5 solar battery charger with charging controller and regulator

solar battery charger with charging controller and regulator jpg

Solar power is a good and clean source of electricity.But  before it is used in houses, it is first used to charge battery then the battery, with the help of inverter circuits, will power up household appliances like lights and TV sets.

During hot sunny days, solar panels can generate voltage above 14V dc or higher , enough to charge a 12V lead-acid battery. But during cloudy days, solar panels can generate voltages even less than 9V to 8V, which is very low enough to charger a 12V battery. In short, during this days, solar panels are useless.
The purpose of this project is to design a low cost (cheap) and simple solar battery charger that has a built in charging controller and regulator that can maximize the solar panels charging capacity and at the same time help the battery charging process continuous regardless the weather is sunny or cloudy.

The project uses a 555 timer IC to generates pulses of voltages at a specified duty cycle and frequency. This generated voltage will be feed to the input of bipolar junction  transistor and as a result generates an output voltage which is enough to charge the battery. This operation is similar to 3V charger project. The circuit also has comparator IC  that  monitors charger output voltage  and  controls the charger off when the battery is fully charge. The comparator also controls the output to more than 13.6V (15V) to ensure proper and continuous battery charging. The project also has an output regulator that limits the output voltage  acceptable to battery charging.The charger project also has a voltage output indicator and a diode to avoid battery charge draining.


  1. What is the value of inductance L?
    It is not defined in the diagram. Please help me with the appropiate value.

  2. I cant give the exact value of inductance but i built it using number 20AWG magnetic wire wound aroud a antenna bararound 20 to 30 turns.

  3. Thanks DH-gm !
    your feedback very helpful to me as i live in a rural area.It is a easily constructable controller.

  4. Hi DH-gm

    Is there a chance of you posting a parts list?
    I'm (very) new circuit building and really battle with figuring out components and values.

  5. Could you PLEASE post the spec of all your parts, such as resistor watts, capacitor types, diode and zenor values? Thank you.