NABCEP Battery Storage Systems & Energy Storage 2

Question 1

In an AC-coupled battery storage system, the battery inverter connects to which bus?

Accepted Answer

The AC electrical panel or AC bus

Answer

The DC output terminals of the solar modules

Answer

The DC input of the grid-tied solar inverter

Answer

The grounding electrode system

Question 2

Which NFPA standard specifically addresses the installation of stationary lead-acid and lithium-ion battery systems in commercial buildings?

Accepted Answer

NFPA 855

Answer

NFPA 70 (NEC)

Answer

NFPA 72

Answer

NFPA 101

Question 3

What is 'cycle life' as applied to battery storage systems?

Accepted Answer

The number of complete charge/discharge cycles before capacity falls below a specified threshold

Answer

The calendar age of a battery in years

Answer

The maximum discharge current the battery can supply

Answer

The time required to complete one full charge cycle

Question 4

Which lithium battery chemistry is most susceptible to thermal runaway if overcharged or mechanically damaged?

Accepted Answer

Lithium nickel manganese cobalt oxide (NMC)

Answer

Lithium iron phosphate (LFP)

Answer

Lithium titanate (LTO)

Answer

Lithium polymer with ceramic separator

Question 5

What is the primary safety concern when installing flooded lead-acid batteries in an enclosed indoor space?

Accepted Answer

Hydrogen gas off-gassing during charging creating explosion risk

Answer

Electromagnetic interference with PV inverters

Answer

Excessive weight loading the floor structure

Answer

DC arc flash from terminal connections

Question 6

For a grid-tied battery storage system to provide backup power during a utility outage, it must include which feature?

Accepted Answer

An automatic transfer switch or islanding-capable inverter

Answer

A DC disconnect rated for battery voltage

Answer

A net metering agreement with the utility

Answer

A separate PV combiner box for the storage array

Question 7

When sizing a battery system for a residential time-of-use (TOU) rate optimization application, what is the primary design driver?

Accepted Answer

Load during high-rate utility pricing periods

Answer

Peak solar irradiance at the site

Answer

The short-circuit current of the PV array

Answer

The wire gauge of the AC service entrance