How is the internal battery resistance measured?
A number of techniques are available to measure the internal battery resistance. One common method is the direct current (DC) load test, which applies a discharge current to the battery while measuring the voltage drop. Voltage over current provides the internal resistance. The alternating current (AC) method, also known as the conductivity test, measures the electrochemical characteristics of a battery. This technique applies either a fixed frequency, or a frequency range from 10 to 1000Hz to the battery terminals. The impedance level affects the phase shift between voltage and current, which reveals the condition of the battery. Some AC resistance meters evaluate only the load factor and disregard the phase shift information. Cadex uses the discreet DC method to measure internal battery resistance. Added to the Cadex 7000 Series battery analyzers, a number of charge and discharge pulses are applied, which are scaled to the mAh rating of the battery tested. Based on the voltage deflec
