20 Amp 12/24V PWM Solar Charge Controller

Intelligent 20A PWM solar charge controller with lithium battery and lead acid battery switching function, DC 12V/24V automatic adjustment, USB output, LCD display, advanced design.
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Delivery date: 6-20 days
Products specifications

Compact 12V/24V PWM solar charge controller is an ideal device for solar energy control system, current 20 amp, with USB port, digital LCD display, easy to use.


Model ATO-PWM-20
DC Voltage 12V/24V Auto Adapt
Charge Current 10A 20A 30A
Discharge Current 10A 10A 10A
USB output 5V 2A
Max Solar Input < 41V
Equalization lithium battery(LIT):12.8V
Lead acid battery(BAT):14.4V
Float Lead acid battery: 13.7V (Defaults, Adjustable range 13-15V)
Lithium battery: 12.0V (Defaults, Adjustable range 11.5-12.8V)
Undervoltage Protection Lead acid battery: 10.7V (Defaults, Adjustable range 9.0-11.5V)
Lithium battery: 10.7V (Defaults, Adjustable range9.0-11.0V)
Disstarge Reconnect Lead acid battery: 12.6V (Defaults, Adjustable range 11.5-13V)
Lithium battery: 11.6V (Defaults, Adjustable range 11.0-11.7V)
Standby Current < 10mA
Operating Temperature -35~+60℃
Dimension 133mm*70mm*35mm
Weight 140g


  • Industrial grade main control chip is adopted. Charge and discharge parameters can be adjusted.

  • Complete 3-stage PWM charging management.

  • Built-in over current, short circuit protection, open circuit protection, reverse connection protection, are self-recovery, no damage to the controller.

  • Double MOS backflow circuit with ultra-low calorific value.

  • Switch function of rechargeable lithium battery and lead-acid battery (long press 3 seconds at the interface of battery type to enter the switch setting), the default is lithium battery.

Wiring Diagram
pwm solar charge controller wiring diagram
Tips: What is The Difference Between MPPT and PWM Charge Controller?

  • Charging Method
    The difference between the PWM controller and the MPPT solar controller is that they charge differently. The PWM is charged in a three-stage charging mode. MPPT is the maximum power tracking technology, and the charging efficiency can be increased to about 30%.
  • Voltage
    When the MPPT solar controller is used, the charging efficiency is more obvious when the high-voltage solar panel is used to charge the low-voltage battery. If the voltage of the solar energy and the battery are the same, for example, it is 12V, then the difference between the practical PWM and the MPPT controller is not very big
  • Power
    If the power of the solar panel is small, it is more appropriate to select a PWM controller. Relatively speaking, if the power of the solar panel is large, MPPT is selected.
    Solar controllers, because the cost of MPPT solar controllers is high, if your solar panel power is small, it is a waste of MPPT controller.
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