When setting up an off-grid system like a solar-powered CCTV camera, the two most important questions are:

1. How much power will my system consume?

2. How many days should my solar panel and battery support without sunlight?

By understanding the relationship between watts (W), amp-hours (Ah), and days of backup, you can make sure your system runs 24/7 without interruption.

Step 1: Understand the Basics

• Watt (W) – The amount of power your device uses per hour.

• Amp-Hour (Ah) – The battery’s storage capacity.

• Days of Backup – How many days your system can keep running without sun.

Formula:

$$\text{Battery Backup (in days)} = \frac{\text{Battery Capacity (Ah) × Battery Voltage (V)}}{\text{Device Power Consumption (W)} × 24}$$

Step 2: Example Calculation

Let’s say you have a solar CCTV system that consumes 20W continuously.
You use a 12V battery rated at 100Ah.

1. Battery capacity = 100 Ah × 12V = 1,200 Wh

2. Daily consumption = 20W × 24h = 480 Wh/day

3. Days of backup = 1,200 ÷ 480 ≈ 2.5 days

So a 100Ah 12V battery can power a 20W CCTV setup for 2.5 days with no sun.

Step 3: Solar Panel Sizing

To recharge your battery, size your solar panel properly.
Formula:

$$\text{Solar Panel Size (W)} = \frac{\text{Daily Consumption (Wh)}}{\text{Average Sun Hours per Day}}$$

If you get 5 hours of good sunlight daily:

• 480 Wh ÷ 5h = 96W

• Add 25% buffer → 120W panel recommended

Quick Reference Table

(Assumes 24/7 usage, 12V battery, 5 sun hours/day)

• Always add 20–30% buffer to panel and battery sizing.

• Consider local climate — areas with frequent cloudy days may need more capacity.

• Use deep-cycle batteries for longer life in 24/7 operation.

• Pair with MPPT solar charge controllers for efficiency.

Conclusion

Choosing the right solar panel and battery setup depends on your device wattage (W), battery amp-hours (Ah), and the number of backup days you need. By calculating correctly, you ensure reliable 24/7 monitoring even during cloudy weather or power outages.

At Merchills Premium, we help businesses and retailers select the right solar and CCTV packages — complete with premium warranty and wholesale pricing.

📩 For custom sizing or bulk orders, email us at contact@merchills.com.