Just a quick video to show a quick reliable way to test household batteries and button type batteries (like the ones found in game carts). There is another method which uses the results of a resistance measurement on the battery, I however find the voltage under load method I show in this video to be much simpler and I've found that it works quite well.

I use a 100 Ohm resistor for testing double and triple A batteries as well as C, D and 9V batteries and
a 4,7K Ohm resistor for testing "button" cell batteries like the CR2032.

Thanks for watching...