Deck 7: Charge Controllers

Question 1

Regarding the selection of an MPPT controller, how is the total input voltage calculated?

Answer 1

The total input voltage is calculated by adding up all of the open circuit voltages (Voc) of the series connected array modules and then multiplying by the voltage correction factor found in Table 690.7 of the NEC.

Question 2

The average energy gain of a PV system when using ____________________ is 10% or more.

Answer 2

MPPT
Maximum Power Point Tracking
Maximum Power Point Tracking (MPPT)

Question 3

In what situation does the National Electric Code require charge controllers with a PV system?

Answer 3

The National Electrical Code requires equipment like charge controllers to control the charging process for PV systems using batteries.

Question 4

When choosing a standard charge controller, how must it relate with system voltage?

Question 5

What are the two categories of charge controllers?

Question 6

Explain two common scenarios where overdischarge can occur.

Question 7

How does a shunt controller prevent overcharging?

Question 8

Many MPPT charge controller manufacturers rate their controllers by the maximum array ____________________ allowed at a specific voltage.

Question 9

____________________ is when a fully charged battery continues to receive a charging current.

Question 10

When a battery has a low state of charge, the charge controller will deliver a large charging current in an effort to charge the battery in a timely manner.

Question 11

The charge termination set point (CTSP) is the voltage level setting of a charge controller that results in a charging current being supplied to the batteries.

Question 12

A PV system that has batteries but no charge controller is often referred to as a(n) _____________________ PV system.

Question 13

Low voltage disconnect (LVD) is the amount of voltage set on a charge controller that when reached causes system loads to be disconnected to prevent battery overdischarging.

Question 14

The series type charge controller uses a sensor (instead of a blocking diode) to prevent reverse current flow at night.

Question 15

In ____________________ temperatures, the charge termination set point (CTSP) is reached before the battery has a chance to become fully charged.

Question 16

The pulse width modulation controller diverts excess charging current to some type of electrical load such as a fan or heater.

Question 17

A low voltage disconnect (LVD) feature allows the charge controller to automatically shut down DC loads when the battery reaches a specified ____________________ limit.

Question 18

A(n) ____________________ is a series of functions programmed into a charge controller so that the controller will optimize system performance during various levels of battery discharging and charging.

Question 19

A PV system charge controller has a primary function of preventing the ____________________ used in a PV system from being overcharged by the PV system array.

Question 20

How does a series type charge controller prevent overcharging?