This set of Automotive Engine Auxiliary Systems Multiple Choice Questions & Answers (MCQs) focuses on “Battery Charging”.
1. Which of the following is provided to charge the battery constantly?
b) Ignition coil
c) Fuse box
Explanation: A generator is provided so that it can constantly charge the battery. The rate of charging current flowing from the generator to the battery depends upon the state of charge of the battery. If the battery is run down, the charging rate will be higher, and as it gradually charged the rate tapers off to lower value.
2. Which of the following decreases within turn decreases the charging rate?
Explanation: The main factor affecting charging is the temperature. The charging rate decreases with, a decrease in temperature, and vice versa. That means a battery, at the higher temperature, would take less time for charging, all other conditions remaining the same.
3. Which of the following causes the corrosion of terminals and clamps?
a) Spilled electrolyte
b) Increase in temperature
c) Decrease in pressure
d) Due to high current
Explanation: The corrosion of terminals and clamps is one of the major factors affecting charging. Due to spilled electrolyte and condensation from gases the internal resistance of the battery increases resulting in a decrease in the charging rate.
4. What are the total hours taken by the battery to charge completely?
Explanation: The battery generally takes from 12-20 hours for recharging a battery depending upon the condition of the battery and the charging rate. However, batteries with sulfate plates require low charging current and hence longer time foe charging.
5. Which of the following is defined as the total capacity of the battery to keep the engine running if the charging system fails?
a) Twenty-hour rate
b) Twenty-minute rate
c) Reserve capacity
d) Cold rate
Explanation: Reserve capacity is an important measurement for the total capacity of the battery. It indicates how long a battery can keep the engine running if the charging system fails. It is the time in minutes for which the battery can supply 25amps.
6. Which of the following is the abbreviation of CCA?
a) Cold-cranking amperes
b) Crankcase accumulation
c) Crankcase alternator
d) Cold-cranking accumulation
Explanation: The abbreviation of CCA is cold cranking amperes. The CCA rating of an automobile battery must equal or exceed the number of cubic inches of engine displacement. The temperature of the cold rate or CCA of the battery at the beginning of discharge is kept -18 degrees centigrade.
7. How is the rate of charging if there are impurities in the electrolyte?
d) Remains the same and decreases as time goes
Explanation: The important factor affecting the charging rate is the impurities present in an electrolyte. The electrolyte impurities decrease the charging rate. Apart from the impurities, gassing also decreases the charging rate of the battery.
8. How many minutes can a battery of two-minute rate supply before the voltage dropping below 1.5volts?
Explanation:Twenty-minute rate of a battery represents the rate of current a battery can deliver continuously for 20 minutes, the cell voltage not dropping below 1.5. The temperature of the battery at the start of the test is brought to 80 degrees.
9. Which are the gasses that get precipitated in the form of bubbles when the battery is overcharged?
a) Hydrogen and helium
b) Nitrogen and hydrogen
c) Hydrogen and oxygen
d) Nitrogen and oxygen
Explanation: The major factor affecting the charging is gassing wherein excessive hydrogen and oxygen bubbles due to overcharging may wash away active material on the plates, decreasing the charging rate. Due to which overcharging must be avoided.
10. Which of the following has no effect on overheating?
a) Weak mixture
b) Defective cooling system
d) Engine speed
Explanation: Metallic particle on insulator tip, eroded electrode indicates that the plug as running overheated this may arise due to weak mixture, defective cooling system, loose-fitting causing the exhaust gases to leak.
11. Which among the following is not a factor affecting the charging of the battery?
a) State of charge
d) Discolouring of electrolyte
Explanation: The factors affecting the charging of a battery are temperature, area of the plate, state of charge, gassing, impurities, corrosion of terminal, and clamps whereas the discoloring of the electrolyte has no effect of charging of the battery.
12. Which of the following converts the 3Phase AC current flowing from the alternator and charges the battery with DC current as shown below?
Explanation: The alternator produces 3 phase AC current which cannot be directly supplied to the battery which operates on DC current therefore a rectifier consisting of 3 diodes rectifies this 3 phase according to DC and charges the battery.
13. Which of the following helps in the identification of the state of the battery?
a) Latent heat of vaporization
c) Latent heat of the cooling
d) Specific gravity
Explanation: The state of the battery charge is checked most commonly by the specific gravity. The temperature is also recorded and the gravity reading is corrected accordingly. This is then compared with the chart supplied by the battery manufacturer to ascertain whether the battery needs to be charged or not.
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