Found a Quality Battery Resistance Tester

[ActiveAl]

@contactcr

I think it’s worth mentioning that the resistance values from this $50 AC tester should not be compared to other chargers and things that give resistance. AC resistance measurements are pretty far apart from DC load resistance measurements. Article: BU-902: How to Measure Internal Resistance - Battery University So while this device is still useful it is not giving you the same measurement you might find in other sources. Also, I don’t think it is as good of an indication of the max discharge a battery can sustain. (like what HKJ or Mooch are giving you)

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:

1. Measure new cell when you first get them, and then take periodic reading afterward to monitor their health.
2. 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.
3. 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!