April 9, 2020
What is a UPS System and how does it work?
UPS (Uninterruptible Power Supply) systems consist of rechargeable batteries, an inverter and a battery charger all stored in one box. An electrician can connect the UPS directly to your house’s main power distribution board so that it automatically switches on during Load Shedding. An alternative way to use a UPS is to connect it directly to what you need to use during Load Shedding, like your fridge, router or laptop. Most UPS's easily connect to a standard wall socket and are designed to instantly supply your home or workplace with electricity when your power goes off.
What to look for when choosing a UPS system
- Is the inverter a "pure sinewave inverter" or a "modified sinevawe inverter"?
Pure sinewave inverters are necessary to safely run a fridge, a freezer, a pump or any device that contains an AC motor. They can power any AC appliance sold in South Africa without any risk of damage. Modified sinewave inverters are cheaper and suitable for most electrical devices that do not contain an AC motor (laptops and lights notably).
- The inverter power rating
Constant (continuous) load and peak load. An inverter rated at 500W (constant) / 800W (peak) can continuously power a load of maximum 500W. When switching on the appliances, the peak load should not exceed 800W. Beware that many appliances necessitate a peak power of 2 to 3 times their rated power consumption: a fan rated at 150W might necessitate up to 450W when switched on.
- The battery capacity and type
Lithium batteries can be drained 100% and recharged hundreds of times without any issues, whereas deep-cycle lead-acid batteries (AGM, gel) should never be discharged at more than 50% of their rated capacity without sustaining damage. A 500Wh (watt x hour) lithium battery can power a load of 500W for 1 hour (or 50W for 10 hours). A 100Ah 12V battery has a nominal capacity of 100W x 12 hours = 1200Wh that can be used at 50%, i.e. 600Wh usable capacity, sufficient for a load of 100W for 6 hours for example. Note that lead-acid batteries need more time to charge than lithium batteries: if the load shedding intervals are 12 hours or less, your lead acid batteries will probably not be fully charged.
A 500W UPS with a 100Ah 12V battery can typically run a 32-inch flat screen LCD TV (50W), a laptop (50W), a DSTV decoder (50W) and a set of low energy lamps (5x 10W) for 3 hours (200W constant load). Keep in mind that the bigger the wattage of your devices, the larger your inverter and the battery bank should be.
What are the advantages of a UPS System?
- Reliable & instantaneous - Automatically switches over when the power goes off
- No interruption - Phone, WiFi router, security cameras, digital cameras, monitors & tablets will stay powered
- Lasts enough time - You can dimension Batteries ensure the system lasts over 5 hours
- Provides surge protection - prevents possible damage to devices caused by power supply interruptions
What is the price of a UPS system?
Prices vary from R4000 for a small modified sinewave UPS system that can power your TV and a few lights, to R60 000 for a system that can power your entire house (May 2020 prices). If the UPS system is connected to your house distribution board, you should factor in the cost of the electrician and need a certificate of conformity.
What is a generator and how does it work?
A generator is a simple, solitary device or machine that produces electricity from petrol, diesel or gas and is used when power from the local grid is not available. Generators are widely used to provide backup power for businesses, homes, farming, food distribution, hospitals and many more.
What can a generator typically power?
A 3000 - 6500W generator running on either petrol or diesel is enough to keep your household appliances running during a blackout, except the geyser, swimming pool pump and electric stove, as these draw too much power.
A smaller 2000W generator is enough to keep your lights, electronics, TV, cell phone and laptop/computer running. Appliances like refrigerators, microwaves, dishwashers, toasters and other heavy-duty, AC appliances require a higher wattage generator.
Unfortunately, standard generators tend to be noisy, and there are many restrictions related to dB (decibel) levels which might apply where you live or work. There are quieter generators made in special containers that reduce the noise level and allow enough airflow to keep it cool. Inverter generators are generators of a more modern type, they are less noisy and use less petrol than conventional 4-stroke generators (about 20% less).
Generators should always be installed outside and not inside a house or garage (the risk of carbon monoxide poisoning is real).
What are the advantages of a generator?
- Quick & automatic - Provides power quickly and can be installed to start automatically during power outages
- Affordable equipment - When used occasionally, generators are cheaper than solar power systems or UPS's
- Safe - Protects the home from dangerous voltage shifts & surges when power returns
What is the price of a generator?
Prices vary from R3000 for a small 1000W, 2-stroke generator to R15 000 for a 6500-7500W 4-stroke generator, whereas suitcase inverter generators typically cost between R12 000 and R30 000 depending on power rating (May 2020 prices). If the generator is connected to your house distribution board, you should factor in the cost of the electrician and need for a certificate of conformity.
Hybrid Solar Power Systems
What is a Hybrid Solar Power System?
A hybrid solar power system blends power from the grid (Eskom), solar panels (photovoltaic panels, or PV panels) and batteries to supply your house or building.
When the sun is shining, the PV panels supply electricity to the house and to the batteries. When there is no sun, the batteries and the grid power the house. During load shedding, the batteries operate like a UPS system and power the house.
Hybrid solar power systems are one of the more expensive alternatives initially, but in the long-term, they can pay off the most. The solar panels charge in the sun and generate the electricity you need with less reliance on Eskom's grid.
What can a Hybrid Solar Power System power?
A 3000-4600W hybrid system will be able to power your household except for the geyser, stove A/C and pool pump. A 8000-12000W system will be able to power everything in your household. A hybrid solar power system is not very budget-friendly, but it will save you up to 80% of your electricity bill and pay itself off in 5 to 10 years. South Africa has a warm, sunny climate and is the perfect place to use solar.
What are the advantages of a Solar Power Hybrid System?
- No maintenance required & very quiet operation
- Zero air pollution - No CO2 & other harmful gasses emissions
- Reliable & flexible – Charge batteries with solar power or Eskom
- Automatic – Automatically & instantly provides power when there is a power failure
- Safe – Clean safe power for sensitive equipment such as electronics & medical devices
- Always available & free – An abundance of solar energy in sunny South Africa
- No future costs – No impact by Eskom and petrol price hikes
What is the price of a hybrid solar power system for a complete house?
in 2020, prices vary from R80 000 to R200 000 including installation and local registration, depending on the size of the solar system (3000W system for household with 400kWh monthly consumption, to 8000W system for household with 1000+kWH monthly consumption).
- Collection of Load Shedding Solutions recommended by EcoDepot
- Article: How to save electricity at home: become energy efficient
- Article: How to stay connected to the WiFi during Load Shedding