Understanding Solar Energy

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Solar Energy for the Layman

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Understanding Solar Energy

  1. 1. Solar Engineering ANDING SO RGY “ MAD EASY OLAR ENER DEpreparation by s.r.kushero“UNDERSTA“ a centre for application of renewable energy preparation by s.r.kushero email : Care.@care-india.com http://www.care-india.com
  2. 2. Solar Engineering ANDING SO RGY “ MAD EASY OLAR ENER DEpreparation by s.r.kushero“UNDERSTA Solar power might be a solution“ a centre for application of renewable energy preparation by s.r.kushero email : Care.@care-india.com http://www.care-india.com
  3. 3. Solar Engineering BASIC How much sunshine will I need? How many solar panels you will need based on the amount of sunshine available daily in your area Using solar power to produce electricity is not the same as using solar t produce h t S l th i l to d heat. Solar thermal principles l i i l It is presumed that at "peak sun", 1000 W/m² of power peak sun W/m reaches the surface of the earth. are applied to produce hot fluids or air. RGY “ MAD EASY One hour of full sun provides 1000 Wh per m² = 1 Photovoltaic principles are used to produce electricity. A kWh/m² -representing the solar energy received in one DE solar panel (PV panel) is made of the natural element element, silicon, which becomes charged electrically when hour on a cloudless summer day on a one-square meter subjected to sun light. surface directed towards the sun. Solar panels are directed at solar south in the northern To put this in some other perspective, the Indian p OLAR ENER hemisphere and solar north in the southern hemisphere Department of E D t t f Energy i di t indicates th amount of solar the t f l (these are slightly different than magnetic compass energy that hits the surface of the earth every +/- hour is greater than the total amount of energy that the entire north-south directions) at an angle dictated by the geographic location and latitude of where they are to be human population requires in a year. Another perspective is that roughly 100 miles square of solar g y ANDING SO installed. installed panels placed in the southwestern U.S. could power thepreparation by s.r.kushero WHOLE United States . Typically, the angle of the solar array is set within a range of between site-latitude-plus 15 degrees and site- The intensity of the Suns radiation changes with the latitude-minus 15 degrees, depending on whether a g , p g“UNDERSTA hour of th d h f the day, ti time of th year and weather conditions. f the d th diti slight winter or summer bias is desirable in the system. To be able to make calculations in planning a system, the total amount of solar radiation energy is expressed in Many solar arrays are placed at an angle equal to the hours of full sunlight per m², or Peak Sun Hours. This site latitude with no bias for seasonal periods. term, Peak Sun Hours, represents the average amount p g“ of sun available per day throughout the year. a centre for application of renewable energy preparation by s.r.kushero email : Care.@care-india.com http://www.care-india.com
  4. 4. Solar Engineering Solar Radiation In India RGY “ MAD EASY OLAR ENER DE Solar Radiation : Sunshine across INDIA ANDING SO A color coded map of INDIA that displays thepreparation by s.r.kushero daily average hours of solar radiation (sunshine). This information will assist you in calculating the number of solar panels you“UNDERSTA will need for your solar power system. a short explanation of Watts, Watt Hours, and Amp Hours“ a centre for application of renewable energy preparation by s.r.kushero email : Care.@care-india.com http://www.care-india.com
  5. 5. Solar Engineering BASIC Electrical charge is consolidated in the PV panel and directed to the output terminals to produce low voltage (Direct Current) - usually 6 to 24 volts The most common output is intended for nominal 12 volts. volts, with an effective output usually up to 17 volts. RGY “ MAD EASY A 12 volt nominal output is the reference voltage, but the operating voltage can be 17 volts or higher DE much like your car alternator charges your 12 volt battery at well over 12 volts. So theres a difference between the reference voltage and the actual operating voltage. ANDING SO OLAR ENERpreparation by s.r.kushero“UNDERSTA“ a centre for application of renewable energy preparation by s.r.kushero email : Care.@care-india.com http://www.care-india.com
  6. 6. Solar Engineering PV system Q. What is a PV system? A. PV technology produces electricity directly from electrons freed by the interaction of sunlight with a solar panel made of semiconductor material. Th power provided i li ht ith l l d f i d t t i l The id d is RGY “ MAD EASY direct current (DC) electricity. The basic building block is known as a cell. Many cells put together are known as a module, and many modules assembled together form an array. A PV system will consist of an array of modules generating DC electricity, an DE inverter, and sometimes battery storage back up with charge controller. Q. How much electricity will a system p y y produce? OLAR ENER A. The amount of power produced will depend upon how large the system is. In Mumbai the average residential customer purchases 5,500 kilowatt-hours (kWh) per year. There is enough sunshine falling upon on the average home to produce this and a ANDING SO system can be designed to offset all electrical needs. The cost to accomplish a 100% ff %preparation by s.r.kushero system may be prohibitive and sometimes it makes more sense to simply reduce or shave your consumption. Some utilities use tiered rates when they charge for consumption which means that the more energy you use the higher is the cost per“UNDERSTA kilo-watt-hour. The most economically feasible size is usually between 50% and 75% of your annual household needs.“ a centre for application of renewable energy preparation by s.r.kushero email : Care.@care-india.com http://www.care-india.com
  7. 7. Solar Engineering FREE electricity At todays prices a single solar panel, rated at 1 Watts sells for about Rs.150- Rs.250 depending on brand. If your system uses several of these panels, this would seem to be quite RGY “ MAD EASY expensive. DE The good news is that todays solar panels have a life expectancy of 25 to 30 today s years or more. And just think, theyll be making FREE electricity that whole time! ANDING SO OLAR ENERpreparation by s.r.kushero“UNDERSTA“ a centre for application of renewable energy preparation by s.r.kushero email : Care.@care-india.com http://www.care-india.com
  8. 8. Solar Engineering Manual The Basics f Solar Power f P d i Th B i of S l P for Producing El t i it Electricity Understanding Parts of a Solar Energy System Overview of the individual components required to assemble a solar power system and produce free electricity from the sun for energy p y p y gy independence. RGY “ MAD EASY 1.Solar Panels which generate the electricity, 2.Charge Controller to control battery charging, DE 3.the Power Inverter that makes 220 volts AC from the batteries to run your appliances, 4.Storage batteries which store the excess power for use when the sun is weak or not available, 5. AC generators for back-up power. ANDING SO OLAR ENERpreparation by s.r.kushero“UNDERSTA“ a centre for application of renewable energy preparation by s.r.kushero email : Care.@care-india.com http://www.care-india.com
  9. 9. Solar Engineering System Overview For electricity from the sun. You will need one or more Solar Panels a Charger Controller a Power Inverter Panels, Controller, Inverter, and of course, Batteries. RGY “ MAD EASY The first component needed is one or more Solar Panels. They supply the electricity and charge the batteries. A y pp y y g DE very small system could get away with a couple 80 watt panels but figure at least 4 to 8 for a small to medium system.. OLAR ENER A Charge Controller. is needed to prevent overcharging of the batteries. Proper charging will prevent damage and increase the life and performance of the batteries. ANDING SO The Power Inverter is the heart of the system It makes system. 220 volts AC from the 12 volts DC stored in the batteries.preparation by s.r.kushero It can also charge the batteries if connected to a generator or the AC line.“UNDERSTA Last are the storage Batteries. They store the electrical power in the form of a chemical reaction. Without storage you would only have power when the sun was shining or the generator was running.“ a centre for application of renewable energy preparation by s.r.kushero email : Care.@care-india.com http://www.care-india.com
  10. 10. Solar Engineering Solar Power : Components A Solar Power energy system can be used by anyone to Charge Controllers supply all their electrical needs, provide back-up power, This device is necessary to protect the batteries from over or even just as a supplement to the normal electrical grid charging and supply them with the proper amount of connection to a utility company. It is ideal for remote energy to promote long battery life. locations where power is unavailable or too expensive to RGY “ MAD EASY hook-up to. Power Inverters The power inverter converts your storage battery power Solar Panels into the 220 volts AC that runs your appliances. It is the DE The S Solar Panels tutorial will give you a simple heart of your solar energy system Unless you only run 12 system. explanation of this most basic electric power generator volt DC appliances you will need a power inverter to supply for solar energy systems. Fixed, Adjustable, and your AC. Tracking type mounting systems are also covered. Getting power from the suns energy is not only Free, but gp gy y , Storage Batteries OLAR ENER its Fun to setup a solar energy system and be your own Without Storage Batteries to store energy you would only utility company have power when the sun was shining or the generator as running. Here we discuss 4 major categories of batteries for solar power systems. The batteries in your system are ANDING SO very important. The care & feeding section of this tutorial is a must read to ensure long battery life and goodpreparation by s.r.kushero performance. AC Generators“UNDERSTA Even the largest Solar Energy System would not have enough power for many consecutive days of no sun. The AC Generator tutorial will tell you what size generator youll need“ a centre for application of renewable energy preparation by s.r.kushero email : Care.@care-india.com http://www.care-india.com
  11. 11. Solar Engineering Solar Panels Solar panels generate free power from the sun by converting sunlight to electricity with no moving parts, zero emissions, and no maintenance. The solar panel, the first component of a electric solar e e gy sys e , s co ec o o energy system, is a collection of individual silicon cells that generate electricity from sunlight. The d dua s co ce s a ge e a e e ec c y o su g e photons (light particles) produce an electrical current as they strike the surface of the thin silicon RGY “ MAD EASY wafers. DE A single solar cell produces only about 1/2 ( 5) of a volt However a typical 12 volt panel about 25 (.5) volt. However, inches by 54 inches will contain 36 cells wired in series to produce about 17 volts peak output. If the solar panel can be configured for 24 volt output, there will be 72 cells so the two 12 volt groups OLAR ENER of 36 each can be wired in series, usually with a jumper, allowing the solar panel to output 24 volts. When under load (charging batteries for example), this voltage drops to 12 to 14 volts (for a 12 volt configuration) resulting in 75 to 100 watts for a panel of this size. ANDING SO Multiple solar panels can be wired in parallel to increase current capacity (more power) and wired inpreparation by s.r.kushero series to increase voltage for 24, 48, or even higher voltage systems. The advantage of using a higher voltage output at the solar panels is that smaller wire sizes can be used to transfer the electric power from the solar panel array to the charge controller & batteries Since copper has gone up considerably batteries.“UNDERSTA in the last few years, purchasing large copper wiring and cables is quite expensive. (thats why pennies are made of mostly zinc today).“ a centre for application of renewable energy preparation by s.r.kushero email : Care.@care-india.com http://www.care-india.com
  12. 12. Solar Engineering Solar Panels An A eco-friendly electric generator. S l f i dl l ti t Solar panelsl generate free power from the sun by converting sunlight to electricity with no moving parts, zero emissions, and no maintenance. The solar panel, the first component of a electric solar energy system, is a collection of individual silicon cells that RGY “ MAD EASY generate electricity from sunlight. DE The photons (light particles) produce an electrical current as they strike the surface of the thin silicon wafers. A single solar cell produces only about 1/2 (.5) of a volt. OLAR ENER However, a typical 12 volt panel about 25 inches by 54 inches will contain 36 cells wired in series to Multiple solar panels can be wired in parallel to produce about 17 volts peak output. increase current capacity (more power) and wired in series to increase voltage for 24, 48, or even ANDING SO higher lt hi h voltage systems. t If the solar panel can be configured for 24 voltpreparation by s.r.kushero The advantage of using a higher voltage output at output, there will be 72 cells so the two 12 volt the solar panels is that smaller wire sizes can be groups of 36 each can be wired in series, usually used to transfer the electric power from the solar with a jumper allowing the solar panel to output 24 jumper,“UNDERSTA panel array to the charge controller & batteries batteries. volts. When under load (charging batteries for Since copper has gone up considerably in the last example), this voltage drops to 12 to 14 volts (for a few years, purchasing large copper wiring and 12 volt configuration) resulting in 75 to 100 watts for cables is quite expensive. (thats why pennies are a panel of this size. made of mostly zinc“ a centre for application of renewable energy preparation by s.r.kushero email : Care.@care-india.com http://www.care-india.com
  13. 13. Solar Engineering Solar Panels : TYPES Amorphous solar panels : These are not really Monocrystalline solar panels : The most crystals, but a thin layer of silicon deposited on a efficient and expensive solar panels are base material such as metal or glass to create made with Monocrystalline cells These cells. the solar panel. These Amorphous solar panels RGY “ MAD EASY solar cells use very pure silicon and are much cheaper, but their energy efficiency is involve a complicated crystal growth also much less so more square footage is process. Long silicon rods are produced g required to produce the same amount of power DE which are cut into slices of .2 to .4 mm as the Monocrystalline or Polycrystalline type of solar panel. Amorphous solar panels can even thick discs or wafers which are then be made into long sheets of roofing material to processed into individual cells that are cover large areas of a south facing roof surface. wired together in the solar panel panel. OLAR ENER Polycrystalline solar panels : Often called Multi-crystalline, solar panels made with ANDING SO Polycrystalline cells are a little less expensive &preparation by s.r.kushero slightly less efficient than Monocrystalline cells because the cells are not grown in single crystals but in a large block of many crystals. This is what“UNDERSTA gives them that striking shattered glass appearance. Like Monocrystalline cells, they are also then sliced into wafers to produce the individual cells that make up the solar panel.“ a centre for application of renewable energy preparation by s.r.kushero email : Care.@care-india.com http://www.care-india.com
  14. 14. Solar Engineering Solar Panels : Wattage The output of a solar panel is usually stated Since the intensity of sunlight contacting in watts, and the wattage is determined by the solar panel varies throughout the day, multiplying the rated voltage by the rated u p y g e a ed o age e a ed we use the term "peak sun hours“ as a e e e pea su ou s amperage. method to smooth out the variations into a RGY “ MAD EASY daily average The formula for wattage is VOLTS times Early morning and late-in-the-day sunlight y g y g DE AMPS equals WATTS WATTS. produces less power than the mid-day sun. So for example, a 12 volt 60 watt solar panel Naturally, cloudy days will produce less measuring about 20 X 44 inches has a rated p power than bright sunny days as well. g y y OLAR ENER voltage of 17.1 and a rated 3.5 amperage. When planning a system your VxA=W geographical area is rated in average peak sun hours per day based on yearly sun p y y y ANDING SO 17.1 17 1 volts times 3 5 amps equals 60 watts 3.5 data.preparation by s.r.kushero If an average of 6 hours of peak sun per day Average peak sun hours for various is available in an area, then the above solar g g p geographical areas is listed in the above“UNDERSTA panel can produce an average 360 watt section. hours of power per day; 60w times 6 hrs. = 360 watt-hours.“ a centre for application of renewable energy preparation by s.r.kushero email : Care.@care-india.com http://www.care-india.com
  15. 15. Solar Engineering Solar Panels Wiring Series S i Solar panels can be wired in series or in parallel to increase voltage or amperage respectively, and they can be wired both in series and in parallel to increase both volts and amps. amps RGY “ MAD EASY Series wiring refers to connecting the positive terminal of + one panel to the negative terminal of another. The resulting - outer positive and negative terminals will produce voltage DE the sum of the two panels, but the amperage stays the same Parallel as one panel. So two 12 volt/3.5 amp panels wired in series produces 24 volts at 3.5 amps. Four of these wired in series would produce 48 volts at 3.5 amps. OLAR ENER Parallel wiring refers to connecting positive terminals to positive terminals and negative to negative. The result is that + voltage stays the same, but amperage becomes the sum of - the number of panels. So two 12 volt/3.5 amp panels wired p pp ANDING SO in parallel would produce 12 volts at 7 amps. Four panels Series/parallel S i / ll lpreparation by s.r.kushero would produce 12 volts at 14 amps. Series/parallel wiring refers to doing both of the above -“UNDERSTA increasing volts and amps t achieve th d i d voltage as i i lt d to hi the desired lt in 24 or 48 volt systems. The following diagram reflects this. In addition, the four panels below can then be wired in parallel to another four and so on to make a larger array.“ a centre for application of renewable energy preparation by s.r.kushero email : Care.@care-india.com http://www.care-india.com
  16. 16. Solar Engineering Solar Installation : Location Where a building is at a considerable distance from the public electricity supply (or grid) - in remote or mountainous areas – PV may be the preferred possibility for generating electricity, or PV may be used together with wind, diesel generators and/or hydroelectric power In such off-grid circumstances batteries are usually used power. off grid to store the electric power. ANDING SO RGY “ MAD EASY OLAR ENER DE In locations near the grid however feeding the grid using PV panels is more practical grid, however, practical, and leads to optimum use of the investment in the photovoltaic system. This requirespreparation by s.r.kushero both regulatory and commercial preparation, including net-metering and feed-in agreements. To provide for possible power failure, some grid tied systems are set up to g p p p g y p“UNDERSTA allow local use disconnected from the grid. Most photovoltaics are grid connected. In the event the grid fails, the local system must not feed the grid to prevent the possible creation of dangerous islanding.“ a centre for application of renewable energy preparation by s.r.kushero email : Care.@care-india.com http://www.care-india.com
  17. 17. Solar Engineering Solar Panels : Placement Shading Shadows Sh di & Sh d Temperature & Wi d l di considerations T t Wind loading id ti When deciding on a location for your solar As previously discussed, you want to mount panels, make sure no shadows will fall on the solar panels in a sunny and non-shaded location p y solar panel array during peak sunlight hours to get maximum sun. But, heat build-up is also a RGY “ MAD EASY (say, 9am to 4pm). Not only will shading of the problem. Because the efficiency of solar panels solar panels significantly reduce their output, but decreases as temperature increases, the solar also could cause damage. Some solar panel p panel mounting system should allow for spacing g y p g DE manufacturers advertise panels that can around the individual solar panels for air withstand shading but they use internal diodes circulation. The idea is to allow air cooling in the which in themselves reduce the power hot sun to reduce the temperature of the solar somewhat. I recommend simply choosing a good p panels. Another consideration is wind loading. By g y OLAR ENER location to start with, even if it means cutting allowing air to flow around the solar panels, not down a few trees or otherwise removing only will they remain cooler, obstacles. ANDING SOpreparation by s.r.kushero“UNDERSTA“ a centre for application of renewable energy preparation by s.r.kushero email : Care.@care-india.com http://www.care-india.com
  18. 18. Solar Engineering Efficiency Losses In all systems there are losses due to such things as voltage losses as the electricity is RGY “ MAD EASY carried across the wires, batteries and inverters not being 100 percent efficient, and other factors. These efficiency losses vary from component to component, and from system to system and can be as high as 25 percent. y g p ANDING SO OLAR ENER DEpreparation by s.r.kushero“UNDERSTA“ a centre for application of renewable energy preparation by s.r.kushero email : Care.@care-india.com http://www.care-india.com
  19. 19. Solar Engineering Solar Panels : Mountings Types of Solar Panel Array Mountings : Fixed, Adjustable, & Tracking Fixed solar panel mounts : If you use th most simple and l t the t i l d least expensive t i type of solar panel mounting system, it will be completely RGY “ MAD EASY stationary. The solar panels should always face the equator. (due south in the northern hemisphere). Dont forget that true south varies from magnetic south. This DE can make a huge difference. For example, true south in eastern Washington state is 161 on a compass instead of 180. The angle of inclination (tilt) in degrees should be set to about your latitude. Slightly more than your latitude will favor the winter sun and slightly less will favor the OLAR ENER summer sun. (for a seasonal cabin for example). Adjustable solar panel mounts : The angle of inclination ( ) (tilt) of an adjustable solar panel mount can be changed j p g ANDING SO 2 or more times during the year to account for the lowerpreparation by s.r.kushero angle of the sun in winter as the earth orbits the sun causing seasonal change. A good rule of thumb is latitude + 15 degrees in the winter and latitude – 15 degrees in the summer This will increase overall solar summer.“UNDERSTA panel output by approximately 25%. I adjust my solar panel array 4 times per year. (Shown here in its summer position). An easy approach that works pretty good is to set the tilt for the winter position in about mid October and b k t summer position i mid. d back to iti in id“ a centre for application of renewable energy preparation by s.r.kushero email : Care.@care-india.com http://www.care-india.com
  20. 20. Solar Engineering Charge Controller A charge controller monitors the batterys state battery s state- Many charge controllers also offer Low Voltage of-charge to insure that when the battery needs Disconnect (LVD) and Battery Temperature charge-current it gets it, and also insures the Compensation (BTC) as an optional feature. The battery isnt over-charged. Connecting a solar LVD feature permits connecting loads to the LVD panel to a battery without a regulator seriously terminals which are then voltage sensitive. If the g risks damaging the battery and potentially battery voltage drops too far the loads are causing a safety concern. RGY “ MAD EASY disconnected - preventing potential damage to both the battery and the Charge controllers (or often called charge loads. BTC adjusts the charge rate based on the regulator) are rated based on the amount of g ) DE temperature of the battery since batteries are amperage they can process from a solar array. If sensitive to a controller is rated at 20 amps it means that you temperature variations above and below about can connect up to 20 amps of solar panel output 75 F degrees. current to this one controller. The most advanced charge controllers utilize a charging principal g g g p p OLAR ENER referred to as Pulse-Width-Modulation (PWM) - To Load Switched which insures the most efficient battery charging and extends the life of the battery. ANDING SO Even more advanced controllers also include Maximum Power Point Tracking (MPPT) whichpreparation by s.r.kushero maximizes the amount of current going into the battery from the solar array by lowering the To Load Always On panels output voltage, which increases the“UNDERSTA charging amps to the battery - because if a panel From Solar Panel can produce 60 watts with 17.2 volts and 3.5 amps, then if the voltage is lowered to say 14 volts then the amperage increases to 4.28 (14v X 4.28 amps = 60 watts) resulting in a 19% increase in charging amps for this example example.“ a centre for application of renewable energy preparation by s.r.kushero email : Care.@care-india.com http://www.care-india.com
  21. 21. Solar Engineering Connections After you connect the Solar Panels to the input Connecting the Batteries terminals of the Charge Controller using the above chart, you can use the same size wire to The batteries are last. They will also require very connect the Charge Controller output to the large cables like the large battery cables in cars. RGY “ MAD EASY batteries since these wires will carry no more The full current to the loads and also the full current than the solar panel wires and will charging current flow thru the entire battery probably be located pretty close to the batteries bank. Connect all the batteries with large high DE anyway. quality cables. Check out the Battery Wiring Diagrams tutorial for examples of Series and Connecting the Power Inverter Parallel wiring techniques that allow the use of battery voltages of 2, 4, 6, or 12 volts. Our new The Power Inverter is next Both the Power next. OLAR ENER Battery Bank Designer tool will show you how to Inverter and the Batteries require the largest connect the batteries for these various voltage wires in the system. During operation, the AC produced by the Power Inverter draws considerable amps from the batteries Not only batteries. ANDING SO are very large wires required, but they should notpreparation by s.r.kushero exceed 6 feet in length to reach the batteries. These wires are like the large battery cables in cars. cars Use the largest size possible An AC possible.“UNDERSTA appliance drawing 10 amps (like a microwave or vacuum cleaner) will require 100 amps at 12 volts DC. Even large cables will get warm. Dont skimp here here.“ a centre for application of renewable energy preparation by s.r.kushero email : Care.@care-india.com http://www.care-india.com
  22. 22. Solar Engineering Wire & Cables To prevent dangerous overheating or inefficient Battery Wiring Diagrams transfer of power, the wires and cables in a solar Learn how to use series and parallel wiring power system must be correctly sized. A convenient chart to determine wire size based on techniques to obtain exactly the power and solar panel power output and the distance voltage you want using 2, 4, 6,or 12 volt between the solar panels and the batteries. For batteries. batteries Series wiring parallel wiring and wiring, using series/parallel combinations show you RGY “ MAD EASY safety and good performance of your solar power system you will have to use the how to build your battery bank into any appropriate size wires when connecting the DE components of your system system. Meters & Monitors This tutorial explains the importance of OLAR ENER monitoring your solar energy system With the system. included voltage chart, you can easily determine the basic level of charge on your batteries using just a simple voltmeter. Taking proper care of y your batteries will ensure good system g y ANDING SO performancepreparation by s.r.kushero Power Requirements This tutorial is a little more advanced but advanced,“UNDERSTA explains more about voltage, current, power, and Ohms Law. Find out about the relationship between AC amps and DC amps. The importance of energy conservation for a solar“ power system is also covered. a centre for application of renewable energy preparation by s.r.kushero email : Care.@care-india.com http://www.care-india.com
  23. 23. Solar Engineering Battery During planning, all of these factors are looked at, and The Deep Cycle batteries used are designed to be discharged and then re-charged hundreds or thousands the one requiring the largest capacity will dictate the of times. These batteries are rated in Amp Hours (ah) - battery size. One of the biggest mistakes made by those usually at 20 hours and 100 hours. Simply stated, amp just starting out is not understanding the relationship hours refers to the amount of current - in amps - which between amps and amp-hour requirements of 120 volt can be supplied by the battery over the period of hours. AC items versus the effects on their DC low voltage batteries. For example, say you have a 24 volt nominal RGY “ MAD EASY system and an inverter powering a load of 3 amps, For example, a 350ah battery could supply 17.5 120VAC, which has a duty cycle of 4 hours per day. You continuous amps over 20 hours or 35 continuous amps would have a 12 amp hour load (3A X 4 hrs=12 ah). for 10 hours. To quickly express the total watts However, in order to determine the true drain on your potentially available in a 6 volt 360ah battery; 360ah DE batteries you have to divide your nominal battery voltage times the nominal 6 volts equals 2160 watts or 2 16kWh 2.16kWh (24v) into the voltage of the load (120v), which is 5, and (kilowatt-hours). then multiply this times your Like solar panels, batteries are wired in series and/or 120vac amp hours (5 x 12 ah). So in this case the parallel to increase voltage to the desired level and calculation would be 60 amp hours drained from your p y increase amp hours. p OLAR ENER batteries - not the 12 ah. Another simple way is to take the total watt-hours of your 120VAC device and divide The battery should have sufficient amp hour capacity to by nominal system voltage. supply needed power during the longest expected period "no sun" or extremely cloudy conditions. A lead- Using the above example; 3 amps x 120 volts x 4 hours acid battery should be sized at least 20% larger than ANDING SO = 1440 watt hours divided by 24 DC volts = 60 amp watt-hours this amount If there is a source of back up power such amount. back-up power, hours. Lead-acid batteries are the most common in PV as a standby generator along with a battery charger, thepreparation by s.r.kushero systems because their initial cost is lower and because battery bank does not have to be sized for worst case they are readily available nearly everywhere in the world. weather conditions. The size of the battery bank There are many different sizes and designs of lead-acid required will depend on the storage capacity required, batteries, but the most important designation is that they the maximum discharge rate, the maximum charge rate,“UNDERSTA are d deep cycle b tt i l batteries. L d id b tt i Lead-acid batteries are and th minimum t d the i i temperature at which th b tt i will t t hi h the batteries ill available in both wet-cell (requires maintenance) and be used. sealed no-maintenance versions. AGM and Gel-cell deep-cycle batteries are also popular because they are maintenance free and they last a lot longer.“ a centre for application of renewable energy preparation by s.r.kushero email : Care.@care-india.com http://www.care-india.com
  24. 24. Solar Engineering Battery Wiring Diagrams Wiring up your battery bank. Use 2, 4, 6, or 12 volt b tt i lt batteries t b ild a system voltage of 12 to build t lt f 12, 24, or 48 volts using series and parallel wiring with just 4 clicks. Battery bank capacities from 300 Amp/Hours to over 4000 Amp/Hours •AWG (American Wire Gauge) RGY “ MAD EASY Based on the distance to your solar panel array & the amount of amperage your panels put out. Configurations are possible for Amp/Hour DE capacities from as little as 300 Amp/Hours to over 4000. To use the Designer, follow these 4 simple steps : Click 2, 4, 6, or 12 volt batteries to build OLAR ENER your Battery 1.Battery Bank. 2. Select the closest Amp/Hour rating for 1 Battery. ANDING SO 3. 3 Choose your System Battery Bank voltage voltage. (your inverter input voltage)preparation by s.r.kushero 4. Select the size of the Battery Bank capacity in Amp/Hours.“UNDERSTA To determine the Amp/Hour capacity you will need, use System Sizing Estimator which will calculate the Amp/Hour capacity of your battery bank and also the number of solar panels required. required“ a centre for application of renewable energy preparation by s.r.kushero email : Care.@care-india.com http://www.care-india.com
  25. 25. Solar Engineering Battery Bank Configurations are possible for AmpHour capacities from as little as 300 AmpHours to over 4000. 4000 To use the Designer follow these 4 simple Designer, steps : RGY “ MAD EASY 1.Battery Bank. Batteries come in various individual sizes. They can be connected to DE increase th system voltage. i the t lt 2. Select the closest Amp/Hour rating for 1 battery. To determine the total Amp/Hour capacity of p p y OLAR ENER your battery bank you must use the rating for 1 battery. 3. Choose your System Battery Bank voltage. (your inverter input voltage) The System Voltage ANDING SO is the combined voltage of the entire batterypreparation by s.r.kushero bank. The Solar Panels, the Charge Controller, and the“UNDERSTA Inverter will all use this voltage voltage. 4. Select the size of the Battery Bank capacity in Amp/Hours.This is the total capacity required to run your solar energy system.“ a centre for application of renewable energy preparation by s.r.kushero email : Care.@care-india.com http://www.care-india.com
  26. 26. Solar Engineering Battery Bank Storage Batteries : the fuel tank of your solar power Industrial strength : Flooded, Gel, and AGM sealed system batteries Without batteries to store energy you would only have power when the sun was shining or the generator was running. This tutorial The next 3 types are the heavier industrial type batteries. describes the 4 basic types of batteries & provides some good tips They are all also considered Deep Cycle and are usually Lead on the care & feeding of your batteries tomaximize their performance Acid types with much thicker internal plates that can withstand and life. many deep discharge cycles. These next 3 are all designed for RGY “ MAD EASY alternative energy systems. 1) RV / Marine / Golf Cart : RV or Marine type deep cycle batteries 2) Flooded types : These are Lead acid batteries that have caps to add are basically for boats & campers and are suitable for only very water. Many manufacturers make these types for Solar Energy use. small systems. They can be used but do not really have the capacity Trojan, Surrette, and Deka are probably the most well known. They are DE for continous service with many charge/discharge cycles for many reasonably priced and work well f many years. All fl d d b tt i bl i d d k ll for flooded batteries years. Regular or Car type batteries should not be used at all release gas when charged and should not be used indoors. If installed because they cannot be discharged very much without internal in an enclosure, a venting system should be used to vent out the gases damage. A very popular battery for small systems is the Golf Cart which can be explosive. battery. 3) Gel : Not to be confused with maintenance free batteries, sealed gel OLAR ENER They are somewhat more expensive th Th h t i than d deep cycle recreational l ti l batteries have no vents and will not release gas during the charging batteries but are probably the least expensive choice for a small process like flooded batteries do. Venting is therefore not required and system on a budget. they can be used indoors. This is a big advantage because it allows the batteries to maintain a more constant temperature and perform better. 4) AGM : Absorbed Glass Mat batteries are in my opinion the best ) G bso bed G ass at batte es a e y op o t e ANDING SO available for Solar Power use. A woven glass mat is used between the plates to hold the electrolyte. They are leak/spill proof, do not out gaspreparation by s.r.kushero when charging, and have superior performance. They have all the advantages of the sealed gel types and are higher quality, maintain voltage better, self discharge slower, and last longer. The Sun Xtender series by Concorde Battery is an excellent example of AGM batteries.“UNDERSTA They are more expensive, but you usually get what you pay for. You will find this type of battery used in airplanes, hospitals, and remote telephone/cell tower installations.“ a centre for application of renewable energy preparation by s.r.kushero email : Care.@care-india.com http://www.care-india.com
  27. 27. Solar Engineering Battery Bank Care and Feeding As a technician, I used to say that if you are not comfortable, then neither is your equipment. I was mostly referring to temperature and humidity In fact battery capacity ratings are humidity. usually specified at 77 degrees F. As batteries get colder RGY “ MAD EASY their voltage drops and performance suffers. DE This is Thi i one major reason I prefer AGM b tt i j f batteries because they can be stored indoors where the temperatures vary less. Another important thing to consider is how deeply you discharge your batteries. This is known as the DOD OLAR ENER (depth of discharge). In other words, how low you let the voltage drop before the next charge cycle. Most battery ratings talk about 50% or so, but they will last longer if you keep them as charged as possible. I like the 70% range. ANDING SOpreparation by s.r.kushero Lead acid batteries like to be fully charged. They will last much longer if you do not discharge them too deeply. This is known as shallow cycling and greatly extends their life.“UNDERSTA However, they can withstand discharges down to 20% or so, but I wouldnt do it too often“ a centre for application of renewable energy preparation by s.r.kushero email : Care.@care-india.com http://www.care-india.com
  28. 28. Solar Engineering Wire & Cables To connect the components of a Solar Energy System, you will need to use correct wire sizes to ensure low loss of energy and to prevent overheating and possible damage or even fire Below is a chart showing the fire. equired wire size for wire lengths to connect RGY “ MAD EASY the solar panels to the Charge Controller. DE Use these numbers for a 12 volt system to achieve a 3% or less voltage drop. The top row represents the Wire gauge size, the left column the number of amps the solar OLAR ENER panels are rated at, and the grid cells show the distances in feet between the Solar Panels and the Charge Controller. ANDING SO This chart shows wire distances for a 3%preparation by s.r.kushero voltage drop or less. NOTE : This chart is an approximate distance reference and is a little conservative. For a much more accurate“UNDERSTA These distances are calc lated for a 12 volt calculated olt system. Multiply distances by 2 for a 24 volt wire sizing, use our new Wire Size system. Multiply distances by 4 for a 48 volt Calculator tool. It can calculate wire size system. using 3%, 4%, or 5% losses plus you can select 12, 24, or 48 volt systems , , y“ . a centre for application of renewable energy preparation by s.r.kushero email : Care.@care-india.com http://www.care-india.com

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