I was tired of throwing out or using bad batteries. Needed to diagnose a device. You simply put a 100 ohm resister across the volt meter and read the voltage your batteries put out. I found two or three batteries in our bad battery box (to be recycled) that were good with this test. Other than that I needed to test why a sprinkler wasn't working and it told me I put a bad battery in thinking it was good.
Here's a video on how to test batteries with an ohm meter.
I noticed years ago when we were buying "batteries" by the case that rechargeable batteries only delivered 1.2 volts but at a much higher rate mA. When the kids were racing battery powered track cars those cars with nicads would smoke the cars with alkaline batteries but would slow down sharply after a few laps while the alkaline powered cars just kept plodding along. I dropped what I thought was a spent ni-cad in my pocket and some how shorted it out with my keys. It instantly lit me up, burned a hole in the bottom of my pocket and welded two keys together.
"They that can give up essential liberty to obtain a little temporary safety deserve neither safety nor liberty."