Understanding the Battery

Transcription

1 Understanding the Battery Materials Needed For this lesson, you will need the following materials: Student Manual Dummy Battery Visuals Understanding a Battery training video Battery Application Guide Battery Price List Setup Needed This lesson requires the following equipment: Projection system TV/DVD/VCR Time Frame Developers Note This lesson is divided into the following segments: Instructor Led Video Exercise TOTAL 35 minutes 10 minutes 10 minutes 55 minutes This lesson provides students with an overview of battery terminology, how they work, and what causes battery failure. It is not intended to be an in-depth analysis of the battery but to provide the knowledge required to identify, remove, and replace batteries during the normal course of a day. Use the dummy battery to help students understand the different pieces and parts of a battery. Pass the different components around to the students during the Before You Begin sections. This will help students better understand realworld battery hardware. Rev 5/30/06

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3 Lesson 2 Understanding the Battery What You Will Learn After completing this lesson you will have accomplished the following actions: Become familiar with common battery terms Understand battery components Learn how a battery works Understand what affects the life of a battery Why These Skills Are Important Members look to you as battery experts. By understanding the composition of the battery you will be able to explain battery failure to the Member. This will result in increased confidence and Member satisfaction. Explain that after 90 days the battery is returned to our battery supplier. Our battery supplier will provide us a new replacement battery, not just recharge it and return it to us. Before You Begin Participants may have previous experience with these key terms. Poll the class to determine their level of experience and adjust your presentation accordingly. Our battery policy is that any battery we sell to a Member is fresh, meaning less than 90 days old. Checking inventory and rotating batteries will ensure that your stock does not get old. Battery Terms Ampere (Amp., A.): The unit of measure of electron flow rate or current through a circuit. Battery Rating: A rating that indicates the condition of the test battery. Capacity: The ability of a fully charged battery to deliver a specified quantity of electricity (amp-hr, AH) at a given rate (amp, A) over a definite period of time (Hr). Circuit: An electric circuit is the path followed by a flow of electrons. A closed circuit is a complete path. An open circuit is a broken or disconnected path. Cold Cranking Amps (CCA): The number of amperes a battery at 0 o F (-17.8 o C) can deliver for 30 seconds and maintain, at least, a voltage of 1.22 volts per cell. Cranking Amps (CA): The number of amperes a batter at 32 o F (0 o C) can deliver for 30 seconds and maintain, at least, a voltage of 1.22 volts per cell.

4 16 Understanding the Battery Current Direct (DC): An electrical current flowing in one direction on an electrical circuit. A battery delivers direct current (DC) and must be recharged with direct current in the opposite direction of the discharge. Element: In a battery, a set of positive and negative plates assembled with separators. Ground: The reference potential of a circuit. In automotive use, the result of attaching one battery cable to the body or frame, which is used as a path for completing a circuit in lieu of a direct wire from a component. Today, over 99% of cars use the negative terminal of the battery as the ground. Negative: Designating electrical potential. The negative battery terminal is the point from which electrons flow during discharge. Open Circuit Voltage (OCV): The voltage of a battery when it is not delivering or receiving power. The OCV should be 2.11 volts for a fully charged battery cell and volts for a fully charged battery. Positive: Designating or pertaining to a kind of electrical potential; opposite of negative. Reserve Capacity Rating: The time in minutes that the battery will deliver 25 amperes at 80 o F. This rating represents the time a battery will continue to operate essential accessories during night and bad weather driving if the alternator or generator fails. Resistance: The opposition to the free flow of current in a circuit. Short Circuit: An unintended current-bypass in an electric device or wiring, generally very low in resistance and thus causing a large current to flow. In a battery, a cell short circuit may be permanent enough to discharge the cell. State of Charge: The amount of electrical energy stored in a battery at a given time expressed as a percentage of the energy when fully charged.

5 Understanding the Battery 17 During this section, introduce the dummy battery. Remove the different parts and briefly explain how a battery works. Battery Components Batteries are made up of the following components: Grids Internal Plates Partitions Cell Partition Electrolyte Plastic Container Terminals Label Date Stamp Terminals Label Date Stamp Plastic Container Electrolyte Cell wall Internal Plates Intercell connector Cell

6 18 Understanding the Battery Grids Explain that the grids look similar to a chainlink fence with a metal sprayed over it. The grids within a battery skeleton compose a framework designed to hold the active material in place and conduct the electrical current produced by the active materials to the battery terminals. Internal Plates Ask: Without making the battery any bigger, how can you make it more powerful? Add more plates per cell. A battery contains both positive and negative plates that enable a lead acid storage battery to conduct electricity: Positive plates are grids covered in a led peroxide paste and are a dark red/brown in color. Negative plates are pasted with grey sponge lead.

7 Understanding the Battery 19 Separators Explain that should the positive and negative plates make contact, it would short and cause the battery to discharge. Separators are thin sheets of non-conducting porous plastic material inserted between the plates. A rib faces the positive plate to allow for more electrolyte volume and minimizes the area of contact with the positive plates. These separators prevent the positive and negative plates from making contact. Cell Cells are alternating positive and negative plates separated from each other by a plastic or vinyl separator. Cells are connected with lead that conducts electricity from one cell to the next. Electrolyte For a 12-volt battery, the container is divided into six cells. Each cell should contain 2.11 volts per cell for a total of volts. Explain that because water is the only portion of the electrolyte that evaporates, it is safe to add distilled water to a Member s battery. A diluted sulfuric acid that contains about 25% sulfuric acid and 75% water by volume and carries the electrical current within the battery between the positive and negative plates. The sulfuric acid in the electrolyte is absorbed within the positive and negative plates. This produces a chemical reaction that is released as electrical power. Plastic Container Explain that the positive terminal is slightly larger than the negative terminal to minimize the danger of installing battery cables in reverse. The container houses the plates, separators, and electrolyte. It is built to withstand extreme heat and cold as well as shock and vibration. Terminals Lead terminals are the battery s external electrical connection points and are normally located on the top or side of the battery.

8 20 Understanding the Battery insert the Understanding a Battery training video. After the video has finished, review this section with the drivers. Label Our battery label is located on the top of the battery. The label contains important information such as the Branded Battery Part Number, CCA, CA, serial number, and the group size as shown in the following graphic: Explain that the Battery Council International establishes the battery group sizes. AAA Battery Label Serial Number Battery Part Number CCA and CA Information B CAA Battery Label Ask: What does CCA stand mean? Cold Cranking Amps or the amps required by the battery to start the car in the cold. Explain that is a battery doesn t have a label, drivers can refer to the batteries on their truck or the OEM listed in the Battery Application Guide. Serial Number Battery Part Number CAA and CA Information

9 Understanding the Battery 21 Date Code Explain that other manufacturers stamp date codes in other places such as near the posts or on the sticker. All battery manufacturers date their product by stamping a date code onto the cover of the container. This code can be used to determine the actual age of the battery. As part of our branded battery, we put a shipped date code label on all of our batteries. The date code indicates the month the battery left the battery manufacturer s warehouse fully charged.: U.S. Date Code Canada Date Code How a Battery Works Ask: What does a battery do? The automotive battery is an electrical storage device that performs several tasks: Provide power to the starter and ignition system to start the engine Stabilize the vehicles electrical system to absorb sudden high voltages fluctuations Provide power to accessories such as lights, fans, and radios when load requirements exceed the supply from the charging system Powers lights, fans, radio And Starts Engine Converts to Electrical Energy Battery s Chemical Energy

10 22 Understanding the Battery Identifying Reasons for Battery Failure Ensure that students understand why batteries fail. Explain that after market additions draw heavily on a battery. The battery s life can be reduced further due to the following factors: Age Storage Temperature Cycling Age The average life of a battery is about three years, not five or six years. Back when batteries would last that long, they were rated closer to 300 CCA. Due to the increased demands on the battery such as air conditioning, power steering, computers, and the lack of airflow around battery, batteries will not last as long. This is why we offer the 3 year free replacement warranty. Storage Explain that the battery stock must be rotated. The first batteries in should be the first batteries out. Batteries have a limited shelf life. After about 13 weeks batteries will gradually discharge to less than optimum operating level. Because of this, none of our batteries are older than 90 days. To ensure that the batteries provided to the Member are fresh and maintained, you will perform the following: Ensure that no battery is more than 90 days old. Check the stored batteries with the tester every 30 days. To preserve the performance and service life of the battery, you will need to recharge the batteries in storage when the open circuit voltage drops to 12.4 volts. Conduct a Battery Test on each battery before installation. Store batteries above 20 o F (-7 o C) to prevent freezing.

11 Understanding the Battery 23 Temperature Extreme high temperatures will significantly shorten battery life by increasing corrosion of the grids and active materials as shown in the following graphic: Cycling The battery stores electricity in the form of chemical energy. Charging and discharging is done via chemical reaction in the battery caused by electrical flow and the reaction between the acid and the lead in the battery. Discharging and charging causes the pores to expand and contract. The oxygen admitted up the positive plate causes the positive plate to shed. The depth and frequency of discharge influences the amount of deterioration. Automotive batteries are not meant to be cycled. After about five times of completely discharging and recharging a battery, it will not recover fully. Discharge Cycle Explain that when a battery is subjected to a high discharge rate, (cranking the engine near 0 o F (-16 o C) for a prolonged period of time (one to two minutes) it will discharge faster. A discharged storage battery can be recharged and the active materials will be restored. If a discharged battery is left for a long time, the plates will absorb the acid, called sulfation, and will harden. When the plates have sulfated they can t move or accept a charge. Charge Cycle When fully recharged the battery is again ready to deliver power. This discharge/ charge cycle can be repeated until the plate or separator deterioration, or some other factor, causes the battery to fail.

12 24 Understanding the Battery Exercise In this exercise, you will identify the different components of the battery. Context: Before you leave on your shift, your supervisor has asked you to explain the different components of the battery to a new driver. Directions: Using the graphic below, answer the following questions about the battery components. A H G B F C D E 1. Name the following components: a. b. c. d.

13 Understanding the Battery 25 e. f. g. h. 2. Name the three major functions of the battery. 3. How does temperature affect the battery? 4. Name three reasons for battery failure. Review the correct answers with the students. Answer any questions they may ask. How Did You Do? Turn to the end of this lesson for answers. If you have any questions, ask your instructor for assistance.

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15 Understanding the Battery 27 Answers 1. a. Terminals b. Electrolyte c. Internal Plates d. Connector e. Cell f. Cell Separator g. Plastic Container h. Label 2. Provide power to operate vehicles starter motor and ignition system to enable an engine to crank over and start. Stabilize the vehicles electrical system to absorb sudden high voltages. Provide power to accessories such as lights, fans, and radios when the charging system cannot. 3. When a battery is connected to an external load, current flows and it starts to become discharged. During discharge, the active material of both plates is being converted to lead sulfate. The plates are becoming more alike and the acid is becoming weaker. This results in a voltage drop since it depends on the difference between the two plate materials and the concentration of the acid. Eventually the battery can no longer deliver electricity at a useful voltage. 4. The chemical reactions that take place during a charge are basically the reverse of those that occur during discharge. The sulfate in both plates is split into their original form, and the water is split into hydrogen and oxygen. 5. Three of the following: Age, Storage, Temperature, Cycling, Shorted Cell