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Battery Energy Capacity Formula:
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Battery energy capacity, measured in watt-hours (Wh), represents the total amount of energy a battery can store and deliver. It's calculated by multiplying the battery's amp-hour (Ah) rating by its voltage (V).
The calculator uses the battery capacity formula:
Where:
Explanation: This simple multiplication gives you the total energy storage capacity of the battery in watt-hours, which is useful for comparing different battery types and calculating runtime for electrical devices.
Details: Knowing a battery's energy capacity helps in selecting the right battery for specific applications, estimating device runtime, and comparing energy efficiency across different battery technologies.
Tips: Enter the battery's amp-hour (Ah) rating and nominal voltage (V). Both values must be positive numbers. Common battery voltages include 3.7V (lithium-ion), 12V (lead-acid), and 1.2V (NiMH).
Q1: What's the difference between Ah and Wh?
A: Amp-hours (Ah) measure charge capacity, while watt-hours (Wh) measure energy capacity. Wh accounts for both voltage and current, providing a more complete picture of a battery's energy storage.
Q2: Why is Wh a better measure than Ah for comparing batteries?
A: Wh accounts for both voltage and current, allowing for direct comparison between batteries with different voltages, while Ah only compares charge capacity at the same voltage.
Q3: How do I calculate device runtime from Wh?
A: Divide the battery's Wh rating by the device's power consumption in watts. For example: 100Wh battery ÷ 20W device = 5 hours runtime.
Q4: Are there any limitations to this calculation?
A: This provides theoretical maximum capacity. Actual capacity may vary based on discharge rate, temperature, age, and battery chemistry.
Q5: Can I use this for all battery types?
A: Yes, the formula works for all battery chemistries (lithium-ion, lead-acid, NiMH, etc.) as long as you use the correct nominal voltage for that battery type.