Hi Dave. For battery testing, We now use all options possible, Hydrometer where possible, Electronic tester ( used with a little bit of scheptism, but at least its another test to take into account ) and the good old Blowerupper drop tester. Also if unsure, We would fit a New battery and charge and test the original battery and leave it stood for a week or so and retest it. ( As infrequent as possible as its more hassle than its worth and its only usually to save the customer a few quid but its still an option in certain cases )
The invention of the Digital testers has not really saved us any work but really made the job take a few seconds longer but gives us another result to think about. ( sometimes convinces us that its faulty or to throw a spanner in the works and confuse things even more )
But where it does come in is when it says in black and white. { "FAULTY BATTERY" . "REPLACE" }
And you can show it to the customer so that he can see for himself that it tests out faulty. But even then I still get several replies something like ----------------WHATS THAT MEAN THEN. ???????????????