The Ampere-Hour

• It is used to measure the current capacity of cells and batteries
• is the amount of energy charge in a battery/cell that will allow one ampere of current to flow for one hour
• It is thus a unit of measuring a cell/battery’s charge
• For example if a battery is rated as 40Ah
• It means it supplies 40Ah
• It would mean that it supplies current at
• 1 ampere for 40 hours or 4 amperes for 10 hours

Examples

• If a 40Ah was connected to :
• a lamp drawing 0.2 amps
• It would take:
• \text{0.2A x t = 40Ah }
• Where t is time in hours
• \text{t=}\dfrac{40}{0.2}
• 200 hours
• If a radio drawing 5 amps was connected instead
• It would last
• \text{t=}\dfrac{40}{5}
• 8 hours

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