Charge Controllers
• Charge Controller Features
• Charge Controller Types
• Charge Controller Set Points
• Charge Controller Applications
1
Charge Controllers
Charge controllers
manage interactions
and energy flows
between a PV array,
battery, and
electrical load.
2
Battery Charging
Single-stage battery charging
is simpler to manage, but
multistage battery charging
brings battery to a higher
state of charge.
3
Overcharge Protection
Charge controllers
protect batteries from
overcharge by
terminating or limiting
charging current.
4
Overdischarge Protection
Charge controllers
protect batteries from
overdischarge by
controlling discharge
current.
5
Charge Controller Status
Most charge controllers
include displays or LEDs
to indicate battery voltage,
state of charge, and/or
presenting operating
mode.
6
Shunt Charge Controllers
Shunt charge controllers
control charging current
by short-circuiting the
array.
7
Series Charge Controllers
Series charge controllers
control charging current by
opening the circuit from the
array.
8
Pulse-Width Modulation
Pulse-width modulation
(PWM) simulates a lower
current level by pulsing a
higher current level ON and
OFF for short intervals.
9
Maximum Power Point Tracking
Maximum power point
tracking manipulates
the load or output
voltage of an array in
order to maintain
operation at or near the
maximum power point
under changing
temperature and
irradiance conditions.
10
Diversionary Charge Controller
A diversionary charge controller regulates
charging current by diverting excess power to an
auxiliary load when the battery is fully charged.
11
Hybrid Charge Controller
Charge controllers
designed for hybrid
PV systems must
manage multiple
current source
simultaneously.
12
Ampere-Hour Charge Controller
Ampere-hour charge
controllers track
cumulative number of
ampere-hours applied
to a battery bank and
discontinue charging
at a preset total .
13
Charge Regulation Setpoints
Charge regulation
setpoints are the
voltage levels at which
the charge controller
interrupts or limits the
charging current from
the array to the battery
bank.
14
Voltage Regulation Setpoints
The optimal voltage regulation setpoints depends
on the type of battery and charge controller.
15
Load Control Setpoints
Load control setpoints
are the voltage levels
at which the charge
controller interrupts or
limits the discharging
current from the battery
bank to the loads.
16
Equalization Charge
The equalization setpoint
brings the battery voltage
to a level that is higher
than the normal charge
regulation voltage.
17
Setpoint Adjustments
Setpoints are adjusted
with controls inside the
charge controller.
18
Battery Temperature Sensors
Temperature probes are
placed between batteries
and connect to a charge
controller to compensate
for the charge regulation
setpoint.
19
Charge Controller Selection Criteria
Many criteria should be
considered when selecting
charge controllers for PV
systems.
20
Voltage Drop
Long conductors between
a charge controller and a
battery bank have
resistance that causes
voltage drops. Voltage
drops affect the voltage
measured by the charge
controller.
21
Voltage Sense Terminals
Additional battery voltage
sense conductors are
often used with larger
charge controllers to avoid
voltage drop and effects
on setpoints.
22
Multiple Arrays
Larger PV system often
use independent charge
controllers for each
array source circuit.
23
Battery Banks With Charge Controllers
Separate charge
controllers are usually
recommended for
charging independent
battery banks.
24
Battery Banks With One Charge Controller
In some cases, a single charge controller may
be used to charge independent battery banks.
25
Self-Regulating PV Systems
To balance a charge to
and from the battery in a
self-regulating PV system,
the load must be well
defined, the battery must
be oversized, and the
array current must be selflimiting.
26
Low-Voltage Modules
Low-voltage modules
control current into a
battery bank without a
charge controller
because their current
automatically falls as the
battery reaches full
charge.
27