Power interruptions and load shedding in South Africa are in all likelihood set to remain for a very long time. But it doesn’t have to be a factor in your home. With some basic knowledge in your back pocket, you can get out there and shop for a solution like a boss. Let’s go!
As a homeowner, you can choose from four broad categories of backup solutions. These are:
· Small uninterruptable power supplies (UPSs)
· Solar systems
Each of these technologies has its own advantages and disadvantages. Your starting point therefore has to be what you want out of a backup system. To keep costs down and equipment size manageable, the rule of thumb is to only consider the most important appliances you’d like to use during a power outage.
UPSs are generally used to keep critical devices operating until a generator can take over for longer support. Depending on the type of UPS you buy, there can be a very short break when power from the utility is lost, ranging from 4 or 5 milliseconds to no interruption at all. They are good for when you need a limited amount of power over a short period of time.
The standby UPS is an entry level unit most commonly used to run a computer and a printer, or appliances that use less than 2kVA to 3kVA. Power is supplied to equipment through a surge and basic voltage regulator, and the battery backup system is only turned on once the utility power source is lost. These units are cheap and offer minimal protection for voltage fluctuation.
Should you want to run more appliances, say a TV, decoder and a light or two, the line interactive UPS is a better solution as it can supply a total power demand of up to 5kVA. High efficiency combined with better utility power filtering protects connected equipment against power surges.
For power needs that exceed 5kVA, an online UPS might be best. These units are the most expensive and least efficient, but they offer continuous power with the greatest protection against voltage fluctuations, making them ideal for larger, expensive electronics in the home.
For longer standby times where you are not running mission critical operations, an inverter or generator is the better option. Inverters work much the same as UPSs but have larger battery charging systems that allow for longer standby times without a generator. Also similar to UPSs, a short break in power occurs as inverters switch from utility to battery power. However, at 10 to 15 milliseconds, the break would not affect most household devices.
Depending on the unit, inverters can be connected to solar systems that can reduce both your utility electricity bill and fuel costs when your system switches to generator power. Solar inverters can also deliver power on sunny days, even when the batteries are depleted.
Portable home generators are still among the most flexible and cost-effective standby solutions for higher power requirements over long periods of time – provided that you have the space outside and don’t mind the noise and higher maintenance costs.
Smaller generators come standard with outlets for extension cords or home services to be plugged in; larger generators need to be wired for transfer switches for manual or automatic change-over from utility to generator. An automatic transfer switch (ATS) monitors utility power, and starts the generator and automatically switches over when utility power is lost. Once the utility power returns, the ATS switches back and turns the generator off.
The maintenance question
Regardless of the solution you install, maintenance has to be part of your decision-making process.
Generators have more taxing maintenance requirements, and their fuel has to be stored and regularly replenished.
On the upside, they don’t have batteries that need to be replaced. Batteries for UPSs and inverters are expensive and have a lifespan of between five and 10 years, depending on the number of charge and discharge cycles and the temperature they are kept in. Home application batteries must be stored at between 20 and 25 degrees. The more load shedding the batteries experience, the shorter their life expectancy will be.
Batteries aside, inverters are almost maintenance free, don’t produce the noise levels of a generator, and don’t require the hassle of storing or topping up with fuel.
Choose the right supplier
You backup power investment is likely to be significant, and warrants careful consideration of supplier. Make sure the supplier you select has a track record and a good reputation for the services it offers. Also ask specific questions about warrantees, spares and services levels.
With the exception of smaller UPSs, inverters or plug-in, manual-start generators, most systems have to be installed and commissioned by qualified electricians for compliance and insurance purposes. It’s an added bonus if the supplier includes installation and commissioning. Should this not be the case, ask about their approved partners to ensure warrantees are honoured.
Deciding on a backup power solution is not a simple matter, but you don’t have to do it alone. Visit www.kva.co.za for expert advice, quality products, support and service from Master Power Technologies.