Build a Smart UPS & Backup System for Raspberry Pi & Jio AirFiber

2024 filed under: reflections

After corrupting my Raspberry Pi's SD card twice due to sudden power cuts, I learned an important lesson: running a 24/7 server without backup power is asking for trouble. Add my Jio AirFiber router to the mix, and every power outage meant losing both internet and my cloud server.

Here's how I built a reliable, affordable backup power system for under �4,000 that provides hours of runtime and automatic clean shutdowns.

The Problem

My setup includes:

Sudden power loss causes:

The Solution: Dual UPS Approach

Instead of one expensive specialized UPS, I use a two-tiered system:

  1. Standard UPS for the router and main power
  2. Mini-UPS modules for direct 5V/12V DC power to devices

This combination provides maximum runtime at minimum cost.

Part 1: Main UPS for Router

Recommended Options

Option A: Artis 650VA UPS (�2,400-�2,600)

Option B: Zebronics ZEB-U725 (�2,800-�3,000)

Why These Models?

For low-power devices like routers and Raspberry Pi, you don't need expensive high-capacity UPS units designed for PCs. These entry-level models provide:

Runtime Calculations

Approximate runtime with 650VA UPS:

Load: 22W (router 12W + Pi 10W)
Battery: 12V 7Ah typical
Runtime = (Battery Wh � Efficiency) / Load
Runtime = (84Wh � 0.7) / 22W
Runtime H 2.5-3 hours

In practice, expect 2-3 hours of full operation during outages.

Part 2: Mini-UPS for Direct DC Power

While the main UPS works, using AC output � wall adapters � DC is inefficient. Mini-UPS modules provide direct 5V/12V DC with integrated battery backup.

5V Mini-UPS for Raspberry Pi

Search for "5V DC UPS" or "Raspberry Pi UPS" on Amazon/AliExpress:

12V Mini-UPS for Router

For Jio AirFiber or similar 12V routers:

How They Work

  1. Normal operation: Mains power charges battery and powers device
  2. Power cut: Instantly switches to battery (no interruption)
  3. Power return: Switches back to mains and recharges battery

No switching delay, unlike traditional UPS which have 5-10ms switchover time.

My Recommended Setup

Configuration 1: Maximum Protection (�4,000)

Advantages:

Configuration 2: Budget-Friendly (�2,500)

Advantages:

Trade-offs:

Installation and Setup

Main UPS Setup

  1. Unbox and charge UPS for 8-12 hours before first use
  2. Connect router's power adapter to UPS outlet
  3. If using Configuration 2, also plug in Pi adapter
  4. Test by disconnecting mains power  devices should stay on

Mini-UPS Setup for Raspberry Pi

  1. Connect mini-UPS input to power source (wall adapter or main UPS)
  2. Connect mini-UPS output directly to Raspberry Pi USB-C power port
  3. Verify 5V 3A output is stable using `vcgencmd get_throttled`
  4. Check that Pi runs correctly on battery power

Mini-UPS Setup for Router

  1. Identify router's power requirements (12V 1-2A typically)
  2. Connect mini-UPS input to mains or main UPS
  3. Connect mini-UPS 12V output to router's DC jack
  4. Verify router boots and maintains connection

Smart Shutdown Integration

The real intelligence comes from detecting power failure and shutting down the Pi gracefully before battery depletes.

Simple Approach: Monitor GPIO

Some mini-UPS modules have a status pin that goes LOW when on battery. Connect to Pi GPIO and monitor:

import RPi.GPIO as GPIO
import os
import time

POWER_STATUS_PIN = 17  # GPIO pin connected to UPS status

GPIO.setmode(GPIO.BCM)
GPIO.setup(POWER_STATUS_PIN, GPIO.IN)

while True:
    if GPIO.input(POWER_STATUS_PIN) == GPIO.LOW:
        # Power failure detected
        time.sleep(120)  # Wait 2 minutes
        if GPIO.input(POWER_STATUS_PIN) == GPIO.LOW:
            # Still on battery after 2 min, shutdown
            os.system('sudo shutdown -h now')
    time.sleep(10)

Advanced Approach: UPS HAT

Purpose-built Raspberry Pi UPS HATs (like Geekworm X728) offer:

Monitoring and Maintenance

Battery Health

UPS batteries degrade over time:

Runtime Testing

Periodically test actual runtime:

  1. Fully charge UPS
  2. Disconnect mains power
  3. Note start time
  4. Monitor until UPS low-battery alarm
  5. Record runtime for reference

Declining runtime indicates battery replacement needed.

Logging Power Events

Create a log of power failures:

#!/bin/bash
echo "$(date): Power failure detected" >> /var/log/power-events.log

Helps identify patterns and UPS effectiveness.

Power Consumption Optimization

To extend runtime, reduce power draw:

Raspberry Pi Optimizations

Router Optimizations

Cost-Benefit Analysis

Total Investment

Artis 650VA UPS:        �2,500
5V Mini-UPS:            �1,000
12V Mini-UPS:           �1,200
-----------------------------------
Total:                  �4,700

What You Get

Alternative Costs

Troubleshooting Common Issues

UPS Keeps Beeping

Likely overloaded. Check that total wattage doesn't exceed UPS capacity. For our setup, 22W is well within limitsif beeping, battery may be failing.

Raspberry Pi Shows Under-Voltage Warning

Mini-UPS output voltage dropping below 4.75V. Check:

Short Runtime Despite New Battery

Future Enhancements

Lessons Learned

1. Prevention is cheaper than recovery: �4,000 for UPS vs. hours of work recreating corrupted systems.

2. Don't skimp on power supply quality: Cheap UPS with poor voltage regulation can damage devices.

3. Test regularly: UPS sitting unused for months may fail when actually needed.

4. Document your setup: When UPS beeps at 3 AM during power cut, you'll want clear notes on what to do.

5. Clean shutdowns save data: Automated shutdown scripts are worth the effort to implement.

Conclusion

Building a backup power system for Raspberry Pi and Jio AirFiber router is straightforward and affordable. The combination of a standard UPS plus mini-UPS modules provides hours of runtime at under �4,000less than the cost of replacing one corrupted SD card and lost work.

For anyone running a home server, NAS, or critical network equipment, backup power isn't optionalit's essential infrastructure. The peace of mind knowing your systems will survive power outages is well worth the investment.

Power cuts are inevitable. Data loss isn'tif you prepare properly.