Internal Resistance Test (AC and DC)

Objective

The Internal Resistance (IR) of a battery is the opposition to the current flow through it. Two methods were used by IEC standard: the AC method or DC method. Thus it is used as ageneral guideline and can provide valuable information about the battery performance. The higher value of IR indicates battery reaching its end-of-life.

Procedure and Standard

Depending on the specified battery internal resistance in the manufacturers datasheet, the proper equipment was selected. For the DC test method, the internal resistance test are embedded into other test program, such as Auto or Cycle test. Thus it takes a few hours until the test is finished. For AC method, the internal resistance can be carried out individually so it only takes a few minutes.

Equipment

**AC method using impedance test on channel #1 only.

Result Sample

The results in the table below are derived from testing on 12V SLA Panasonic LC-R127R2P1 batteries.