Solar Related Frequently Asked Questions

 

Q:	What can I operate on Solar power?
A:	Theoretically everything in an average house or office. Although solar energy is free, the amount of energy produced and stored is determined by PV panel and battery space available.
Q:	Can you give me some examples of practical applications?
A:	General household lights, entertainment, computer, gate motor and so on. In addition to PV panels, gas stoves, solar powered geysers and fridges go a long way to reducing dependency on electricity.
Q :	How does solar equipment work?
A :	PV (photovoltaic) panels generate electricity even on overcast days. The absorption of light in the solar cells builds up electric voltage (volts). Because solar cells do not store electricity, all energy generated is fed through a regulator to the battery and stored there
Q :	How long do PV panels last?
A :	Life expectancy is around 20 years depending on the type. All parts are designed for outside use. Highveld hail and thunderstorms and coastal environs have no or little impact on the solar panel.
Q :	What maintenance needs to be carried out?
A :	Other than a wipe down or a rinse with a house pipe, no maintenance is needed for a PV panel. However, if lead acid batteries are used, acid levels need to be checked every six months and topped up if necessary.
Q :	How do I measure the size of equipment required?
A :	To work out your average consumption per day simply add up the specified power of appliances (watts) and multiply it by the daily hours these appliances will be used. This will give you your daily requirement.

 

 

Inverter Related Frequently Asked Questions

    

Q :	What is an inverter?
A :	An inverter takes DC power ( Direct Current like battery or solar, for example) and converts it into 220v AC (Alternating Current household power) for powering electronic equipment and appliances.
Q :	Why are they called inverters?
A :	Originally converters were large rotating electromechanical devices. Essentially they combined a synchronous ac motor with a commentator so that the commentator reversed its connections to the ac line exactly twice per cycle. The results is ac-in dc-out. If you invert the connections to a converter you put dc in and get ac out. Hence an inverter is an inverted converter.
Q :	How can an inverter be used?
A :	With a large enough battery bank, almost anything within reason can be operated from a power inverter – assuming the inverter has the proper power output for the given load. Everyday appliances such as microwaves, power tools, TV’s, lights, audio/visual equipment, battery chargers, fluorescent lights, fans and computers are common loads. An inverter sized for loads with high start-up current can be used to power air compressors, water pumps, heaters, ventilation fans, and air conditioners.
Q :	What is Sine wave ?
A :	It is the ideal waveform for the transfer of AC power. There are two types of waveforms available. A "modified sine wave", and the "true sine wave". Modified Sine Wave - The modified sine wave is not really a sine wave at all. It is a "stepped wave". It achieves voltage regulation by varying in width according to the battery voltage and the load. Thus, the wave is not as smooth as a sine wave. The quality of modified sine wave inverters should not be underestimated. They are highly capable, and (by narrowing the waveform) they save energy when running only small loads, as happens during most of the day in a typical home. Modified sine inverters have been successful in many thousands of remote home, Recreational Vehicles and marine systems since 1986.         True Sine Wave - Also known as Pure Sine Wave, is the most reliable waveform and provides power almost identical to a standard wall outlet. The power produced fully assures that your "sensitive loads" will be correctly powered, with no interference. Some appliances are likely to require Pure Sine Wave including digital clocks, battery chargers, light dimmers, variable speed motors, and audio/visual equipment. For these reasons, true sine wave inverters can be more expensive choice.
Q :	Why do I hear buzzing on my Hi-fi when using a modified sine wave inverter?
A:	Some entry level Hi-fi’s use power supplies that cannot eliminate common-mode noise. These would require a pure sine wave inverter to operate noise-free.
Q :	How do I know which inverter to buy?
A :	Different devices require specific wattages to run correctly and efficiently. Please use this easy formula to determine the correct size inverter: AMPS x 220 = Watts Example: 10 Amp Cooling Unit X 220 = 2200 Watts
Q :	What is the Low Voltage Alarm & Shutdown?
A :	The low voltage alarm will sound when the DC source falls below 10 volts and the automatic shutdown will power off the inverter. This is to save your batteries from full discharge thereby extending their life span.
Q :	Is my inverter weatherproof?
A :	No. Treat your inverter like you would your TV. You wouldn't put your TV outside in the rain, please don't leave your inverter there either. Be aware of lightning storms. If struck, your inverter would go into a permanent overload state and will need replacing.
Q :	How do I charge the battery for my inverter?
A :	Because inverters operate from a DC (Direct Current) power source, usually a battery bank (one or more batteries), the battery will have to be recharged at some point. (Remember that a battery discharged more than 80% is probably close to being dead.) Depending on the inverter load and runtime required, most power-use applications will be covered by the charged battery. If the load is large (air conditioner, large draw power tools, large microwave, fridge/freezer etc.) the user should verify that the installed inverter is of large enough capacity to cope with this power requirement.

 

Battery installation tips.

 

Replace any cables and connectors that have corrosion, rust, or other damage.

·         Do not install batteries in a non-ventilated or sealed compartment.

·         Do not lift or handle the batteries by the terminals.

·         Do not over tighten terminal bolts

 

Battery Related Frequently Asked Questions

Q :	Can I use a car or truck battery?
A :	If the battery is not a deep cycle battery it will not last. Deep cycle batteries are designed to cope with the discharging and charging and have a longer lifespan than regular batteries
Q :	Do you ever add acid to a battery?
A :	No. Only distilled, de-ionised or approved battery water should be added to maintain the recommended levels. Most batteries today are maintenance free.
Q :	What are common mistakes made by lead acid battery owners?
A:	Undercharging : Generally caused by not allowing the charger to restore the battery to full state of charge after use. Continually operating the battery in a partial state of charge, or storing the battery in a discharged state results in the formation of lead sulphate compounds on the plates. These conditions reduce the battery's performance and may cause premature battery failure. Undercharging will also cause stratification. Overcharging : Continuous charging causes accelerated corrosion of the positive plates, excessive water consumption, and in some cases, damaging temperatures within a lead acid battery. Deep cycle batteries should be charged after each discharge of more than 50% of the batteries rated capacity, and/or after prolonged storage of 30 days or more.

 

The regulator / controller ensures that batteries are not overcharged.

 

Battery Charging Related Questions

Q :	Can a standard car charger be used with my deep cycle batteries?
A :	If you want to recharge large commercial batteries you must ensure the charger output is sufficiently high enough before charging commences. If you are charging deep cycle batteries the answer is no. Deep cycle batteries require a higher charging voltage and charge current than the average car charger can produce.
Q :	How long will it take my batteries to fully recharge?
A :	The amount of time it takes a battery to charge depends on the type of battery and charger and on how long it took to discharge (slow or fast). As a rule of thumb you can divide the battery capacity by the maximum charge capacity and add four hours. The four hours is for the so-called after-charging time, where the battery determines how much more current it needs to get back to a fully charged state. For example, an empty 100 Ah battery connected to a 20A battery charger would take about 100 divided by 20 = 5 + 4 hours to charge, 9 hours in total. If the battery had been only 50% discharged the calculation would be: 50 divided by 20 = 2.5 + 4 hours, 6.5 hours in total.

Regulators or Controllers:

Q :

What type or size regulator / controller should I buy?

A :

Regulator type and size are determined by the size and number of PV panels used and may vary with each application. With the exception of the ‘MPPT’ type, regulators are similar in their performance. A MPPT (maximum power point tracking) regulator / controller is a technically advanced battery charger for off-grid PV systems and enables the use of high voltage PV’s (up to 36v) to charge either 24v or 12v battery systems. Depending on make and model, it may disconnect loads when the battery has been discharged to a low state of charge.