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30 Amp Solar Charge Controller SCC-30AB

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1. amp A Division of Samlex America Inc 30 Amp Owner s ess cec Solar Charge Manual operatino your C t I 9 charge controller ontroiler SCC 30AB INDEX QD 09 oM Gv Ur Bw UO Safety Instr ctions esce rev eter ya eI EH TO EEG EIER REA VE e ey EL ERE RRERES 3 General Description of PV Solar System 5 General information Batteries essent 15 Irnitroduction and Featu res eene aa a 28 Construction Layout and Controls sess 33 Installation and Operation sssssssssseseseeeeeeeeeennee nente nennen 38 TroubleshooOtlfig 5r cra oeetekis EUR FEURRE e ISI te EO III EUYgS a e CPM EE ieia 45 Specifications eee ie eas cane dese OA 47 Warranty esnan aaa aa ae ne ial anand wees 49 SAFETY INSTRUCTIONS Please read these instructions before installing or operating the Charge Controller to prevent per sonal injury or damage to the Charge Controller General Installation and wiring compliance Installation and wiring must comply with the local and National Electrical Codes and must be done by a certified electrician Preventing electrical shock The negative system conductor should be properly grounded Grounding should comply with local codes Disassembly repair should be carried out by qualified personnel only Disconnect all input and output side connections before working on any circuits associated with the Charge Controller Turni
2. 26 GENERAL INFORMATION BATTERIES As explained tt will be seen from the above that the final rated capacity of the batteries is almost 2 times the energy required by the load in AH Thus as a Rule of Thumb the AH capacity of the batteries should be twice the energy required by the load in AH For the above example the 12 V batteries may be selected as follows Use 6 Group 27 31 12 V 105 AH batteries in parallel to make up 630 AH or Use 3 Group 8D 12 V 225 AH batteries in parallel to make up 675 AH Battery Charging Stages and Charging Currents It is recommended that the batteries may be charged at 10 to 13 of the Ampere Hour capacity of the battery 20 Hour Discharge Rate Also for complete charging return of 100 capacity it is recommended that a 4 stage charger may be used Constant Current Bulk Charging followed by Constant Voltage Boost Absorption Charging followed by Constant Voltage Float Charging followed by Constant Voltage Equalization Equalization is carried out only when some cells do not charge fully and the individual cell voltages differ by more than 0 2 V cell Also equalization is carried out only for non sealed vented flooded wet cell batteries Batteries and Battery Charging in Vehicles RVs Alternators Isolators Inverters It is recommended that for powering an inverter one or more auxiliary deep cycle batteries should be used that are separate from the starter SL
3. PV Solar Cell J ra 12cm 1 Fig 2 3 PV Solar Cell The basic element of a PV System is the photovoltaic PV cell also called a Solar Cell An example of a PV Solar Cell made of Mono crystalline Silicon is shown in Fig 2 3 This single PV Solar Cell is like a square but with its four corners missing it is made this way Theory of Operation of PV Solar Cell Sunlight photons External circuit Encapsulate seal Top electrical contact P Type material Boran doped Silicon PIN junction N Type material Phosphorous doped Silicon Base contact Fig 2 4 Construction and Working of PV Solar Cell A PV Solar Cell is a semiconductor device that can convert solar energy into DC electricity through the Photovoltaic Effect Conversion of solar light energy into electrical energy When light shines on a PV Solar Cell it may be reflected absorbed or passes right through But only the absorbed light generates electricity GENERAL DESCRIPTION OF PV SOLAR SYSTEM When light enters the PV Solar Cell some of the Photons packets of electro magnetic wave energy from the light energy are absorbed by the semiconductor atoms The energy of the absorbed light is transferred to the negatively charged electrons in the atoms of the solar cell With their newfound energy these electrons escape from their normal positions in the atoms of the semiconductor photovoltaic material and become
4. Controller It is based on an advanced design using a microcontroller for digital accuracy and fully automatic operation It can be used for 12V or 24V systems for solar charging The PWM battery charging has been optimized for longer battery life The unit is designed for user friendly operation Please take the time to read this Owner s Manual and follow the instructions step by step to help you make full use of the charging system Features e Advanced microcontroller based high performance design for digital accuracy and fully automatic and intelligent operation Dual voltage capability can be used with 12 V 24 V Solar Systems e 30A charging capacity enables use of up to 360 W of 12 V or 720 Watts of 24 V Solar Panels Series Mode PWM Pulse Width Modulation charging design for low loss higher efficiency charging and longer battery life e 4Stages of charging for 100 return of capacity and long battery life Bulk Absorption Float and Equalization Stages Choice of 8 sets of Absorption Float Equalization voltage settings to enable complete and safe charging of a wide range of Lead Acid Ni Cd Batteries Convenient 2 X 16 character LCD Display with backlight for display of operating information and data Additional LED indication for displaying the charging stages Optional remote Battery Temperature Sensor BTS Model DC BTS A C for temperature compensation to ensure improved charging of batteries that experience wid
5. Programs A Battery Type These are generic Lead Acid wet cell Lead Antimony Lead Calcium sealed AGM sealed Gel Cell and Ni Cd battery types B Voltage This is the PWM Absorption Stage with constant voltage charging The PWM Absorption voltage is the maximum battery voltage that will be held constant As the battery becomes more charged the charging current tapers off until the battery is fully charged C Float Voltage When the battery is fully charged the charging voltage will be reduced to 13 4 volts for all battery types It will be 14 5V for Ni Cd D Equalization Voltage During an equalization cycle the charging voltage will be held constant at this voltage 41 INSTALLATION amp OPERATION E Equalization Time The charging at the selected equalization voltage will continue for this number of hours F Equalization Interval Equalizations are typically done once a month Most of the cycles are 28 days so the equalization will begin on the same day of the month Each new cycle will be reset as the equalization starts so that a setting day period will be maintained Equalization Procedure Standard Equalization Programs Both automatic and manual equalizations can be performed using the standard charging programs Manual Equalization The SCC 30AB is shipped with the DIP Switch 5 set for manual equalization only This is to avoid an unexpected or unwanted automatic equalization In the Manual Mode the push button
6. SYSTEM PV Cell Types PV cells are most commonly made of Silicon and come in two varieties crystalline and thin film type as detailed in Table 2 1 Cell types include Mono crystalline Silicon Poly crystalline Silicon Amorphous Silicon a Si Gallium Arsenide GaAs Copper Indium Diselenide CulnSe2 CIS Cadmium Telluride or a combination of two materials in a tandem cell Bulk type Wafer based Crystalline Mono Crystalline Si Poly Crystalline Si Poly Crystalline Band Pros High efficiency Hion eiidenay wih respect to price Increased manufacturing cost caused by the Cons supply shortage of silicon Thin film type Amorphous Si CIGS CdTe Polymer organic Low pice Low manufacturing Pros Low price 3 Able to awiomete Can be more efficient still all manufacturing 1 in research process Cons Low efficiency Low efficiency Table 2 1 PV Cell Types PV Module Panel and PV Array To increase their utility a number of individual PV cells are interconnected together in a sealed weatherproof package called a Panel Module For example a 12 V Panel Module will have 36 cells connected in series and a 24 V Panel Module will have 72 PV Cells connected in Series To achieve the desired voltage and current Modules are wired in series and parallel into what is called a PV Array The flexibility of the modular PV system allows designers to create solar power systems that can meet a wide var
7. above values of voltage Vmp and current Imp at this Maximum Power Point MPP Rated power in Watts Pmax Vmp X Imp Example of I V Curve and Ratings of a 12 V PV Solar Panel Amps 0 lee SHORT CIRCUIT CURRENT MAXIMUM POWER x VOLTAGE CURRENT x 0 5 10 15 20 open 25 CIRCUIT VOLTAGE Fig 2 9 Example of l V Curve and Ratings of a 12 V PV Solar Panel The I V Curve for a typical 12 Volt PV Solar Panel is shown in Fig 2 9 This Maximum Power Point in the example curve given above is where Vmp is 17 Volts and the current Imp is 2 5 amps Therefore the rated or the maximum power Wmax in watts is 17 Volts times 2 5 Amps or 42 5 Watts Standard Test Conditions STC for Specifying PV Solar Modules The I V curve is also used to compare the performance of PV Solar Modules The curve is therefore generated based on the performance under Standard Test Conditions STC of sunlight and device temperature of 25 C It assumes there is no shading on the device Standard sunlight conditions on a clear day are assumed to be 1 000 Watts of solar energy per square meter 1000 W m or 1 kW m This is sometimes called one sun or a peak sun Less than one sun will reduce the current output of the PV device by a proportional amount For example if only one half sun 500 W m is available the amount of output current is roughly cut in half 14 GENERAL INFORMATION BATTERIES Battery Types There are seve
8. and corrosion of the lower portion of the plates Gassing of the electrolyte from a controlled overcharging equalization will stir and remix the acid into the battery electrolyte NOTE Excessive overcharging and gassing too vigorously can damage the battery plates and cause shedding of active material from the plates An equalization that is too high or for too long can be damaging Review the requirements for the particular battery being used in your system When to Equalize The ideal frequency of equalizations depends on the battery type Lead Calcium Lead Antimony etc the depth of discharging battery age temperature and other factors One very broad guide is to equalize flooded batteries every 1 to 3 months or every 5 to 10 deep discharges Some batteries such as the L 16 group will need more frequent equalizations The difference between the highest cell and lowest cell in a battery can also indicate the need for equalization Either the specific gravity or the cell voltage can be measured The battery manufacturer can recommend the specific gravity or voltage values for your particular battery Normally if the cell voltage differential is gt 0 2 V equalization may be necessary 32 CONSTRUCTION LAYOUT amp CONTROLS General SCC 30AB is designed for flush mounting on a wall panel The controls and indications are built on the Front Panel face plate that has 4 countersunk holes for flush mounting Fig 5 1 All t
9. controls and indications are given below Front Panel Charge Status LED Indications LED STATE Blinking Green 1 Green B 2 Green B 3 Green B 4 Green B ink inks inks inks INDICATION Charging is in the state of Bulk or Absorption depending upon the number of blinks as follows For 12 V Battery gt 0 75 V below Absorption Voltage setting 0 75 V below Absorption Voltage setting 0 5 V below Absorption Voltage setting 0 25 V below Absorption Voltage setting For 24 V Battery gt 1 5 V below Absorption voltage setting 1 5 V below Absorption Voltage setting 1 0 V below Absorption Voltage setting 0 5 V below Absorption Voltage setting 5 Green Blinks Solid Green Solid Orange Solid Red Blinking Red Push Buttons BUTTONS Display Reset Amp Hours Equalization Start Stop 34 At Absorption Voltage setting At Absorption Voltage setting Charging is in the state of Float Charging is in the state of Equalization Charging is in the state of fault Over current or low DC voltage or operating temp below 0 C 32 F Charging is in the state of fault Over Temperature ACTION Push to change the display as in Fig 5 3 Push and hold to reset Amp Hours When DIP Switch 5 is set at OFF hold Restart Stop Equalization for 5 sec to manually start equalization Press it for 2 sec to stop equalization CONSTRUCTION LAYOUT amp CONTROLS LCD Display The LCD Di
10. flow around the controller s face plate Do not install in a sealed compartment with batteries Never allow the solar array to be connected to the controller with the battery disconnected This can be a dangerous condition with high open circuit solar voltage present at the terminals Use only copper wire with minimum 75 C insulation rating and between 10 AWG 5 2 mm and 14 AWG 2 1 mm gauge The Negative system conductor should be properly grounded Grounding should comply with local codes GENERAL DESCRIPTION OF PV SOLAR SYSTEM What is Photovoltaic PV The word photo voltaic is derived from two different words the word photos from the Greek meaning light and the word voltaic developed from the name of the Italian scientist Volta who studied electricity This explains what a PV system does it converts light energy from the sun into electrical energy What is in a Photovoltaic PV system Non Grid tied PV Solar System Charge Controller DC AC Power Inverter PV Solar Panel Module or Array Battery Fig 2 1 Non Grid tied PV System Block Diagram Fig 2 1 shows a Block Diagram of a typical non grid tied Photovoltaic PV System with its main components It consists of a PV Solar Panel Module Charge Controller Batteries and Power Inverter The PV Solar Panel Module or Array converts the solar light energy into DC electrical energy The Charge Controller conditions the DC electric
11. is sufficient to connect one bypass diode for every 15 20 cells Bypass diodes also allow current to flow through the PV module when it is partially shaded even if at a reduced voltage and power Bypass diodes do not cause any losses because under normal operation current does not flow through them bypass diodes load Figure 2 7 Parallel PV cell with bypass diodes Current I Voltage V and Power P Curves of a PV Solar Panel Module and how the PV Solar Panel Module is rated Voc Vmp Isc Imp Pmax Fig 2 8 Current I Voltage V and Power P Curves 12 GENERAL DESCRIPTION OF PV SOLAR SYSTEM A Current I versus Voltage V Curve of a PV Solar Module I V Curve shows the possible combinations of its current and voltage outputs A typical I V curve for a 12 V Module is shown in Fig 2 8 The power in a DC electrical circuit is the product of the voltage and the current Mathematically e Power P in Watts W The Current I in Amperes A X the Voltage V in Volts V ie WZVxA A PV Solar Cell or a Panel Module produces its maximum current when there is no resistance in the circuit i e when there is a short circuit between its Positive and Negative terminals This maximum current is known as the Short Circuit Current and is abbreviated as I When the Cell Panel Module is shorted the voltage in the circuit is zero Conversely the maximum voltage occurs when there is a break in
12. marked Equalization is used to both start and stop a manual equalization Hold the push button down for 5 seconds to start and 3 seconds to stop an equalization depending on whether an equalization is in progress or not There are no limits to how many times the push button can be used to start and stop equalizations Equalizations will be terminated automatically as per the charging program selected if the push button is not used to manually stop the equalization Automatic Equalization If the equalization DIP Switch 5 is moved to the ON position the equalizations will begin automatically as per the charging program selected Other than starting the automatic and manual equalizations are the same and follow the standard charging program selected The push button can be used to start and stop equalizations in both the manual and automatic mode Typical Equalization The automatic equalizations will occur at the selected charging program from DIP Switch 2 4 When equalization begins Auto or Manual the battery charging voltage increases up to the Equalization Voltage Veq The battery will remain at Veq for the time specified in the selected charging program The equalization process will continue until the voltage has been held above the bulk Absorption setting for a cumulative period of one two or three hours A second manual equalization cycle can be started with the push button if needed If the equalization cannot be completed
13. part of the electrical flow or current in an electrical circuit A special electrical property of the PV Solar Cell a built in electric field provides the force or voltage needed to drive the current through an external load such as a light bulb To induce the built in electric field within a PV Solar Cell two layers of somewhat differing semiconductor materials are placed in contact with one another See Fig 2 4 One layer is an N type semiconductor e g Phosphorus doped Silicon with an abundance of Electrons which have a Negative electrical charge The other layer is a P type semiconductor e g Boron doped Silicon with an abundance of Holes which have a Positive electrical charge Although both materials are electrically neutral N type silicon has excess Electrons and P type silicon has excess Holes Sandwiching these together creates a P N Junction at their interface thereby creating an electric field When N type and P type silicon come into contact excess electrons move from the N type side to the P type side The result is a buildup of Positive charge along the N type side of the interface and a buildup of Negative charge along the P type side Because of the flow of electrons and holes the two semiconductors behave like a battery creating an electric field at the surface where they meet the P N Junction The electrical field causes the electrons to move from the semiconductor toward the Negative surface
14. the circuit This is called the Open Circuit Voltage V c Under this condition the resistance is infinitely high and there is no current since the circuit is incomplete Typical value of the open circuit voltage is located about 0 5 0 6 V for Crystalline Cells and 0 6 0 9 V for Amorphous Cells These two extremes in load resistance and the whole range of conditions in between them are depicted on the I V Curve Current expressed in Amps is on the vertical Y axis Voltage in Volts is on the horizontal X axis The power available from a photovoltaic device at any point along the curve is just the product of Current I in Amps A and Voltage V in Volts V at that point and is expressed in Watts At the short circuit current point the power output is zero since the voltage is zero At the open circuit voltage point the power output is also zero but this time it is because the current is zero Maximum Power Point and Rated Power of PV Solar Panel Module There is a point on the knee of the I V Curve where the maximum power output is located and this point is called the Maximum Power Point MPP The voltage and current at this Maximum Power Point are designated as Vmp and Imp The values of Vmp and Imp can be estimated from V and I as follows Vmp 0 75 0 9 Voc Imp 0 85 0 95 l lt 13 GENERAL DESCRIPTION OF PV SOLAR SYSTEM The rated power of the PV Solar Module in Watts Pmax is derived from the
15. 96 of the battery capacity is discharged and then recharged f an SLI battery is used for this type of deep discharge application its useful service life will be drastically reduced 18 GENERAL INFORMATION BATTERIES This type of battery is not recommended for the storage of energy for inverter applications However they are recommended as starting battery for the back up generator Deep Cycle Lead Acid Batteries Deep cycle batteries are designed with thick plate electrodes to serve as primary power sources to have a constant discharge rate to have the capability to be deeply discharged up to 80 capacity and to repeatedly accept recharging They are marketed for use in recreation vehicles RV boats and electric golf carts so they may be referred to as RV batteries marine batteries or golf cart batteries Units of Battery Capacity Ampere Hours AH and Reserve Minutes RC The battery capacity is the measure of the electrical energy the battery can store and deliver to a load It is determined by the amount of current any given battery can deliver over a stipulated period of time The energy rating is expressed in Ampere Hours AH As a bench mark the battery industry rates batteries at 20 Hour rate i e the number of Amperes of current the battery can deliver for 20 Hours at 80 F 26 7 C till the voltage drops to 10 5 Volts for 12 V battery and 21 V for 24 V battery For example a 100 AH battery will deliver 5 Amperes
16. Acid and water In a fully charged battery the Positive Plate is in the form of Lead Dioxide the Negative Plate is in the form of Lead and the Sulphuric Acid in the electrolyte has the maximum concentration of 33 596 v v Electrochemical Reactions during Charging and Discharging of Lead Acid Battery Electrical power in the Lead Acid Battery is produced by reversible electrochemical reactions as follows During discharging the Sulphuric Acid in the electrolyte reacts with the Positive and Negative plates resulting in conversion of the active materials in the two plates to Lead Sulphate At the same time electrons are released that create the electrical current that flows to the load The concentration of Sulphuric Acid in the electrolyte is reduced as the battery gets discharged the electrolyte becomes pure water when the battery is fully discharged 15 GENERAL INFORMATION BATTERIES During charging reverse electrochemical reactions take place Under the influence of the charging voltage fed to the battery by the external battery charger charge controller electrons are fed back to the battery and the Lead Sulphate at the Positive and Negative Plates is converted back to Lead Dioxide at the Positive Plate and Lead at the Negative Plate and the concentration of Sulphuric Acid is restored will revert to 33 5 v v when the battery is fully charged Gassing due to Excessive Overcharging During charging the battery is required to b
17. Antimony Calcium Tin and Selenium The two most common alloys used today to harden the grid are Antimony and Calcium Batteries with these types of grids are sometimes called Lead Antimony and amp Lead Calcium batteries Tin is added to Lead Calcium grids to improve cyclability The major differences between batteries with Lead Antimony and Lead Calcium grids are as follows Lead Antimony batteries can be deep cycled more times than Lead Calcium batteries Flooded Lead Antimony batteries require more frequent maintenance as they near end of life since they use an increasing amount of water and require periodic equalization charges Lead Calcium batteries have lower self discharge rates and therefore will draw less current while kept in storage SLI Starting Lighting Ignition Batteries Everybody is familiar with the SLI batteries that are used for automotive starting lighting ignition and powering vehicular accessories SLI batteries are designed to produce high power in short bursts for cranking SLI batteries use lots of thin plates to maximize the surface area of the battery for providing very large bursts of current also specified as Cranking Amps This allows very high starting current but causes the plates to warp when the battery is cycled Vehicle starting typically discharges 1 396 of a healthy SLI battery s capacity The automotive SLI battery is not designed for repeated deep discharge where up to 80
18. CPFO9 Heat Sink SR Open Battery Temperature Sensor BTS displays m FAULT LED Solid Red Blinking Red Solid Red Solid Red Solid Red N a DESCRIPTION Over Current Heat Sink over Temperature Display Panel Error Low Voltage Low Operating Temperature Battery Temperature is below 0 C CAUSE OF FAULT REMEDY The current exceeds 45 A Heat sink temperature exceeds 90 C The CPU is not able to exchange data with the Display Panel 1 Low battery voltage 9 V for 12 V Battery 18 V for 24 V Battery 2 If this symptom is for a 12 V Battery System check amp ensure that DIP Switch 1 at the back of the unit is selected for 12 V battery and not for 24 V battery Operating temperature is below 0 C 32 F Ensure operating temperature is above 0 C 32 F 1 Lower limit of temperature compensation ISOLE 2 Negative values can t be displayed Table 7 1 Fault Indications amp Remedies 45 TROUBLESHOOTING SYMPTOM 1 BATTERY IS NOT CHARGING Check the green LED indicator The green CHARGING LED should be on if it is daytime Check that the proper battery charging algorithm program has been selected by DIP Switches 2 3 4 Table 6 1 Check that all wire connections in the system are correct and tight Check the polarity and of the connections Measure the PV array open circuit voltage and confirm it is within normal limits If the voltage is low or
19. I batteries The inverter should be powered from deep cycle batteries For charging the starter SLI and the auxiliary deep cycle batteries the output from the alternator should be fed to these two sets of batteries through a battery isolator of appropriate capacity The battery isolator is a device that will allow the alternator to charge the two sets of batteries when the engine is running The battery isolator will allow the inverter to be operated from the auxiliary batteries and also prevent the starter SLI batteries from charging the auxiliary deep cycle batteries when the engine is not running Battery isolators are available from auto RV marine parts suppliers A majority of smaller vehicles have 40 to 105 Ampere alternator and RVs have 100 to 130 Ampere alternator When in use the alternators heat up and their output current capacity can drop by up to 2596 When heated up their charging voltage may also not reach the desired Absorption Voltage and will result in return of only about 80 of the battery capacity In case the current output of the standard alternator is not adequate to charge the two sets of batteries rapidly and fully to 10096 of their capacity use heavy duty alternator that can produce higher current and voltage required to charge multiple battery systems These alternators are available with auto RV parts suppliers 27 INTRODUCTION amp FEATURES The SCC 30AB is a Series Type of PWM Pulse Width Modulation Charge
20. N amp OPERATION Standard Battery Charging Programs The SCC 30AB provides 8 standard battery charging algorithms programs that are selected with DIP Switches 2 3 4 These standard algorithms are suitable for Lead Acid batteries ranging from sealed Gel AGM maintenance free to flooded to L 16 cells and Ni Cd etc Table 6 1 below summarizes the major parameters of the standard charging algorithms Note that all the voltages are for 12V systems For 24 V system multiply the voltages by 2 Consult the battery manufacturer battery specifications amp select the appropriate Algorithm The unit is preset for Battery Type 1 off off off for a sealed VRLA battery For a generic non sealed vented flooded well cell Lead Acid battery choose Battery Type 4 Note 1 All voltage values are at 25 C 77 F 2 All the voltages given in the Table are for 12V Battery System For 24V Battery Systems multiply the voltage values by 2 A B S D E F DIP PWM Equalize Equalize Switches Banery Absorption groat ae Time Interval 2 3 4 yp Voltage 9 9 hours days Off Off Off anma 1 Sealed 4 0 3 4 None Off Off On 2 Sealed 4 1 13 4 14 2 1 28 Off On Off 3 Sealed 4 3 13 4 14 4 2 28 Off On On 4 Flooded 4 4 13 4 15 1 3 28 On Off Off 5 Flooded 4 6 13 4 15 3 3 28 On Off On 6 Flooded 4 8 13 4 15 3 3 28 On On Off 7 L 16 5 0 13 4 15 3 E 14 On On On 8 Ni Cd 6 0 14 5 None Table 6 1 Standard Battery Charging
21. al voltage and current produced by the PV Solar Panel Module or Array to charge a battery The battery stores the DC electrical energy so that it can be used when there is no solar energy available night time cloudy days etc DC loads can be powered directly from the PV Solar Panel Module Battery The inverter converts the DC power produced by the PV Solar Panel Module stored in the battery into AC power to enable powering of AC loads GENERAL DESCRIPTION OF PV SOLAR SYSTEM Grid tied PV Solar System Fig 2 2 shows a Block Diagram of a typical Grid tied PV Solar System In this system the Solar Panels Modules Arrays directly feed to an inverter and the inverter is connected to an Electricity Transmission and Distribution System referred to as the Electricity Grid such that the system can draw on the Grid s reserve capacity in times of need and feed electricity back into the Grid during times of excess production Solar Array Two way Metering 4 DC AC Power Inverter A Eee Powerto Controller Protection me and from grid Fig 2 2 Grid tied PV Solar System Block Diagram In order to safely transmit electricity to your loads and to comply with your power provider s grid connection requirements you may need the following additional items Power conditioning equipment Safety equipment Meters and instrumentation GENERAL DESCRIPTION OF PV SOLAR SYSTEM
22. are not indicated Formula 1 given above may be used to calculate the AC watts by multiplying 120 VAC 230 VAC by the AC current in Amperes The next step is to derive the DC current in Amperes A from the AC watts as per Formula 2 above An example of this calculation for a 12V inverter is given below Let us say that the total AC Watts delivered by the12 V inverter 1000 W Then using Formula 2 above the DC current to be delivered by the 12 V batteries 1000 W 10 100 Amperes Next the energy required by the load in Ampere Hours AH is determined For example if the load is to operate for 3 hours then as per Formula 3 above the energy to be delivered by the 12 V batteries 100 Amperes x 3 Hours 300 Ampere Hours AH Now the capacity of the batteries is determined based on the run time and the usable capacity From Table 3 2 Battery Capacity versus Rate of Discharge shown above the usable capacity at 3 Hour discharge rate is 6096 Hence the actual capacity of the 12 V batteries to deliver 300 AH will be equal to 300 AH 0 6 500 AH And finally the actual desired rated capacity of the batteries is determined based on the fact that normally only 8096 of the capacity will be available with respect to the rated capacity due to non availability of ideal and optimum operating and charging conditions So the final requirements will be equal to 500 AH 0 8 625 AH note that the actual energy required by the load was 300 AH
23. as the temperature rises the charging voltage is required to be reduced and as the temperature is decreased the charging voltage has to be increased All charging voltage set points are normally specified at 25 C 77 F In PV systems battery temperatures often vary up to 15 C from the 25 C reference The Absorption Voltage for a 12 V battery must then be adjusted as shown in the Table below or a controller with Temperature Sensor should be used assuming Voltage Coefficient of Temperature Change as 5 mV C Cell or 30mV 03 V for a 6 cell 12 V battery BATTERY TEMPERATURE ABSORPTION VOLTAGE 40 C 13 95 V 25 C Reference 14 4 V Reference 10 C 14 85 V In case temperature compensation is not provided the warmer battery at 40 C will begin to heat and outgas at 13 95 V and will continue to overcharge until the non compensated Absorption Voltage set point is reached 14 4 V In cooler temperatures the 10 C battery will experience severe undercharging resulting in sulfation It is recommended that a battery charger charge controller with a provision for temperature sensing and compensation should be used if the battery electrolyte temperature varies more than 5 C to 10 C 9 F to 18 F Self discharge The battery discharges itself even without any load connected to it This effect is caused by secondary reactions at its electrodes and proceeds faster with higher temperature or in older batteries Thermody
24. becomes the Positive terminal of the 12 V bank Similarly the four Negative terminals of Batteries 1 to 4 are paralleled connected together and this common Negative connection becomes the Negative terminal of the 12 V battery bank Series Parallel Connection String 1 String 2 a 1 Battery 2 Battery 3 Battery 4 Solar Charge Controller SCC30 AB rear view Cable B Fig 3 4 Series Parallel Connection 24 GENERAL INFORMATION BATTERIES Figure 3 4 above shows a series parallel connection consisting of four 6V 200 AH batteries to form a 12 V 400 AH battery bank Two 6 V 200 AH batteries Batteries 1 and 2 are connected in series to form a 12 V 200 AH battery String 1 Similarly two 6 V 200 AH batteries Batteries 3 and 4 are connected in series to form a 12 V 200 AH battery String 2 These two 12 V 200 AH Strings 1 and 2 are connected in parallel to form a 12 V 400 AH bank When 2 or more batteries battery strings are connected in parallel and are then connected to a charger See Figs 3 3 and 3 4 attention should be paid to the manner in which the charger is connected to the battery bank Please ensure that if the Positive output cable of the battery charger Cable A is connected to the Positive battery post of the first battery Battery 1 in Fig 3 3 or to the Positive battery post of the first battery string Battery 1 of String 1 in Fig 3 4 then the Negative output cable of the battery charge
25. bination of direct solar radiation as well as diffused light bounced off of surrounding surfaces PV Solar Cells are usually coated with anti reflective material so that they absorb the maximum amount of radiation possible The output current of the PV Solar Panel Module can increase due to what is known as the Edge of the Cloud Effect As the sun moves into a hole between the clouds your solar panels will see full direct sunlight combined with reflected light from the clouds They will absorb more energy than they could on a cloudless day Thus a factor of 1 25 times the Short Circuit Current Isc is recommended when sizing the current capacity of the Charge Controller The output current of the PV Solar Cell has a positive Temperature Coefficient The output current increases with the rise of temperature However it is negligible less than 0 1 C of the Short Circuit Current Isc The output voltage of the PV Solar Cell has a Negative Temperature Coefficient The output voltage increases with decrease in temperature For example a Silicon Cell has a Temperature Coefficient of 2 3 mV C Cell Hence during cold winter days the voltage will rise As a Rule of Thumb the voltage rating of the Charge Controller should be sized as 1 25 times the Open Circuit Voltage rating Voc of the PV Solar Panel Module to ensure that the Charge Controller is not damaged due to over voltage GENERAL DESCRIPTION OF PV SOLAR
26. consist of a rectangular grid made out of alloyed Lead with rectangular holes in it as shown in Fig 3 1 below Fig 3 1 Grid structure of Positive and Negative Plates in a Lead Acid Battery 17 GENERAL INFORMATION BATTERIES The holes in the grid of the plates are filled with a paste of active material made out of a mixture of Red Lead and 33 dilute Sulphuric Acid different manufacturers use modified mixtures The paste is pressed into the holes in the grid This paste remains porous and allows the Sulphuric Acid in the electrolyte to react with the lead inside the plate increasing the surface area many fold At this stage the Positive and Negative plates are identical Once dry the plates are then stacked together with suitable separators and inserted in the battery container After the electrolyte has been added to the cell the cell is given its first Forming Charge During this Forming Charge the Lead paste in the Positive plate gradually turns to Lead Dioxide chocolate brown color and the Lead paste in the Negative plate turns to Sponge Lead slate gray color Such charged cell is ready to be used The above grid structure of the plates is made from a Lead alloy A pure Lead grid structure is not strong enough by itself to stand vertically while supporting the active material Other metals in small quantities are alloyed with Lead for added strength and improved electrical properties The most commonly alloyed metals are
27. ct battery Positive first amp then battery Negative Installation Steps This section provides a brief overview of how to get started using the SCC 30AB controller However please review the entire manual to ensure best performance and years of trouble free service Notes e The SCC 30AB prevents reverse current leakage at night through an internal MOSFET Switch so an external Blocking Diode is not required in the system e The connector terminals will accept a maximum wire size of AWG 10 up to 5 2 mm e Tighten each terminal clamping screw to 20 inch pounds of torque The SCC 30AB is designed to regulate power from a PV array Other chargers can be connected directly to the battery however with no effect on the SCC 30AB Steps 1 As explained earlier in Chapter 4 SCC 30AB is designed for flush mounting on a wall panel It has a face plate and a projecting part at the back consisting of the PCB with the Terminal Strip connector for the Battery Temperature Sensor BTS and the DIP switches The wall panel will be required to be cut to accommodate the projections of the circuit board mounted on the back of the faceplate All the wiring 2 wires from the Solar Array 2 wires to the battery and 2 wires to the optional Battery Temperature Sensor if used will be led to the connections at the back of the unit from behind the wall panel Make sure that the pocket created behind the cut out in the wall panel is clear so t
28. d Shunt connected MOSFET Switch During the initial constant current Bulk Charge Stage see Fig 4 1 the Series connected MOSFET Switch in a Series Type of controller like SCC 30AB is kept on continuously till the PWM Absorption Voltage is reached During this time the solar panel delivers nearly constant current that is equal to or nearly equal to the Short Circuit Current I corresponding to the voltage of the discharged battery see Fig 2 9 For example for a panel with Short Circuit Current of 2 7 A and discharged battery voltage of 11 V this current will 2 7 A Once the battery voltage reaches the Absorption Voltage Fig 4 1 further charging takes place at constant voltage in the Absorption Equalization Float stages During the above constant voltage stages the PWM control circuit switches on and switches off the MOSFET Switch at a frequency of several hundred cycles per second Thus instead of a steady output from the controller it sends out a series of short charging pulses to the battery like a very rapid on off switch The controller constantly checks the state of the battery to determine how long wide the pulses will be In a fully charged battery in Float stage with no load it may just tick and send very short pulses to the battery In Equalization Absorption stages the pulses would have longer duration and will be almost continuous The controller checks the state of charge on the battery between pulses and adj
29. d by temperature because the charging may go into PWM absorption almost every day If the battery temperature is colder the charging will begin to regulate too soon and the battery may not be recharged with a limited solar resource If the battery temperature rises the battery may heat and gas too much Equalization A colder battery will lose part of the benefit of the equalization A warmer battery may heat and gas too much Float Float is less affected by temperature changes but it may also undercharge or gas too much depending on how much the temperature changes The Battery Temperature Sensor BTS corrects the three charging set points noted above by the following values reference temperature is 25 C 77 F 12 volt battery 0 030 volts per C 0 017 volts per F 24 volt battery 0 060 volts per C 0 033 volts per F ad INSTALLATION amp OPERATION The temperature sensed by the BTS at the battery is displayed on the LCD screen under the screen display Heatsink BTS see Fig 5 3 As the LCD display is not capable of displaying negative values battery temperature below 0 C will not be displayed If the battery temperature falls below 0 C the display will read C and temperature compensation is disabled Variations in battery electrolyte temperature can affect charging battery capacity and battery life The greater the range of battery temperatures the greater the impact on the batte
30. e charged in a controlled manner in the final Absorption Stage 2 4 V per cell at 25 C 77 F or 14 4 V for a 12 V battery at 25 C 77 F that restores the last 20 to 30 of the capacity On completion of this stage of charging the Lead Sulphate at the Positive and Negative Plates is fully converted back to Lead Dioxide at the Positive Plate and Lead at the Negative Plate Any further charging at this voltage or higher than this voltage results in electrolysis of water in the electrolyte to Hydrogen and Oxygen and this undesirable condition contributes to waste of energy This process is known as gassing Gassing is also produced during the timed Equalization Stage performed only for vented flooded wet cell batteries when the battery is intentionally overcharged 2 5 to 2 6 V per cell 15 to 15 6 V for 12 V batteries so that weaker cells are brought up to the full charge too equalized Non sealed vented flooded wet cell batteries have open vents to release Hydrogen and Oxygen produced during gassing The above un intentional electrolysis of water during overcharging results in loss of water and reduces the level of the electrolyte in this type of batteries When the level of the electrolyte is reduced the upper portion of the plates in the cells will not be immersed in the electrolyte and will result in loss of battery capacity Hence these types of batteries are required to be topped up with distilled water periodically t
31. ect proves to be the result of defective material or workmanship the equipment will be repaired or replaced at the Warrantor s option without charge and returned to the Purchaser at the Warrantor s expense No refund of the purchase price will be granted to the Purchaser unless the Warrantor is unable to remedy the defect after having a reasonable number of opportunities to do so Warranty service shall be performed only by the Warrantor Any attempt to remedy the defect by anyone other than the Warrantor shall render this warranty void There shall be no warranty for defects or damages caused by faulty installation or hook up abuse or misuse of the equipment including exposure to excessive heat salt or fresh water spray or water immersion No other express warranty is hereby given and there are no warranties which extend beyond those described herein This warranty is expressly in lieu of any other expressed or implied warranties including any implied warranty of merchantability fitness for the ordinary purposes for which such goods are used or fitness for a particular purpose or any other obligations on the part of the Warrantor or its employees and representatives There shall be no responsibility or liability whatsoever on the part of the Warrantor or its employees and representatives for injury to any persons or damage to person or persons or damage to property or loss of income or profit or any other consequential or resulting da
32. er electrical parts and could cause an explosion Remove metal items like rings bracelets and watches when working with batteries The batteries can produce a short circuit current high enough to weld a ring or the like to metal and cause a severe burn If you need to remove a battery always remove the ground terminal from the battery first Make sure that all the accessories are off so that you do not cause a spark Charge Controller related Please ensure the input voltage fed to the Charge Controller does not exceed 50 VDC to prevent permanent damage to the Charge Controller Ensure that the maximum Open Circuit Voltage Voc of the 12 V nominal Solar Panel Solar Array is less than 50 V If two 12 V nominal Solar Panels are being used in series to make a 24 V nominal Solar Array make sure that the maximum Open Circuit Voltage Voc of each of the 12 V Panels is less than 25 V Do not exceed the maximum current rating of 30 A The Short Circuit Current of the Solar Array should be less than 30 A Do not exceed a battery voltage of 24V nominal Do not use a battery less than 12V Charge only 12 or 24 volt Lead Acid batteries when using the standard battery charging programs or Ni Cd batteries when DIP Switch number 2 4 is in the ON position DO NOT short circuit the PV array or load while connected to the controller This will damage the controller The controller should be protected from direct sunlight Ensure adequate space for air
33. er in sunlight Also be careful not to short circuit the Solar Panel Module Array while connected to the controller since this will damage the controller 7 For most effective surge protection it is recommended that the Negative system conductor be properly grounded Dip Switch Settings Five DIP Switches permit the following parameters to be adjusted at the installation site NAME DESCRIPTION DIP Switch 1 ON Selection of battery voltage for 12V system OFF Selection of battery voltage for 24V system DIP Switch 2 3 4 Battery charge control mode Battery charging algorithm see Table 6 1 DIP Switch 5 ON Selection of Auto Equalization OFF Selection of Manual Equalization NOTE Factory preset condition Battery Charging Notes The SCC 30AB manages many different charging conditions and system configurations Some useful functions to know are given below Solar Overload Enhanced radiation or edge of cloud effect conditions can generate more current than the controller s rating The unit will reduce this overload up to 13096 of rated current by regulating the current to safe levels If the current from the solar array exceeds 150 the controller will interrupt charging Battery Types The SCC 30AB s standard battery charging programs are suitable for a wide range of Lead Acid battery types These standard programs are select by DIP Switch 2 4 There is also one program for Ni Cd battery see Table 6 1 40 INSTALLATIO
34. er temperature variations during the year MOSFET based reverse current blocking for night time battery discharge prevention This allows much lower losses as compared to Diode based blocking Specially designed for RVs boats and trucks allows convenient and aesthetic flush mounting on walls panels Industry leading warranty Requirements of Battery Charging in PV Systems Batteries in PV Systems are commonly subject to abusive conditions that are generally due to e Under charging due to low sun peak hours e Excessive charging in high sun peak hours Inappropriate or ineffective charge control for the battery technology The individual or combined effects of sun peak hour changes poor charge control and the daily load changes can be potentially damaging to the battery Cheaper charge control strategies such as simple on off PV array shedding Non PWM control will generally provide the battery with sufficient charging current to complete the Bulk Charge Phase which will return the battery to 80 State of Charge After the Bulk Charge Phase the Taper or Absorption Charge Phase is very important in preventing stratification hard sulfation and pre mature capacity loss 28 INTRODUCTION amp FEATURES PWM Battery Charging PWM Pulse Width Modulation battery charging is the most efficient and effective method for recharging a battery in a solar system The PV array is connected to the battery through a series or parallel calle
35. for 20 Hours Battery capacity is also expressed as Reserve Capacity RC in minutes Reserve capacity is the time in minutes for which the battery can deliver 25 Amperes at 80 F 26 7 C till the voltage drops to 10 5 Volts for 12 V battery and 21 V for 24 V battery Approximate relationship between the two units is as follows Capacity in AH Reserve Capacity in RC minutes x 0 6 Typical Battery Sizes The Table below shows details of some popular battery sizes BCI GROUP BATTERY VOLTAGE V BATTERY CAPACITY AH 27 31 12 105 4D 12 160 8D 12 225 Ges 6 220 Battery Council International Golf Cart Table 3 1 Popular Battery Sizes 19 GENERAL INFORMATION BATTERIES Reduction in Usable Capacity at Higher Discharge Rates As stated above the rated capacity of the battery in AH is normally applicable at a discharge rate of 20 Hours As the discharge rate is increased the usable capacity reduces due to Peukert Effect This relationship is not linear but is more or less according to the Table below HOURS OF DISCHARGE USABLE CAPACITY 20 100 87 96 83 96 75 96 70 96 60 96 50 96 1 40 96 e N UU Ui O OO Table 3 2 Battery Capacity versus Rate of Discharge Using the above Table will show that a 100 AH capacity battery will deliver 100 i e full 100 AH capacity if it is slowly discharged over 20 hours at the rate of 5 Amperes However if it is discharged at a rate of 50 Amperes then theoretically it sho
36. hat the back portion carrying the PCB is not damaged when the unit is pushed back into the cut out section of the wall the panel for flush mounting The front face plate of the SCC 30AB acts as the heat sink for the heat dissipating components mounted on the PCB at the back of the Front Panel face plate Hence please ensure that the Front Panel face plate is not located near a heat generating source and that there is adequate cooling air flow across the face plate to remove the heat dissipated from its surface 38 INSTALLATION amp OPERATION A drawing for making the cutout in the wall panel is given at Fig 6 1 not to scale A full scale template is also included in the gift box to help direct marking the area to be cut out 4 screws have been provided to fix the unit to the wall panel 1 25 mm 1 25 mm 1 4 6 mm 1 25 mm Cut the wall panel along the dotted line with a jig saw This will create a pocket in the wall panel for flush mounting of Charge Controller SCC 30AB 1 4 6 mm 1 4 6 mm P 4 1 4 108 mm 33 4 96 mm 7 178 mm 1 4 6 mm Outline of the front panel 7 5 190 mm Fig 6 1 Drawing for making the cut out in the wall panel 2 Make sure the PV currents will not exceed the ratings of the SCC 30AB 3 The connections to the SCC 30AB terminals are shown in the drawing at Fig 5 2 A barrier type of Terminal Strip has been pr
37. he electronics DIP switches for settings terminal strip for connections for the PV Array and the Battery and terminal for the optional Battery Temperature Sensor BTS are mounted on a PCB that is in turn mounted at the back of the face plate Fig 5 2 For flush mounting on the wall panel a suitable cutout is required to be made in the wall panel to accommodate the PCB at the back of the unit As the components at the back of the unit will be hidden and protected behind the wall panel the components at the back of the unit are exposed and do not have a protective cover PLEASE HANDLE THE UNIT CAREFULLY TO PREVENT ANY DAMAGE TO THE EXPOSED COMPONENTS AT THE BACK OF THE UNIT NOTE As the unit will be connected to 12 V 24 V Nominal Solar Array battery system there is no likelihood of electrical shock samlexsol lt Status e Bulk Absorption Float Equalization Fault Model Solar Charge Controller SCC30AB e Fig 5 1 Front Panel of SCC 30AB O 9 DIP Switch DIPSwiteh Solar Battery Charging PV 1 Select Battery Voltage ON DVS OFF 234 Bulk Flos Volt Vol OFFOFFOFF 140V Made in Taiwan s See SUE BTS BTS O Fig 5 2 Back view of SCC 30AB 33 CONSTRUCTION LAYOUT amp CONTROLS Controls amp Indications The description and the functions of the
38. horter time to charge as compared to the battery which sees higher series resistance and hence will experience over charging and its life will be reduced 25 GENERAL INFORMATION BATTERIES Sizing the Inverter Battery Bank One of the most frequently asked question is how long will the batteries last This question cannot be answered without knowing the size of the battery system and the load on the inverter Usually this question is turned around to ask How long do you want your load to run and then specific calculations can be done to determine the proper battery bank size There are a few basic formulae and estimation rules that are used Formula 1 Power in Watts W Voltage in Volts V x Current in Amperes A Formula 2 For an inverter running from a 12 V battery system the DC current required from the 12 V batteries is the AC power delivered by the inverter to the load in Watts W divided by 10 amp for an inverter running from a 24 V battery system the DC current required from the 24 V batteries is the AC power delivered by the inverter to the load in Watts W divided by 20 Formula 3 Energy required from the battery DC current to be delivered A x time in Hours H The first step is to estimate the total AC watts W of load s and for how long the load s will operate in hours H The AC watts are normally indicated in the electrical nameplate for each appliance or equipment In case AC watts W
39. iety of electrical needs Fig 2 5 shows PV cell Panel Module and Array 10 GENERAL DESCRIPTION OF PV SOLAR SYSTEM Array Fig 2 5 PV cell Module and Array The cells are very thin and fragile so they are sandwiched between a transparent front sheet usually glass and a backing sheet usually glass or a type of tough plastic This protects them from breakage and from the weather An aluminum frame is fitted around the module to enable easy fixing to a support structure The picture in Fig 2 6 shows a small part of a Module with cells in it It has a glass front a backing plate and a frame around it Aluminum frame Backing Sheet Fig 2 6 Construction of a typical Mono crystalline PV Solar Panel 11 GENERAL DESCRIPTION OF PV SOLAR SYSTEM Bypass Diodes As mentioned PV Solar cells are wired in series and in parallel to form a PV Solar Panel Module The number of series cells indicates the voltage of the Panel Module whereas the number of parallel cells indicates the current If many cells are connected in series shading of individual cells can lead to the destruction of the shaded cell or of the lamination material so the Panel Module may blister and burst To avoid such an operational condition Bypass Diodes are connected anti parallel to the solar cells as in Fig 2 7 As a consequence larger voltage differences cannot arise in the reverse current direction of the solar cells In practice it
40. in one day it will continue the next day or days until finished After equalization is completed charging will return to PWM Absorption 42 INSTALLATION amp OPERATION Temperature Compensated Battery Charging An optional Battery Temperature Sensor BTS Model No DC BTS A C is available for temperature compensated battery charging The BTS consists of a temperature sensing probe that is installed on the battery post The temperature of the battery post reflects the approximate temperature of the electrolyte A pair of 10 metres wires marked amp connect the temperature sensing probe to the 2 terminals marked BTS at the back of the unit Fig 5 2 As the battery gets warmer the gassing increases As the battery gets colder it becomes more resistant to charging Depending on how much the battery electrolyte temperature varies it is important to adjust the charging for temperature changes Various voltage set points given in the specifications are indicated at a reference temperature of 25 C 77 F It is recommended that the optional Battery Temperature Sensor BTS Model No DC BTS A C may be used if the battery electrolyte temperature measured at the terminal stud varies more than 5 C to 10 C 9 F to 18 F from the reference temperature of 25 C 77 F There are three battery charging parameters that are affected by temperature PWM Absorption This is the most important part of charging that is affecte
41. ion Cycle CYCLE in days These parameters are automatically set once a particular battery type charging algorithm corresponding to one of the 8 options has been selected using DIP Switches 2 3 4 See Chapter 6 Table 6 1 Screen 7 Displays the heat sink temperature Heatsink in C the metal plate of the front panel acts as the heat sink It also displays the temperature of the battery in C when the optional Battery Temperature Sensor BTS Model No DC BTS A C is used NOTE The battery temperature can not be displayed below 0 C If the battery temperature falls below 0 C the display will read C 36 CONSTRUCTION LAYOUT amp CONTROLS Fault Messages The LCD displays might have the following fault messages when SCC 30AB stops operating DISPLAY DESCRIPTION CAUSE OF FAULT Alarm OC Over Current The current exceeds 15 of the rated current Over Current Alarm OT Heat Sink over Heat sink temperature exceeds 90 C emperature Alarm CPFOO Display Panel The CPU is not able to exchange data with the Link Master error error Display Panel Alarm CPFO4 Low Battery voltage 1 Batteries are discharged below the minimum DC DC 9V for 12V Battery acceptable level or Low Volt 18V for 24V Battery 2 DIP Switch 1 is set for 24V battery but the battery is 12V Alarm CPFO9 Low operating Operating temperature of the unit is below the Heat Sink SR Open temperature specified limit of O C or 32 F Battery Temperature Ba
42. ition to reducing the battery capacity sulfate build up is the most common cause of buckling plates and cracked grids Deep cycle batteries are particularly susceptible to lead sulfation 31 INTRODUCTION amp FEATURES Normal charging of the battery can convert the sulfate back to the soft active material if the battery is fully recharged However a solar battery is seldom completely recharged so the soft lead sulfate crystals harden over a period of time Only a long controlled overcharge or equalization at a higher voltage can reverse the hardening sulfate crystals In addition to slowing or preventing lead sulfation there are also other benefits of equalization of the solar system battery These include Balance the individual cell voltages Over time individual cell voltages can drift apart due to slight differences in the cells For example in a 12 cell 24V battery one cell may be less efficient in recharging to a final Absorption Voltage of 28 8 volts 2 4 V cell Over time that cell only reaches 1 85 volts while the other 11 cells charge to 2 45 volts per cell The overall Absorption Voltage is 28 8V but the individual cells are higher or lower due to cell drift Equalization cycles help to bring all the cells to the same voltage Mix the electrolyte In flooded batteries especially tall cells the heavier acid will fall to the bottom of the cell over time This stratification of the electrolyte causes loss of capacity
43. led VRLA type of AGM or Gel Cell Batteries Battery Efficiency A lead acid battery has an efficiency of only 75 85 The energy lost appears as heat and warms the battery This means that the Ampere Hour AH energy required to charge a battery to its full rated capacity will be approximately 120 to 130 higher than the AH capacity rating of the battery Depth of Discharge and Battery Life The more deeply a battery is discharged on each cycle the shorter the battery life Using more batteries than the minimum required will result in longer life for the battery bank A typical life cycle chart is given in the Table below DEPTH OF DISCHARGE CYCLE LIFE OF CYCLE LIFE OF CYCLE LIFE OF OF AH CAPACITY GROUP 27 31 GROUP 8D GROUP GC2 10 1000 1500 3800 50 320 480 1100 80 200 300 675 100 150 225 550 Table 3 4 Typical Cycle Life Chart It is recommended that the depth of discharge should be limited to 50 24 GENERAL INFORMATION BATTERIES Effect of Temperature on Battery Voltage The temperature of the electrolyte affects the rate of chemical reactions in the batteries as well as the rate of diffusion and the resistivity of the electrolyte Therefore the charging characteristics of the battery will vary with temperature This is nearly linear and the Voltage Coefficient of Temperature Change is normally taken as 3 mV to 5 mV C Cell Please note that the Voltage Coefficient of Temperature Change is negative This means that
44. lines X 16 characters alpha numeric 1 LED for status display 47 SPECIFICATIONS CHARACTERISTICS SPECIFICATIONS ENVIRONMENTAL Ambient temperature 0 C to 45 C Storage temperature 55 C to 85 C Humidity 95 Non Condensing MECHANICAL Dimensions L x W x D fap eee On IMS Weight With gift box 1 2 lbs 0 55 kg Net weight 0 8 Ib 0 36 kg Powder coated steel for indoor Enclosure face plate use only ACCESSORIES INCLUDED 4 pieces Insulated spade lugs for input output connections For 4 8 stud AWG 12 10 wire size 4 pieces Self tapping screws for fixing the face plate 7 x 19 5 8 Type 25 point Flat head Philips drive Specifications subject to change without notice 48 WARRANTY 5 YEAR Limited Warranty SCC 30AB manufactured by Samlex America Inc the Warrantor is warranted to be free from defects in workmanship and materials under normal use and service This warranty is in effect for 5 years from the date of purchase by the user the Purchaser For a warranty claim the Purchaser should contact the place of purchase to obtain a Return Authorization Number The defective part or unit should be returned at the Purchaser s expense to the authorized location A written statement describing the nature of the defect the date of purchase the place of purchase and the Purchaser s name address and telephone number should also be included If upon the Warrantor s examination the def
45. mage which may be claimed to have been incurred through the use or sale of the equipment including any possible failure of malfunction of the equipment or part thereof The Warrantor assumes no liability for incidental or consequential damages of any kind Samlex America Inc the Warrantor 110 17 Fawcett Road Coquitlam BC V3K 6V2 Canada 604 525 3836 49 NOTES 50 NOTES 51 110 17 Fawcet SCC 30AB_Charge_Controller_Manual_Feb2011
46. namic instability of the active materials and electrolytes as well as internal and external short circuits lead to capacity losses which are defined as self discharge This loss should be small particularly in respect of annual storage Self discharge of loss of capacity per month for various types of batteries is as follows Lead Acid 3 to 496 Ni Cd 6 to 2096 Ni Fe 4096 22 GENERAL INFORMATION BATTERIES Loss of Battery Capacity at Low Temperatures Batteries lose capacity in low temperatures At 32 F 0 C a battery will deliver about 70 to 80 of its rated capacity at 80 F 26 7 C If the electrolyte temperature of the battery bank is lower than 80 F 26 7 C additional batteries will be needed to provide the same usable capacity For very cold climates an insulated heated battery compartment is recommended Freezing of Electrolyte For applications with low ambient temperature the lead acid battery must also be protected against freezing of the electrolyte The risk of freezing depends on the state of charge The chart given below illustrates the freezing limit as a function of the state of charge 40 Temperature C slushy until hard o 20 40 60 80 100 State of charge Series and Parallel Connection of Batteries Series Connection Cable A Battery 4 Battery 3 Battery 2 Battery 1 o Jr TO Pv 18 T 6V Ba
47. ng the on off control on the Charge Controller to off position may not entirely remove dangerous voltages e Be careful when touching bare terminals of capacitors The capacitors may retain high lethal voltages even after the power has been removed Discharge the capacitors before working on the circuits Installation environment The Charge Controller should be installed indoor only in a well ventilated cool dry environment Do not expose to moisture rain snow or liquids of any type Preventing fire and explosion hazards Working with the Charge Controller may produce arcs or sparks Thus the Charge Controller should not be used in areas where there are inflammable materials or gases requiring ignition protected equipment These areas may include spaces containing gasoline powered machinery fuel tanks battery compartments Precautions when working with batteries Batteries contain very corrosive diluted sulphuric acid as electrolyte Precautions should be taken to prevent contact with skin eyes or clothing Batteries generate hydrogen and oxygen during charging resulting in evolution of explosive gas mixture Care should be taken to ventilate the battery area and follow the battery manufacturer s recommendations Never smoke or allow a spark or flame near the batteries SAFETY INSTRUCTIONS Use caution to reduce the risk of dropping a metal tool on the battery It could spark or short circuit the battery or oth
48. o ensure that the plates in the cells are fully immersed in the electrolyte Some non sealed vented flooded wet cell batteries come with catalytic caps to recombine any emitted Hydrogen and Oxygen Sealed VRLA batteries are designed to recombine the Hydrogen and Oxygen back into water and hence Sealed VRLA batteries are not required to be topped up with distilled water That is why these batteries are also called maintenance free batteries Sealed VRLA batteries use safety valves to release any excessive gas pressure built up inside the battery due to malfunction or overheating If this happens e g by overcharging the valve vents the gas and normalizes the pressure producing a characteristic acid smell Valves can sometimes fail however if dirt and debris accumulate allowing pressure to build up that will result in damage to the battery 16 GENERAL INFORMATION BATTERIES Sealed Lead Acid SLA or Valve regulated Lead Acid VRLA Batteries Sealed Lead Acid SLA batteries or Valve Regulated Lead Acid VRLA batteries can either be Gel Cell or AGM Absorbed Glass Mat In a Gel Cell battery the electrolyte is in the form of a gel In AGM Absorbed Glass Mat battery the electrolyte is soaked in Glass Mat In both these types the electrolyte is immobile There are no refill caps and the battery is totally sealed Hydrogen and Oxygen released during the charging process is not allowed to escape and is recombined inside the batte
49. onal details on Equalization given below 4 Float When a battery becomes fully charged dropping down to the float stage will provide a very low rate of maintenance charging while reducing the heating and gassing of a fully charged battery When the battery is fully recharged there can be no more chemical reactions and all the charging current is turned into heat and gassing The purpose of float is to protect the battery from long term overcharge From the PWM absorption stage charging is dropped to the float voltage This is typically 13 4V for a 12V battery Equalization l Caution e Equalization is carried out only for non sealed vented flooded well cell lead acid batteries Do not equalize sealed VRLA type of AGM Gel cell batteries Top up the electrolyte with distilled water after completion of equalization Routine equalization cycles are often vital to the performance and life of a battery particularly in a solar system During battery discharge sulfuric acid is consumed and soft lead sulfate crystals form on the plates If the battery remains in a partially discharged condition the soft crystals will turn into hard crystals over time This process called lead sulfation causes the crystals to become harder over time and more difficult to convert back to soft active materials Sulfation from chronic undercharging of the battery is the leading cause of battery failures in solar systems In add
50. ovided for connecting the PV array and the battery M 4 screws with clamping washers are used to make the connection A flat or a 2 Philips head screw driver may be used to tighten these screws Tighten each terminal clamping screw to 20 inch pounds of torque The distance between the barriers is 9 mm and a standard Spade Type of terminal lug meant for 8 Stud and AWG 10 AWG 12 wire may be used at the end of the wires to be connected to these terminals 4 such terminal lugs are provided with the unit for ease of installation 4 Set the DIP Switch 1 for the voltage system set the DIP Switch 2 3 4 for battery charging algorithm see Table 6 1 5 Connect the BATTERY first Be careful that bare wires do not touch the metal case of the controller Connect battery Negative first and then the battery Positive The BATTERY must be connected before the Solar Panel ModuleyArray to properly start the microcontroller activate protections amp guide installation A battery below 9 V for 12 V battery or 18 V for 24 V battery may not start the microcontroller properly Make sure the battery is charged before installing the system 39 INSTALLATION amp OPERATION 6 Connect the Solar Panel Module Array next The green LED indicator will light if the Solar Panel Module Array is connected during the daytime and the Solar Panel Module Array is wired correctly Remember that the Solar Panel Module Array will generate power whenev
51. protection devices like Lightning Rods Surge Suppressors shielded cables etc However in small PV systems these protections are seldom incorporated Because there is less system level protection small PV Charge Controllers are more susceptible to damage by high voltage transients Transient Voltage Surge Suppressors TVSS are used to protect the input and output sections of the Charge Controller The TVSS clamps the high voltage of the transient to a safe level The Clamping Voltage is seen by the MOSFET and temporarily stresses the MOSFET In a Series Type oF Charge Controller the MOSFET Switch is located between the input terminals and the battery Hence the voltage seen across the MOSFET Switch during high voltage transient condition is lower and is equal to the Clamping Voltage of the TVSS minus the battery voltage This produces lower stress In a Shunt Type Charge Controller the MOSFET Switch sees the full Clamping Voltage and therefore it is stressed to a higher degree Lesser switching noise during charging the Shunt MOSFET Switch experiences higher level of stress because it is in a high temperature reverse bias standoff position The voltage applied across the Series MOSFET Switch is lesser and so experiences lesser stress and is therefore more reliable A Shunt Type requires a Schottky Diode in series with the battery to prevent short circuiting of the battery during the time the MOSFET switch shunts the PV Array In a Serie
52. r Cable B should be connected to the Negative battery post of the last battery Battery 4 as in Fig 3 3 or to the Negative Post of the last battery string Battery 4 of Battery String 2 as in Fig 3 4 This connection ensures the following If the Positive output cable of the battery charger Cable A is connected to the Positive battery post of the first battery Battery 1 in Fig 3 3 or to the Positive battery post of the first battery string Battery 1 of String 1 in Fig 3 4 and the Negative output cable of the battery charger Cable B is connected to the Negative battery post of the first battery Battery 1 as in Fig 3 3 or to the Negative Post of the first battery string Battery 1 of Battery String 1 as in Fig 3 4 the following abnormal conditions will result Caution The resistances of the interconnecting cables will be balanced All the individual batteries battery strings will see the same series resistance All the individual batteries will charge at the same charging current and thus will be charged to the same state at the same time None of the batteries will see an overcharge condition The resistances of the connecting cables will not be balanced The individual batteries will see different series resistances All the individual batteries will be charged at different charging current and thus will reach fully charged state at different times The battery with lower series resistance will take s
53. ral different types of battery chemistries like Lead Acid Nickel Iron Ni Fe Nickel Cadmium Ni Cad etc The batteries consist of individual cells that can be connected in series to obtain the required battery voltage Batteries are either sealed also called Valve Regulated Lead Acid VRLA or non sealed vented flooded wet cell Nickel Iron Ni Fe and Nickel Cadmium Ni Cad Battery Nickel Iron Ni Fe and Nickel Cadmium Ni Cad also called alkaline batteries have a nominal cell voltage of 1 2 volts per cell The nominal voltage of a Ni Cad Ni Fe battery bank can be made the same as a lead acid bank just by juggling the number of cells 10 cells for 12 volts 20 cells for 24 volts and 40 cells for 48 volt systems However the Ni Cad Ni Fe battery bank must be charged to a higher voltage to fully recharge and will drop to a lower voltage during discharging compared to a similarly sized lead acid type battery Lead Acid Battery A Lead Acid battery consists of a number of 2 V nominal cells actual voltage of the cell is 2 105 V that are connected in series e g a 12 V nominal battery will have six 2 V nominal cells in series actual voltage of the 6 cells will be 2 105 x 6 12 63 V Each 2 V nominal cell in this battery consists of an independent enclosed compartment that has Positive and Negative Plates also called Electrodes dipped in electrolyte that is composed of diluted Sulphuric Acid solution of 33 5 v v Sulphuric
54. red by the solar panel into the batteries with effect from the time the solar panel has been connected or with effect from a desired starting reference point after the counter is set to 0 The counter can be set to zero with the help of the Push Button marked Reset Amp Hours Push and hold the Push Button till the counter resets to 0 For example due to its 75 to 85 efficiency a lead acid battery requires up to around 130 of Amp Hour energy as compared to its rated Amp Hour capacity to recharge fully Hence during start of recharging of say a fully discharged 100 AH battery the Amp Hours counter can be set to 0 As 130 Amp Hour of energy will be required to re charge a fully discharged 100 AH battery a healthy battery is likely to be fully recharged when the Amp Hour counter approaches 130 Amp Hours Screen 3 Counts the total running Ampere Hours Amp Hours of energy in Ah delivered by the solar panel into the batteries This will only reset if the battery connection is removed Screen 4 Shows the charging Mode in progress Bulk or Absorption or Equalization or Float Screen 5 Shows the Bulk Absorption and Float voltages that have been set for the desired battery type charging algorithm corresponding to one of the 8 options that can be selected with the help of DIP Switches 2 3 4 See Chapter 6 Table 6 1 Screen 6 Displays the Equalization Voltage EQU in Volts Equalization Time EQU T in Hours and Equalizat
55. rray still disconnected If the battery voltage is measured at the PV array terminals PV and PV the controller may be damaged CHARACTERISTICS SYSTEM Nominal system voltage Current rating Set point accuracy Minimum voltage to start the micro controller activate protections and guide operation Total self consumption current INPUT SIDE Solar panel array Maximum open circuit voltage Voc of the solar panel array Maximum operating voltage of the solar panel array Maximum short circuit current Isc of the solar panel array BATTERY CHARGING Charging algorithm Charging stages Battery Temperature Compensation Voltage coefficient of Temperature change when using optional Battery Temperature Sensor BTS Model DC BTS A C Temperature compensation range PROTECTIONS High temp shutdown Temp of the face plate that is used as a heat sink Over current overload shut down DISPLAY Backlit LCD LED SPECIFICATIONS SPECIFICATIONS 12 VDC or 24 VDC Selected by DIP Switch 30A 50 mV 9 VDC for 12 V Battery System 18 VDC for 24 V Battery System 50 mA 50 VDC 34 VDC 30A PWM Bulk Absorption Float Equalize Selectable With optional Battery Temperature Sensor BTS Model DC BTS A C supplied with 10 metres of wire 5mV C cell 25 C reference 10mV C cell 25 C reference 0 C to 50 C 90 C disconnect solar panel array 70 C re connect solar panel array 45A 2
56. ry For example if the battery temperature falls to 10 C 50 F this 15 C 27 F change in temperature with respective to the reference of 25 C 77 F will change the PWM Absorption equalization and float set points by 0 90 V in a 24 V system and 0 45 V in a 12 V system Typical compensation is given in Table 6 2 below BATTERY ELECTROLYTE VOLTAGE COMPENSATION TEMPERATURE 12 VOLT BATTERY 24 VOLT BATTERY 50 C 122 F 0 75V 1 50V AS GANTS 0 60 V 1 20V 40 C 104 F 0 45V 0 90 V S5 7 S15 AF 0 30 V 0 60 V 30 C 86 F 0 15 V 0 30 V 25 C 77 F Reference O V Reference 0 V Reference 20 C 68 F 0 15 V 0 30 V 1ISC SF 0 30 V 0 60 V 10 C 50 F 0 45 V 0 90 V SC fan Ge 0 60 V 1 20 V 0 G 32 F 0 75 V 1 50 V Table 6 2 Temperature Compensation TROUBLESHOOTING The SCC 30AB is very rugged and designed for the most extreme operating conditions Most PV system problems will be caused by connections voltage drops and loads Troubleshooting the SCC 30AB controller is simple Some basic troubleshooting procedures are listed below Protections amp Fault Messages on the LCD Display amp Fault LED Table 7 1 gives fault messages displayed on the LCD screen and status of the Red Fault LED when SCC 30AB stops operating due to protections system error DISPLAY Alarm OC Over Current Alarm OT Alarm CPFOO Link Master Error Alarm CPF04 DC DC Low Volt Alarm
57. ry Hence there is no water loss and the batteries are maintenance free These batteries have safety valves on each cell to release excessive pressure that may be built up inside the cell The Gel Cell is the least affected by temperature extremes storage at low state of charge and has a low rate of self discharge An AGM battery will handle overcharging slightly better than the Gel Cell Non Sealed Vented Flooded Wet Cell Lead acid Batteries In a non sealed vented flooded wet cell battery each individual cell compartment has a refill cap that is used to top up the cell with distilled water and to measure the specific gravity of the electrolyte using a hydrometer When fully charged each individual cell has a voltage of approximately 2 105 V and electrolyte specific gravity of 1 265 As the cell discharges its voltage and specific gravity drop Thus a healthy fully charged 12 V nominal battery with each of the 6 cells fully charged to 2 105 V will measure a standing voltage of 12 63 V at 25 C 77 F Also in a healthy battery all the individual cells will have the same voltage and same specific gravity If there is a substantial difference in the voltages 0 2 V or higher and specific gravities of the individual cells the cells will require equalization Construction of Battery Cell Plates Lead Antimony and Lead Calcium Batteries During construction both the Positive and the Negative plates are similar Both the plates
58. s Type this Schottky Diode is not required Elimination of the Schottky Diode in the Series Type has the following associated advantages Lower voltage drop less heating and consequent lower losses Reverse leakage through the Schottky is eliminated Battery Charging Algorithm Selecting the best method for charging your battery together with a good maintenance program will ensure a healthy battery and long service life Although the SCC 30AB s battery charging is fully automatic the following information is important for getting the best performance from your SCC 30AB Charge Controller and battery Four Stages of Solar Charging Fig 4 1 represents the 4 stages of charging used in the SCC 30AB VOLTAGE 2 ABSORPTION NIGHT NIGHT TIME Fig 4 1 Solar Charging Stages 30 INTRODUCTION amp FEATURES 1 Bulk Charging In this stage the battery will accept all the current provided by the solar array The value of this current will be equal to the Short Circuit Current Isc of the solar array 2 PWM Absorption When the battery reaches the Absorption Voltage the PWM begins to hold the voltage constant This is to avoid over heating and over gassing the battery The current will taper off to safe levels as the battery becomes more fully charged 3 Equalization Many batteries benefit from a periodic boost charge to stir the electrolyte equalize the cell voltages and complete the chemical reactions See additi
59. splay is a 2 Line 16 character display with backlighting The Push Switch marked PUSH Select Display and HOLD Reset Amp Hours is used to manipulate the LCD functions Every time the Push Switch is pressed momentarily the screen display scrolls The scrolling sequence is shown in Fig 5 3 Please note that the 7 screens are sequential amp are displayed in a continuous loop 1 2 3 4 5 6 7 1 2 3andsoon LED Display Screens Amp Watts BatV Screen 1 0 0 0 0 12 0 I PUSH Display Select Amp Hours 0 Ah I PUSH Display Select Screen 2 Total Amp Hours 0 Ah I PUSH Display Select PUSH Display Select v Mode Charger State Bulk I PUSH Display Select Screen 3 Screen 4 Bulk Float 14 0V 134V SHIeenos 9 PUSH Display Select EQU EQU T CYCLE s 142V Thr 28day creen 6 I PUSH Display Select Heatsink BTS 250C 250C Screen 7 Fig 5 3 LCD Display Flow 35 CONSTRUCTION LAYOUT amp CONTROLS The details of information provided in the LCD screens are given below Screen 1 e Shows the solar array current charging current in Amperes Amp battery voltage in V BatV and the power delivered by the solar array fed to the batteries in Watts Watts The value of Watts the charging current in Amperes Amp x Battery Voltage in V BatV Screen 2 e tisaresettable counter that displays the Ampere Hours Amp Hours of energy in Ah delive
60. ttery temperature 1 Lower limit of temperature compensation is 0 C Sensor BTS displays is below 0 C 2 Negative values can not be displayed sae ORC NOTE See Table 7 1 under Chapter 7 Troubleshooting for remedies Table 5 1 Fault Messages Back of the Unit The back of the unit Fig 5 2 has the following input output connections and DIP Switches for various settings NAME DESCRIPTION PV Connecting terminal for Solar Array Positive AES Connecting terminal for Solar Array Negative Battery Connecting terminal for Battery cable Positive Battery Connecting terminal for Battery cable Negative DIP Switch 1 ON Selection of battery voltage for 12V system OFF Selection of battery voltage for 24V system DIP Switch 2 3 4 Battery charge control mode Battery charging algorithm DIP Switch 5 ON Selection of Auto Equalization OFF Selection of Manual Equalization BTS Battery Temperature Sensor for temperature compensation NOTE Factory preset condition Table 5 2 Control Terminal Connection At the back of the unit 37 INSTALLATION amp OPERATION EN Warning This unit will be damaged if the battery is connected in reverse polarity ENSURE that the battery and wires are correctly connected before proceeding Damage due to reverse battery connection is not covered under warranty When connecting the battery connect the battery Negative first amp then the battery Positive When disconnecting the battery disconne
61. ttery yf 6V Battery yf 6V Battery yf 6V Battery 2 C Solar Charge Controller SCC30 AB rear view Cable B Fig 3 2 Series Connection When two or more batteries are connected in series their voltages add up but their AH capacity remains the same Fig 3 2 above shows 4 pieces of 6 V 200 AH batteries connected in series to form a battery bank of 24 V with a capacity of 200 AH The 23 GENERAL INFORMATION BATTERIES Positive terminal of Battery 4 becomes the Positive terminal of the 24 V bank The Negative terminal of Battery 4 is connected to the Positive terminal of Battery 3 The Negative terminal of Battery 3 is connected to the Positive terminal of Battery 2 The Negative terminal of Battery 2 is connected to the Positive terminal of Battery 1 The Negative terminal of Battery 1 becomes the Negative terminal of the 24 V battery bank Parallel Connection Cable A Battery 1 Battery 2 Battery 3 Battery 4 12V Battery 12V Battery oS Solar Charge Controller SCC30 AB rear view Fig 3 3 Parallel Connection When two or more batteries are connected in parallel their voltage remains the same but their AH capacities add up Fig 3 3 above shows 4 pieces of 12 V 100 AH batteries connected in parallel to form a battery bank of 12 V with a capacity of 400 AH The four Positive terminals of Batteries 1 to 4 are paralleled connected together and this common Positive connection
62. uld provide 100 AH 50 2 hours However the Table above shows that for 2 hours discharge rate the capacity is reduced to 50 i e 50 AH Therefore at 50 Ampere discharge rate the battery will actually last for 50 AH 50 Amperes 1 Hour State of Charge SOC of a Battery The Standing Voltage of a battery can approximately indicate the State of Charge SOC of the battery The Standing Voltage is measured after disconnecting any charging device s and the battery load s and letting the battery stand idle for 3 to 8 hours before the voltage measurement is taken The Table 3 3 shows the State of Charge versus Standing Voltage for a 12 volt battery system at around 80 F 26 7 C For 24 volt systems multiply by 2 for 48 volt systems multiply by 4 20 GENERAL INFORMATION BATTERIES PERCENTAGE OF STANDING VOLTAGE OF CELL VOLTAGE 12 V BATTERY FULL CHARGE 12 V NOMINAL BATTERY HAS 6 CELLS IN SERIES 100 12 63 V 2 105 V 9096 12 6 V 2 0 V 8096 12 5 V 2 08 V 7096 12 3 V 2 05 V 6096 122 V 2 03 V 5096 12 4 V 2 02V 4096 12 0 V 2 00 V 3096 11 8V 1 97 V 2096 117 V 1 95 V 1096 11 6 V 1 93 V 096 lt 11 6V lt 1 93 V Table 3 3 State of Charge versus Standing Voltage 12 V Battery Check the individual cell voltages If the inter cell voltage difference is more than a 0 2 V the battery will have to be equalized Please note that only the non sealed vented flooded wet cell batteries are equalized Do not equalize sea
63. usts itself each time This technique allows the current to be effectively tapered and the result is equivalent to constant voltage charging Series and Shunt Type of Charge Controller When the MOSFET Switch is connected in series with the PV Array and the battery the Controller is called Series Type When it is connected in parallel across the PV Array the Battery it is called Shunt Type In Series Type the MOSFET Switch is kept open when the battery is fully charged The PV Array stops supplying current during this period In the Shunt Type when the battery is fully charged the MOSFET Switch is kept closed to shunt divert the full Short Circuit Current of the PV Array away from the battery Advantages of Series Type of Charge Controller A series Type of Charge Controller has the following advantages over a Shunt Type Power systems experience temporary over voltage conditions For example when lightning strikes extremely high electrostatic energy is discharged This energy induces damaging high voltage transients in exposed and un protected electrical circuit elements like cables etc and these high voltage transients are fed to the electrical devices and cause damage if 29 INTRODUCTION amp FEATURES the device is not adequately protected PV Systems and associated cabling are installed in exposed locations and are more prone to the damaging effects of high voltage transients Large PV Systems employ numerous lightning
64. where they become available to the electrical circuit At the same time the Holes move in the opposite direction toward the positive surface where they await incoming electrons The electrical current is fed to the external load through the top electrical contact surface normally in the form of a grid and the bottom base contact The Open Circuit Voltage V of a PV Solar Cell is just under 0 6 V Factors Affecting Voltage and Current Output of the PV Solar Cell The amount of electric current generated by photon excitation in a PV Solar Cell at a given temperature is affected by the incident light in two ways e By the intensity of the incident light By the wavelength of the incident rays GENERAL DESCRIPTION OF PV SOLAR SYSTEM The materials used in PV Solar Cells have different spectral responses to incident light and exhibit a varying sensitivity with respect to the absorption of photons at given wavelengths Each semiconductor material will have an incident radiation threshold frequency below which no electrons will be subjected to the photovoltaic effect Above the threshold frequency the kinetic energy of the emitted photoelectron varies according to the wavelength of the incident radiation but has no relation to the light intensity Increasing light intensity will proportionally increase the rate of photoelectron emission in the photovoltaic material In actual applications the light absorbed by a PV cell will be a com
65. zero check the connections at the PV array itself Disconnect the PV array from the controller when working on the PV array Check that the load is not drawing more energy than the PV array can provide Check if there are excessive voltage drops between the controller and the battery This will cause undercharging of the battery Check the condition of the battery Determine if the battery voltage declines at night with no load If it is unable to maintain its voltage the battery may be failing Measure the PV voltage and the battery voltage at the SCC 30AB terminals If the voltage at the terminals is the same within a few tenths of volts the PV array is charging the battery If the PV voltage is close to the open circuit voltage of the panels and the battery voltage is low the controller is not charging the batteries and may be damaged SYMPTOM 2 BATTERY VOLTAGE IS TOO HIGH 46 First check the operating conditions to confirm that the voltage is higher than specifications Check that the proper battery charging algorithm program has been selected by DIP Switches 2 3 4 Table 6 1 Check that all wire connections in the system are correct and tight Disconnect the PV array and momentarily disconnect the lead from the BATTERY positive terminal BAT Reconnect the battery terminal and leave the PV array disconnected The Green charging light should not be lit Measure the voltage at the PV array terminals PV and PV with the a

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