Battery Energy and Runtime Calculator
This free online battery energy and run time calculator calculates the theoretical capacity, charge, stored energy and runtime of a single battery
If we want to calculate how much energy – in other words, how many watt-hours – is stored in a battery, we need information about the electric charge in the battery. This value is commonly expressed in amp-hours – amps (units of electric current) multiplied by hours (units of time) – see the hours calculator.
This is known as the "hour" rate, for example 100Ahrs at 10 hours. If not specified, manufacturers commonly rate batteries at the 20-hour discharge rate or 0.05C. 0.05C is the so-called C-rate, used to measure charge and discharge current. A discharge of 1C draws a current equal to the rated capacity.
This battery energy and runtime calculator determines the theoretical capacity, charge, stored energy, and run time of a single battery and several batteries with the same characteristics connected in series and in parallel to form a battery bank. It can be used both for batteries and for galvanic cells or batteries.
For example, for a battery with the rated capacity Cbat = 8 Ah, at 2C discharge would deliver the battery's rated capacity in 0.5 hours with the current Ibat =16 A. A 1C discharge of the same battery would deliver the rated capacity with the current of 8 A it in one hour.
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