The hybrid solar UPS is another milestone for taping the huge untapped potential of the solar energy our planet receives. The design is simple yet effective. It consists of a solar panel, with a solar charge controller and an inverter circuit, the solar UPS can effectively eliminate the low effective & highly polluting Diesel generators.

The system cannot be a primary source of power due to uncertain rate of power production in different period of year, but can be used as a back-up supply of power.

In the project, the 12V battery gets charged by solar energy until it receives a predetermined level. A solar charge controller has been taken to control the amount of charge passing through the battery.

Once the load is switched on, the battery supplies power through an inverter circuit stepping 12V DC to 230V AC.

Step 1: Block Diagram

Solar energy provides innumerable benefits:-

1. Renewable in nature

2. Viability in long run

3. No pollution

4. No harmful products or chemicals produced

5. Can be both used as on-grid or as an alternate supply when power fails

6. Can be used in far-flung areas

7. Lessens the use of kerosene lamps which produces obnoxious flames

Step 2: Solar Charge Controller

The solar charge controller is the ultimate controller which controls the energy flowing into the battery. Either from the solar panel or from the mains supply. A relay has been provided to switch between the two. Primarily, the solar panel needs to provide about 12V DC to charge the battery. If the solar fails to achieve the voltage, then the relay switches supply from the mains line. This ensures the battery is always fully charged.

The major functions are:-

1. Low voltage protection

2. Over-voltage protection

3. Battery cutoff

4.Overcharge protection

Step 3: Inverter Circuit

The battery gets charged by solar charge controller. The IC 4047 being wired as a astable multivibrator, with its frequency fired at 50Hz. The MOSFETS run on the output of Ic 4047.

I have used a step-up transformer which switches up the 12V DC into 230V AC and the output is filtered with a capacitor. A transformer is also used as a back-up supply to charge the battery if the solar panel fails to provide due to adequate amount of sunlight.

Step 4: Components Required

1. Transformer (2 pieces)

2.Solar panel (12V, 10W)


4.Diodes( IN 4001,4007)



7. IC CD 4047

8. IC CA 3130



THE cost of this project ranges from Rs 2100 to Rs 2500, depending upon the nature of components and use.



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