Due to a variety of factors mains electricity supply is getting less and less reliable. While the national demand for electricity is increasing steadily, the generation capacity is not keeping pace. The supply of the fossil-fuels required by the power stations is also getting less certain. As fuel prices continue to rise the reserve stockpiles of fuel held by the power companies is being reduced to critically low levels. Also the incidence of extreme weather events is increasing, and these too, often result in power cuts (e.g. winter snow storms of 2011 and 2012, hurricane force winds of Oct 2013).
While mains power is on, the inverter-charger charges the battery (or batteries). When mains power fails the inverter-charger instantly switches to drawing power from the batteries and converting that power into AC power. Thus any appliances connected to the system will have a continuous supply and will not be affected. For example computers will continue to run with no data loss, and sensitive medical equipment will operate perfectly.
For background information on Inverter-Chargers Read this article.
GEL BATTERIES are rechargeable valve-regulated lead-acid with a gelified electrolyte. They are maintenace free, so no need to keep them upright. As they are sealed there is no risk of spillage or evaporation. They are more resistant to extremes of temperature, shock or vibration. They require a stabilised, regulated charging system. They are slower to charge and must never be over-charged. They have a lower capacity for given dimensions and have less ability to dissipate heat.
LEAD-ACID BATTERIES are fine with a conventional charging system and are less expensive for any given capacity. They are excellent at dissipating heat. They need to be kept upright and need the electrolyte (water) to be topped up from time to time.
Both of these types of batteries are Lead Acid. When Calcium is added to the battery plates it improves the performance of the battery and there is less internal gassing of the battery. Therefore the battery terminals require little or no maintenance.
Ah stands for Ampere-Hour and is a measure for battery capacity. It is calculated by multiplying the current flow in amperes by the time in hours of discharge. (Example: A battery which delivers 10 amperes for 15 hours delivers 10 x 15 = 150 Ah).
A deep-cycle battery is a lead-acid battery designed to be regularly deeply discharged using most of its capacity. A deep-cycle battery is designed to discharge between 50% and 80% of its capacity, depending on the manufacturer and the construction of the battery. Although these batteries can be cycled down to a 20% charge, the best lifespan vs cost method is to keep the average cycle at about 50% discharge. There is a direct correlation between the depth of discharge of the battery, and the number of charge and discharge cycles it can perform.
4 x 60W filament bulbs (240W)
4 x 11W low energy bulbs (44W)
Laptop Computer (65W)
Desktop Computer (150W)
Kettle (2000W)
42" plasma TV (270W)
Microwave (900W)
Dishwasher (1000W)
Washing Machine (700W)
Fridge/freezer (50W)
TOTAL = W
All appliances have their power consumption written on them somewhere. Modern Fridges, freezers, washing machines etc have an energy rating which indicates how efficient they are, and says what their power cnosumption is. For example an A+ rated fridge freezer is quoted as consuming 268kWh of electricity per year. i.e. 268,000/365 = 734Wh per day, or 734/24 = 31W per hour average consumption. Hence the fridge takes on average about 30W of power (less than you think)!
Alternating current (AC) has a continuously varying voltage that swings from positive to negative. This has great advantages in power transmission over long distances. Power from your power company is carefully regulated to be a perfect sine wave, because that is what naturally comes out of a generator.
On the other hand, a pure sine wave is expensive to make in an inverter. The most inexpensive way to make AC is to switch it on and off - a square wave. A modified sine wave is designed to simulate a sine wave in the most important respects so that it will work for most appliances. It consists of a flat plateau of positive voltage, dropping abruptly to zero for a while, then dropping again to a flat plateau of negative voltage, back to zero for a while, then returning to the positive voltage.
The following gadgets work well with a modified sine wave: computers, motor-driven appliances, toasters, coffee makers, most stereos, ink jet printers, refrigerators, TV's, VCR's, many microwave ovens, etc.
Appliances that are known to have problems with the modified sine wave are some digital clocks, some battery chargers, light dimmers, some battery operated gadgets that recharge in an AC receptacle, some chargers for hand tools. In the case of hand tools, the problem chargers usually have a warning label stating that dangerous voltages are present at the battery terminals when charging.
Why do I need to consider an uninterruptible supply system (UPS)?
