the manufacturer. We recommend you choose an inverter with 20 to 50% extra of total power required and with minimum of twice the power of the largest device you will be using. The reason for requiring twice the largest power device is that the power rating on any device is based on continuous power. When an electronic device is starting up, there is a surge of current. This power surge is normally two times, but can be up to seven times (such as ac motors), of the rated continuous power. Therefore chosing an inverter with a higher power output will reduce the risk or damaging your electrical items, power supply or the inverter itself.
Example: You want to power a computer, some lights and a radio with power as below.
2 x 60W lights: 120W
Total Power Needed: 430W
For this application, an inverter with minimum power of 600W is recommended.
As 600W is twice the power of the highest power device and the total power of 430W is still within the maximum power rating of the inverter. Of course it will be more ideal to move one step up and choose a 1000W inverter which would allow for additional devices to be powered or added on in the future.
Many specifications on the product only quote current (amps) instead of power, to convert current to power, below formula can be used:
To convert Amps to Watts:
Current (Amps) × 230 (AC voltage) = Power (Watts)
This formula yields a close approximation of the continuous load of the appliance.
To calculate approximate start-up load:
Power (Watts) × 2 = Start-up Load
This formula yields a close approximation of the starting load required by the appliance, although some appliances may require an even greater starting load.
Note: Induction motors such as air conditioners, refrigerators, freezers and pumps may have a startup surge of up to seven times their continuous power rating.
Most often the start-up load of the appliance or power tool determines whether an inverter has the capability to power it.
For example, you have a freezer with a continuous load of 2 Amps, and a start-up load of 6 Amps:
2 Amps x 240 Volts = 480 Watts continuous
6 Amps x 240 Volts = 1440 Watts starting load
You would need an inverter with peak-surge rating greater than 1440W.
To work out current/battery capacity requirement (for 12V system):
Power (Watts) / 12V = Current hour (Ah)
Many small inverters (300W and under) come with crocodile clips which are attached to the positive and negative terminals of the battery.
Larger inverters (500W and over) must be hard-wired directly to a battery. The cable size depend on the distance between battery and inverter, and will be specified in the instruction manual for the inverter.
When connecting the inverter to the battery use the thickest wire available, in the shortest length practical.
Inverter Power Output < 1m 1m – 2m 2m – 3m
600W 6 4 2
1000W 4 2 1/0
1500W 2 1 3/0
2500W 1/0 3/0 350
NOTE: These are general recommendations for inverters that utilise a single cable set (one positive and one negative cable) only and may not be correct for all inverters or applications. Additionally, some inverters require two or more cable sets and therefore may require a different cable size than listed.
Cable size recommendations may vary among inverter brands and models; please check the Instruction manual for the model you have purchased before you buy the wire for it. The maximum length generally recommended is 3m, and shorter runs are recommended to reduce resistance and heating effect of the cable and improve the efficiency. If longer distance is required from battery to the device, it is recommended to extend from the AC output rather than on the DC input side.
Call us at Arthur Energy for all your INVERTERS AT VERY HIGH DISCOUNT 07032862249
DISCLAIMER: this article has not trained you as an inverter installer, it is only for information purpose, even as a DIY enthusiasts you still need expert advice on how to properly install and manage all your inverters, kindly call in today or visit any of our offices to purchase your PURE SINEWAVE INVERTERS