automotive electrical I Chapter 5

conventional battery construction

- "+" plates - "-" plates - separators - case - plate strap (connects plates together) - electrolyte - terminals

Charge Rate

- 1 amp for every positive plate in the cell

Automotive Battery

- 12.6 v - 6 cells connected in series - each cell produces 2.1v

Fully Charged battery

- 12.68V -1.265 specific gravity - # amps or less and remains for 1 hour

Cell element

- 9-13 plates - "+" &"-" plates insulated from each other using separators - "+" side of cell element connects to "-" side of the next cell element

Charging a battery (high amp)

- Do not overcharge (2hrs)(15.5v) - Do not allow over 125F temperature - Doesn't fully charge - Good for jumpstart

disadvantages of maintenance free battery

- Grid growth in high temperature - cannot withstand deep cycle - low capacity - faster discharging from parasitic loads - shorter life expectancy

Current capacity

- Indication of the ability to deliver cranking power to the starter - indicates ability to provide reserve power to electrical system

Ultra Capacitors

- Large electrode surface & small distance between electrodes - uses electrolyte - used in hybrids and experimental fuel cell EV's - discharge high voltages and quickly recharge - can absorb energy from braking

Grids

- Make up "+" &"-" plates - made from Lead alloys (antimony)

Conductance test

- Measures plate surface available for chem. reaction - determines amount of power battery can supply and ability to conduct current - higher conductance value- better performance - should read 110%-140% of CCA if fully charged

HEV & EV batteries

- Nickel cadmium (NiCad) -Nickel metal hydride (NiHM) - Lithium Ion (Li-ion) - Lithium polymer (Li-Poly)

maintenance-free battery

- Sealed (no additional water needed) - Made from Calcium, caladium, stramonium - reduces gassing & self discharging - no antimony used

Electrolyte temperature

- Specific gravity standard temperature is 80F - When standard temperature goes up, specific gravity goes down (+0.004 for 10F up) - when standard temperature goes down, specific gravity goes up (-0.004 for 10F) down

Battery case must withstand

- Temp. extremes - vibration - acid absorption

Drain test

- Test for parasitic drain - Must pass open circuit test with 11.5v or over - maximum acceptable is 30mA - must use ammeter that can read under 1A - wait till computer shuts off

Reserve capacity rating

- Time that a fully charged battery at 80F can be discharged at 25A before battery voltage drops to 10.5 volts - indicates the amount of time a battery can drive with headlights on before the charging system fails

Cleaning a battery

- Use baking soda and water to clean battery - baking soda neutralizes acid

Low maintenance battery

- able to open up and test electrolyte - 3.4% less antimony

Absorbed glass mat battery separation

- acid permeated vitreous separators (sponges which absorb acid)

Capacity test

- battery must pass Open circuit or state of charge test accurate results, if not- recharge -Specified load: 50% of CCA for 15 seconds - must be over 9.6V to pass - correct reading according to temp

recombination battery advantages

- can be installed in any position - no electrolyte loss - corrosion free - lasts 4x longer than conventional battery - withstands deep cycle - rated over 800CCa

Parasitic drain can cause

- computer to go into "limp in" mode - can set off false trouble codes - computer can increase low engine speed to compensate for low battery voltage

3 minute charge test

- determine battery ability to accept charge - must have failed capacity test to get accurate results - connect charger and set to 40A, (25-30 for maint. free), must maintain for 3 minutes - If over 15.5V- sulfated

cold cranking amps (CCA)

- determined by load that a battery can deliver for 30 seconds in 0F - must maintain 1.2v per cell - terminal voltage cannot fall below 7.2V

Open circuit test

- determines battery state of charge - battery must be stabilized - place load on battery for 15 seconds - if battery has been recharged perform capacity test and wait 10 minutes to stabilize - 12.4v (75%) or higher is charged

Battery size selection depends on

- engine size - engine type - climate conditions - vehicle options - 1 CCA per cubic inch of displacement

recombination battery

- gel cell -no liquid electrolyte - low electrical resistance (separators) - spiral design (larger plate surface) - close plate spacing ( lowered resistance) - Voltage and Amp output is higher (0.6V)

Sulfation

- interferes with cells ability deliver current & accept charge - An accumulation of lead sulfate on the plates and at the bottom of a (lead) storage cell.

Advantages of Maintenance free battery

- larger reserve for electrolytes above plates - increased resistance to overcharging -Longer shelf life (18 months) - Higher CCA

Current capacity- depends on

- materials used for construction - size of cell plates - weight of active materials - weight of sulfuric acid in electrolyte

Charging Recombination battery

- over charging can dry out electrolyte by forcing hydrogen & oxygen out - If constantly undercharged sulfate builds up on "+" terminal -Can only use specific charger - Modern chargers support - Charger must limit voltage: Max-14.4 V, Min-13.8V at 68F - If voltage is less than 10 V, charge will be much slower

Cell connection- plate straps

- over partition - thru partition -external

Memory saver

- saves: radio, fuel trim, trans shift schedule - set before: servicing, testing, charging - do not connect if doing electrical repairs

42V system

- used in HEV's - Battery is 36V, charging system is 42V -Allows manufacturer to electrify mechanical and hydraulic systems

Material expanders

- used in plates to build cells - affect battery lifespan - can be used instead of active materials - keep manufacturing cost low

Capacity test ( If voltage is bellow specifications)

- wait 10 minutes - if V is below 12.45V- recharge & retest- if fails again, replace - if V above 12.45V- replace battery

Hybrid battery

- withstands 6 deep cycles and retains 100% charge - "+" plate- 2.75% antimony alloy (reduce grid growth & corrosion - "-" plate- calcium alloy (reduce gassing) - separators- glass w/resin coating - reduced electrical resistance - increased resistance to chemical contamination - better crank performance & battery life

Charging a battery (low amps)

-between 3-15A - Lead sulfate converts to Lead dioxide & lead sponge through the whole plate

Plate construction

-ground lead oxide - acid - material expanders - all pressed into the grid

cranking amps (CA)

-indication of battery's ability to provide cranking amps at 32F - To convert CA to CCA, divide CA by 1.25

Absorbed glass mat battery

-variation of a recombination battery - holds electrolyte in moistened fiberglass matting (sandwiched between high purity lead plates) - compressed into 6 cells - used in hybrids and EV"s for accessories

Technician A says that the 3-minute charge test is performed after a battery has failed a capacity test. Technician B says that if battery voltage is below 15.5 volts at the end of the 3-minute charge test, the battery is probably sulfated. Who is correct? a. Technician A b. Technician B c. Both A and B d. Neither A nor B

a. Technician A

While performing the battery leakage test the voltmeter reads 120 mv. Technician A says this below specifications and is acceptable. Technician B says the battery case may be porous. Who is correct? a. Technician B b. Neither Technician A nor Technician B c. Technician A d. Both Technician A and Technician B

a. Technician B

At the conclusion of the load test the battery voltage reads 9.3 volts at 80°F. This indicates. a. The battery may need replacement b. The test lead connections were not properly attached c. There is excessive leakage across the top of the battery case d. A good battery

a. The battery may need replacement

A customer's battery is always dead when she attempts to start her car in the morning. After jumping the battery one time in the morning, the car will start throughout the day with no problems. All of the following can be the cause EXCEPT: a. The starter motor is drawing too much current. b. The glove box light is staying on. c. A computer is not powering down. d. A relay contact is stuck closed.

a. The starter motor is drawing too much current.

A maintenance-free battery has failed the capacity test. Technician A says if the voltage recovers to 12.45 volts, the battery is still good. Technician B says if the voltage level does not return to 12.4 volts, recharge the battery and repeat the capacity test. Who is correct? a. A only b. B only c. Both A and B d. Neither A nor B

b. B only

Technician A says the battery provides electricity by releasing free electrons. Technician B says the battery stores energy in chemical form. Who is correct? a. A only b. B only c. Both A and B d. Neither A nor B

b. B only

The construction of the battery is being discussed. Technician A says the 12-volt battery consists of positive and negative plates connected in parallel. Technician B says the 12-volt battery consists of six cells wired in series. Who is correct? a. A only b. B only c. Both A and B d. Neither A nor B

b. B only

When charging a battery: a. Connect a voltmeter across the battery terminals while the battery is charging and keep the charge rate at fewer than 10 volts. b. Disconnect the negative battery cable before charging to prevent damage to the alternator and computers. c. Charge at an amperage rate of 50% of the CCA rating. d. All of the above.

b. Disconnect the negative battery cable before charging to prevent damage to the alternator and computers.

Ampere- hour rating

Amount of steady current that a fully charged battery can supply for 20 hours at 80F without terminal voltage falling below 10.5V

Absorbed glass mat battery discharging & charging

Hydrogen and Oxygen captured and recombined to form water in electrolyte

+ Plate

Lead dioxide

Hydrometer

Measures specific gravity of of electrolyte to determine battery charge

Electrolyte

Sulfuric acid diluted with water - 64% water, 36% sulfuric acid

state of charge test

Use hydrometer to test specific gravity

Ice crystals are found in the electrolyte. This can be caused by: a. A discharged battery. b. Use of tap water. c. Reversed battery connections. d. Improper hold-downs.

a. A discharged battery.

Battery terminal connections are being discussed. Technician A says when disconnecting battery cables, always disconnect the negative cable first. Technician B says when connecting battery cables, always connect the negative cable first. Who is correct? a. A only b. B only c. Both A and B d. Neither A nor B

a. A only

The specific gravity of a battery has been tested. All cells have a corrected reading of about 1.200. Technician A says the battery needs to be recharged before further testing. Technician B says the battery is sulfated and needs to be replaced. Who is correct? a. A only b. B only c. Both A and B d. Neither A nor B

a. A only

While jump-starting a vehicle with a second vehicle, a puff of smoke is observed and the engine ground cable is burned. Technician A says this happened because the two vehicles were touching. Technician B says this was caused by connecting the negative jumper cable to the disabled vehicle's engine ground. Who is correct? a. A only b. B only c. Both A and B d. Neither A nor B

a. A only

Charging a battery with a battery charger is being discussed. Technician A says that battery-charging voltage should never exceed 15 volts. Technician B says that a battery can be considered fully charged when its open circuit voltage exceeds 12.1 volts after it has been stabilized. Who is correct? a. Technician A b. Technician B c. Both A and B d. Neither A nor B

a. Technician A

Which of the following statements about NiMH cells is NOT true? a. When the NiMH cell discharges, hydrogen moves from the anode to the cathode electrode. b. Nickel-metal hydride batteries have an anode electrode that contains nickel hydroxide. c. The alkaline electrolyte has no active role in the chemical reaction. d. The plates are separated by a sheet of fine fibers saturated with an aqueous and alkaline electrolyte.

b. Nickel-metal hydride batteries have an anode electrode that contains nickel hydroxide.

Technician A says that a battery terminal test is performed by placing voltmeter leads between the positive battery post and the negative battery terminal. Technician B says that the total amount of voltage drop between the negative battery post and the negative battery terminal should not exceed 300 mV. Who is correct? a. Technician A b. Technician B c. Both A and B d. Neither A nor B

b. Technician B

Technician A says that an ammeter is used when performing a battery leakage test. Technician B says that a fully charged battery will have a specific gravity of at least 1.265.Who is correct? a. Technician A b. Technician B c. Both A and B d. Neither A nor B

b. Technician B

Battery terminology is being discussed. Technician A says grid growth is a condition where the grid grows little metallic fingers that extend through the separators and short out the plates. Technician B says deep cycling is discharging the battery almost completely before recharging it. Who is correct? a. A only b. B only c. Both A and B d. Neither A nor B

c. Both A and B

Technician A says battery polarity must be observed when connecting the battery cables. Technician B says the battery must be secured in the vehicle to prevent internal damage and the possibility of shorting across the terminals if it tips. Who is correct? a. A only b. B only c. Both A and B d. Neither A nor B

c. Both A and B

Technician A says the best way to charge the HV battery is by allowing the engine to run. Technician B says an on-board jump assist method may be available to start the engine if the HV battery SOC is too low. Who is correct? a. A only b. B only c. Both A and B d. Neither A nor B

c. Both A and B

Technician A says the largest demand on the battery is when it must supply current to operate the starter motor. Technician B says the current requirements of a starter motor may be over 100 amps. Who is correct? a. A only b. B only c. Both A and B d. Neither A nor B

c. Both A and B

The battery current drain test is being discussed. Technician A says that an ammeter that can accurately read less than 1 amp should be used. Technician B says that a current drain caused by an internally shorted battery should not be measured with an ammeter. Who is correct? a. Technician A b. Technician B c. Both A and B d. Neither A nor B

c. Both A and B

The battery open circuit test is being discussed. Technician A says the battery must be stabilized before the open circuit voltage test is performed. Technician B says a test result of 12.4 volts is acceptable. Who is correct? a. A only b. B only c. Both A and B d. Neither A nor B

c. Both A and B

The current capacity rating of the battery is being discussed. Technician A says the amount of electrical energy that a battery is capable of producing depends on the size, weight, and active area of the plates. Technician B says the current capacity rating of the battery depends on the types of materials used in the construction of the battery. Who is correct? a. A only b. B only c. Both A and B d. Neither A nor B

c. Both A and B

The hybrid battery is being discussed. Technician A says the hybrid battery can withstand at least six deep cycles and still retain 100% of its original reserve capacity. Technician B says the grid construction of the hybrid battery consists of approximately 2.75% antimony alloy on the positive plates and a calcium alloy on the negative plates. Who is correct? a. A only b. B only c. Both A and B d. Neither A nor B

c. Both A and B

When performing a load test, the load applied is equal to: a. Three times the CCA rating b. The CCA rating c. One-half the CCA rating d. One-half the amp-hour rating

c. One-half the CCA rating

Battery rating methods are being discussed. Technician A says the ampere-hour is determined by the load in amperes a battery is able to deliver for 30 seconds at 0°F (217.7°C) without terminal voltage falling below 7.2 volts for a 12-volt battery. Technician B says the cold cranking rating is the amount of steady current that a fully charged battery can supply for 20 hours at 80°F (26.7°C) without battery voltage falling below 10.5 volts. Who is correct? a. A only b. B only c. Both A and B d. Neither A nor B

d. Neither A nor B

Which statement concerning the battery leakage test is correct? a. The test is used to determine if the battery can provide current and voltage when loaded. b. A voltmeter reading of 0.05 when performing the test is acceptable. c. Both A and B. d. Neither A nor B

d. Neither A nor B

Vents

release hydrogen gas when battery is charging

- if each cell has 0.5 specific gravity difference-

replace

-if good specific gravity but bad voltage-

replace

- Plate

sponge lead

- if specific gravity is all good or all bad-

test voltage

Which of the following statements about battery ratings is true? a. The ampere-hour rating is defined as the amount of steady current that a fully charged battery can supply for 1 hour at 80°F (26.7°C) without the cell voltage falling below a predetermined voltage. b. The cold cranking amps rating represents the number of amps that a fully charged battery can deliver at 0°F (-17.7°C) for 30 seconds while maintaining a voltage above 9.6 volts for a 12-volt battery. c. The cranking amp rating expresses the number of amperes a battery can deliver at 32°F (0°C) for 30 seconds and maintain at least 1.2 volts per cell. d. The reserve-capacity rating expresses the number of amperes a fully charged battery at 80°F can supply before the battery's voltage falls below 10.5 volts.

d. The reserve-capacity rating expresses the number of amperes a fully charged battery at 80°F can supply before the battery's voltage falls below 10.5 volts.

- if specific gravity is low but voltage is high-

discharged- possible charging system problem

chemical reaction

electric current moves from "+" to "-" plates through the separators