Valve Regulated Lead Acid Batteries

Transcription

1 Motors I Automation I Energy I Transmission & Distribution I Coatings Batteries - VRLA Valve Regulated Lead Acid Batteries User Manual

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3 User Manual Series: Sealed Batteries Language: English Document: / 00 Publication Date: 08/2018

4 Summary of the Revisions The information below describes the revisions made to this manual. Version Revision Description - R00 First edition

5 Summary 1 SAFETY INSTRUCTIONS QUALIFIED PERSONNEL SAFETY WARNINGS IN THE MANUAL GENERAL INFORMATION RECEIVING AND STORAGE INSTALLATION PRECAUTIONS INSTALLATION CHARACTERISTICS OF VRLA BATTERIES WORKING PRINCIPLE ELECTROCHEMICAL OXYGEN RECOMBINATION BATTERY CHARGE, DISCHARGE & SERVICE LIFE CHARGE CHARACTERISTICS CHARGE CURVE ON FLOAT DUTY RELATION BETWEEN FLOAT VOLTAGE AND AMBIENT TEMPERATURE EQUALIZING CHARGE CHARGE CURVE FOR CYCLIC USE SUPPLEMENTARY CHARGE DISCHARGE CHARACTERISTIC LIFE CHARACTERISTIC ON FLOAT DUTY RECORDS MAINTENANCE TROUBLESHOOTING SEALED VRLA BATTERY CONSTRUCTION

6 Summary

7 Safety Instructions 1 SAFETY INSTRUCTIONS This manual contains the information necessary for the correct use of the VRLA Battery. The following instructions are extremely important for a good performance of your VRLA Battery and should be thoroughly observed during the installation, maintenance and operation of the system. Failure to observe the product instructions may result in operational accidents, damages to the environment, battery and interconnected equipment as well as void the warranty QUALIFIED PERSONNEL All the installation, commissioning, operation, start-up and maintenance must be carried out by qualified personnel. During the execution of maintenance jobs, the legal provisions in force in the country of installation must be respected. Maintenance and operation must be carried out exclusively by qualified personnel familiarized with the characteristics of the panel, in compliance with all applicable IEC safety directions and standards of other technical entities, also observing other paramount instructions. The procedures of NR-10 must also be followed. It is recommended to request the intervention of personnel from WEG technical assistance to perform maintenance and repair jobs. 1.2 SAFETY WARNINGS IN THE MANUAL DANGER! Not following the procedures recommended in this warning can lead to death, serious injuries and considerable material damages. ATTENTION! It identifies the risks of unsafe operations that may cause minor injuries or material damages. NOTE! The text aims at providing important information for the full understanding and proper operation of the product. ATTENTION! Make sure the power is disconnected before installation. Otherwise, electric shock may cause serious injury or death. Always work with the equipment disconnected. When performing any tests, maintenance or repairs, first remove the power supply and then disassemble the equipment. NOTE! In case of doubt about this product / manual, contact our Technical Assistance department. Capital cities and metropolitan areas: / Other locations: VRLA Batteries 1-1

8 Safety Instructions VRLA Batteries

9 General Information 2 GENERAL INFORMATION In order to correct and safely install and use the VRLA Batteries, it is necessary to read this technical manual carefully. Pay attention to safety during installation so as to avoid accidents. In case of any questions concerning this Technical Manual or technical problems, please contact WEG or our nearest Authorized Service. 2 DANGER! Do not touch any uninsulated terminal or connectors to avoid electric shock. Gases generated from explosion may cause eye injury or even blindness. It is prohibited smoking or producing sparks and flames near VRLA Batteries. Vitriol acid can cause blindness or serious burns. Do not loosen the safety valves. Keep batteries in a well-ventilated environment when in operation. Maintenance and repair of VRLA Batteries should be performed by specialized technicians. 2.1 RECEIVING AND STORAGE Visually inspect the package when opening it, looking for signs of tampering or damage to the VRLA Batteries during transportation. Check that the information on the product nameplate corresponds to the purchased model. If any problem is detected, immediately notify the carrier. Open the packaging near the installation site and check the accessories accompanying the product. Check carefully to ensure that there is no damage or leaks in the battery container cases. If any battery falls or if any container case suffers an abnormal impact, please report it to WEG Technical Assistance or the nearest Authorized Service. If batteries are not immediately installed after the delivery, it is necessary to store them in a clean, ventilated, dark location, with temperature between 5 C and 30 C. When stored, the battery capacity will gradually decrease due to the self-discharge. Do not store the batteries for more than twelve months, as this will affect their performance and service life. If the storage time exceeds 4 months, the batteries must be charged with a voltage of 2.43 ± 0.1 V per element for 24 hours and recharged at least every 4 months. A relatively high temperature will accelerate the battery self-discharge. From 25 C, for each temperature increase of 10 C, the recharge interval shall be reduced by half. For example, if the battery is stored at 35 C, its initial charge or recharge interval shall be 2 months. If the batteries are not properly charged, their performance and service life will be affected, voiding the warranty. ATTENTION! Batteries (internal or external) stored for more than 120 days (at 25 C) without a 24-hour recharge lose their warranty. VRLA Batteries 2-1

10 General Information VRLA Batteries

11 Installation Precautions 3 INSTALLATION PRECAUTIONS Use the following protective equipment when moving, installing and handling the VRLA Batteries: 1. Safety goggles or protective face masks. 2. Safety shoes. 3. Proper handling instruments. 4. Do not wear metal objects such as jewelry and the like. Due to the VRLA Batteries weight, take care to avoid impacts during handling. It is strictly prohibited smoking or using lighters, matches, among others, near VRLA Batteries. Keep the batteries away from any kind of electric arc. 3 VRLA Batteries are pre-charged, so avoid short-circuiting in order to prevent damages or injuries. Install the batteries in a ventilated location and at ambient temperature (25 C). Do not install them in locations where there is a risk of flood or where water may reach. Tighten the screws and nuts on the connection terminals to the specified torque. Clean the battery container cases and covers with a damp cloth to prevent static electricity and sparks. It is prohibited using organic solvents or detergents, which could damage the battery container cases. In normal operation, there should be no electrolyte leakage into the container cases after the perfect battery sealing. However, if the container case is damaged, vitriol acid may leak. If electrolyte comes into contact with skin or clothing, flush with large amounts of water. If eyes are affected, wash quickly with large amounts of water and seek immediate medical assistance. Make sure that the positive (+ / red) and negative (- / black) terminals are connected correctly. Connectors, terminals and interconnections of the battery contain lead or lead compounds and other chemicals that are also harmful to health. Therefore when handling the battery, always use protective equipment. Wash the hands after handling batteries. VRLA Batteries 3-1

12 Installation Precautions VRLA Batteries

13 Installation 4 INSTALLATION 1. Batteries. Keep a side clearance of at least 20 mm for ventilation and 150 mm on top for maintenance. 2. Connectors. If there is oxidation on the battery terminals, clean them until they have metallic shine, apply vaseline to inhibit the formation of high-strength oxide, and then install the connectors. Make sure that all terminals, positive (+ / red) and negative (- / black), are connected correctly. The cables must be installed according to the technical drawing or according to the instruction of a qualified professional. Tighten the connection screws with a proper torque wrench. The recommended torque values are indicated in Table 4.1 on page 4-1: Table 4.1: TScrew tightening torque Screw Torque M5 6 to 7 N*m M6 8 to 10 N*m M8 10 to 12 N*m 4 3. Measure the electric voltage. After installing the connectors, measure the total electric voltage of the bank, which should be the total voltage of all the cells. If there is inconsistency, check the polarities of every monobloc and every terminal connection. 4. Numbering of the cells. Stick the self-adhesive labels with the cell numbers and the bank polarity signal on top of the first and last cells. The first cell at the bank positive terminal must be marked as No.1, and the other cells must be marked sequentially. 5. Install the VRLA Battery protections. After checking the electric voltage and the cell number arrangement, place the protections on top of the batteries. VRLA Batteries 4-1

14 Installation VRLA Batteries

15 Characteristics of VRLA Batteries 5 CHARACTERISTICS OF VRLA BATTERIES 1. Service life time. The robust lead-calcium grids ensure moderate corrosion, providing a service life time of 15 years on stand-by duty and under optimal conditions of floating charge and operating temperature. 2. Excellent characteristics of high-efficiency discharge. VRLA batteries are equipped with low electrical resistivity plates and conductive parts, which reduce the internal ohmic resistance, ensuring high discharge efficiency. 3. Construction with Triplex sealing. The valve-regulated sealed construction with triplex reinforcement in the sealing of the terminals and poles inhibits the electrolyte leakage and ensures the tightness of the batteries under normal operating conditions, preventing the ingress of external air. 4. Low self-discharge. Due to the use of lead-calcium alloy grids, VRLA batteries provide low self-discharge and high reliability performance. At ambient temperature, the monthly self-discharge of the batteries is approximately 3% of its rated capacity High Safety. VRLA batteries are provided with explosion-proof safety valves to inhibit gas production. They are also manufactured to inhibit internal flame in the presence of sparks. 6. High efficiency in the Recharge. Exclusive formulas are used in the lead paste composition of the positive plates to ensure that the batteries can be easily recharged. 7. Absence of Electrolyte Stratification. Special additives are used in the electrolyte to provide a gelatinous consistency without drainage, leakage or stratification, allowing homogeneous reactions on the surface of the plates. VRLA Batteries 5-1

16 Characteristics of VRLA Batteries VRLA Batteries

17 Working Principle 6 WORKING PRINCIPLE 6.1 ELECTROCHEMICAL A lead-acid battery is an electric energy storage device that converts electric energy into chemical energy. When required, the stored chemical energy can be converted again into electric energy to feed external systems. In the discharge state, part of the PbO2 of the positive plates becomes PbSO4 and part of the lead of the negative plates also becomes PbSO4. In this electrochemical reaction, both positive and negative electrodes generate PbSO4. In the charge state the lead sulfate (PbSO4) on the positive and negative plates become PbO2 and Pb respectively. At the discharge, the concentration and density of the electrolyte H2SO4 decreases gradually, while during the charge it increases. The charge and discharge processes are carried out by electrochemical reactions. Charge Positive: PbSO 4 + 2HO 2 PbO 2 + H 2SO 4 + 2H + + 2e + Discharge Secondary reaction: HO 2 Charge 1/2O 2 + 2H - + 2e Charge Negative: PbSO 4 + 2H + 2e + Pb + H 2SO 4 Discharge 6 Charge Secondary reaction: 2H + 2e H OXYGEN RECOMBINATION Figure 6.1: Electrochemical Reaction Positive plates generate oxygen in the final stage of the charge process. With the condition of sufficient additives in the negative, the oxygen propagates to the negative plates through the separators and reacts with the spongy lead, forming lead oxide and then lead sulfate and water. Negative plates must be maintained slightly depolarized or in a state slightly lower than the full charge state, so that the battery does not reach the potential for oxygen gasification. Therefore, the gasification and loss of water will be inhibited, making the battery sealed and maintenance free. Positive PbSO 4 Negative Charge PbSO 4 PbO 2 Charge Overcharge Pb O 2 O 2 H 2O H 2SO 4 + PbO Figure 6.2: Oxygen Recombination VRLA Batteries 6-1

18 Working Principle VRLA Batteries

19 Battery Charge, Discharge & Service Life 7 BATTERY CHARGE, DISCHARGE & SERVICE LIFE 7.1 CHARGE CHARACTERISTICS The charge condition is one of the most important factors in the use of VRLA Battery. The battery performance and service life are directly related to the charge methods and charge parameters used. It is recommended that the battery be charged at a temperature between 5 ºC and 30 ºC. At any temperature below 5 C or above 35 C, there will be an incomplete charge or overheating, and consequently the service life will decrease. 7.2 CHARGE CURVE ON FLOAT DUTY Charge voltage Charge volume Charge volume (%) Charge current (A) Charge voltage (V) Discharge 2 Charge with constant voltage and limited current: - Charge voltage: 2.30 V / Cell - Charge current: 0,2 C 10A 3 Temperature: 25 ºC Figure 7.1: Characteristic charge curve on float duty 7.3 RELATION BETWEEN FLOAT VOLTAGE AND AMBIENT TEMPERATURE In the normal temperature range of 5 C to 30 C, the float voltage per element is from 2.25 V to 2.29 V. For battery charge on float duty, normally, a constant voltage is adopted, but with limited current. The initial current should be limited to 0.1 C10 A and not exceeding 0.2 C10 A. 1. At 25 C the float voltage should be 2.27 V per element. 2. The float voltage should be adjusted when the ambient temperature changes. The compensation coefficient is - 3 mv / C, i.e., float = [ (t-25)] x n. VRLA Batteries 7-1

20 Battery Charge, Discharge & Service Life 7.4 EQUALIZING CHARGE An equalizing charge is required when the operation, for a long time on float duty, causes a voltage unbalance in some elements of the battery bank. The equalizing charge can prevent stratification and reduce plate sulfation, providing the return of all cells to similar voltage levels. Uneven distribution of voltages of the elements is the main cause of failure of the VRLA Battery. Requirements for VRLA Batteries equalizing charge: Equalizing charge every three months or every 20 discharge cycles. Equalizing charge method: with equalizing charge voltage from 2.42 to C, maximum current of 0.3 C10 A and charge time from 12 to 24 hours. When the charge current is stable for approximately 2 to 3 hours, stop the equalizing and return to the float duty. Before the equalizing charge, leave the battery 100% discharged. 7.5 CHARGE CURVE FOR CYCLIC USE Batteries for cyclic service should be charged at a constant voltage, but with a limited current. From 20 C to 25 C, the battery charge voltage is 2.40 V per element. The initial current should not be higher than 0.2 C10 A, and the battery will be fully charged in approximately 24 hours. 7 In the final stage of the charge, if the current value remains stable for 3 hours, it indicates that the battery is fully charged. Charge curves are shown in Figure 7.2 on page 7-2: Charge voltage Charge volume Charge volume (%) Charge current (A) Charge voltage (V) Discharge 100 % (0.2 C 10 A X 10h) 50 % (0.2 C 10 A X 5h) 2 Charge with constant voltage and limited current: - Charge voltage: 2.40 V / Cell - Charge current: 0.2 C 10A 3 Temperature: 25 ºC / 77 ºF Charge time (Hr) Figure 7.2: CCharacteristic charge curve for cyclic use 7-2 VRLA Batteries

21 Battery Charge, Discharge & Service Life 7.6 SUPPLEMENTARY CHARGE Due to the self-discharge in batteries stored for a long time, the remaining capacity will be shortened gradually. The relation between the remaining capacity, temperature and storage time is shown on Figure 7.3 on page 7-3. For Supplementary Charge, the charge method with constant voltage should be adopted, but with limited current. The charge current should be from 0.05 C10 to 0.10 C10, the charge voltage ± 0.05 V / element and the duration of the charge from 24 to 36 hours. After long storage time, the batteries must be recharged before use Supplementary charge is not required. Used on floating charge. 80 Excess of capacity (%) ºC 30 ºC 20 ºC Supplementary charge is required Supplementary charge performance will be affected It is prohibited reaching this state Storage Time (Month) Figure 7.3: Remaining capacity, temperature and storage time Table 7.1: Storage time, charge voltage, current and time Charge Voltage (V / Cell) Maximum Charge Current C C C Maximum Charge Time VRLA Batteries 7-3

22 Battery Charge, Discharge & Service Life 7.7 DISCHARGE CHARACTERISTIC If the discharge speed is different, the final discharge voltage will also be different. The higher the discharge currents, the lower the final discharge voltages; inversely, lower discharge currents will produce higher final discharge voltages. Typically, the final discharge voltage of the elements is in the range between 1.8 V and 1.6 V. The capacity of the batteries in AH is lower with high discharge currents. Characteristic discharge curves are shown on Figure 7.4 on page Voltage (V) C 10A 0.55 C 10A 0.25 C 10A A A Min Hr Note: C10 = Capacity rate 10h Figure 7.4: Characteristic discharge curve Discharge Capacity X Temperature: The discharge capacity of the batteries depends on temperature. The lower the temperature, the lower the capacity of the batteries. The battery discharge capacity increases with the temperature. However, very high temperatures will dramatically reduce the battery service life. The best operating temperature for the batteries is between 20 C and 25 C. The following equation provides the battery capacity at a Ct temperature with capacity at 25 C: C t C K(t - 25) Where: C25 = Discharge capacity at 25 C (AH). Ct = Discharge capacity at t C (AH). t = The environmental temperature at the time of discharge ( C) K = Coefficient of temperature compensation. Discharge in 10 h: K = / ºC Discharge in 5 h: K = / ºC. Discharge in 3 h: K = / ºC Discharge in 1 h: K = / ºC. 7-4 VRLA Batteries

23 Battery Charge, Discharge & Service Life Temperature X Capacity Curves according to Figure 7.5 on page 7-5: Effective capacity (%) Temperature ºC Figure 7.5: Temperature x capacity curve 7.8 LIFE CHARACTERISTIC ON FLOAT DUTY In the recommended situation of charge on float duty at 25 C, the battery is designed for a service life of around 15 years. This battery service life time is related to ambient temperature, discharge depth, discharge speed and float voltage. Discharge depth, discharge frequency, inadequate float voltage are factors that will directly affect the operational life of the batteries. The characteristic curves of the life time on float duty are shown on Figure 7.6 on page 7-5: Service life (year) Float voltage charge: 2.26 V / Cell ºC Temperature ºC Figure 7.6: Life characteristic curve on float duty VRLA Batteries 7-5

24 Battery Charge, Discharge & Service Life Life time on Float Duty X Temperature: According to the Arrhenius equation, the battery life time varies with the temperature, and it's reduced by 50% for each 10 degree increase in ambient temperature. 1n K1 Ea 1 1 K2 R T2 T1 Where: K1: equal. constant at temperature T1. K2: 1 (equal. constant at temperature T2). Ea: activation energy. R: constant of air, J mol K-1. T1: absolute ambient temperature during discharge (Kelvin). T2: reference temperature 293 K. Table 7.2: Service life time on Float Duty x Temperature Float Voltage Battery Service Life at Different Temperatures (Year) Charge (V) 20 ºC 25 ºC 30 ºC 40 ºC 50 ºC VRLA Batteries

25 Records 8 RECORDS Operation records are very important for the protection and maintenance of VRLA batteries. The corresponding information is useful for confirming battery service life and for adjusting their longevity. Batteries can operate at temperatures lower than 25 C; however, the charge time will be relatively long. After battery installation and one week of operation in float duty, you are requested to record the following information: 1. Total voltage of the batteries. 2. Charge voltage. 3. Float voltage of each monobloc. 4. Internal resistance of each monobloc. For each monobloc, position the probes of the internal resistance meter on the two most distant terminals diagonally. 5. Ambient temperature. 6. Check that all connections have been tightened to the correct torque. Use a multimeter to test the internal resistance of each interconnection cable. Perform the tests according to the position of the probes indicated in the instruction manual. If the figures are 20% above the figures obtained during installation, check the torque of the connections again. If the data remains high, clean the terminals and interfaces between terminals and interconnection cables. 8 VRLA Batteries 8-1

26 Records VRLA Batteries

27 Maintenance 9 MAINTENANCE Wear a protective mask or safety goggles when approaching batteries and be sure they are far away from locations with smokers or any kind of fire. The battery service life can be extended by means of proper maintenance. Every maintenance procedure requires experienced professionals to perform them. 1. Check. Try to perform all checks of charge condition on float duty. The measurements must be made according to the supplier s specifications and the records must be made for occasional comparisons. 1.1 Monthly check: Record all float voltages of the monoblocs Record the voltage and current supplied by the rectifier/charger Record the temperature and the situation of the ventilation and monitoring devices Record the visual inspection of the monobloc unit: Appearance of the batteries: terminals, connectors, any corrosion in the batteries. Distance between monoblocs. Any cracks or leaks in the batteries. Any monobloc deformation. 1.2 Quarterly Check: In addition to the monthly checks indicated above, record: Internal resistance of each monobloc. Temperature of the negative terminal of each monobloc. Check the resistance of connections by sampling (at least 10% or 6 connections). If the resistance is greater than the initial resistance, it is necessary to check all the connections and find out why. (Check different connections at each inspection). 1.3 Annual check and initial check: In addition to the checks indicated in items 1.1 and 1.2, check the following points and keep the records to compare with the previous records: Check all the resistances of the connections. Check the input voltage and AC current of the rectifier Special checks: Batteries should be inspected for damages in special situations (e.g., excessive discharges, excessive loads caused by excessive voltage supplied by the rectifier, etc.). The inspection must include all annual checks and the corresponding records must be provided. 2. Residual ripple voltage of the rectifier It is recommended that the residual ripple voltage of the rectifier be at most 0.5% of the charge voltage and that the period of ripple be shorter than 8 milliseconds. 3. Battery cleaning. Use normal water or carbonated water to clean the monoblocs and covers. 4. Capacity test. If the batteries are working properly there is no need to carry out a capacity test. This test must only be done when you are not sure about the battery capacity. The final discharge voltage should not be less than the value specified for the discharge duty used. Before testing the capacity, make sure that the batteries are fully charged for more than 48 hours on float duty. Alternatively, provide an equalizing charge for 24 hours and then leave the batteries resting from 8 to 24 hours. VRLA Batteries 9-1

28 Maintenance VRLA Batteries

29 Troubleshooting 10 TROUBLESHOOTING Tabela 10.1: Troubleshooting Nº. Common failures Solution 1 Leakage Contact the supplier for replacements 2 Cracks Contact the supplier for replacements 3 Low float voltage If it continues after 24 to 48 hours of equalizing charge, contact the supplier 4 Reduced battery capacity If it continues after 24 to 48 hours of equalizing charge, contact the supplier 5 High pole temperature Inspect connection points, ventilation, charger and charge current 6 Abnormal appearance Contact the supplier for replacements 7 Ground Fault Check leaks or ground fault detector 8 Abnormal resistance Check connections and charge method 10 VRLA Batteries 10-1

30 Troubleshooting VRLA Batteries

31 Sealed VRLA Battery Construction 11 SEALED VRLA BATTERY CONSTRUCTION Positive pole Intercell connector Valve Negative pole Sealing washer Ring Cover Negative plate Separator Positive plate ABS container case 11 VRLA Batteries 11-1