Electronic – Area under voltage vs time discharge curve

batteriesbattery-operateddischarge

Will the area under a voltage vs. time graph of a battery discharge curve (with a constant current load) give the amp-hour capacity rating of the battery?

Best Answer

No, in your case it is not the area that tells you the capacity, but the length of time before the voltage is so low that the battery is considered discharged. For example, if the battery started out a 4.0 V, then decreased over 1.9 hours to 2.7 V when you considered it empty, the capacity is 1.9 hours times the discharge current. If the discharge current was 1.3 A, for example, then the capacity was (1.9 h)(1.3 A) = 2.5 Ah.

The area under the graph is proportional to the total energy the battery delivered. Actually its merely the time integral of volts. But you said that the current was constant, so volts is proportional to power, and the time integral of power is energy.

Related Topic