Automotive Batteries Questions and Answers

Answer: C

A difference of more than about fifty points of specific gravity between cells indicates an internal fault that charging will not cure. A low level does affect a reading, which makes the last option a genuine check to make first. The shared behaviour explains why these belong together and the differences explain why both exist. Naming what changes and what stays the same is the reliable route through questions of this shape. Checking the units of each quantity catches a wrong formula before the arithmetic begins.

Answer: D

Only the water evaporates or is lost by electrolysis, so water alone is added. Adding acid raises the density beyond the correct figure and damages the plates. Tap water introduces minerals that poison the plates. Naming the cost of a choice alongside its benefit is what turns a fact into a design decision. Working the distinction through on a single concrete case fixes it more firmly than any rule of thumb. Tracing the requirement back to the physical constraint that produces it makes the answer follow.

Answer: A

Calcium alloy grids raise the gassing voltage so little water is lost, and the cells are sealed. Antimony was the older alloy and gasses more. Recombination caps genuinely return some water, which makes the last option a real feature. Reading the definition literally, rather than recalling a summary, avoids the usual confusion. A symptom that appears under one condition and not another is what narrows the diagnosis quickly. Reading the definition literally, rather than recalling a formula, is the reliable route through questions of this shape.

Answer: B

Absorbed glass mat batteries hold the electrolyte in a fibreglass separator, which allows a high current and permits mounting in any orientation. Gel batteries thicken the acid instead, which is a genuinely different immobilisation method. Most errors here come from carrying across a result from a neighbouring case where it does not hold. The order in which the effects act is what decides the outcome, so it is worth establishing first. Most errors here come from carrying a result across from a neighbouring case where it does not hold.

Answer: C

Stop start cycling discharges and recharges the battery hundreds of times a day, which destroys a conventional flooded battery. Deep cycling is better suited to gel or traction batteries. Cranking current is high but not the defining advantage. Naming what changes and what stays the same is the reliable route through questions of this shape. Checking which component actually carries the load settles most questions of this kind at once. Checking the units of each quantity catches a wrong formula before the arithmetic begins.

Answer: D

The energy management system tracks battery ageing and adapts its charging strategy, so a new battery must be registered with a scan tool. Omitting it leaves the system charging for the old battery's condition. Pre-charging is good practice in any case. Working the distinction through on a single concrete case fixes it more firmly than any rule of thumb. Tracing the requirement back to the physical constraint that produces it makes the answer follow. Checking the units of each quantity catches a wrong formula before the arithmetic begins.

Answer: A

Energy management measures state of charge and health and commands the alternator through the engine controller, charging hard on overrun and little under acceleration. The last option describes part of that strategy inverted, which is why it tempts. A symptom that appears under one condition and not another is what narrows the diagnosis quickly. Naming the cost of a choice alongside its benefit is what turns a fact into a design decision.

Answer: B

Recuperation takes energy that would be wasted as heat in the brakes and stores it, which is a form of regeneration available on any vehicle. Threshold charging is a real simple strategy, which makes the last option a plausible alternative approach. The order in which the effects act is what decides the outcome, so it is worth establishing first. Reading the definition literally, rather than recalling a summary, avoids the usual confusion. Most errors here come from carrying a result across from a neighbouring case where it does not hold.

Answer: C

A load tester draws roughly half the cold cranking amps and the voltage must stay above a defined figure. Conductance testing achieves a similar assessment without a heavy load, which makes the last option a genuine modern alternative. Checking which component actually carries the load settles most questions of this kind at once. Most errors here come from carrying across a result from a neighbouring case where it does not hold. Naming the cost of a choice alongside its benefit is what turns a fact into a design decision.

Answer: D

A conductance tester injects a small signal and infers plate condition, so it needs no heavy current and can test in situ. Neither method measures capacity directly. Cell faults show in both tests to some degree. Tracing the requirement back to the physical constraint that produces it makes the answer follow. Naming what changes and what stays the same is the reliable route through questions of this shape. A limit that survives making every external component ideal is an intrinsic one, and worth knowing for that reason.