Are The Batteries Dead?

The other day when I got home, the carbon monoxide detector indicated low-battery. I wonder how many of us just remove the batteries and toss them out?

I removed these three and tested them with a digital multi-meter voltage tester to reveal that only one of them was dead. The other two had at least 1.5 volts, like new AA batteries.

The same thing happened with a strand of decorative LED's. They would not light, but when I tested each battery, only one of them showed zero volts. I replaced it, and the lights work like new.

Although other power sources might be better, we continue to use disposable batteries. To avoid throwing away good ones, I recommend using a voltage tester.