Understanding Power Consumption and Battery Life for Relays

In this article, we will break down the power consumption and battery life calculations for two different relay scenarios, each powered by a different voltage and type of power source.

Power Consumption of a 5 Volt Relay Powered by a 5 Volt 1 Ampere Charger

To begin, let's consider the power consumption calculation for a 5V relay powered by a 5V, 1A mobile charger. We will calculate the power consumption and total energy used in 24 hours.

Power Calculation

The power consumed by the relay can be calculated using the formula:

Power (W) Voltage (V) × Current (A)

For a 5V relay and a 5V, 1A charger:

Power 5V × 1A 5W

Total Energy Consumption

To find the total energy consumed over 24 hours, use the formula:

Energy (Wh) Power (W) × Time (h)

For 24 hours:

Energy 5W × 24h 120Wh

Battery Life of a 12 Volt Relay Powered by a 9 Volt Non-Rechargeable Battery

Next, we will calculate the battery life of a 12V relay powered by a 9V non-rechargeable battery with a nominal capacity of 500mAh.

Assumptions and Calculations

Assuming the relay operates at a similar current as the 5V relay (1A), we can calculate the battery life.

Battery Energy Calculation

The total capacity of the 9V battery in watt-hours (Wh) can be calculated using the formula:

Capacity (Wh) Voltage (V) × Capacity (mAh) / 1000

Converting 500mAh to Ah:

500mAh 0.5Ah

Now calculating the energy:

Capacity 9V × 0.5Ah 4.5Wh

Battery Life Calculation

The power consumption of the relay is:

Power 12V × 1A 12W

The battery life in hours can be calculated using:

Battery Life (h) Battery Capacity (Wh) / Power Consumption (W)

Substituting the values:

Battery Life 4.5Wh / 12W ≈ 0.375h or 22.5 minutes

To convert the battery life to days:

Battery Life (days) ≈ 0.375h / 24h ≈ 0.0156 days or about 22.5 minutes

Summary:

The energy consumed by the 5V relay over 24 hours is 120Wh. The battery life of a 12V relay powered by a 9V battery with a 500mAh capacity is approximately 0.0156 days, or about 22.5 minutes.

If you have any further questions or specific details about the relays, feel free to ask!