Amps to Ampere-hours Calculator
Convert between Amps (A) and Ampere-hours (Ah) using time duration.
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Amps to Amp Hours Calculator: Battery Capacity Guide
Convert Amps (A) to Amp Hours (Ah) with our comprehensive calculator. Learn how to calculate battery capacity and runtime with practical examples for various applications.
What is Amp Hours (Ah)?
An Amp Hour (Ah) is a unit of electrical charge that measures battery capacity. It represents the amount of current (in amperes) a battery can supply over one hour. For example, a 100Ah battery can theoretically provide 1 amp for 100 hours, or 10 amps for 10 hours.
Key Point: 1 Amp Hour = 1,000 milliamp hours (mAh), commonly used in smaller devices like phones and power banks.
Amps to Amp Hours Calculation
To calculate Amp Hours from current consumption, use this formula:
Where:
- Ah Battery capacity in Amp Hours
- A Current in Amperes
- Hours Time duration in hours
Amp Hours to Watt Hours Conversion
For comparing batteries with different voltages, convert Amp Hours to Watt Hours:
Where:
- Wh Energy capacity in Watt Hours
- Ah Capacity in Amp Hours
- V Voltage in Volts
Practical Examples
Battery Runtime Calculation
Given:
- Device Current Draw = 2A
- Usage Time = 5 hours
Required Battery Capacity:
Ah = 2A × 5 hours = 10AhEnergy Capacity Comparison
Given:
- 12V Battery: 100Ah
- 24V Battery: 50Ah
Energy Capacity in Watt Hours:
12V Battery: 100Ah × 12V = 1200Wh 24V Battery: 50Ah × 24V = 1200WhImportant Note: Always consider voltage when comparing battery capacities. Two batteries with different Ah ratings may store the same amount of energy.
FAQs About Amps to Amp Hours
What’s the difference between Amps and Amp Hours?
Amps measure current flow at a specific moment, while Amp Hours measure electrical charge capacity over time. Think of Amps as flow rate and Amp Hours as total volume.
How do I size a battery for my application?
Multiply your device’s current draw (in amps) by the desired runtime (in hours) to get the minimum required Amp Hours. Add 20% for safety margin and to account for battery aging.
Why do batteries not last as long as calculated?
Real-world factors like temperature, discharge rate (Peukert effect), and battery age can reduce actual runtime. Always size batteries with a safety margin for reliable operation.
