Even though most camera bodies these days use some sort of Lithium-ion battery, chances are there’s still some gear in your bag that still runs off alkaline batteries. If you’ve ever found yourself in need of checking the charge on those batteries but you happen to leave your volt meter at home (I know … what were you thinking!?) here’s a cool little life hack that’ll give you the info your need.
The test comes to us courtesy of life hacker and how-to guy Kipkay. All you need to perform the test and check if your alkaline batteries are juiced is a hard surface.
Drop each battery (with the flat, negative end down) from a couple of inches up. If the battery is charged, it should make a solid thud and most likely stay standing. If, however, the battery is dead, it will bounce and fall over immediately.
Unfortunately, this will only work with alkaline batteries, so don’t go dropping your Lithium-ion rechargeables. The reason this works is that, as alkaline batteries discharge, the chemistry inside changes and produces Hydrogen gas, creating pressure and making it easier for the battery to bounce and topple.
Chances are you’re already familiar with this “out-gassing” as it’s called. It’s the same force that often causes the insulating seals and/or battery canister to crack open and leak.
Update: Here’s a second video by bajarider1000 demonstrating the exact same trick:
Update: It appears that the drop test differences seen in the videos above may have more to do with the brand of battery than the batteries’ level of charge. Consider this test “probably bogus.”