Skip to main content

Rechargeable Batteries Test

Green Power-Up

How many batteries do you and your family use and throw away? According to the Environmental Protection Agency , Americans buy 3 million gadget batteries per year—and the average person tosses more than eight of them. If you’re in a family of gadget fans like my family, you probably use more. At times, I think we consume more batteries than food. But recently, we stopped throwing batteries away.

Instead of buying disposable batteries that can be used only once before disposal, we’re now using rechargeable cells that can be topped off and reused hundreds of times. Every time I recharge them, it means fewer batteries end up sitting in landfills.

This decision wasn’t just a green one. Though there’s a hefty upfront investment for rechargeables, it does make sense economically. With a four-pack of rechargeable AA batteries including the charger selling for around $30, the rechargeable system pays for itself quickly.

You will probably break even after roughly four months of use if you recharge a pair of AAs every week. I don’t know about you, but between remote controls, music players, and flashlights we use much more than that in a week at my house.

But even the rechargeables won’t last forever. Most rechargeable batteries can be renewed somewhere between 300 and 1,000 times, depending on the chemicals used to store the electricity. That amounts to many years of weekly use.

Don’t worry about the effect of the battery charger on your electric bill . Most chargers use just a few watts – less electricity than a child’s night light. Worst case scenario: weekly charging could add up to 13 cents a year to your bill.

That power has to come from somewhere, and in the U.S., chances are that your local power station is burning coal or natural gas to generate the electricity that contributes to global warming.  All told, sustainability non-profit organization Cleaner and Greener estimates that amount of power equals about 2 pounds of carbon dioxide released into the atmosphere per year. As far as greenhouse gases go, this is much less of a cost to the environment than the dumping of 100 more pairs of disposable AA batteries would be.  

Over the past few weeks, I’ve used four sets of rechargeable AA batteries and their chargers (from Energizer, Rayvac, PowerGenix and Sanyo). These are the newest four rechargeable  battery models on the market, all released within the last six months. I tested them in every product I could, from a TV remote control, to an alarm clock.

To see how these different brands shape up, I gave each a hard workout that included using a CD player and flashlight. For comparison, I repeated these tests with fresh disposable Duracell batteries (link to testing page).

While disposable AA batteries are rated to supply 1.5 volts, they generally deliver 1.6 volts when new. By contrast, most rechargeable cells create about 1.4 volts when fully charged. That number decreases slowly as the power drains out of the cells, and most devices designed to run on a pair of AA batteries stop working at about 1.2 volts.

There is an exception to that rule in this roundup: PowerGenix’s NiZn cells start out at nearly 1.8 volts, which is good and bad. These batteries lasted the longest, outpacing both disposable and rechargeable cells. But, for some uses they’re too much. They actually managed to burn out two flashlight bulbs after only about 10 minutes of use.

Bottom line: Rechargeables are green, in more ways than one. They can help the environment by preventing the disposal of harmful batteries in landfills, and save you hundreds of dollars a year. If there are compelling reasons not to use the latest rechargeable batteries, we’d like to hear them.