BATTERY SERVICE
Contents
1. BATTERY SERVICE This Automotive Series BATTERY SERVICE has been developed by Kevin R Sullivan Professor of Automotive Technology Skyline College All Rights Reserved v1 1 Visit us on the web at www autoshop101 com BATTERY SERVICE Battery services are routinely performed These services include 1 Testing 2 Charging 3 Cleaning 4 Jumping a dead battery 5 Adding water Page 1 Autoshop101 com All rights reserved BATTERY TESTING Battery testing has changed in recent years although the three areas are basically the same the equipment has improved 1 Visual Inspection 2 State of Charge a Specific Gravity b Open Circuit Voltage 3 Capacity or Heavy Load Test Note This does not include the Midtronics battery tester which has a different test procedure and will be discussed later in this module Page 2 Autoshop101 com All rights reserved VISUAL INSPECTION Battery service should begin with a thorough visual inspection This inspection may reveal simple easily corrected problems 1 Check for cracks in the battery case and broken terminals Either may allow electrolyte leakage which requires battery replacement 2 Check for cracked or broken cables or connections Replace as needed 3 Check for corrosion on terminals and dirt or acid on the case top Clean the terminals and case top with a mixture of water and baking soda A battery wire brush tool is needed for heavy corrosio2. attery If it is hot 125 F to the touch interrupt the charging turn off until the battery cools and lower charge rate Page 21 Autoshop101 com All rights reserved CHARGING PROCEDURE AUTOMATIC CHARGER 1 Determine the type of battery sealed or accessible If sealed the battery must be charged using a slow rate A sealed battery does not allow access to the cells or the addition of water or measuring specific gravity If accessible the battery may be charged at either the slow or fast rates 2 Insure the charger is disconnected from the power source and or the charger is turned off 3 Connect the charger to the battery positive cable to the positive terminal or negative cable to the negative terminal Insure a good connection by rocking back and forth 4 Plug in the charger If there is a setting switch for regular or deep cycle batteries use regular setting for regular accessible batteries and sealed gel electrolyte batteries Use deep cycle setting for standard deep cycle batteries and maintenance free batteries Always refer to battery charger instruction manual before using battery charger 5 Periodically check the battery for excessive heat by placing your hand on the side of the battery If it is hot 125 F to the touch interrupt the charging turn off until the battery cools 6 During the charge cycle the charger senses the battery s state of charge and will input amps at the appropriat
3. ctrolyte in a discharged battery By weight the electrolyte in a fully charged battery is about 36 acid and 64 water The specific gravity of water is 1 000 The acid is 1 835 times heavier than water so its specific gravity is 1 835 The electrolyte mixture of water and acid has a specific gravity of 1 270 usually stated as twelve and seventy 36 64 ACID WATER ELECTROLYTE S G 1 835 S G 1 000 S G 1 270 Page 5 Autoshop101 com All rights reserved SPECIFIC GRAVITY READINGS By measuring the specific gravity of the electrolyte you can tell if the battery is fully charged requires charging or must be replaced It can tell you if the battery is sufficiently charged for a capacity heavy load test The battery must be at least 75 charged to perform a heavy load test The heavy load test will be discussed later In other words each cell must have a specific gravity of 1 230 or higher to proceed CELLREADINGS PERCENT CHARGED If the battery is less than 75 charged it must be fully recharged before proceeding If the battery is 75 or higher proceed to a heavy load test A battery not sufficiently charged will fail because it is discharged SPECIFIC GRAVITY EXCESSIVE CELL VARIATION READINGS Variation in specific gravity among cells cannot vary more than 0 050 The variance is the difference between the lowest cell and the highest cell A battery must be condemned for excessive cell variation if mor
4. e rate As the battery approaches a full state of charge the input amperage will decrease 7 After charging is complete verify the charger is turned off and disconnected from the power source before removing charger cables Page 22 Autoshop101 com All rights reserved CHARGING PROCEDURE MANUAL CHARGER 1 Determine the type of battery sealed or accessible If sealed the battery must be charged using a slow rate A sealed battery does not allow access to the cells for the addition of water or measuring specific gravity If accessible the battery may be charged at either the slow or fast rates 2 Insure the charger is disconnected from the power source and or the charger is turned off 3 Connect the charger to the battery positive cable to the positive terminal or negative cable to the negative terminal Insure a good connection by rocking clamp back and forth 4 Plug in the charger set the charge rate and turn on the charger 5 Periodically check the battery for excessive heat by placing your hand on the side of the battery If it is hot 125 F to the touch interrupt the charging turn off until the battery cools 6 After charging is complete insure charger is turned off and disconnected from the power source before removing charger cables Page 23 Autoshop101 com All rights reserved CHARGING RATES MANUAL CHARGER The table below is used to calculate the charge rate and time of batteries
5. e that 0 050 In the example below the highest SG reading is cell 1 shown in green while the lowest SG reading is cell 5 shown in blue the difference is 0 070 which requires battery replacement Cell 5 if failing Cell 1 Cell 2 Cell 3 Cell 4 Cell 5 Cell 6 1 260 1 230 1 240 1 220 1 190 1 250 Many factors contribute to cell variation for example if water was just added to that cell the cell is then diluted with water resulting is a lower specific gravity reading Recharging the battery would correct this false reading In some cases if a battery that has cell variation slightly over the specification and is only about 50 charge charging the battery at a slow rate of charge 5A may reduce the cell variation thus saving the battery Page 6 Autoshop101 com All rights reserved SPECIFIC GRAVITY TEST PROCEDURE HYDROMETER 1 Wear suitable eye protection 2 Remove vent caps or covers from the battery cells 3 Squeeze the hydrometer bulb and insert the pickup tube into the cell closest to the battery s positive terminal 4 Slowly release the bulb to draw in only enough electrolyte to cause the float to rise Do not remove the tube from the cell 5 Read the specific gravity indicated on the float Be sure the float is drifting free not in contact with the sides of top of the barrel Bend down to read the hydrometer at eye level Disregard the slight curvature of liquid on the float 6 Record your readings and rep
6. eat the procedure for the remaining cells SUCTION HYDROMETER Page 7 Autoshop101 com All rights reserved ADJUSTED SPECIFIC GRAVITY READINGS Temperature correction is needed because specific gravity changes with temperature Cold thickens the electrolyte and raises the specific gravity Heat thins the electrolyte and lowers the specific gravity Hydrometers are calibrated at 80 F 26 7 C Electrolyte temperatures above or below 80 F must be adjusted For every 10 F increment below 80 F subtract 0 004 to the hydrometer readings and for each 10 F increment above 80 F add 0 004 to the readings See the examples below 71C 160F fr 32 65 5C 150F H H 26 60C 140F HH 24 exampce eee elie ae ELECTROLYTE TEMPERATURE 40 49C 120F HU 16 eee d 23C 110F J 12 RLS R eK i 1 4c 32 5C 9OF HH 42 PHYOROMETEA READING oe 12a 27C 80F Fr o HroROMETER TEMPERATURE i00F 91C 7OFHH 45 ADD SPECIFIC GRAVITY 008 155C GOF LH gg CORRECTED SPECIFIC GRAVITY IS 1 248 j 10C 50FHH 125 45C 40F HH 16 a 1C 30F H 20 AFULLY CHARGED BATTERY HAS A SPECIFIC 6 5C 20F HH 24 GRAVITY OF ABOUT 1 265 12C 10F HH 28 Page 8 Autoshop101 com All rights reserved SPECIFIC GRAVITY TEST PROCEDURE REFRACTOMETER A Refractometer optically measures the specific gravity No temperature correction is needed 1 Wear suitable eye protection 2 Remove vent caps or covers from the batter
7. en use the OEM battery rating found in most repair manuals MAINTENANCE FREE KIDE STANDARD 5 O a Kre uaar un uu Mav ause Koc ENORDE 0000000000 Disiibuted by Exide Corporation Reading PA 1601 AATIONVIGE WARRANTY HOTLINE 1 800 STAART IT Page 12 Autoshop101 com All rights reserved HEAVY LOAD TEST PROCEDURE 1 Install the load tester as shown in an earlier slide 2 Load the battery by turning the Load Increase control until the ammeter reads 3 times the amp hour AH rating or one half the cold cranking ampere CCA rating 3 Maintain the load for no more than 15 seconds and note the voltmeter reading 4 If the voltmeter reading during the test is 9 6 volts or higher the battery is good 9 5 volts or below the battery is defective and needs replacement Note Results will vary with temperature Low temperatures will reduce the voltage reading so the electrolyte should be at 70 F or above If not use the following conversion table Voltage Temperature Page 13 Autoshop101 com All rights reserved CURRENT DRAINS Parasitic drains are the small current drains required to operate various electrical systems such as the clock computer memory or alarms that continue to work when the car is parked and the ignition is off All vehicles today have parasitic drains and over time will drain all batteries if not driven or charged periodically The problem is when the parasitic drain becomes excessive usua
8. g this test It is possible to place one lead of the ammeter on the battery post and the other on the battery clamp while at the same time lifting the battery clamp off the battery post On side terminal batteries connect the voltmeter with alligator clips and let sit until the timers run out Page 15 Autoshop101 com All rights reserved BATTERY DISCHARGE CASE DRAIN Check for battery discharge case drain across the top of the battery using a digital voltmeter Connect the negative black test lead to the battery s negative terminal post and connect the positive red test lead to the top of the battery case If the meter reads more than 0 5 volt clean the case top using a solution of baking soda and water Remove excess water from top of battery Sse Acceptable Battery Discharge Page 16 Autoshop101 com All rights reserved BATTERY CLAMP POST RESISTANCE Resistance between the battery terminal post and the clamp can account for the battery not being completely recharged and is often a problem Although it may visually look all right oxidation of the metal or slight corrosion can cause excessive resistance at the connection thus creating a voltage drop and lowering current flow to the starter Battery post and clamps should be cleaned at each battery inspection To check for excessive resistance perform a voltage drop between the battery terminal post and the clamp shown below while cranking the engine The
9. lly over 35 milliamps Unwanted battery drain can also be the reason why a battery keeps discharging Unwanted battery drain can be a result of excessive parasitic drain or if the top of the battery is wet or has excessive corrosion it could create a path between the two battery posts causing a current drain usually 0 5 volt potential or higher will result in a battery discharge This is called Case Drain Page 14 Autoshop101 com All rights reserved PARASITIC DRAIN Check for excessive battery drain or parasitic loads using an ammeter Make sure all electrical loads are off in the car doors closed and the key is out of the ignition switch Disconnect one of the battery cables from the battery placing an ammeter in series between the battery post and cable clamp The current draw reading should be less than 35 milliamps A reading higher than this or manufacturer specifications would indicate excessive battery drain Something is on allowing current to flow running down the battery Vehicles today typically will draw less than 020 amps 20 milliamps of current to maintain electronic memories and circuits Note If the battery is disconnected parasitic drains may temporarily increase Circuits in the engine and body computers are activated and will run until internal timers runout This reactivation period could be anywhere from a few seconds to almost 30 minutes Whenever possible avoid disconnecting the battery while performin
10. lts Current 10 amps maximum Time 8 hours maximum Note Always use a voltage regulated battery charger with limits set to the above ratings Overcharging can cause the safety valves to open and battery gasses to escape causing premature failure These gasses are flammable You cannot replace water in sealed batteries that have been overcharged Any battery that becomes very hot or makes a hissing sound while recharging should be disconnected immediately BATTERY TERMINAL CLEANING Over a period of time sulfuric acid will corrode battery terminals clamps and hold down This corrosion adds resistance and lowers current flow to and from the battery Corrosion can be easily cleaned with a mild solution of baking soda and water Battery terminals and cables are routinely removed cleaned and reinstalled A battery brush which has both an external and internal brushes is ideal for cleaning the terminal posts and the inside of clamp Page 25 Autoshop101 com All rights reserved BATTERY JUMPING with Booster Cables Jump starting a dead battery with a booster battery or battery in a car can be dangerous so the proper sequence of connections will prevent sparks First connect the two positive terminals one from the good battery and the other to the dead battery Next connect one end of the jumper cable to the negative terminal of the booster Good battery Finally connect the other end to a good ground on the engine away from the dead ba
11. n on the terminals 4 Check for a loose battery hold down or loose cable connections Clean and tighten as needed CHECK CABLES CHECK CHECK w CHECK ELECTROLYTE LEVEL CHECK CASE Page 3 Autoshop101 com All rights reserved VISUAL INSPECTION CONTINUED 5 Check the electrolyte fluid level The level can be viewed through the translucent plastic case or by removing the vent caps and looking directly into each cell The proper level is 1 2 above the separators about 1 8 below the fill ring shown below Add distilled water if necessary Do not overfill 6 Check for cloudy or discolored electrolyte caused by overcharging or vibration This could cause high self discharge Correct the cause and replace the battery STATE OF CHARGE The state of charge of a battery can be easily check in one of two ways Specific Gravity Test Open Circuit Voltage Test Note 1 A state of charge test is required to determine if there is sufficient charge in the battery to properly perform a capacity test explained later 2 The only exception to this is the MIDTRONICS Battery Tester This new state of the art capacitance tester will be discussed later in this module Page 4 Autoshop101 com All rights reserved SPECIFIC GRAVITY Specific gravity means exact weight A Hydrometer or a Refractometer compares the exact weight of electrolyte with that of water Strong electrolyte in a charged battery is heavier than weak ele
12. of various strengths and states of charge using a manual wheel type charger Example A battery with an RC Reserve Capacity rating of 80 RC and the state of charge is only 25 specific gravity first select the correct RC rating in the yellow column 80 RC in our example Now select the charge rate either 5 or 10 amps under the state of charge column 10 amps in our example Where the two reading intersect 10 amps under 25 and 80 RC will provide the amount of time in minutes 180 to charge the battery Note If you are wondering where to get the RC rating of a battery that only has a CCA rating on it refer to your battery vender for such information It should be readily available from their product application book If not place battery on a low charge rate and check electrolyte specific gravity every 30 minutes until charged soRC 3 150 75 225 180 300 1150 eoRC 90 4 180 90 270 135 360 180 7oRC 10B 50 210 105 315 155 420 210 sorc 120 e0 240 120 aeo MBa 480 240 soRC 13B 6 270 135 405 200 540 270 wooRc 150 7B 300 150 450 225 600 300 M0RC 165 80 330 165 495 240 660 330 120RC 180 90 360 180 540 270 720 360 CHARGE TIME IN MINUTES Page 24 Autoshop101 com All rights reserved CHARGING RATE OPTIMA GEL CELL BATTERY A Gel Cell Battery requires a shorter charge time Optima recommends use of a voltage regulated charger set to the limits below Voltage 13 8 to 15 0 vo
13. r higher proceed to heavy load test If the battery is less than 12 4v the battery must be fully recharged before testing Be sure to remove the surface charge completely this is the number one mistake technicians make If need be place a load tester on the battery and load the battery for 10 seconds at approximately 200 amps Allow a few minutes for the battery to recover then measure the open circuit voltage This should remove the surface charge and allow an accurate open circuit voltage measurement Remember a reading of 12 4 volts or higher load test the battery 12 3 volts or less recharge the battery of charge 12 6v 100 12 4v 75 12 2v 50 12 0v 25 11 9v 0 Page 11 Autoshop101 com All rights reserved HEAVY LOAD TEST While a State of Charge test determines the battery s state of charge it does not measure the battery s ability to deliver adequate cranking power A capacity or heavy load test measures the battery s ability to deliver current A battery load tester such as a Sun VAT 40 is used Note the battery must be at least 75 charged before a heavy test can be performed DETERMINE CAPACITY RATING The capacity rating is located on the battery label Ratings can be expressed in CCA Cold Cranking Amps AH Amp Hour or JIS Japanese Industrial Standard JIS uses a six digit code not shown A conversion table is offered below that can be printed If no rating is found on the battery th
14. ttery If a spark occurs it won t be near the battery thus reducing the chance for explosion If the jump starting from another vehicle start the vehicle running the engine at 1500 RPM for a few minutes While the engine is running start the dead vehicle Never jump start a frozen battery DEAD BATTERY BOOSTER BATTERY Page 26 Autoshop101 com All rights reserved BATTERY JUMPING with Booster Pack The portable booster pack is a lead acid gel cell type battery Typically capacity ranges from 250 1000 CCA ratings Both consumer and professional versions are available It contains an accessory plug and has a test button to verify its own state of charge Booster battery packs have proven to be a safe and effective in jump starting vehicles To use Connect the red booster pack cable to the positive terminal of the battery and the other cable end toa good ground on the engine away from the dead battery ADDING WATER Under the rare occurrence of adding water to a battery use only Distilled water Minerals and chemicals that are commonly found in regular drinking water will react with the plate material and shorten battery life Under normal conditions the addition of water should not be required However the addition of water may be necessary when the battery has been overcharged for overcharging results in excessive evaporation of water from the electrolyte The water level should be no higher than 1 8 inch below the bo
15. ttom of the vent well To avoid permanent damage make sure the electrolyte level never drops below the top of the plates Also avoid over filling this may result in electrolyte overflow from the battery Page 27 Autoshop101 com All rights reserved
16. uttons Enter information the unit requests such as in or out of vehicle and rating method such as CCA CA MCA etc 3 The automated test will take a few seconds giving accurate results Note No load test is required and a state of charge test does not need to be done No skill is required Hook it up and go Although the Midtronics is not 100 accurate it have proven to be more reliable than human error Page 19 Autoshop101 com All rights reserved BATTERY CHARGING All battery chargers operate on the same principle an electric current is applied to the battery to reverse the chemical action in the cells Never connect or disconnect leads with the charger turned ON Follow the battery charger manufacturer s instructions DO NOT attempt to charge a battery with frozen electrolyte When using a battery charger always disconnect the battery ground cable first This will minimize the possibility of damage to the alternator or electronic components in the vehicle The battery can be considered fully charged when all cells are gassing freely and when there is no change in specific gravity readings for more than one hour A slow charge is 5 or 10 amps while a fast charge is generally 15 amps or higher A slow charge is always preferred BATTERY CHARGER TYPES Battery chargers are available in two classifications Manual and Automatic Automatic chargers typically the type consumers purchase pulse and cycle the charge current and
17. voltage drop reading should be 0 0 volts Any voltmeter reading higher than zero volts requires cleaning the connection and rechecking Page 17 Autoshop101 com All rights reserved MIDTRONICS BATTERY TESTER Midtronics test equipment is safe and simple to use while providing an accurate diagnosis in seconds Midtronics battery testers are based on the measurement of battery conductance rather than a load test Midtronics can even test a discharged battery to determine its condition This tester is recommended by most automotive vehicle manufacturers The 500 series model shown below not only can test the battery but the starting and charging systems as well MIDTRONICS OPERATION Conductance is a measurement of the battery s ability to produce current To measure conductance the tester creates a small signal that is sent through the battery then measures a portion of the AC current response Conductance is a measure of the plate surface available in the battery which determines how much power the battery can supply As a battery ages the plate surface can sulfate or shed active material which adversely affects its ability to perform In addition conductance can be used to detect cell defects shorts and open circuits which will reduce the ability of the battery to deliver current Page 18 Autoshop101 com All rights reserved MIDTRONICS BATTERY TEST PROCEDURE 1 Connect the tester to the battery 2 Push a couple of b
18. voltage rates This automatic cycling rate protects the battery from damage and allows the charge rate to taper over time Manual chargers shown below also known as wheel chargers are preferred by automotive professionals These charges do not cycle but rather provide a constant non tapering charge The constant charge rate allows the technician to accurately calculate the charge time to prevent overcharging of the battery Automatic Charger Manual Charger Page 20 Autoshop101 com All rights reserved GENERAL RULES FOR CHARGING A BATTERY Always leave the vent caps in place during charging Always follow the battery charger manufacturer s instructions Always charge batteries in a well ventilated area and wear eye protection and protective clothing such as a rubber apron and rubber gloves Always keep sparks or flames away from the battery Do not smoke near a battery Recharge the battery at the same rate at which it was discharged If the discharge was slow then charge at a slow rate if the discharge was rapid then charge at a higher rate When in doubt always use a slow charge Never charge a battery that is connected to a vehicle Disconnect the battery and charge Excessive voltage can damage electrical circuits on the vehicle Recheck specific gravity readings periodically determine if further charging is still required Periodically check the battery for excessive heat by placing your hand on the side of the b
19. y cells 3 Place one drop of electrolyte on the refractometer lens and close the prism 4 Hold the refractometer up to the light and reading chart from view finder 5 Record your readings and repeat the procedure for the remaining cells PLACE ONE OROP OF ELECTROLYTE UNDER LENS VIEW READING FROM VIEW FINDER Page 9 Autoshop101 com All rights reserved SPECIFIC GRAVITY TEST PROCEDURE AC Delco Battery with built in Hydrometer 1 Wear suitable eye protection 2 Observe the built in hydrometer Green Dot is visible the battery is sufficiently charged for further testing Heavy Load Test Dark Green Dot is visible the battery needs to be recharged before further testing Light or Yellow Dot is visible replace the battery ee Dark green Light or dot not yellow visible replace charge battery before testing Page 10 Autoshop101 com All rights reserved OPEN CIRCUIT VOLTAGE A digital voltmeter must be used to check the battery s open circuit voltage Analog meters are not accurate and cannot be used 1 Turn on the headlamps high beam for several minutes to remove any surface charge 2 Turn headlamps off and connect the digital voltmeter across the battery terminals 3 Read the voltmeter A fully charged battery will have an open circuit voltage of 12 6 volts On the other hand a totally dead battery will have an open circuit voltage of less than 12 0 volts Note If the battery is 12 4v o
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