Although VRLA batteries have dominated the Industrial Battery Market since they became commercially available in the mid 1980’s the lead-acid Planté battery still has an important part to play. It has been argued that the Planté battery is the most reliable emergency power supply available. Whether this is true or not is a matter of opinion. What is true, is that there are many Planté batteries still in service that were installed over 20 years ago and some are still in reliable operation over 30 years of age. Planté batteries are still manufactured by a small number of companies and remain popular in many industries where reliability is paramount.
Because the voltage of VRLA batteries is not as stable as Planté batteries and specific gravity measurements cannot be taken, instruments that measure the ohmic resistance of batteries has gained popularity in trying to determine their condition. Ohmic measuring instruments were first introduced for use on VRLA monoblocs of 6V and 12V up to about 400Ah and not for 2V 1000Ah Planté batteries where the accuracy is debatable. The accuracy of these instruments remains the subject of much discussion even for VRLA batteries. In some respects it is unfortunate that these ohmic measuring instruments are sometimes used to determine the state of health of Planté batteries because they were not designed to work on large capacity cells. There is little doubt that some readers of this article will disagree arguing that they have an instrument that will work on any battery including vented NiCd. This argument is not the subject of this article but is intended to give a more practical understanding of measurements that can be readily taken with a high degree of reliability on Planté cells.
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Occasionally we are asked very interesting questions. Recently we were asked how much heat an industrial standby battery generates. It is fair to say, it depends on whom you ask. Different battery manufacturers have different answers to this question and the different method of calculation gives significantly different answers.
The heat emitted or generated is sometimes referred to as “heat loss”.
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This article discusses test discharging of VRLA batteries. The principal is almost identical to the procedure that should be followed when testing vented Lead-Acid batteries but some important changes are necessary to obtain the correct results.
The article covers the broad spectrum of testing and some manufactures and users may prefer to test batteries in a slightly different way. Never the less, this article follows the UK accepted practice as given in BS 6290 Part 4 1997. It also discusses the International Standard IEC 60896 -
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The document is intended to give the reader a better understanding of the difference between the major classifications of BS 6290 Part 4 (Lead-acid stationary cells and batteries – Part 4 Specification for classifying valve regulated types) and IEC 60896 – 22 (Stationary lead-acid batteries – Part 22: Valve regulated types – Requirements).
This document is not intended to comment on the specification classifications or make any judgement to the validity of tests or claims by manufacturers. The article is intended to draw attention to the different classifications and how the British Standard varies with the latest International Standard.
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The open circuit voltage of lead acid cells can give us useful information providing it is used correctly.
This article shows the relationship between the open circuit voltage and state of charge of lead-acid cells and how to interpret the values. The values are always considered as that of a single cell and monobloc voltages must be averaged according to the number of cells. This method was developed primarily for VRLA cells where the specific gravity cannot be measured. Measurement of the specific gravity will give a good indication of the state of charge. For measurement of either specific gravity or open circuit voltage, the fully charged and fully discharged specific gravity must be known. Used correctly, the method described in this article will give reasonable results to the state of charge of cells on open circuit.
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There have been many myths about lead-acid battery cycling.
This article will give the reader a better understanding of the more important aspects of battery cycling and battery choice.
Different applications are discussed along with charger requirements and how the number of cycles varies with the depth of discharge. This article looks at applications where the recharge is not regular such as solar and wind charging. Intermittent diesel charging is also discussed.
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