Chosing the right backup system for your home or work can be a tricky task, especially if you’re unfamiliar with how an inverter works or how much power you need to produce. Your solar installer should help you make the right choice, but you’re likely to have questions about the products and options presented so hopefully by understanding the basics, you'll be in a better position to make the right choices.
The power requirement at your home can be different from your neighbour's home or another business. So do not just blindly install the same inverter (in terms of power) in your home. Before buying an inverter and battery, do a little homework and understand the basics.
What is my power requirement?
One of the most important factors that you must know before buying an inverter is your “power requirement”. Simply, this refers to the electrical appliances (like fan, lights, television, CFL etc.) you want to run at the time of a power outage or loadshedding. You can work out your power requirement by adding up the power consumed by various electrical equipments.
For example:
Suppose you want 3 fans, 3 tube lights, 1 CFL (lamp) & 1 television to operate at the time of a power failure.
Below is the power consumed by these items:
1 fan = 70 Watts
1 tube light = 60 watts
1 CFL = 25 watts
1 Television = 120 watts
Therefore your total power requirement is ( 3*70 +3*60 + 25 + 120) = 535 watts
What is the VA rating of the inverter I need?
VA stands for the Volt ampere rating. It is the voltage and current supplied by the inverter to the items you wish to power. If an inverter operates with 100% efficiency, then the power requirement of the electrical items and power supplied by inverter is same. However, most inverters have the efficiency range from 60 % to 80%. This efficiency is also called the power factor of an inverter and is simply the ratio of power required by the appliances to power supplied by an inverter. The power factor of most inverters ranges from 0.6 to 0.8.
For example:
Power supplied (or VA rating of inverter) = Power requirement ( power consumed by equipments in watts) / Power factor( efficiency).
Here average value of power factor or efficiency is considered i.e. 0.7 Power of inverter (VA) = 535/0.7 = 765 VA or 5kW inverter
The OUCO 5kW 1 phase Hybrid Inverter ticks all the boxes!
Why a hybrid inverter?
A hybrid inverter is a great option because it can work with both renewable and traditional energy sources, while an inverter can only work with renewable energy sources. This means that when you invest in a hybrid inverter, you don't have to purchase solar panels as part of the backup system. This gives you flexibility to add solar later on when you have the budget or your requirement for backup power increases.
What battery does my inverter need?
Battery is the backbone of an inverter system. The performance and life of an inverter largely depend upon the battery quality. The next big question is “how much back up will a battery provide?” or for “how many hours it can run all of your appliances”. This is what is called the battery capacity. It is the battery capacity that decides the back up hours. It is expressed in Ah (Ampere Hours).
So how to decide how much battery backup is required for your inverter? To find this out lets do a reverse calculation. Consider that you need a battery that provides back up for 3 hours.
For example:
Battery capacity = Power requirement (in watts) * Back up hours ( in hrs) / Battery Voltage (in volts)
Battery Capacity = (535 * 3) / 12 = 133 Ah
** Value of Battery voltage is taken 12V to work out kWh to equal 1.560kWh.
So if you want to run 3 fans, 3 tube lights, 1 CFL and 1 TV for 3 hours during power failure you would need 5kW hybrid inverter and 2.4kWh lithion ion battery.
Why lithium ion batteries?Lithium-ion batteries contain relatively low levels of toxic heavy metals found in other types of batteries, such as lead-acid and nickel-cadmium (NiCd) batteries. They are lightweight and compact, while providing high energy density which results in a "bigger punch". They are also low maintenance, provide more charge cycles and have a low self-discharge rate.
You can look at the OUCO range of lithium ion batteries here:
When to add solar panels?
The awesome part of a hybrid system is that you can add solar panels when you need to. Generally speaking this is a good option when the municipal electricity supply is "down" too often to charge your batteries. The number of solar panels you can connect to your inverter is identified by its wattage rating. For example, if you have a 5kW inverter, you can connect approximately 5,000 watts (or 5 kW) of solar panels. Using 300W solar panels, you could then connect roughly 17 solar panels.
Long-term energy independence is possible, you just need to know what your options are and which products are best for you and your budget.
Contact us on sales@ganelec.co.za to learn more.