I read through the article you linked and it was helpful. Thanks. Fortunately, there is a lot you can do with AC resistance measurements, such as:
- Measure new cell when you first get them, and then take periodic reading afterward to monitor their health.
- Compare measurements against the battery's datasheet to determine if it is in specification. For example, the Samsung 30Q datasheet identifies a typical 1 kHz AC resistance specification of 13.13 ± 2 mΩ. The SM8124A I recently purchased measured my six Orbtronics 30Qs with an average resistance of about 11.5 mΩ (See Table 2.), which is within the datasheet specification. I was shocked that my $50 AC tester was able to provide measurements with this seeming accuracy. Perhaps this is a one-off fluke.
- Compare a known battery with one that is suspected of being a fake. For example, if a battery measures considerably more AC resistance than a real 30Q, then it is probably not a 30Q.
Update: I saved this post too quickly and had to make edits. Thanks!