Are you looking for a reliable backup power solution for your WiFi router, CCTV, or small appliances? In this detailed post, we’ll explore how to test a Cute LIT 220W inverter with an Auto Load/Off Changeover Circuit, ensuring smooth and automatic power backup with zero downtime.

This guide is powered by a real schematic (see image below) that was tested with actual loads like LED bulbs, routers, and small fans to measure performance and battery efficiency.

✅ What You’ll Learn:

1. How to build and test a 220W inverter system
2. Working principle of auto-changeover IPS circuits
3. Circuit diagram analysis
4. Real load testing & performance results
5. LED power indicators & backup time estimation

📷 Circuit Diagram:

Below is the schematic diagram used for the test. Designed using EasyEDA:

⚙️ Circuit Diagram Explanation:

This circuit is a Mini DC IPS Auto Load/Off Changeover System, designed to switch between the main DC input and a 12V battery when the main power fails.

🧩 Key Sections:

🔌 Input Power Section:

Power Socket (IN): Receives 12V DC from an adapter or solar system.

PWR1 + LED2: A 1K resistor with a red LED (LED2) indicates when input power is present.

⚡ Relay Section:

Relay (SRD-05VDC-SL-C): A 5V coil relay used to switch between power sources.

Relay Pins:

Pin 2 & 5: Connected to DC input (activates coil)

Pin 3 (COM): Connected to load output

Pin 4: Ground

D1 (1N4007): Flyback diode across the relay coil to prevent voltage spikes.

🔋 Battery Section:

BAT Connector: Connected to a 12V DC lead-acid or Li-ion battery.

When the relay is not energized (power off), the load connects to the battery via NC (Normally Closed) pin.

🔁 Auto Load Switch Logic:

NO Connector: Connected to DC input — powers the load when relay is ON.

NC Connector: Connected to battery — powers the load when relay is OFF.

NC1/NO1 + LEDs: Status LEDs to indicate which source is currently supplying power.

🔦 LED Indicators:

NC1 + NC2: Red LEDs indicate when load is running on the battery.

NO1 + NO2: Red LEDs indicate when load is running on the main power.

🔧 Circuit Components (as per schematic):

Relay: SRD-05VDC-SL-C

Diodes: 1N4007, 6A10

Resistors: 1K Ohm (x3)

LEDs: 5mm Red (x3)

Power Socket: DC input

Battery Connector: 12V DC (Typical)

NC/NO Terminals: Output connections

GND: Common ground line

🧠 How It Works:

When AC mains (via adapter) is ON, the relay activates and powers the load directly.

When mains fail, the relay deactivates, switching the load to the battery.

The LED indicators show active power source.

Diodes protect the relay and ensure reverse current protection.

📷 Schematic Overview:

Below is the tested circuit diagram for the mini auto-load/off IPS system used in this test:

🔍 Real Load Test with Cute LIT 220W Inverter:

We tested the system with:

💡 12V 10W LED Bulb

🌐 WiFi Router (5V via buck converter)

🌀 Mini DC Fan

🔌 USB mobile charger

Total load: ~45W

Backup Time: 2.5+ hours on a 12V 7.5Ah Battery

YouTube Video:

📊 Final Thoughts:

If you want a low-cost DIY UPS or IPS system, this auto changeover circuit is a must-have. It ensures your devices stay online without manual switching. Combined with the Cute LIT 220W inverter, this becomes a powerful mini-IPS system that you can rely on during power cuts.