DIY Mini DC IPS Auto Load/Off Changeover Device for Solar System – Step-by-Step

Are you tired of manually switching between solar and battery power for your DC loads? This Mini DC IPS Auto Changeover Circuit is your perfect DIY solution! Ideal for solar home systems, routers, or small DC appliances, this circuit automatically switches the load from solar to battery power during low sunlight or when solar power goes off.

Required Components:

1. Relay: SRD-12VDC-SL-C (12V coil)
2. Diodes: 6A10 (D2), 1N4007 (D1)
3. Resistors: 1KΩ × 3 (PWR1, NC1, NO1)
4. LED indicators: 3 pcs (PWR, NC2, NO2)
5. Screw terminals (IN, BAT, NO, NC)
6. Female DC socket for solar input

1. How this auto changeover circuit works
2. Components used in the circuit
3. PCB design and layout
4. 3D view of the assembled board
5. How to use it with your solar setup

This smart and simple relay-based system automatically shifts your DC load (e.g., a 12V WiFi router) from Solar Power (Main) to Battery Backup when solar voltage drops or disconnects. When power resumes, it auto-returns to the solar source.

Solar/DC Adapter IN powers the relay coil.

When solar is present, the relay pulls to NO (Normally Open) — load runs on solar.

When solar fails, the relay de-energizes — shifting the load to NC (Battery) side.

The LEDs (NO2 and NC2) indicate the active power source

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3D Assembled View with components in place

This 3D preview shows how your final PCB will look after soldering.

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Connect the 12V Solar Output to the IN terminal.

Battery Backup goes to the BAT terminal.

DC Load (Router, Light, etc.) connects to NO (for Solar) and NC (for Battery).

Plug and play!

Use a good quality 12V relay for durability.

Add a fuse before the input for safety.

Test with a multimeter before final load connection.

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With this DIY DC Changeover Module, your solar-based system becomes smarter and more reliable. Perfect for small setups that need 24/7 uptime. Easy to build, cheap, and super effective.