servicing commercial batteries ch16

1. What is the correct service recommendation for a battery whose charging voltage increases to 15.8 volts at a 40-amp charge rate after 2 minutes?

• a. Charge it at a lower charge rate

• b. Scrap the battery

• c. Put the battery on a trickle charge

• d. Return the battery to service-it is fully charged

2. Which of the following statements best explains the term battery capacity?

• a. Battery capacity is the combined volume and weight of cell plates.

• b. Capacity is the volume of battery electrolyte.

• c. Capacity is the ability of a battery to hold an electrical charge.

• d. Capacity is the ability of a battery to deliver amperage at an acceptable voltage.

3. At what level is a loss of battery capacity unacceptable?

• a. When a battery loses more than 20% of its electrolyte

• b. A loss of 20% or more of its original supply of electrical power

• c. A loss of 10% or more of plate active material

• d. Whenever the battery becomes sulfated

4. Technicians A and B were discussing the 0.2 amps of current drawn from the battery after the ignition was switched off. Technician A says that all late-model commercial vehicles continue to draw a small amount of current from the batteries when the ignition is switched off. Technician B says that key-off electrical loads are typically produced by control modules before they switch to sleep mode. Who is correct?

• a. Technician A

• b. Technician B

• c. Both Technician A and Technician B

• d. Neither Technician A nor Technician B

5. Two technicians were examining the results of a conductance tests on three batteries in a battery bank. One battery had close to 100% of its rated capacity, another 50%, and the

other less than 10%. Technician A says that failed batteries were likely sulfated. Technician B said the batteries did not receive the same charging voltage. Who is correct?

• a. Technician A

• b. Technician B

• c. Both Technician A and Technician B

• d. Neither Technician A nor Technician B

6. After a 15-second high-amperage discharge load test, the cut-off voltage of a 12-volt 500 CCA battery was 9.5 volts when loaded with 250 amps. The battery temperature was 80°F (27°C). What is the correct service recommendation?

• a. Scrap the battery

• b. Charge and retest the battery

• c. Return the battery to service

• d. Recommend replacing the battery with one having a smaller CCA rating

7. Technician A says that a fully charged battery should have an open-circuit voltage of at least 12.25 volts. Technician B says that, if the battery has been recently charged, a light load applied to the battery for a few minutes removes a surface charge. Who is correct?

• a. Technician A

• b. Technician B

• c. Both Technician A and Technician B

• d. Neither Technician A nor Technician B

8. Technician A says that conductance testing measures a battery's internal resistance. Technician B says that all conductance testing must be performed on fully charged batteries since internal resistance changes according to the state of charge. Who is correct?

• a. Technician A

• b. Technician B

• c. Both Technician A and Technician B

• d. Neither Technician A nor Technician B

9. Technician A says that a set of four batteries connected in a series-parallel arrangement that produces 24 volts can be charged while connected using a 12-volt battery charger. Technician B says that to charge the batteries, only a 24-volt charger can be used. Who is correct?

• a. Technician A

• b. Technician B

• c. Both Technician A and Technician B

• d. Neither Technician A nor Technician B

10. How does battery resistance change?

• a. It decreases as a battery moves from 0% to 100% charged

• b. It drops to as little as 3 ohms as it ages

• c. Resistance drops as the amount of amperage supplied by the battery goes up

• d. Resistance typically increases with age