For example, daily outdoor temperatures might vary by six degrees (°C) between night and day, whereas the internal temperature of a battery exposed to the ambient swings might only deviate by one or two degrees. When an SLA battery is being discharged; the lead (Pb) on the negative plate and the lead dioxide (PbO2) on the positive plate are converted to lead sulphate (PbSO4). But if you do this continuously, or even just store the battery with a partial charge, it can cause sulfating. AMBIENT TEMPERATURE.. Temperature is possibly the most common cause of life failure in lead acid battery systems, high ambient battery room temperature is a common issue that needs to be addressed within any battery installation environment. A Guide To VRLA Battery Discharge Testing. This video is about a tea man who has bought an electric vehicle, but in lead acid version. Freezing the battery, depending on the type of lead acid battery used, may also cause irreversible failure of … Essential battery systems should be regularly checked and maintained to ensure integrity, this can include electrical measurements of each battery and environment observation to ensure ambient temperature, airflow and general battery room conditions are kept suitable and within the manufacturers recommended operating parameters. Under ideal conditions the products of evaporation (oxygen and hydrogen) are recombined into water inside the battery. Every discharge takes life out of the battery. Resistance creates more heat. Contamination of electrolyte is extremely rare in VRLA batteries and is usually a factory defect. Journal of Pouez Souzces, 36 (1991) 415-438 415 Failure modes of lead/acid batteries* B. Culpin Chlonde bzdzcstnal Battenes, P O Boa 5, Clij7ozz Junction, Swzntenz, Manchester M2.' Charge – discharge times for high capacity batteries are very long and using accelerated life testing to determine battery lifetime is most likely to lead to misleading results since battery life depends on temperature, rate and depth of discharge and the test conditions used to accelerate the occurrence of failures are quite likely to introduce new and unrepresentative failure modes. An increase of 8.3°C (15°F) can reduce lead-acid battery life by 50% or more. For lead acid batteries, it is essential to recharge after use. The team at Blue Box Batteries are always available to provide this information upon request. Vented batteries (sometimes called “flooded” batteries) evaporate all the time, but they are designed to make it easy to know when the electrolyte level is dropping and to replenish with water. Initially this sulfate is soft and can be reconverted back to electrolyte when the battery is put on recharge. It's used to protect everything from switchgear to telecommunications equipment. Incorrect battery application – UPS batteries are made specifically for UPSs, just as other batteries … This paper analyses the failure of cast on strap in lead-acid battery under vibration mode. Of the two, internal temperature is more important. Without care, it could be dead inside one. Above this temperature, battery life is reduced. Short excursions, such as an occasional increase from 25 °C to 30 °C for a few hours can be tolerated, but average temperatures above optimum for weeks or months at a time will definitely shorten the life. This can lead to capacity loss due to deteriorating contact between the conductive particles within the cell as well as external problems in fitting the cell into the battery enclosure. If you’re storing your unused lead acid battery inside the car, make sure you disconnect the ground. During discharge, such as when the battery is used to start the car or power the headlights, the sulphuric acid in the electrolyte is depleted, leaving an electrolyte solution with a higher proportion of water. Conversely, cold temperature can improve the lifetime of the battery, but at the cost of reducing the energy that be pulled from it. You will hear, “For every 10 °C of average temperature above 25 °C the life of the battery is reduced by 50%.”   Such claims sometimes don’t say it, but they refer to internal temperature. When connecting batteries in series and parallel it is essential to use torque settings as advised by the manufacturer and make this common for each battery connection. Common reasons for early life failure of lead acid batteries. Overcharging can dramatically shorten the life of a battery and, in worst case, can lead to thermal runaway. The swelling-up of the battery may also cause great damage to the internal components and parts. Exposure to excessive levels of lead can cause Sulfation is caused when a battery's State-of-Charge drops below 100% for long periods or under charging. Of course ambient temperature can cause a change in internal temperature, but the rate of change in internal temperature lags well behind the external temperature. As always, if there is any doubt of correct procedure please consult the manufacturers manual applicable to the battery type and range you are installing. In this unit we go into more depth about how, when and why a lead-acid battery might be made to fail prematurely. All manufacturers will issue manuals providing instruction for installation of batteries, it is important to ensure to carry out works using the information provided. PO15 7AZ. Not allowing for the battery to return to its charged state will cause the battery to form sulfate on on its lead plates and seriously compromise the batteries performance. As time goes on, the performance declines further and the battery gets smaller in terms of holding capacity. The study is conducted on 12 V/75 Ah AGM valve regulated lead-acid battery with up and over connector arrangement which is normally used in automobile application. Premature dehydration is a failure condition which can lead to other failure modes. Undercharging occurs when the battery is not allowed to return to a full charge after it has been used.Easy enough, right? It is also why VRLA is frequently referred to as “low maintenance” (i.e., frequent electrolyte replenishment is not required). How Much Heat Does A Lead Acid Battery Generate? (Spoiler alert: This reaction cannot be avoided because the electrodes in a lead acid environment are always reactive. In this unit we go into more depth about how, when and why a lead-acid battery might be made to fail prematurely. With care, a lead acid battery can last for seven years or more. For small ampere-hour, high-rate VRLA batteries (i.e., UPS batteries), service life might be only around three years. All lead acid batteries have a finite number of discharge and recharge cycles, how many cycles a battery system will provide is dependent on the type of battery chemistry being used (for example AGM or Gel) and the depth of discharge of each cycle. The biggest problem with high temperature is dehydration (evaporation of electrolyte) discussed below. A deep discharge Lead shedding is a natural phenomenon that can be reduced but not eliminated. As you discharge a lead-acid battery, lead topping up cells with distilled water and cleaning. The integrity of any standby power system is reliant on the battery installed, if the battery is degraded then the system will not provide the necessary or expected back up power when required. High temperature can have a short-term benefit of pulling more energy out of the battery, but at the cost of reducing the life of the battery. Despite a century of experience, collective knowledge, and wide-spread preference for lead-acid batteries, they are not without some short-comings. At the same time the sulphuric acid (H2SO4) is converted to water (H2O). Most of the world's lead–acid batteries are automobile starting, lighting, and ignition (SLI) batteries, with an estimated 320 million units shipped in 1999. It can be the result of human error (i.e., setting the wrong parameters on the charger), or charger failure. A battery that reaches the end of life through this failure mode … Others can tolerate thousands of short discharges, but fewer deep discharges. We hope you have found the points of consideration raised within this blog article to be useful. Catalysts can sometimes be field-installed as an after-sale accessory and can sometimes rejuvenate an aging battery. Temperature is possibly the most common cause of life failure in lead acid battery systems, high ambient battery room temperature is a common issue that needs to be addressed within any battery installation environment. In 1992 about 3 million tons of lead were used in the manufacture of batteries. Hard lead sulfate crystals fills the pours and coats the plates. Comparing VRLA Battery Specification Standards. See our extensive document library offering product data sheets and brochures. Overheating It has many causes and it can lead to irreversible changes to the chemicals used in the cells, gassing, expansion of the materials, swelling and distortion of the cell casing. Continued undercharging will inevitably lead to failure of the battery altogether. Temperature-compensated charging is the most common. Once released the gasses are lost forever and the battery will dry out. Sedimentation and spalling can occur in an aging battery. In UPS applications, charging voltage varies depending upon the stage of charging. Failure to do this can lead to batteries significantly under performing and charging becoming inefficient. This chemistry is my focus in this post. Some battery manufacturers include catalysts in the design of their cells, thereby increasing the initial cost of the battery. Some battery types can only tolerate a few cycles in the life of the battery. Lead acid batteries have a moderate life span and the charge retention is best among rechargeable batteries. In a normal charge, the chemical reaction is reversed. Planté Battery Values – On float cell voltages, ohmic measurements & specific gravities. Todays manufacturing processes are highly automated which has lead to genuine manufacturer faults becoming quite uncommon, however the types of deficiencies that can occur include faulty post seal design, paste irregularities (paste lumps causing shorts between plates), case weaknesses and internal connection issues. The effect of temperature is generally expressed in terms of half-life. This is because when a battery is discharge the electricity produced is created by the electrolyte converting to sulfate crystals on the plates of the battery. How to Avoid Swelling Up of the Battery? If not maintained, flooded lead acid battery slowly losses water. Battery Replacement Criteria Ø Failure to hold a charge, as shown by cell voltage and specific-gravity measurements, is a good indicator for further investigation into the need for battery replacement Ø Conducting a Load test will show what capacity if any is left in the battery The reason can normally be traced back to: Malfunctioning alternator, regulator, or starter motor Slipping (incorrectly adjusted alternator charging belt) Electrical fault e.g. Common reasons for early life failure of lead acid batteries. Whiteley, As temperature increases, charging voltage decreases proportionately, until charging ceases altogether. If plates get dried, then there is no reversal for failure of battery. As the name implies, undercharging means applying less voltage over time than is necessary to maintain a cell at a desired state of charge. Hampshire. Other chemistries will behave similarly, but the constants involved will differ. This can be a serious issue for environments that are reliant on back up power from uninterruptible power supplies, and even critical when emergency lighting is considered. 2. SLA batteries are maintenance free but flooded lead acid batteries require regular maintenance i.e. For an in depth look at how temperature affects lead acid battery life please refer to our previous blog post How Does Temperature Affect Lead Acid Batteries?. 4500 Parkway, Solent Business Park, The chief aging mechanism is accelerated corrosion of the positive plates, grid structure, and strap, which increases exponentially as a function of temperature. Lead-acid car batteries are made up of plates of lead and lead dioxide submerged in an electrolyte solution of about 35 per cent sulphuric acid and 65 per cent water. Background. So what causes early life failure in VRLA battery systems and how can maximum service life be achieved? The battery may also fail as an open circuit (that is, there may be a gradual increase in the internal series resistance), and any batteries connected in series with this battery will also be affected. If you’re testing an automobile battery, take the vehicle for a 20+ minute drive, then shut off the engine for 4 hours.For other types of lead acid batteries, charge them all the way before letting them rest for 4 hours. The deeper the discharge of each cycle then the less cycles the battery will be able to provide. Most conditions are preventable with proper monitoring and maintenance. The outcome is that the battery experiences extreme pressure inside that swells up and deforms it. Discounted prices are available for bulk orders, please contact us to discuss your requirement. In light of the ongoing situation relating to COVID-19, all of our employees will be working from home, however we are still available on 02381 789197 and normal working hours apply. Some UPS and external battery chargers are capable of temperature-compensated charging, but battery temperature sensors are frequently provided only as an option. Cycling service refers to operation in which it is anticipated that the battery cycles frequently with minimum time on float charge, which is common in stored energy systems such as wind, solar, or installations supplied by an unreliable grid. Although the manufacturer specifies the runtime of portable equipment based on a battery performing at 100 percent, most packs in the field operate at less capacity. © PowerShield Limited 2019 | All Rights Reserved | Privacy Policy. Both the developed lead acid absorbent glass ma (AGM) battery … Unused lead acid batteries need to be stored fully charged in a dry and cool place. Approximately 85% of premature deep cycle and starting batteries failures that are not recharged on a regular basis is due to an accumulation of sulfation. Most valve regulated lead acid battery manufacturers will specify a temperature range of 21 to 25 degrees celsius as necessary to achieve optimum service life. Perhaps the biggest single cause of premature failure is leaving a battery in a partial, or complete, state of discharge for more than a few days. Sustained over charging can lead to destructive thermal runaway which can cause the battery to rupture and melt. Caution is suggested, however, as field modifications introduce the possibility of human error and/or contamination, and should only be performed by factory-trained technicians. Energy storage in a battery can conceptually be divided into three imaginary segments of the available energy,the empty zonethat can be refilled, and the unusable part(rock content). Conversely, internal temperature can be driven up by factors unrelated to ambient temperature (to be discussed later). Figure 1 illustrates these three sections. Avoid cranking your engine for longer than 10 – 15 seconds. While it takes a bit of time, this process of charging and then resting the battery … This cycle can continue until heat is so high that the cell dries out and catches fire or melts. The challenge is to keep those failures from happening prematurely. Lead is a highly toxic metal that produces a range of adverse health effects particularly in young children. For any battery system to operate properly it must first be correctly installed with careful handling and manufacturers installation instructions observed and followed. Most conditions are preventable with proper monitoring and maintenance. Properly maintained VLA batteries might get in excess of fifteen years of service. Larger VRLA batteries might get around eight-to-ten years. IEEE 1881defines thermal runaway as:  “A condition that is caused by a battery charging current or other process, which produces more internal heat than the battery can dissipate.” For example, excess charging current (caused by internal short or improper charging) creates heat. This list is not all inclusive, but some of the main considerations are: When we speak of temperature, we must understand that there are two primary temperature conditions:  ambient temperature (i.e., room or air temperature) and internal temperature (i.e., electrolyte temperature). The following offers some of the main causes of life failure that should be understood. A catalyst is a device added to the vent of a VRLA cell to improve the hydrogen-oxygen recombination process inside the cell, thereby reducing dry out and extending the life of the battery. Charge the battery fully, then let it rest for 4 hours. The concern is with extended release of gas. The battery selection process (prior to purchase) should consider the reliability of utility power and therefore the probability of frequent cycling. Dehydration is the natural consequence of old age. However, the VRLA valve can release gas under high temperature or high internal pressure conditions. Thermal runaway will be discussed in greater depth in a future unit. And it will continue to do so for the foreseeable future. Lead-acid batterieshaving lead calcium grid structures are particularly susceptible to aging due to repeated cycling. This results in a loss of sulfuric acid from the electrolyte in the battery, which can never … Over-watering a lead-acid battery, which is usually caused by watering the battery in a discharged state, causes the electrolyte to overflow out of the vent caps. VRLA batteries, sometimes called “starved electrolyte” or “immobilized electrolyte (or erroneously termed “sealed lead-acid” [SLA] or “maintenance free”), have far less electrolyte than a vented battery, and the cell container is opaque so it is impossible to see what is happening internally. Several means are available to detect and preclude thermal runaway early in the cycle. A pack should b… Assembly of test battery. 7- … For example, initial charging following a discharge is at a higher voltage (referred to as “bulk charge”) than at standby (referred to as “float charge”). Figure 1 shows a common lead-acid battery. Batteries that are exposed to over charging can experience excessive gassing, water consumption and grid corrosion causing the battery to fail in a very short amount of time. Dehydration. This list is not all inclusive, but some of the main considerations are: Temperature tolerance. Over a long time (e.g., weeks or months), undercharging will result in the loss of battery capacity and/or shorter battery life due to self-discharge. The acid is extremely corrosive and is also a good carrier for soluble lead and lead particulate. In this work, the failure mode of the lead acid battery under 17.5% depth of discharge was predicted. 2LR (UK) D. A. J. Rand CSIRO Dzt,zszon of Mzneral Products, P O Box 124, Port Melbourne, Vzc 3207 (Austraba) (Received March 27, 1991) Abstract The delivery and storage of electrical energy m lead/acid batteries … Elevated temperatures reduce battery life. Most valve regulated lead acid battery manufacturers will specify a temperature range of 21 to 25 degrees celsius as necessary to achieve optimum service life. A “cycle” means that the battery is discharged and then charged back to its full capacity. The lead-acid battery is the primary source of backup power for today's mission critical systems. But despite their important role, batteries fail. It requires temperature sensors to be strategically placed on cells throughout the battery. How Does Temperature Affect Lead Acid Batteries? To avoid incorrect charging it is always best to make sure you are using the correct type of charger, rated correctly to suit your battery type. Temperature is possibly the most common cause of life failure in lead acid battery systems, high... OVER CHARGING.. An earlier unit mentioned a couple of issues. Monitoring systems should be able to detect and alarm overcharging conditions. Battery manufacturers specify the optimum operating temperature for the battery, usually 25 °C, and all promises about life are predicated on that. UPS operation, by contrast, assumes that the battery will be on float charge for almost all of its life. Fareham, Overcharging or short-circuiting of the battery is the only reason for swelling up of the lead acid battery. Lead-acid batteries contain sulphuric acid and large amounts of lead. That is why the nominal life expectancy of a VRLA battery is about half the life of a VLA battery. At 32 degrees Fahrenheit (0 degrees Celsius) lead acid batteries almost don’t lose charge. Battery failure rates, as defined by a loss of capacity and the corrosion of the positive plates, increase with the number of discharge cycles and the depth of discharge. Heat creates resistance. If this recharge is delated by any significant time period then the sulfate will harden and not convert back, this is known as battery sulfation. I will be assuming that the failure rate of the battery is described by the Arrhenius equation. An occasional “burp” is normal and is usually of no consequence. Blue Box Batteries Ltd. This is the fourth in a series of units that will educate the reader on the part played by a battery in an uninterruptible power system (UPS). Thermal runaway is a catastrophic failure. Overcharging is any excessive charge that results in damage to a cell or battery. Contamination is more of a concern for VLA batteries when periodic replenishment of water to the electrolyte occurs (for example, using tap water instead of distilled water). “Battery life” is a nebulous term that is often exaggerated by marketing people who use terms such as “design life or “useful life.”   Service life is the only one that matters to a user and is defined by IEEE 1881 as, “the period of useful operation under specified conditions, usually expressed as the time period or number of cycles that elapse before the ampere-hour capacity falls to a specified percentage of the rated capacity.”   So if you anticipate that your battery will experience a lot of discharges and/or will be exposed to a lot of heat and/or will be poorly maintained, the service life of your battery will be significantly shorter than the same battery under optimum conditions.