Batteries are a perfect example of the double-edged sword of technology. They are really great in that they can put electrical power in the palm of your hand. They are really bad because if you are not careful you can waste a lot of money on them, you can ruin your expensive little play-pretty, or you could even hurt yourself.
Used to be there were two kinds of batteries: big, heavy lead-acid batteries for cars and such, and dry cells for your flashlight. But then some whiz kids started looking at them and we started getting all kinds of new, improved batteries that used things like mercury, cadmium, nickel, and now lithium.
We go through a fair number of batteries around here. Double A, triple A and nine volt are the most popular. Sometimes you have a play-pretty that isn't acting right and the first thing you do is replace the batteries. Sometimes that fixes it, sometimes it doesn't, but the old batteries end up in the discard pile. Given the price of batteries (EXTREMELY HIGH), my compulsive self requires that I sit down and test all of the batteries in the discard pile before consigning them to the recycling bin. Today I found two nine volt batteries that are probably still good. I say probably because they measure nine volts on my multimeter. Generally speaking, measuring the voltage on any kind of small battery, except for the lithium ones, can give you a pretty good indication of whether it is any good or not. If they show any less than full voltage I will toss them. By less I mean a tenth of a volt.
This test doesn't work with Lithium batteries. Fortunately I don't have many of those.
The meter test works, but it's kind of a hassle. I have to hold the battery and two test leads and I don't have a gripping hand. And then I have to peer at the meter and try and make out whether it reads 1.5 or 1.4 volts. So I looked on Amazon for a battery tester. They have 2,000 different battery testers for sale. I am sorry, that does not really help me. Google wasn't any better. They found all kinds of outfits from hype-mongers to specialized industrial technologists.
I poked around for a while, but eventually I gave up and decided I would just stick with my multimeter, clumsy as it is.
3 hours ago