Battery Life Calculator

Battery Life is evaluated from Battery Capacity, Load Current and Efficiency Factor. The calculation reports Estimated Runtime, Estimated Runtime and Battery Energy.

Results

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About the Battery Life Calculator

Battery Life is treated here as a quantitative relation between Battery Capacity, Load Current, Efficiency Factor and Battery Voltage and Estimated Runtime, Estimated Runtime, Battery Energy and Load Power.

The calculator uses a multi formula configuration. Each reported value is read as a direct evaluation of the stored rules with the declared field formats and units.

Formula basis:
t (hours) = C (mAh) / I (mA) x efficiency
t (days) = t (hours) / 24
Energy (Wh) = C (mAh) x V / 1,000
Power (mW) = I (mA) x V

Interpret the outputs in the order shown by the result fields. Optional inputs affect only the outputs that depend on those variables.

Formula & How It Works

The calculation applies the following relations exactly as recorded in the metadata:

t (hours) = C (mAh) / I (mA) x efficiency
t (days) = t (hours) / 24
Energy (Wh) = C (mAh) x V / 1,000
Power (mW) = I (mA) x V

Each output field is produced by substituting the supplied inputs into the relevant relation and then applying the declared rounding or text format.

Worked Examples

Example 1: Smartphone Daily Use

Inputs

capacity: 3561 current_ma: 300 efficiency: 85 voltage: 3.87
Estimated Runtime: 10.09 hours. Estimated Runtime: 0.42 days. Battery Energy: 13.78 Wh. Load Power: 1,161 mW

With Battery Capacity = 3,561, Load Current = 300, Efficiency Factor = 85 and Battery Voltage = 3.87 as the stated inputs, the result is Estimated Runtime = 10.09 hours, Estimated Runtime = 0.42 days and Battery Energy = 13.78 Wh. Each value corresponds to the declared output fields.

Example 2: Home UPS Backup — Internet Router

Inputs

capacity: 7200 current_ma: 800 efficiency: 70 voltage: 12
Estimated Runtime: 6.3 hours. Estimated Runtime: 0.26 days. Battery Energy: 86.4 Wh. Load Power: 9,600 mW

With Battery Capacity = 7,200, Load Current = 800, Efficiency Factor = 70 and Battery Voltage = 12 as the stated inputs, the result is Estimated Runtime = 6.3 hours, Estimated Runtime = 0.26 days and Battery Energy = 86.4 Wh. Each value corresponds to the declared output fields.

Example 3: IoT Temperature Sensor — 1 Year Target

Inputs

current_ma: 0.5 efficiency: 90 voltage: 3.6
Estimated Runtime: 0 hours. Estimated Runtime: 0 days. Battery Energy: 0 Wh. Load Power: 1.8 mW

With Load Current = 0.5, Efficiency Factor = 90 and Battery Voltage = 3.6 as the stated inputs, the result is Estimated Runtime = 0 hours, Estimated Runtime = 0 days and Battery Energy = 0 Wh. Each value corresponds to the declared output fields.

Example 4: Electric Bike Battery Range

Inputs

capacity: 17500 current_ma: 5000 efficiency: 85 voltage: 48
Estimated Runtime: 2.98 hours. Estimated Runtime: 0.12 days. Battery Energy: 840 Wh. Load Power: 240,000 mW

With Battery Capacity = 17,500, Load Current = 5,000, Efficiency Factor = 85 and Battery Voltage = 48 as the stated inputs, the result is Estimated Runtime = 2.98 hours, Estimated Runtime = 0.12 days and Battery Energy = 840 Wh. Each value corresponds to the declared output fields.

Common Use Cases

  • Calculate how long a phone battery lasts with a specific app
  • Find runtime of a UPS backup battery under load
  • Determine battery pack capacity needed for an IoT sensor