Arizona AZ L-95 Battery
Energy Storage Systems
Contractor Practice Exam |
Questions, Verified Answers &
Detailed Rationales |
Complete Contractor License
Exam Prep Study Guide |
Updated 2026
1. What is the primary function of a battery energy
storage system (BESS)?
A. To generate electricity from natural gas
B. To store electrical energy for later use
C. To increase utility voltage automatically
D. To eliminate all electrical loads
Correct answer: To store electrical energy for later use
Rationale: A BESS stores electrical energy, typically in
batteries, and releases that energy when needed for
backup power, load shifting, peak shaving, renewable-
energy integration, or other applications.
2. Which battery chemistry is most commonly
associated with modern stationary lithium-ion energy
storage systems?
A. Nickel-cadmium only
B. Lithium iron phosphate
C. Lead peroxide only
D. Carbon-zinc
,Correct answer: Lithium iron phosphate
Rationale: Lithium iron phosphate (LFP) is widely used
in stationary BESS applications because of its thermal
stability, long cycle life, and relatively favorable safety
characteristics compared with some other lithium-ion
chemistries.
3. What is the purpose of a battery management system
(BMS)?
A. To provide building lighting
B. To monitor and control battery operating conditions
C. To replace the utility transformer
D. To operate fire sprinklers mechanically
Correct answer: To monitor and control battery
operating conditions
Rationale: The BMS monitors parameters such as
voltage, current, temperature, state of charge, and
battery condition and can initiate protective actions
when unsafe or abnormal conditions occur.
4. What does SOC stand for in battery terminology?
A. System Output Control
B. State of Charge
C. Safety Operating Circuit
D. Storage Overcurrent
Correct answer: State of Charge
Rationale: State of charge indicates the amount of
energy remaining in a battery relative to its usable
capacity, normally expressed as a percentage.
5. What does SOH generally represent?
,A. State of Health
B. System Operating Heat
C. Safety Output Handling
D. Storage Overhead
Correct answer: State of Health
Rationale: State of health is an indication of the
battery's condition and remaining performance
capability compared with its original or reference
condition.
6. What is the primary purpose of an inverter in an AC-
coupled BESS?
A. Convert AC to gasoline
B. Convert DC battery power to AC and/or AC to DC as required
C. Increase battery temperature
D. Remove the need for overcurrent protection
Correct answer: Convert DC battery power to AC and/or
AC to DC as required
Rationale: Batteries store energy as DC. A bidirectional
inverter/PCS allows energy to flow between the DC
battery system and the AC electrical system.
7. What does PCS commonly mean in a BESS?
A. Power Conversion System
B. Protective Cooling Switch
C. Primary Circuit Sensor
D. Power Conduit Standard
Correct answer: Power Conversion System
Rationale: The PCS performs power conversion between
the battery's DC system and the AC electrical system
and commonly provides controlled charging and
discharging.
, 8. What is the purpose of an energy management
system (EMS)?
A. To manage system operation and energy flow
B. To physically manufacture batteries
C. To replace every circuit breaker
D. To extinguish battery fires
Correct answer: To manage system operation and
energy flow
Rationale: An EMS coordinates operating strategies
such as charging, discharging, load management,
renewable integration, and sometimes grid-support
functions.
9. Which measurement describes the electrical pressure
in a circuit?
A. Ampere
B. Ohm
C. Volt
D. Watt-hour
Correct answer: Volt
Rationale: Voltage is electrical potential difference and
is commonly described as electrical pressure.
10. Which unit measures electric current?
A. Volt
B. Ampere
C. Watt
D. Ohm
Correct answer: Ampere
Energy Storage Systems
Contractor Practice Exam |
Questions, Verified Answers &
Detailed Rationales |
Complete Contractor License
Exam Prep Study Guide |
Updated 2026
1. What is the primary function of a battery energy
storage system (BESS)?
A. To generate electricity from natural gas
B. To store electrical energy for later use
C. To increase utility voltage automatically
D. To eliminate all electrical loads
Correct answer: To store electrical energy for later use
Rationale: A BESS stores electrical energy, typically in
batteries, and releases that energy when needed for
backup power, load shifting, peak shaving, renewable-
energy integration, or other applications.
2. Which battery chemistry is most commonly
associated with modern stationary lithium-ion energy
storage systems?
A. Nickel-cadmium only
B. Lithium iron phosphate
C. Lead peroxide only
D. Carbon-zinc
,Correct answer: Lithium iron phosphate
Rationale: Lithium iron phosphate (LFP) is widely used
in stationary BESS applications because of its thermal
stability, long cycle life, and relatively favorable safety
characteristics compared with some other lithium-ion
chemistries.
3. What is the purpose of a battery management system
(BMS)?
A. To provide building lighting
B. To monitor and control battery operating conditions
C. To replace the utility transformer
D. To operate fire sprinklers mechanically
Correct answer: To monitor and control battery
operating conditions
Rationale: The BMS monitors parameters such as
voltage, current, temperature, state of charge, and
battery condition and can initiate protective actions
when unsafe or abnormal conditions occur.
4. What does SOC stand for in battery terminology?
A. System Output Control
B. State of Charge
C. Safety Operating Circuit
D. Storage Overcurrent
Correct answer: State of Charge
Rationale: State of charge indicates the amount of
energy remaining in a battery relative to its usable
capacity, normally expressed as a percentage.
5. What does SOH generally represent?
,A. State of Health
B. System Operating Heat
C. Safety Output Handling
D. Storage Overhead
Correct answer: State of Health
Rationale: State of health is an indication of the
battery's condition and remaining performance
capability compared with its original or reference
condition.
6. What is the primary purpose of an inverter in an AC-
coupled BESS?
A. Convert AC to gasoline
B. Convert DC battery power to AC and/or AC to DC as required
C. Increase battery temperature
D. Remove the need for overcurrent protection
Correct answer: Convert DC battery power to AC and/or
AC to DC as required
Rationale: Batteries store energy as DC. A bidirectional
inverter/PCS allows energy to flow between the DC
battery system and the AC electrical system.
7. What does PCS commonly mean in a BESS?
A. Power Conversion System
B. Protective Cooling Switch
C. Primary Circuit Sensor
D. Power Conduit Standard
Correct answer: Power Conversion System
Rationale: The PCS performs power conversion between
the battery's DC system and the AC electrical system
and commonly provides controlled charging and
discharging.
, 8. What is the purpose of an energy management
system (EMS)?
A. To manage system operation and energy flow
B. To physically manufacture batteries
C. To replace every circuit breaker
D. To extinguish battery fires
Correct answer: To manage system operation and
energy flow
Rationale: An EMS coordinates operating strategies
such as charging, discharging, load management,
renewable integration, and sometimes grid-support
functions.
9. Which measurement describes the electrical pressure
in a circuit?
A. Ampere
B. Ohm
C. Volt
D. Watt-hour
Correct answer: Volt
Rationale: Voltage is electrical potential difference and
is commonly described as electrical pressure.
10. Which unit measures electric current?
A. Volt
B. Ampere
C. Watt
D. Ohm
Correct answer: Ampere
