Having made batteries I for one realize just how difficult reliable battery testing is.
When Sims introduced the maintenance free Besco batteries , the assembly package came with a mile of assorted electrical testers
And many of them were done before the battery was assembled.
However there were so many warranty claims they resurected to old carbon pile load tester and applied this to every battery .
NO more warranty claims .
And we spent better than a month being taught how t calibrate & use the new fancy dancy computer controlled testing gear
So I am big fan of carbon pile ( Toasters) although if you leave them on for too long on modern ultra thin plate batteries you can cause the plates to warp.