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Charge Controllers

• Charge Controller Features

• Charge Controller Types

• Charge Controller Set Points

• Charge Controller Applications

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Charge Controllers

Charge controllers manage interactions and energy flows between a PV array, battery, and electrical load.

Charge controllers manage interactions and energy flows between a PV array, battery, and electrical load.

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Battery Charging

Single-stage battery charging is simpler to manage, but multistage battery charging brings battery to a higher state of charge.

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Overcharge Protection

Charge controllers protect batteries from overcharge by terminating or limiting charging current.

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Overdischarge Protection

Charge controllers protect batteries from overdischarge by controlling discharge current.

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Charge Controller Status

Most charge controllers include displays or LEDs to indicate battery voltage, state of charge, and/or presenting operating mode.

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Shunt Charge Controllers

Shunt charge controllers control charging current by short-circuiting the array.

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Series Charge Controllers

Series charge controllers control charging current by opening the circuit from the array.

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Pulse-Width Modulation

Pulse-width modulation (PWM) simulates a lower current level by pulsing a higher current level ON and OFF for short intervals.

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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.

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Diversionary Charge Controller

A diversionary charge controller regulates charging current by diverting excess power to an auxiliary load when the battery is fully charged.

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Hybrid Charge Controller

Charge controllers designed for hybrid PV systems must manage multiple current source simultaneously.

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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 .

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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.

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Voltage Regulation Setpoints

The optimal voltage regulation setpoints depends on the type of battery and charge controller.

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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.

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Equalization Charge

The equalization setpoint brings the battery voltage to a level that is higher than the normal charge regulation voltage.

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Setpoint Adjustments

Setpoints are adjusted with controls inside the charge controller.

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Battery Temperature Sensors

Temperature probes are placed between batteries and connect to a charge controller to compensate for the charge regulation setpoint.

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Charge Controller Selection Criteria

Many criteria should be considered when selecting charge controllers for PV systems.

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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.

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Voltage Sense Terminals

Additional battery voltage sense conductors are often used with larger charge controllers to avoid voltage drop and effects on setpoints.

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Multiple Arrays

Larger PV system often use independent charge controllers for each array source circuit.

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Battery Banks With Charge Controllers

Separate charge controllers are usually recommended for charging independent battery banks.

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Battery Banks With One Charge Controller

In some cases, a single charge controller may be used to charge independent battery banks.

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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 self-limiting.

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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.