This is not a product review this is rather one recommendation for the people which dealing with several handheld devices and a wide range of battery types.
Reliable battery capacity diagnosis by a quick test this is only possible when the tester it self can perform this test by adding load over the battery, this is nothing different as method from the one used for car batteries.
About eight years ago, I did discover this
Ansmann Energy Check LCD Battery Tester, and I did immediately added it in my tool box when I found it at the price point of 45 Euro shipped to Greece.
About seven year later my
Ansmann Energy Check LCD it did failed but not regarding internal electronics, the wire of this tester which connects with the test probe, this started failing apart - external insulation started decomposing and becoming dust.
I had to improvise by replacing this coiled wire by another at exact resistance, so it factory measuring calibration this to not be altered.
While I am not thrilled regarding build quality of products Ansmann Made in China, this very specific product it is a significant innovation.
Internal electronic circuit includes one processor which calculates and deliver test results as soon battery under test this is under load for few seconds (fixed time).
My hobby this is digital photography for 18 years up to date , lots of 1.2V AA Ni-Mh in my ownership, I was in need to be aware of which specific battery cell started to deteriorate first.
Today many smart chargers they can deliver battery capacity tests and perform benchmarks too, but this is possible for very limited battery cell types.
Ansmann Energy Check LCD - Product page