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These 10 free BSC questions are organized by exam domain, so you can see how each part of the Battery, Starting, & Charging System Diagnostic Certification - EECS800 blueprint is tested. Reveal the answer and explanation under each question.
During bench charging, a flooded lead-acid battery becomes abnormally hot. The technician decides to interrupt charging and reaches for the negative clamp. The charger's power switch is accessible away from the battery. What takes priority?
Correct answer: C - Switch off charger power before disconnecting the battery leads.
After measuring current, a technician disconnects a digital multimeter from the circuit. The red lead is still in the 10-A jack. Before placing the probes across a 12-V battery to measure terminal voltage, the meter must be configured with:
Correct answer: A - The red lead in the V/Ω jack and DC voltage selected.
A marine battery has the correct dimensions, polarity, chemistry, and voltage for an engine requiring at least 800 CCA. The only cranking rating visible on the replacement's label is 900 MCA. Is that sufficient evidence that it meets the engine's cranking requirement?
Correct answer: C - No; MCA describes cranking performance at a warmer temperature than CCA.
As a serviceable flooded lead-acid battery supplies a steady load, normal discharge produces which paired changes?
Correct answer: B - Specific gravity falls, and lead sulfate forms at both electrodes.
An EECS800 assessment takes only seconds in a warm service bay and reports an estimated 680 CCA. A customer asks whether 680 A actually flowed through the tester's clamps. Which explanation accurately describes this result?
Correct answer: A - Cranking capability was estimated from the battery's response to a small electrical signal.
The previous battery record for a car lists 650 CCA and flooded construction. Its approved replacement is labeled 12-V AGM, 760 CCA. During EECS800 setup, which combination evaluates the battery now installed?
Correct answer: D - 12 V; AGM; 760 CCA
Two 950-CCA batteries supply a diesel's 12-V system in parallel. To judge the left battery individually, a technician enters 950 CCA and connects the EECS800 to its posts without disconnecting the parallel cables. An estimated 1,200 CCA is reported. What has been established about the left battery?
Correct answer: A - The reading also reflects the battery connected in parallel.
A delivery van returns with an undercharged battery. At 2,000 rpm with the headlights and blower on, alternator B+ measures 14.6 V relative to its case, while the battery posts measure 13.7 V. The positive charging path drops 0.80 V and the ground path drops 0.10 V; the vehicle allows a maximum of 0.20 V per path. Where does the evidence direct the repair?
Correct answer: B - The alternator-to-battery positive cable and connections
A light-duty diesel cranks slowly with a correctly specified, fully charged battery that has passed its performance tests. Cranking current is 340 A against a specified 140-220 A range, and both cable paths meet their loaded voltage-drop limits. A coworker concludes that the starter must be defective. Which additional check addresses the main alternative explanation?
Correct answer: D - Check the engine for excessive resistance to rotation.
Battery load-test record: isolated, fully charged 12-V flooded battery; 700 CCA; 350 A applied for 15 seconds; internal battery temperature 30°F; voltage at 15 seconds 9.35 V. The manufacturer's minimum is 9.10 V at 30°F and 9.60 V at 70°F or above. A service writer flags the result as a failure because it is below 9.60 V. How should this record be classified?
Correct answer: A - Passing this load test; the result does not support replacement.
The BSC exam also covers these domains. Drill them in the full free practice test:
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