MPPT SCCO v1.0

The SCCO v1.0 is a MPPT solar charger with multi chemistry battery support and a charging current of up to 4A based on the CN3795 IC.
The board features an adjustable output of up to 20V 2A. This device is mainly designed for low power applications such as IoT-devices.

Specifications:

  • 6.6V – 30V 4A (solar) input
  • Up to 20V 4A charging current, set with external resistors, input voltage has to be higher than charging voltage (VReg)
  • Support for Li-Ion, LiFePO4 batteries (single and multi cell support)
  • Up to 28V 2A output, adjustable with potentiometer, VReg has to be to lower then the desired output voltage
  • MPPT functionality, MPPT voltage set with external resistors
  • LED status indication (if the LED is on, the battery is being charged, if the LED is off the charging is done or VIN is under VBAT or VIN is under 6.5V)
  • Can be used as voltage source if battery is absent
  • Overvoltage protection (no undervoltage or over current protection)

Pictures:

Demonstration video:

Resistor combinations:

External resistors for setting the VReg and VMPPT voltage are in 1206 package.

VReg resistor combinations:

  • 4.2 volts: R1 = 20.000 Ohms , R2 = 8060 Ohms
  • 3.7 volts: R1 = 20.300 Ohms , R2 = 9770 Ohms

VMPPT resistor combinations:

  • 9V: R3 = 2000 Ohms, R4 = 13.000 Ohms
  • 12V: R3 = 2200 Ohms, R4 = 20.000 Ohms
  • 18V: R3 = 2000 Ohms, R4 = 28.000 Ohms
  • 24V: R3 = 2000 Ohms, R4 = 39.000 Ohms

Charging current:

RCS\;value\;=\dfrac {0,12} {Charging\;current}

External resistor for setting the battery charging current (RCS) is in 2512 (1 watts) package.

RCS resistor values:

  • 1A = 0.12 Ohms
  • 2A = 0.06 Ohms
  • 3A = 0.04 Ohms
  • 4A = 0.03 Ohms

Efficiency:

Please note: Always use battery protection systems when handling with batteries.