ARDUINO SOLAR CHARGE CONTROLLER ( Version 2.0)
One year ago, I began building my own solar system to provide power for my village house.Initially I made a LM317 based charge controller and an Energy meter for monitoring the system.Finally I made PWM charge controller.In April-2014 I posted my PWM solar charge controller designs on the web,it became very popular. Lots of people all over the world have built their own. So many students have made it for their college project by taking help from me.I got several mails every day from people with questions regarding hardware and software modification for different rated solar panel and battery. A very large percentage of the emails are regarding the modification of charge controller for a 12Volt solar system.
You can see my other version charge controllers
To solve this problem I made this new version charge controller so that any one can use it without changing the hardware and software. I combine both the energy meter and charge controller in this design.
Specification of version-2 charge controller :
1.Charge controller as well energy meter
2. Automatic Battery Voltage Selection (6V/12V)
3.PWM charging algorithm with auto charge set point according to the battery voltage
4.LED indication for the state of charge and load status
5. 20×4 character LCD display for displaying voltages,current,power,energy and temperature.
7.Reverse current flow protection
8.Short Circuit and Over load protection
9. Temperature Compensation for Charging
Electrical specifications :
1.Rated Voltage= 6v /12V
2.Maximum current = 10A
3.Maximum load current =10A
4.Open Circuit Voltage = 8-11V for 6V system /15 -25V for 12V system
Step 1: Parts and Tools Required :
8.Transistors ( 2N3904 or 2N2222)
9.Resistors( 100k x 2, 20k x 2,10k x 2,1k x 2, 330ohm x 5)
10.Ceramic Capacitors (0.1uF x 2)
11.Electrolytic Capacitors ( 100uF and 10uF)
14.Bi Color LED ( Amazon )
19.Push Button ( Amazon )
1.Soldering Iron ( Amazon )
2.Wire Cutter and Stripper ( Amazon )
3.Screw Driver ( Amazon )
4.Cordless Drill ( Amazon )
5.Dremel ( Amazon )
6.Glue Gun ( Amazon )
7.Hobby Knife ( Amazon )
Step 2: How The Charge Controller Works :
The heart of of the charge controller is Arduino nano board.The arduino MCU senses the solar panel and battery voltages.According to this voltages it decides how to charge the battery and control the load.
The amount of charging current is determined by difference between battery voltage and charge set point voltages. The controller uses two stages charging algorithm.According to the charging algorithm it gives a fixed frequency PWM signal to the solar panel side p-MOSFET. The frequency of PWM signal is 490.20Hz(default frequency for pin-3). The duty cycle 0-100% is adjusted by the error signal.
The controller gives HIGH or LOW command to the load side p-MOSFET according to the dusk/dawn and battery voltage.
The full schematic is attached bellow.
For more detail: ARDUINO SOLAR CHARGE CONTROLLER ( Version 2.0)