by Russell Krick Publisher The GoodheartWillcox Co Inc

by Russell Krick Publisher The Goodheart-Willcox Co. , Inc. Tinley Park, Illinois © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only

© Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only

q q q q Battery principles Battery functions Battery construction Wet- and dry-charged batteries Maintenance-free battery Battery ratings Battery temperature and efficiency © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only

q An automotive battery is an electrochemical device q It produces and stores direct current electricity © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only

Battery Parts © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only

Discharging q Changes chemical energy into electrical energy q Stored energy is released © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only

Charging q Electrical energy is converted to chemical energy q Energy is stored until needed © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only

Battery Cycling q Repeated charging and discharging q Deep cycling m going from a very low charge to full charge m can shorten service life © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only

Basic Battery Cell q Contents: m negative plate m positive plate m container m electrolyte (battery acid) q When a load is connected to the cell, current will flow through the load © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only

Lead-Acid Battery Cell Electrolyte causes a chemical reaction between the plates, producing 2. 1 volts © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only

Cell Action (Charging) q Alternator causes free electrons to be deposited on the negative (–) plate q This causes the plates to have a difference in potential (electrical pressure or voltage) © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only

Cell Action (Discharging) q Load is connected across the terminals q Current flows through the load to equalize the difference in charges on the plates q Excess electrons (current) move from the negative plate through the load to the positive plate © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only

Battery Cycling © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only

q Operate the starting motor, ignition system, fuel injection, and other electrical devices during cranking q Supply electrical power when the engine is not running q Supply electrical power when current demands exceed alternator output q Act as a capacitor (voltage stabilizer) q Store energy for extended periods © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only

q Batteries must be built to withstand harsh conditions: m severe vibration m extreme temperatures m corrosive chemicals m high current discharge m prolonged periods without use © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only

Battery Element q Battery plates m grid coated with porous lead m several in each cell q Lead strap m one connects several negative plates m another connects several positive plates q Separators m insulating material between plates that keep them from touching each other © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only

Battery Element Most automotive batteries have six elements © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only

Case, Cover, and Caps q Battery case m high-quality plastic m holds the elements and electrolyte q Battery cover m bonded to the top of the case m seals the top q Battery caps m keep electrolyte from splashing out m serve as spark arrestors © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only

Case, Cover, and Caps Case holds the elements and electrolyte © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only

Electrolyte q Mixture of sulfuric acid and distilled water q Poured into each cell until plates are covered q Also known as battery acid q Warning: electrolyte causes serious burns or blindness if it comes in contact with your skin or eyes! © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only

Electrolyte should just touch the split ring in the top of the case © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only

Charge Indicator Changes color to show the general state of charge of the battery © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only

Battery Terminals Means of connecting the battery to the vehicle’s electrical system © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only

Battery Voltage q Open circuit cell voltage is 2. 1 volts q Cells are connected in series q Battery voltage depends on the number of cells q A 12 -volt battery has 6 cells and an open circuit voltage of 12. 6 volts q A 6 -volt battery has 3 cells and an open circuit voltage 6. 3 volts © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only

Battery Voltage © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only

Two-Battery Systems q Parallel m connected negative to negative m connected positive to positive m two 12 -volt batteries produce 12 volts, high current q Series m connected positive to negative m two 12 -volt batteries produce 24 volts © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only

Battery Cables A. Post-type B. Side terminal C. Braided ground D. 90º post-type E. Solenoid-tostarter © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only

Cable Connections The negative cable grounds on the engine block and the positive cable connects to the starter solenoid © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only

Battery Tray and Retainer Holds battery securely in place. May house a battery temperature sensor. © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only

Battery Tray and Heat Shield Protects battery from excess engine heat by routing air between heat shield and battery case © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only

q No difference in the materials used in each q Only difference is in how they are prepared for service © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only

Wet- and Dry-Charged Batteries q Wet-Charged Battery m filled with electrolyte and charged at the factory m very common in many locations q Dry-Charged Battery m m © Goodheart-Willcox Co. , Inc. contains fully charged elements does not contain electrolyte leaves the factory in a dry state has a long shelf life Permission granted to reproduce for educational use only

q Does not use removable filler caps q Calcium is used to make the plates, which reduces gassing q Reduced water loss decreases service requirements q Less gassing results in less chemical loss, which results in increased battery life © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only

q Works like a lead-acid battery q Contains a pastelike electrolyte q The electrolyte will not leak out if the case is cracked or broken, and the battery will continue to function © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only

Gel Battery q A complete seal eliminates gassing and reduces the risk of explosion q Improper charging can burn a void in the electrolyte gel q Burning can permanently lower power output q A specific charging rate is required, which is not required with a lead-acid battery © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only

q Also known as an AGM battery q Contains a fiber matting that absorbs the liquid electrolyte q Battery has only enough electrolyte to wet the matting © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only

Absorbed Glass Mat Battery q Vibration and impact resistant and will not leak, even if the case is damaged q Sealing does not allow gassing, reducing the risk of explosion q Not as sensitive to improper charging as gel batteries © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only

q Cold cranking rating q Reserve capacity rating q Amp-hour rating © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only

Cold Cranking Rating q Determines the current a battery can deliver for 30 seconds at 0ºF (-18ºC) while maintaining terminal voltage of 7. 2 volts (1. 2 volts per cell) q Expressed as cold cranking amps (CCA) q Indicates ability to crank the engine at cold temperatures q Typical applications: m 305 CCA for small 4 -cylinder engine m 450 CCA for 8 -cylinder engine © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only

Reserve Capacity Rating q Time needed to lower battery terminal voltage below 10. 2 volts (1. 7 volts per cell) at a discharge rate of 25 amperes at 80ºF (27ºC) q Expressed in minutes m example: If a battery is rated at 90 minutes and the charging system fails, the driver has approximately 90 minutes of driving time with a current use of 25 amperes before the battery goes completely dead © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only

Amp-Hour Rating q Once used to indicate battery power q Measures the current that the battery could produce for 20 hours at 80ºF (27ºC) with the battery voltage above 10. 5 volts © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only

q As battery temperature drops, output is reduced m chemical process is slowed m battery cannot produce as much current © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only

Temperature versus Efficiency © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only

Parasitic Loads q Current draw present when engine and ignition are shut off q Computers and clock require constant power q Over prolonged periods, these may discharge the battery enough to prevent starting © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only