AT 121 - Chapter 17a Automotive Batteries and Service - Part 2Name: _________________________________________Date: __________________________________________Battery service can be broken up into several areas: battery inspection, battery cleaning, battery testing, parasitic drain testing, charging a battery, and jump starting a battery. This lab is designed to explain and help you understand how to perform these tests and why they are important.  SECTION 4 Parasitic Draw/Battery TestingTools you will need:Safety GlassesVehicle with 12 Volt batteryDVOMFUSED Jumper WiresWARNING! FAILURE TO FOLLOW THIS SECTION OF THE LAB WORD FOR WORD WILL LEAD TO MISDIAGNOSIS, POSSIBLE DAMAGE TO THE VEHICLE, DVOM, AND THE INSTRUCTOR WILL BE REALLY UPSET!!This test is very important. It allows a technician to locate the source of a battery that “keeps going dead”. Here is the basic logic for this lab. Many vehicles made after 1990 have multiple on board computer systems. These systems are, in fact, “still on and have power” after the key has been turned off and the occupants have left the vehicle. These computer systems turn on and off by way of “time out” and “wake up”. Most computer systems take up to an hour to “time out” (turn off) after the vehiclehas been turned off. These same modules will “wake up” (turn on) when the vehicle is turned on or when the battery is reconnected. Therefore turning the vehicle on, or carelessly connecting or disconnecting the battery, or opening the door without a “latch lock” while testing for a parasitic drain, will lead to misdiagnosis, wasted time, and money! Make certain the ignition switch is in the Lock/Off position, all electrical accessories are off, and doors closed. If equipped with a hood lamp, remove the bulb or disconnect its electrical connector.1 – The battery goes dead overnight. The battery and charging system have been tested and check out OK. 2 - Using a DVOM, install the DVOM in series with the vehicle’s battery and measure the current draw through the meter to the vehicle. DO NOT DO THE FOLLOWING!Turn on any accessories, headlights, flashers, or turn on the ignition.Do not have the door open with the dome light on. (This may have been done for you)3 – Once an excessive draw is seen on the meter, unplugging vehicles fuses ONE AT A TIME will locate the source of the excessive current draw. Once the meter shows an excess of current, the fuse on the circuit with the excessive draw has been located. KEEP TRACK OF THE FUSES THAT YOU PULL! DO NOT REINSTALL THE FUSES UNTIL YOU FIND THE FUSE THAT CAUSES THE CURRENT TO DROP!4 – At this point the circuit and its components of that fuse can be tested and checked out finding the source of the excessive draw.Note: Things like a glovebox lamp or interior lamp left on will lead to misdiagnosis as theywill cause a draw of well over 1 amp. Loosen (but do not remove) the negative battery cable. Install (or hold) a jumper wire from the negative battery terminal to the negative batterycable.  Remove the battery cable from the terminal, but DO NOT disconnect the jumper wire!Once the cable is removed from the terminal, install the jumper wire to the battery terminal.MAKE SURE THE CONNECTION IS NOT BROKEN!1 Set the DVOM on the 10 or 20 Amp setting. Install the meter so it is in series with the negative battery cable and the negative battery terminal. Remove the jumper wire, but MAKE SURE THE CONNECTION IS NOT BROKEN with the DVOM and the battery! If the amp reading is over 5 amps, wait 2 minutes. If the reading does not come down soon after that, get the instructor.  A typical reading should be under .05 A (50 miliamps). Anything over 50 mA is considered excessive draw and must be diagnosed.The parasitic draw on this vehicle is ________________________QA drain of ____________________________ amps is considered a parasitic drain.The DVOM should be set on the ______________________ setting.Disconnect the __________________________ lamp, and make sure the _____________________ is not open.The vehicle ignition should be in the ___________________________ position.Turning the vehicle ___________________, or carelessly connecting or disconnecting the ___________________, or opening the door without a _______________________ while testing for a parasitic drain, will lead to misdiagnosis, wasted time, and ____________________________! When finished have the instructor sign off on your work. _____________________________________ SECTION 5 Battery Charging – Automatic and Manual ChargersTools you will need:Safety GlassesVehicle with 12 Volt batteryAutomatic Battery ChargerManual Battery Charger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 – this is critical to battery health!Battery chargers are available in two classifications: Manual and Automatic. Automatic chargers (typically the type consumer’s purchase) pulse and cycle the charge current and voltage rates. This automatic cycling rate protects the battery from damage and allows the charge rate to taper over time.Manual chargers, 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.2GENERAL 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