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Guidelines for handling, maintaining, and charging batteries safely and efficiently. Topics include safety precautions, equipment requirements, and testing instruments. It also covers the importance of regular inspections and record keeping for effective battery maintenance.
Typology: Exercises
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Crown Battery Manufacturing Company 1445 Majestic Drive Fremont, OH 43420 (419)334‐ (419)334‐7416 fax www.crownbattery.com Dec 09
A motive power battery is a portable energy source for supplying DC (direct current) to electric vehicles. Crown Battery manufactures lead‐acid motive power batteries. A motive power battery consists of cells connected in a series and assembled in a tray, typically made out of steel. The battery can be assembled in many shapes and sizes, depending on the voltage and ampere‐ hour (AH) capacities. Cells are the main component in a lead‐acid battery. Each cell consists of positive and negative plates alternating; there is always one more negative plate than positive plate. The positive plate consisted of the positive grid and active material. The positive grid is cast from premium antimonial alloy and designed to withstand the rigors of deep cycling and maximum current capabilities. The positive grid uses offset internal wires are designed for less internal resistance and maximum active material retention. The active material is manufactured with premium lead oxide and mixed with additives to exact specifications using the latest state‐of‐the‐art equipment, applied uniformly and cured under atmospherically controlled conditions to assure optimum chemical conversation. The negative plate is manufactured to specifications that uniformly balance the negative to positive active material for maximum performance and chemical efficiency. Motive power batteries generally have model numbers that look like the following: 12 ‐ 85 ‐13. In this example the 12 shows how many cells are in the battery, each cell has a nominal voltage of two volts. The 85 shows the AH capacity of each plate and the 13 shows how many plates are in each cell, to calculate the AH capacity take the number of positive plates (remember there is one more negative than positive) and multiply it by the AH capacity of the plate. In this example that would mean this battery is a 24 volt battery with an AH capacity of 510. The number of cells will always show you the voltage of the battery and the cell type will always show the AH capacity of the battery. How a Battery Works A battery is a storage device which stores energy in a chemical form and releases the energy on demand in an electrical form. The battery releases power by the reaction of the electrolyte (acid and water) with the active material in the plates. In a fully charged battery, the positive active material is lead dioxide (PbO₂); the negative active material is sponge lead (Pb); and the electrolyte is a solution of sulfuric acid (H₂SO₄) and water. The specific gravity of the electrolyte is between 1.275 and 1.290. The open circuit voltage of each cell is 2.12 to 2.18 volts. The Discharging of a Battery When a battery is connected to an electrical load, the stored energy is release as DC electrical energy. During the process of conversion, the internal components of the cells undergo a change chemically.
The sulfuric acid (H₂SO₄) combines with the lead peroxide (PbO₂) of the positive plates and the sponge lead (Pb) of the negative plates and transforms them to lead sulfate (PbSO₄). The reaction may be shown as follows: PbO₂ 1 Pb 1 2H₂SO₄ 2PbSO₄ 1 2H₂O Lead 1 Sponge 1 Sulfuric Lead 1 Water peroxide lead acid sulfate The Charging of a Battery The chemical energy in a battery is restored by charging the battery, reversing the discharge reaction. During the charge and especially towards the end of it, hydrogen and oxygen gas are produced by the electrolytic breakdown of water on the plates surface. The reaction may be shown as follows: 2H₂O 2H₂ 1 0 ₂ Water Hydrogen 1 Oxygen Gas gas How a Battery is Rated The vehicle specifications, application and type of operation help determine the battery voltage and AH capacity that is selected. A battery is rated by its capacity to deliver or discharge energy over a set period of time and that capacity is expressed in ampere‐hours (AHs). The North American standard is a six hour rate. For example, a battery rated at 510 AH at a six‐hour rate can deliver 85 amperes continuously for six hours before it becomes fully discharged. Many factors, such as plate size, number of plates per cell, specific gravity of the electrolyte and the rate of discharge help determine the AH capacity. Most motive power/traction batteries are rated at a six‐hour rate, at 77°F and at the manufacturer’s specified fully charged specific gravity (1.275‐1.290); actual AH capacity availability will vary with any change. Effects of Rate of Discharge on AH Capacity As the discharge rate is increased, the active material available to the electrolyte is decreases, limiting the available AH capacity. In opposition if the discharge process is extended beyond the six‐hour standard, the AH capacity available will be increased. Effects of Electrolyte Temperature on AH Capacity As the electrolyte temperature varies from 77°F, the capacity available also varies. Lower temperatures increase the viscosity of the electrolyte making its circulation in the pores of the plates more difficult, decreasing the AH capacity. Higher temperatures, the opposite is true, increasing the capacity. At temperatures above 120°F the charging current of conventional charging equipment may rise out of control, damaging the battery permanently (“thermal runaway”).
A lead‐acid motive power battery can be an extremely useful and safe source of electrical power. On the other hand, if improperly used it can be an extremely dangerous piece of equipment. The difference between the two conditions is determined by the care and safety procedures exercised in handling batteries. Before considering the safety procedures, first consider the hazards inherent to a lead‐acid battery. The Hazards A lead‐acid battery, by its construction exposes working personnel to four potentially dangerous elements: sulfuric acid, explosive gasses, electricity and heavy weight. A sulfuric acid solution is used as the electrolyte in lead‐acid storage batteries and has a concentration of approximately 40% by weight of sulfuric acid in water. Even in this diluted state, sulfuric acid is a strong oxidizing agent and can burn the skin and eyes; and “eat” holes in clothes made of many common materials such as cotton and rayon. An explosive mixture of oxygen and hydrogen is produced in a lead‐acid storage battery during the charging process. The two gasses can combine explosively if a spark or flame ignites them. Because hydrogen is so light it normally floats away and disperses into the air before it can be collected into an explosive mixture. If it accumulates into gas pockets, however, it will explode when ignited. The battery on discharge produces electricity and while most people cannot “feel” voltages through their bodies below 35 to 40 volts, all motive power batteries should be regarded as potentially dangerous. A lead‐ acid battery is capable of discharging extremely high rates and under conditions of direct shorting can cause much damage and serious injury. The weight of these heavy batteries can crush hands and feet if care is not taken when charging and handling them. Adequate and proper handling equipment should be provided. The average lift truck battery weighs over 2000 pounds. The Safety Procedures In 1970 Congress passed the Occupation Safety and Health Act (OSHA). The act established the minimal acceptable standards for safe and healthy working conditions. The act not only pinpoints the responsibility of the employer and employee, but also establishes the penalties for disregarding the standards. It would be well to remember that OSHA standards are minimum requirements. The safety procedures suggested in the manual have been compiled from standards developed over the years by profession and technical organizations and by battery manufacturers and users who have had the experience necessary to create the most effective safety standards. They exceed the minimum standards of OSHA for personnel safety and include procedures for safeguarding equipment as well. NOTE: The information presented is of a general nature. It should not be construed as a legal opinion.
Wearing Jewelry Personnel who work around batteries should not wear jewelry made of conductive material. Metal items can short circuit a battery and in the process become hot enough to cause a sever burn. Removing Batteries If a battery is to be removed from a truck, (1) open the electrical circuit of the truck (turn key or switch off), (2) set the brake or chock the wheels and (3) unplug the battery. The same procedure applies if the battery is to be charged in the truck. Never try to move a battery by pulling its cables. Batteries should be changed or charged only by personnel who are trained and authorized to perform these jobs. Protected Chain Hoists For handling batteries, chain hoists should be equipped with a chain container or bucket to prevent a dangling chain from shorting the battery. If a container or bucket is not available, the battery may be covered with a non‐conducting material such as plywood or plastic. An insulated battery‐ lifting beam can be used with any type of overhead hoist. The safe way to lift a battery uses an insulated lifting beam. It reduces the possibility of damaging the tray and shorting the cell connectors. Protective Eyeglasses, Headgear and Footwear The use of safety glasses and safety hats made of a non‐conducting material is suggested when batteries are being handled or serviced. Steel‐toed shoes are also recommended. Lifting Batteries Steel trayed batteries have holes or eyes for lifting. The eyes used in conjunction with an insulated battery‐ lifting beam and an overhead hoist is the recommended way to lift a battery. If a battery is lifted with two chains attached to a hoist at a single, central point forming a triangle, the procedure is unsafe and can damage the steel tray. Battery as a Counterbalance In most industrial trucks a battery is used as a counterbalance for a carried load. Before installing a new or different battery, check the manufacturer of the truck for the recommended range of battery weight. The battery service weight is usually stamped into the steel tray near one of the lifting holes. A battery with the wrong weight can change the center of gravity of the truck and cause it to upset.
known gas, is fourteen times lighter than air and rises and disperses very rapidly. Normally, insignificant quantities of gases are released by a battery during the first part of the charge, as most of the charging current is used in charging the battery. Only during the last stages of the charge does the process become inefficient, so that an increasing portion of the current is used up by the creation of heat and gases. Eye‐Wash and Emergency Shower Facilities The kinds of equipment available for eyewash and acid neutralization vary widely as to capability and cost. Regardless of the equipment selected, it should be located in the immediate work area. The three most popular types of equipment are described below. ‐ Chemical Burn Station: This is the lowest cost type of safety equipment. It consists of a plastic squeeze bottle containing a buffering solution for the relief of acid burns on skin, clothing or in the eyes. The bottle usually holds about a quart of solution. It is held in brightly‐colored, molded receptacle about 1 ½ feet square that can be mounted on the walls of the battery charging areas or battery repair shops. Its use is practical in smaller battery charging areas and at battery repair shops where acid with a specific gravity of 1.400 or higher is not handled. Before installing chemical burn station equipment check to see if it is acceptable to your company Safety and Medical Departments. ‐ Eyewash Fountain: A water fountain‐type of device with two openings that facilitates washing both eyes at once. This type of safety equipment is useful when 1.400 specific gravity acid is regularly used for gravity adjustment, etc. ‐ Deluge Shower: This is a shower‐type device with a handle or foot treadle for turning it on full force. When high specific gravity sulfuric acid (above 1.400) is handled regularly, it is recommended that a deluge shower and an eyewash station be installed. Vent Caps Stay In Keep the vent caps in the cells at all times, except when removal is necessary to service or repair the cells. This precaution reduces the probability of electrolyte splash and prevents foreign matter from entering and damaging the cells.
Acid Splash in the Eyes Acid splashing into the eyes is the most dangerous condition possible while handling higher specific gravity acid or electrolyte. If it happens, the eyes should immediately be flooded gently with running water for at least 15 minutes, followed as quickly as possible with an examination by a physician. Special care should be taken to check for persons wearing contact lenses. The lenses should be removed if acid gets into the eyes, and then thoroughly rinsed with water. WARNING: Do not place a buffering or neutralizing agent in the eyes without the expressed approval of your Safety Director. Acid Splash on Skin Acid or electrolyte spilled or splashed on the skin should be washed off under running water. If a burn develops, it should be reported to a supervisor and treated medically. Acid Splash on Clothing When acid is splashed on clothing, use a weak solution of bicarbonate of soda to neutralize the acid. When clothes are soaked or splashed over large areas, they may be removed, the acid neutralized with bicarbonate of soda and/or rinsed in running water until free of acid. The sooner the clothing is rinsed, the less chance of damage to the material. Care should be taken not to spill acid into acid‐resistant boots. Boots should be checked prior to each wearing to make sure that they are dry and that no acid or chemical has been left inside. Protective Clothing Normal working clothing can be worn in battery charging and battery repair areas for routine battery work. Acid resistant clothing is not as susceptible to acid damage as garments made of cotton, rayon or similar materials. If sulfuric acid with specific gravity higher than 1.400 is handled during gravity adjustments, etc., the following protective clothing and equipment can be used: ‐ Acid resistant gloves ‐ Acid resistant arm gauntlets ‐ Acid resistant apron ‐ Acid resistant boots ‐ Plastic face shield
Inspect Package Upon receiving a battery, inspect immediately for any damage that may have occurred while in transit. Look for broken or missing wood blocking boards that secure the battery and keep it from shifting on the pallet. Broken boards may indicate that the battery may have tipped over and that a closer inspection should be performed. Wet spots on top and sides of the battery generally indicate that the battery has been tipped over and there may be some electrolyte loss or internal damage. Any damage or electrolyte loss should only be corrected by a qualified professional battery repairperson as soon as possible. Filing a Claim If there is evidence that the battery was damaged in transit, be sure that you make note of it on the shipping papers. Keep in mind that if you sign the shipping papers receiving the damaged battery, you will be responsible for filing a damage claim with the carrier. Depending on the extent of the damage, you may wish to refuse delivery and the battery will be returned to and the claim filed by Crown Battery. Some in transit damage can cause serious internal problems that may have an effect on overall battery life and performance. Contact your Crown battery representative to have it evaluated by a professional battery person. Freshening Charge After the battery has been received and there are no visible signs of damage, the battery should be given a freshening. A freshening charge should be given to bring the battery to a fully charged condition before placing it into service. It will take approximately three hours at the finish rate to bring the battery to a full charged condition. Battery chargers with auto/start/stop using the equalizing charge mode will charge the battery and terminate the charge cycle after the required charge time. NOTE: This battery was shipped with the correct electrolyte level from the factory. The electrolyte levels may settle during shipping, causing variances in the levels. Do not add water until the battery has been given a freshening charge. If water is needed, follow the basic battery care instructions included with the battery. Installation Instructions The battery should fit within the battery compartment of the lift truck. If there is additional space, the battery must be blocked to keep it from sliding or moving within the compartment. Make sure that the battery cables and power connector will plug into the lift truck connector. Make sure any excess cable is kept within the confines of the battery or truck compartment to prevent damage to the power cables. The battery must be charged on a battery charger that matches the battery voltage and amp hour capacity for the duty cycle required. If you are not sure of the correct size requirements, contact your local Crown Battery representative.
Today’s industrial battery is designed and built to give anywhere from 1000 to 2000 operations/charge cycles, depending on the application and the operating environment. If such a battery were to complete one cycle per workday, the life expectancy would be four to eight years. Exactly how much life a battery will provide depends, to a great extent, on how well you take care of your battery. The following maintenance procedures, properly carried out at the correct time, will go a long way toward extending the life of the battery and making it more efficient. Routine battery maintenance consists of three functions:
Determining if a Battery is Properly Charged If the battery charging equipment is functioning properly and if the battery is in a healthy condition, there is little chance for an improperly charged battery. If some doubt about its operation exists the following checks are a quick way to determine a proper, fully charged battery:
Electrolyte Temperature Point Correction °F (°C) 140 (60) 21 137 (58) 20 134 (57) (^19) 131 (55) (^18) 128 (53) 17 125 (52) 16 122 (50) 15 119 (48) 14 116 (47) (^13) 113 (45) (^12) 110 (43) 11 107 (41) 10 104 (40) (^9) 101 (38) (^8) 98 (37) 7 95 (35) 6 92 (33) (^5) 89 (32) (^4) 86 (30) 3 83 (28) 2 80 (27) (^1) 77 (25) (^) No Correction 74 (23) ‐ 1 71 (22) ‐ 2 68 (20) (^) ‐ 3 65 (18) (^) ‐ 4 62 (17) ‐ 5 59 (15) ‐ 6 56 (13) (^) ‐ 7
Treatment of Sulfated Batteries Lead Acid Motive Power Batteries can become unbalanced or sulfated if they are not recharged or equalize charged on a regular basis. Likewise over‐discharging or unbalanced discharge can cause low uneven cell voltages. The treatment for restoring the battery to its full potential involves charging and discharging the battery in a very tightly controlled manor. This is a last resort remedy in order to salvage a battery that’s been allowed to get into this condition. This may or may not be successful, as sulfate is extremely hard to remove from the cell plates and if let in this condition, may not be reversible. Step 1. A. Charge the battery as normal to a fully charged condition. B. Record all individual cell voltages and specific gravities. These readings will be used later to measure how successful the treatment was. C. Starting with a cool (less than 80 °F) fully^ charged^ battery,^ charge^ the^ battery^ at^ 2.5^ amps^ per^100 amps of battery capacity. A 24 ‐85FC‐ 21 has a capacity of 850 A.H. Therefore the charge rate would be 21 amps. Charge the battery for at least 24 hours. Stop the charge, if the battery temperature goes to 120 °F or higher. Step 2. A. Let the battery cool back down to about 80 °F B. The battery can now be discharged. Using a discharge rate of 1.33 per 100 amps of the battery capacity. A 24 ‐85FC‐ 21 battery with a capacity of 850 amps will need to be discharged at 11 ‐ 12 amps for 96 hours. DO NOT allow any cell to fall below 1.50 volts while on discharge. Stop the discharge test if any cell falls below 1.50 volts. Step 3. A. Charge the battery as normal to a fully charged condition. B. Record all individual cell voltages and specific gravities. C. Compare the readings to the initial readings taken and note if there is any increase in gravity and voltage. Step 4. A. If the treatment restored the battery to normal conditions (Sp. Gr. 1.285‐1.300 and voltage 2.13 – 2.18) and all cells are fairly equal and the treatment was successful. B. If the readings are still uneven or no improvement was gained, then repeat steps #1 thru # Step 5. A. If after the second series of treatment the battery does not improve, the battery should be considered unrepairable and should be replaced.
A certain amount of water loss is normal in all batteries and it should be replaced with “pure” tap or distilled water. In some areas around the country, tap water may contain chemicals or other impurities harmful to batteries. If water is needed, add just enough to bring the electrolyte to the proper level. Batteries should be filled only at the end of the charging cycle. Overfilling is the most common error made when watering and it can cause tray corrosion. Since tray corrosion can cause extensive damage to batteries and vehicles, extreme caution must be taken to avoid overfilling the batteries. Tray Corrosion Motive power battery trays are mostly made of steel that is protected with an acid resistant coating. Regardless of how good the coating is, if a break in the coating exposes the steel tray to sulfuric acid spilled from the battery, the acid will corrode the tray. How quickly the tray corrodes depends on how much and how often acid is spilled on top of the battery and how often the battery is cleaned. The major cause of tray corrosion is overwatering or overfilling a battery. When overfilled, the electrolyte will spill on top of the battery. Although the water in the electrolyte will evaporate, the highly concentrated acid solution remains and gives the appearance of dampness. If the acid is not removed, the tray will eventually corrode. To prevent corrosion, batteries should be cleaned any time the accumulation of dampness or acid becomes significant. A good technique to follow while watering batteries is to use a flashlight focused on the vent hole being watered. Visually watch the electrolyte level rise and stop watering the instant the proper level is reached. Each cell is filled the same way. Cell filling equipment that automatically fills batteries to the proper level is available. In addition to causing tray corrosion, the accumulation of acid in conjunction with the corrosion can cause grounds. Two significant grounds can create an external short through the case of the battery. As a result, some or all of the cells continually discharge. As the current carrying ability of the multiple grounds increases, further complications such as jar leakage, overheating, cell failure, etc., can occur. Additionally grounds can also cause serious problems or failures in the electronic controls and electrical components of the vehicle. To test for a ground in a battery, set the voltmeter to handle the full open circuit voltage of the battery being tested. Place the positive probe on the positive terminal of the battery and the negative probe on the spot of the steel tray where bare steel is exposed. Make sure that the negative probe penetrates the paint to the steel. To detect the location of the ground, move the positive probe from intercell to intercell connector until the lowest voltage reading is found. This will be the grounded cell. To clear the ground, clean the top of the battery of acid and corrosion and dry. If the ground is still present, reseal the battery with asphaltic compound.
