No doubt, a power inverter is very useful as an alternative or backup power supply. This is especially true for countries like Nigeria where epileptic power supply has become a cankerworm, to say the least. Even in places where there is adequate power supply, inverters can help you to cut down electricity bills, considerably.
Inverters use direct current (DC) from sources like batteries, solar panels etc, to produce alternating current (AC), which is the same type of electricity we get from the mains power supply. In other words inverters can be used to run our electrical appliances when there is power outage or a generator is not available. Eventually, the energy from the source will be spent, and will have to be replenished; unless of course the source is solar or other similar free energy sources.
Most people have not started enjoying this luxury, while some of those who have, are not really getting the best out of it. This is largely due to insufficient information. It is for this reason that I hereby present some useful tips as a guide.
Here are some useful factors that one should consider before acquiring a power inverter:
*How much electric power do you consume?
*What VA, (voltage * current), rating of inverter do you need?
*How much backup time do you expect?
*How many batteries would you require?
*Type of battery.
*Availability of another power source for recharging the battery.
*Consult with people in the know, like us.
1)How much power do you require?
The amount of power required depends on the total power consumed by all the appliances you wish to run with the inverter. Let's say you want to use 3 lights 1 fan 1 television and perhaps a sound system.
We calculate the total power as follows:
3 lights - 20 *3=60 watts
1 fan - 50 watts
1 TV - 70 watts
1 sound system - 80 watts
Total =260 watts.
2)What VA rating of inverter do you need?
The VA rating of the inverter represents the total voltage and current that it supplies to the load. This value is usually higher than the actual power as calculated above, depending on the efficiency of the inverter system. Usually, it can be somewhere between 60-85%, depending on the quality.
To determine the required VA, let us assume that the efficiency is 75%, to be conservative. The VA=Total Power/ efficiency ; VA 260/0.75=347VA.
However, in practice, it is necessary to derate this value, in order to give room for the inverter to operate comfortably. This also ensures the durability of the inverter. A safe derating factor would be to double the VA, hence we have 347*2=694. So a 700VA inverter would be adequate.
3)How much backup time do want?
The backup time means how long you want the battery to last while running the inverter. This depends on the capacity of the battery, which is denoted by the Ampere hour or Ah. Common standard ratings range from 60Ah to 200Ah. To determine the required backup time, let's say you want to run at full load, which is seldom the case. And you want the battery to last for 3hrs, then the Ah is determined by considering the current supplied by the inverter at the given load. This current is extracted from the total VA consumed by the load; from our example above, the current= 700/12V (the battery voltage)= 58A. So for 3hrs we need 3*58=174Ah.
A 200Ah battery will be required to run more comfortably due to inefficiencies associated with real life systems.
Note that you may decide to power all your appliances or just some vital ones, at any point in time; you don't always have to run at full load all the time. That is one of the advantages of the inverter over generators, you can conserve the battery when you reduce load by turning off some appliances at certain periods.
4)The number of batteries required.
The number of batteries depend on;
a) The desired backup time
b) The voltage required by the particular type of inverter
a) If you want to increase the backup time you can cascade two or more batteries in parallel. Say you want to double it to 6hrs you can use two batteries and so on.
b) Certain inverters work at higher voltages other than 12V. This is especially true of inverters of higher ratings from about 1500VA and above. In this case you might need two or more batteries connected in series.
5)The type of battery to be used
The type of battery you use, plays a very vital role. Some people might decide to use normal car batteries. These might suffice where one desires to cut costs, or if car batteries are readily available. However, this type of battery is not suitable for inverters because it is not usually meant to operate at deep discharge cycles. Hence it can not last long in terms of backup time. Moreover, most of them emit poisonous gases especially during recharge, therefore they are not suitable for indoors use.
A much better type is the sealed maintenance free battery that does not emit such gases. In fact there are deep discharge ones specially made for inverters.
Deep discharge batteries have more backup time which means that you can run on inverters for longer periods after recharge.
6)Availability of another power source for charging the battery
Another important factor is the availability of an alternative power supply to recharge the battery when it is flat. Batteries store energy which is spent during inverter operation (discharge). Therefore there should be a means of replenishing the energy (recharge).
This energy source can be from the mains power supply, generator or solar panels etc. In other words a battery inverter system is useless where there is no means of recharging the battery. When the mains power supply is available or while running a generator, the battery gets recharged so that when these sources are absent, the inverter can supply power.
Most inverters have a charger integrated but it is possible to use a separate stand-alone charger, if the in-built one is not adequate to supply enough charge to your battery, especially if the battery capacity is high.
Installing solar panels is a very good idea especially since the energy from this source is free and readily available every day during the day while the sun shines. Some inverters come solar ready; which means that they have in-built solar charge controller while others require a separate charge controller.
7)Consult with those in the know.
Needless to say, it is wise to seek advice from someone who knows about these things, so that you don't waste your money. That way you will be able to get the best out of your investment.
Inverters use direct current (DC) from sources like batteries, solar panels etc, to produce alternating current (AC), which is the same type of electricity we get from the mains power supply. In other words inverters can be used to run our electrical appliances when there is power outage or a generator is not available. Eventually, the energy from the source will be spent, and will have to be replenished; unless of course the source is solar or other similar free energy sources.
Most people have not started enjoying this luxury, while some of those who have, are not really getting the best out of it. This is largely due to insufficient information. It is for this reason that I hereby present some useful tips as a guide.
Here are some useful factors that one should consider before acquiring a power inverter:
*How much electric power do you consume?
*What VA, (voltage * current), rating of inverter do you need?
*How much backup time do you expect?
*How many batteries would you require?
*Type of battery.
*Availability of another power source for recharging the battery.
*Consult with people in the know, like us.
1)How much power do you require?
The amount of power required depends on the total power consumed by all the appliances you wish to run with the inverter. Let's say you want to use 3 lights 1 fan 1 television and perhaps a sound system.
We calculate the total power as follows:
3 lights - 20 *3=60 watts
1 fan - 50 watts
1 TV - 70 watts
1 sound system - 80 watts
Total =260 watts.
2)What VA rating of inverter do you need?
The VA rating of the inverter represents the total voltage and current that it supplies to the load. This value is usually higher than the actual power as calculated above, depending on the efficiency of the inverter system. Usually, it can be somewhere between 60-85%, depending on the quality.
To determine the required VA, let us assume that the efficiency is 75%, to be conservative. The VA=Total Power/ efficiency ; VA 260/0.75=347VA.
However, in practice, it is necessary to derate this value, in order to give room for the inverter to operate comfortably. This also ensures the durability of the inverter. A safe derating factor would be to double the VA, hence we have 347*2=694. So a 700VA inverter would be adequate.
3)How much backup time do want?
The backup time means how long you want the battery to last while running the inverter. This depends on the capacity of the battery, which is denoted by the Ampere hour or Ah. Common standard ratings range from 60Ah to 200Ah. To determine the required backup time, let's say you want to run at full load, which is seldom the case. And you want the battery to last for 3hrs, then the Ah is determined by considering the current supplied by the inverter at the given load. This current is extracted from the total VA consumed by the load; from our example above, the current= 700/12V (the battery voltage)= 58A. So for 3hrs we need 3*58=174Ah.
A 200Ah battery will be required to run more comfortably due to inefficiencies associated with real life systems.
Note that you may decide to power all your appliances or just some vital ones, at any point in time; you don't always have to run at full load all the time. That is one of the advantages of the inverter over generators, you can conserve the battery when you reduce load by turning off some appliances at certain periods.
4)The number of batteries required.
The number of batteries depend on;
a) The desired backup time
b) The voltage required by the particular type of inverter
a) If you want to increase the backup time you can cascade two or more batteries in parallel. Say you want to double it to 6hrs you can use two batteries and so on.
b) Certain inverters work at higher voltages other than 12V. This is especially true of inverters of higher ratings from about 1500VA and above. In this case you might need two or more batteries connected in series.
5)The type of battery to be used
The type of battery you use, plays a very vital role. Some people might decide to use normal car batteries. These might suffice where one desires to cut costs, or if car batteries are readily available. However, this type of battery is not suitable for inverters because it is not usually meant to operate at deep discharge cycles. Hence it can not last long in terms of backup time. Moreover, most of them emit poisonous gases especially during recharge, therefore they are not suitable for indoors use.
A much better type is the sealed maintenance free battery that does not emit such gases. In fact there are deep discharge ones specially made for inverters.
Deep discharge batteries have more backup time which means that you can run on inverters for longer periods after recharge.
6)Availability of another power source for charging the battery
Another important factor is the availability of an alternative power supply to recharge the battery when it is flat. Batteries store energy which is spent during inverter operation (discharge). Therefore there should be a means of replenishing the energy (recharge).
This energy source can be from the mains power supply, generator or solar panels etc. In other words a battery inverter system is useless where there is no means of recharging the battery. When the mains power supply is available or while running a generator, the battery gets recharged so that when these sources are absent, the inverter can supply power.
Most inverters have a charger integrated but it is possible to use a separate stand-alone charger, if the in-built one is not adequate to supply enough charge to your battery, especially if the battery capacity is high.
Installing solar panels is a very good idea especially since the energy from this source is free and readily available every day during the day while the sun shines. Some inverters come solar ready; which means that they have in-built solar charge controller while others require a separate charge controller.
7)Consult with those in the know.
Needless to say, it is wise to seek advice from someone who knows about these things, so that you don't waste your money. That way you will be able to get the best out of your investment.
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