easyMultiple ChoiceObjective-mapped
Laptop Battery Not Charging: BMS Failure Diagnosis
A user reports that their laptop battery no longer charges and the system only runs when plugged in. You test the AC adapter and it outputs correct voltage. Inside the battery, which component is most likely failed?
Quick Answer
The answer is a faulty battery management system (BMS). When a laptop battery stops charging but the AC adapter is confirmed to output correct voltage, the BMS is the most likely failed component because it governs the charging logic and communication between the battery cells and the laptop. Even if the individual lithium-ion cells are healthy, a failed BMS will prevent the battery from accepting a charge or reporting its status, leaving the system to run only on AC power. On the CompTIA A+ Core 1 220-1201 exam, this scenario tests your understanding of battery charging circuitry and the BMS’s role as the “gatekeeper” for power flow. A common trap is to assume the cells themselves are dead, but the BMS failure is the root cause when the adapter is verified working. Remember the memory tip: “BMS blocks the charge” — if the adapter is good but the battery won’t charge, suspect the management system, not the cells.
⚠ Common exam trap
The 220-1201 exam often tests the misconception that battery failure always means the cells are dead, but the trap here is that the BMS can fail independently and prevent charging while the cells remain functional, especially when the AC adapter and laptop power path are verified working.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The battery management system (BMS) is faulty.
The battery management system (BMS) is the circuit board inside the battery pack that controls charging, monitors cell voltage and temperature, and communicates with the laptop. Since the AC adapter outputs correct voltage and the laptop runs on AC power, the BMS is the most likely failed component because it can prevent charging even if the lithium-ion cells are healthy. A faulty BMS may stop communicating with the laptop's embedded controller, causing the system to treat the battery as absent or non-functional.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The lithium-ion cells have degraded.
Why it's wrong here
Degraded cells would still show some charge or cause shorter runtime, not a complete failure to charge.
- ✓
The battery management system (BMS) is faulty.
Why this is correct
A failed BMS prevents the battery from communicating with the charger and accepting power, causing no charging.
- ✗
The DC jack on the laptop is loose.
Why it's wrong here
The DC jack issue would affect power to the whole system, but the system runs fine on AC adapter.
- ✗
The laptop's motherboard charging circuit is damaged.
Why it's wrong here
If the motherboard circuit were bad, the system wouldn't run on AC power either.
Go deeper
Related to this question
About these practice questions
One of 972 original 220-1201 practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
Same concept, more angles
1 more way this is tested on 220-1201
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A customer complains that their laptop battery no longer holds a charge and the laptop only works when plugged in. The technician confirms the battery is removable. What is the most appropriate first step in servicing this issue?
easy- A.Update the battery driver in Device Manager.
- B.Run a battery calibration utility from the manufacturer.
- ✓ C.Power off the laptop and remove the battery.
- D.Replace the AC adapter to see if the charging circuit is faulty.
Why C: The correct first step is to power off the laptop and remove the battery. This ensures safety and prevents electrical shorts or damage during replacement. After removal, the technician can install a new battery.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 220-1201 practice question is part of Courseiva's free CompTIA certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 220-1201 exam.