That power normally is obtained as electricity supplied by national grid electricity producers. Power stations that generate power through coal, nuclear or other.
Due to power outages and ever increasing electricity tariffs the time has come to self provide for times of no power and even for electricity off the grid.
Starting with a way of self providing for those hours when there is no power to building up a system where you are totally self sufficient for your power requirements and off the national electricity grid.
In order to have power during times of no national power you require power from your own source.
Power that you have obtained from the national source when available and stored or power generated through other means, stored and used as per your requirements.
To date storage of electrical power means storing it in a battery or batteries.
On days of power the battery is charged and when no normal electricity is available, this stored power are used to operate your appliances.
This power supply can be extended by generating your own power through solar panels. The technology in this field is ever increasing and prices for the different units required to make up a system, declining.
Lets compare water flow to electricity flow.
We have a pump, a volume of water and a pipe through which the water flows.
The pump creates pressure and the volume of water flows. No pressure no flow, the more pressure the more flow.
Electricity flows as water in the form of electrons passing through a conductor as copper wire.
A pump in the form of a battery creates pressure.
The amount of pressure in electricity is measured in Volts (v).
The rate at which the electricity flows is measured as electric currant in Amps (a).
The electrical power that is available is voltage x amps and measured in Watts (w).
Voltage is the force behind the currant.
The higher the voltage, the higher the force, the higher the rate of flow.
Amp Ampere (a) the unit for measuring the volume of electricity flow. Electricity flow is the number of electrons passing a section in a medium, as copper wire.
The rate at which electricity flows is measured as an electric currant. That is the number of electrons passing a section of wire per second. 5241000000000000000 electrons passing the section in 1 sec is defined as 1 joule passing. A joule is a derived unit of energy and the rate, how fast that flow of joules, measured in ampere (a).
Watt (w) a unit of power, the electrical energy consumption rate of one joule per second, also as currant flow of one ampere with voltage of one volt. An electrical appliance rated 100 w means it will consume 100 watts per hour
For power storage from the national grid you require a battery, battery charger and an inverter.
All in one kits are available as a combined inverter charger.
You plug it in at an electricity outlet. It charges the battery when power is available. Charging stops when the battery is fully charged. Stored power is used when required.
Batteries for power storage is measured in ampere hours (ah). The higher rating the more electricity stored. Power stored calculation: Voltage (v) x ampere per hour (ah) = Power watts (w).
a 12v Battery with a rating of 100 ah = 12v x 100 ah = 1200 w available power for your appliances.
Ordinary 12v car battery is not suitable at all for storing power in these applications. The thin electrodes inside will erode quickly with use and recharging and battery life ends quickly.
Deep cycle batteries with better built thicker electrodes ensure longer battery life.
Gel and Lithium batteries has an even longer battery life.
Battery technology is ever improving with prices declining.
Inverters convert stored DC battery power to run your AC appliances.
Inverters are rated in continuous and peak/surge power.
Continuous power is the total watts supported continuously.
Peak/surge power is the power that is provided for a brief period when starting the equipment/appliance.
Induction motors driving such devices as air conditioners, refrigerators, freezers, pumps, etc. may well have a start up peak/surge of 3 - 7 times the continuous rating.
Working out the power required is converting Amps to watts
Multiply the equipment/appliance Amps x 230 (AC voltage) = Watts (approximate)
Calculate approximate continuous and start up load (peak/surge watts)
So if you want to run an appliance with a continuous load of 5 Amps and a peak load of 15 Amps :
Power : V x I = VA i.e. 230VAC x 5A = 1150 Watts continuous power.
Power : V x I = VA i.e. 230VAC x 15A = 3450 Watts peak/surge (also known as starting current)
You would need an inverter with a continuous rating of approximately 1500 watts and with a peak/surge rating of approximately 3500 watts.
It is always advisable to build in a safety factor by overrating the continuous rating by 20 - 25%.
This is the best output waveform and all appliances are able to run off it without interference or overheating.
Some of its advantages are as follows: Output voltage waveform is pure sine wave with very low harmonic distortion and the same as the ESKOM supply. (National grid electrical supplier)
Inductive loads like microwave ovens and motors run correctly, quieter and cooler.
Reduces audible and electrical noise in fans, fluorescent lights, audio amplifiers, tv, game consoles, fax, and answering machines.
Prevents crashes in computers, unreadable print outs, and glitches and noise in monitors.
It can be efficiently electronically protected in overload, over voltage, under voltage and over temperature conditions.
The Modified sine-wave inverter has limitations.
Some of the appliances that may experience problems when running off Modified Sine-wave inverters:
Laser printers, photocopiers, magneto-optical hard drives,
Some fluorescent lights with standard ballasts,
Power tools employing "solid state" power or variable speed control, Some battery chargers for cordless tools,
Produces interference in some television sets, Digital clocks with radios, Sewing machines with speed/microprocessor control, Medical equipment such as oxygen concentrates
Power required to run your household will depend on the power that your appliances use.
Power used is measured in watts as every electrical appliance is rated in watts.
That means your Led TV could be rated as 80 watts which means it is using 80w per hour.
An led globe rated at 6 watts use 6w per hour. An ordinary old globe rated 60 watts use 60 w per hour.
Want to save electricity change your light bulbs to 6 w globes and look for appliances that use less electricity.
Appliances using a heating element uses the most electricity as geysers, stoves, heaters, tumble driers, irons, etc and to a lesser extent freezers and fridges.
For stoves, gas is an option.
For warm water a dedicated solar geyser or gas works well.
First, decide which appliances will be required to run.
From that you calculate your power requirements in order to build up a system to give you the required electrical power.
TV 160 w/h
Decoder 110 w/h
5 x 6w lights 30 w/h
=300 watts usage per hour.
Ampere Hours Ah to Kilowatt per hour (kwh) conversion, multiply the Ah and the Voltage (v)) of the battery = watts.
12 v Battery x 100 ah = 1200w available per battery.
Divide 1200w by 300w is simply calculated, 4 hours of use.
But nothing is that simple.
The inverter also use power and the batteries should not be run flat the whole time as it will reduce its life.
The suggestions are that batteries should not be run down more than 50%.
As new battery technology evolves this is becoming better, as batteries in electrical cars.
But the better the battery the higher the price.
So lets say you buy two batteries coupled in series. 2 x 12v batteries 100 ah = 2400w divide by 300w is 8 hours of use. This is a basic system for times of power outages.
For generating power from the sun you require solar panels and and a solar inverter.
Solar panels, photovoltaic, absorb sunlight as a source of energy to generate direct current electricity.
Solar inverter or PV inverter, is a type of electrical converter which converts the variable direct current (DC) output of a photo-voltaic (PV) solar panel into a utility frequency alternating current (AC) that can be fed into a commercial electrical grid or used by a local, off-grid electrical network.
Solar panels are also rated per watt which means how many watts generated per hour.
A 100w rating means that it generates and supply 100w per hour. A good Canadian solar panel rated at 540w can generate and charge a battery 540w per hour.
With 4 hours of sunlight 2160 w. is generated, 8 hours = 4320w. As every thing in life the more power you need, the better rated panels, the higher capacity batteries, the higher rated inverter, the higher the cost.
As of now Nov 2019 a simple 24v 1200w inverter charger cost R2000.
100ah deep cycle batteries R2000 x 2 = R4000 = 2400 w power available for use. R6000
Solar panel 540w R2900
Solar inverter R800
6 Hours of sunshine 6 x 540 = 3240 w generated power per panel per day.
Power generated depends on panels and weather conditions. So factor this in your calculations.
Even just Installing a solar pump for your swimming pool and running it off two solar panels will save electricity costs.