Solar power for various applications

When using solar power to run appliances it is important to understand the basics like photovoltaic module which is commonly known as a solar panel. The solar panel is the component that captures the sun’s energy.
There is a requirement to have the solar panel connected to an invertor and battery so that energy is stored when there is no sunlight.
Brief explanation of direct current (DC) and alternating current (AC)
Electricity flows in two ways, either in an alternating current or direct current.
Voltage of DC cannot travel very far until it begins to lose energy while AC can provide more power and transfer over longer distances. Energy stored in a battery is DC whereas appliances use AC.
The amount of usable electricity generated will be limited by the size and efficiency of the solar panel, and inverter. To change from DC to AC, an inverter is needed.
Measuring solar energy
Solar energy is measured in kilowatt hours (kWh).
1kilowatt is equivalent to 1000 watts. 1kWh = the amount of electricity that is required to burn a 100 watt light bulb for 10 hours. For solar panels, the measurement of kWh refers to the amount of energy produced by the panel.
Salman Khan from Solar Afrika provides insight on solar back up energy supplies. Adding that each are made up of three components:
1. The solar panels
2. Inverter
3. Batteries
The solar panels generate DC and AC electricity and that is transferred to the inverter which in turn converts raw energy into the consumable energy sources. This is stored in the battery. The electric grid and all devices which run on electricity use alternating current, therefore it is extremely important to have the solar power that is generated, converted using an inverter.
Khan says: “Although a small number of solar energy producing products are able to transfer DC power directly to devices, majority of solar arrays and other units require a solar power inverter for the power to be transferred to the electrical grid”
Types of solar power inverters. There are three distinct types of solar energy inverters. Each serves a different
function and is used for different types of solar energy systems, although each inverter still converts DC into AC:
• stand-alone inverters
• Grid tie inverters
• Hybrid inverters
Stand-alone inverters are used for off-grid solar arrays. In off-grid arrays, the solar panels generate direct current energy which is then stored in rechargeable batteries. When energy is required, the direct current is passed from the battery to the stand alone inverter and then converted into alternating current which can then be used to power a home or for any other electricity needs.
All three components vary in sizes and capabilities and are dependent on the demand of the manufacturer or household.
One can install a 5w panel to 1000w panel and multiply them according to the need of the consumer. The bigger the panel the bigger the capabilities of the inverter and batteries required.
The procedures are as follows:
• Install an emergency battery-based back-up system which can be kept charged by the grid when the grid is on line. This system will provide power until the batteries are depleted.
• Install a battery-based backup system which can be kept charged with a grid, gas generator or solar panels. This can
work in a home or a business that has grid power or in an off grid situation where there is no grid power.
• Or, if there is already a solar grid tie electrical system, a battery-based backup system can be installed. It can be kept charged with the grid, when grid electricity is available, or with the grid tie system’s solar panels and even when the grid is down. This can be planned at the time the grid tie system is purchased, or added later.
Types of batteries
There are three main types of batteries that are commonly used in renewable energy systems, each with its’ own advantages and disadvantages. Flooded or “wet” batteries are the most cost efficient and the most widely used batteries in hotovoltaic
applications. They require regular maintenance and need to be used in a vented location. These are extremely well suited for renewable energy applications.
Sealed batteries come in two varieties, the gel cell and absorbed glass mat (AGM) type. The gel cell uses a silica additive in its electrolyte solution that causes it to stiffen or gel, eliminating some of the issues with venting and
spillage. The Absorbed Glass Mat construction method suspends the electrolyte in close proximity with the plate’s active material. These batteries are sealed, requiring virtually no maintenance. They are more suitable for remote applications where regular maintenance is difficult, or enclosed locations where venting is an issue.
Flooded lead acid
Flooded lead acid batteries are the most commonly used batteries, and have the longest track record in solar electric systems. “They usually have the longest life and the lowest cost per amp-hour of any of the other choices. The downside is
that they do require regular maintenance in the form of watering, equalizing charges and keeping the terminals clean,” adds Khan. These cells are often referred to as “wet” cells, and they come in two varieties: the serviceable, and the
maintenance-free type (which means they are designed to die as soon as the warranty runs out). The serviceable wet cells come with removable caps, and are the smarter choice, as it allows for status to be checked with a hydrometer.
Gelled electrolyte sealed lead acid
Gel sealed batteries use silica to stiffen or “gel” the electrolyte solution, greatly reducing the gasses, and volatility of the cell. Since all matter expands and contracts with heat, batteries are not truly sealed, but are “valve regulated”.
This means that a tiny valve maintains slight positive pressure. AGM batteries are slowly phasing out gel technology, but there still are many applications for the gel cells. The recharge voltage for charging gel cells are usually lower than the other styles of lead acid batteries, and should be charged at a slower rate. When they are charged too fast, gas pockets will form on the plates and force the gelled electrolyte away from the plate, decreasing the capacity until the gas
finds its way to the top of the battery and recombines with the electrolyte.
Sealed absorbed glass mat (AGM)
Absorbed glass mat (AGM) is a class of valve-regulated lead acid battery (VLRA) in which the electrolyte is held in glass mats as opposed to freely flooding the plates. This battery is achieved by weaving very thin glass fibres into a mat to increase surface area enough to hold sufficient electrolyte for the lifetime of the cell.
The advantages to using the AGM batteries are many, yet these batteries are typically twice the cost of its flooded cell
counterpart. On the plus side, these cells can hold roughly 1.5 times the amp hour capacity of a similar size flooded battery due to their higher power density. Another factor that improves its efficiency is the higher lead purity used in AGM cells. Because of its sandwich construction, each plate no longer has to support its own weightThe low internal resistance allows these to be charged and discharged much faster than other types. AGM cells function well in colder temperatures and are highly resistant to vibration. There are many advantages to using the AGM cells over its flooded counterpart that are beyond the scope of this article
Deep cycle versus shallow cycle
Lead acid batteries are designed to absorb and give up electricity by using a reversible chemical reaction. In battery lingo, a cycle on a battery occurs when the battery is discharged and charged back to the same level. How deep a battery is discharged is referred to as depth of discharge (DOD).
Starting lighting and ignition
Automotive starting, lighting, and ignition batteries (SLI) have a short or “shallow” depth of discharge, as it is designed to produce a high amount of current in a very short time. These batteries are not recommended for use in
photovoltaic systems, as it would quickly be ruined by the deep cycles required for extended use.
Deep cycle
Deep cycle batteries are designed with thicker lead plates, which have less overall surface area than its thinner SLI
counterparts. Because of the reduced availability of surface area for chemical reactions, deep cycle batteries produce
less current than an SLI type battery,yet produces current for longer periods of time. Deep cycle batteries can be
discharged up to 80 percent DOD without damage depending on the model. In order to increase battery life manufacturers recommend discharging deep-cycle batteries only down to 50 percent in order to increase battery life.
Battery Components
Battery technology has not changed much in the last 100 years. The standard construction method involves flooding lead plates in sulphuric acid. The chemical reaction between the positively charged lead plate and the negatively charged acid allows the battery to store and “give” electricity. The thickness of the lead plate is closely related to the lifespan of the battery because of a factor called “positive grid corrosion”. The positive lead plate gradually wears away over time. Thicker plates are used in deep cycle batteries. This usually translates to a longer battery life. Although plate thickness is not the only factor related to longer lifespan, it is the most critical variable.
Battery lifespan
Most of the loss incurred in charging and discharging batteries is due to internal resistance, which is eventually wasted as heat. Efficiency ratios are relatively high considering that most lead acid batteries are 85 to 95 % efficient at storing the energy it receives. Deep cycle batteries used in renewable energy applications are designed to provide many years of reliable performance with proper care and maintenance. Proper maintenance and usage play a major role in battery
lifespan. Toiling over your battery bank daily with complex gadgets and a gallon of distilled water, however, is not necessary. The most common causes of premature battery failure include loss of electrolyte due to heat or overcharging, undercharging, excessive vibration, freezing or extremely high temperatures and using tap water among others.
Solar Afrika: Tel +27 82 691 6048;

The Solar Stik “generator” System
The Solar Stik “generator” System has been designed to provide the operator with a solution that meets five key principles:
• Portability
• Expandability
• Adaptability
• Autonomy
• Durability
Solar stik can be the primary power generator for nearly any mobile application.
It has been designed as a portable power system that does not require a forklift nor trailer to move it in to operation. An addition to its design is that it generates “usable” power. It can replace a small (2kW or less) portable fuel-driven
power generator and can also be used to streamline the operation of larger generators -up to 3kW using the new PROVerter
™ technology.
It is a complete “turn-key” package, ready for immediate operation. There are no further requirements for basic installation and operation.
• Lightweight, rugged and portable
• There are many System configurations available to the operator as well as accessory options that will tailor the system
to the required power model, capability, and application.
• When selecting a system, an operator can build either a custom solution by choosing specific components to meet the user’s need or purchase one of the popular “turn-key” Solar Stik System packages.
It is versatile and can be used in a wide spectrum of applications that ranges from recreational to tactical. It is able to
perform as a complete micro-grid or a standalone generator.
It can support medical gear, logistics tools, communications,tactical equipment,computers, refrigerators, televisions,radios,fans, rechargeable devices,or just basic lights at home.
Although primarily designed to provide power for smaller portable applications,it offers an “Open Architecture” which allows the system to incorporate multiple sources of power and appliance loads.
The system also incorporates varying levels of “Power Management”, which provides the operator with a seamless flow of power throughout the circuit.