Battery Power

With the proper care, your changes can last a lot longer than you might think

April 25, 2002|By Bill Husted | Bill Husted,COX NEWS SERVICE

Treat it wrong and it can set your pants on fire.

Treat it right and you can talk a little longer on your cell phone.

Batteries aren't glamorous. In fact, you seldom think of them until they stop working.

Then your cellular phone won't ring. Your laptop computer stops working. Your car won't start. And that fancy little palm-sized computer of yours is just a lump in your pocket.

Batteries are the Rodney Dangerfield of technology. But give them a little respect and you can save hundreds of dollars a year. If you depend on your cell phone as an emergency lifeline, what you know about batteries could save your life.

You'll get plenty of advice about batteries, and a lot of it is wrong.

To get an unbiased picture of the do's and don'ts, we talked to a battery researcher at Georgia Tech as well as the man responsible for all the battery tests at Consumer Reports magazine.

Let's take a look at some of the conventional wisdom:

Rechargeable batteries should be fully discharged before they're charged again.

Wrong. Read the manual that came with your cell phone or laptop and chances are it says that the rechargeable batteries need to be fully discharged before you charge them again. According to this much-debated theory, nickel cadmium batteries - common in some laptops and phones - develop a memory. The theory says if you recharge the battery while it's still got juice left, it will eventually fail to take a full charge. Instead it'll remember that half-charged state and return to it.

Experts aren't convinced

"We don't see it," said Mark Connelly, director of testing for battery applications at Consumer Reports. "We hear about it, but when we try it in the laboratory we don't see it."

Gary E. Gray of Georgia Tech's Aerospace & Transportation Laboratory and Center for Innovative Fuel Cell and Battery Technologies agreed.

"Most nicads don't develop a memory," Gray said. "They permanently lose capacity due to constant charging or old age," not the memory effect.

So how do you keep your nickel cadmium batteries in top shape?

"They should be charged just prior to use and left off the charger until time to recharge them for their next use," said Gray. "For things like rechargeable vacuums and flashlights, this approach won't work because the user can't predict when he'll need them. In this case the user must leave them on the charger and expect to replace the nicads or the entire device every few years."

It doesn't hurt the battery to discharge completely before recharging - just don't try to speed up the process by shorting it out.

Batteries stored in the refrigerator last longer.

"That's right," said Connelly. "We put batteries in a refrigerator over a long period of time and we did see small differences. That seemed to buttress the common wisdom."

However, the difference in shelf life isn't great. So feel free to store batteries in a relatively cool and dry place and save the fridge for hamburger.

Expensive batteries will perform better than cheap ones .

"I typically buy the cheapest alkaline batteries I can find," said Gray. "They all perform similarly."

Connelly largely agreed.

"Our advice is to buy by price. The differences are small," he said. "If the battery is going in anything but a high-drain device [such as a digital camera with flash] you can buy by price."

For gadgets that quickly drain a battery, the premium brands often have a small advantage, Connelly said, but when you figure in the higher cost, the cheapest are the best bargain for most uses.

Both said that you can ignore brands and feel safe with a no-name battery.

"I have taken apart store-brand batteries and found them to be almost identical to some of the big-name manufacturers," said Gray.

Buying advice

The experts also had some tips to pass along to consumers.

"Buy batteries in bulk," said Connelly. "It seems like the more you buy, the more you save."

He said alkaline batteries have a shelf life of many months.

"I avoid the batteries that are labeled `heavy duty,'" said Gray. "These aren't alkaline and ... can't deliver the power and capacity of an alkaline cell."

You wouldn't think that a battery would be dangerous, but tell that to the guy whose pants caught on fire.

"I read once about a fellow who went to purchase some replacement nicads," said Gray. "He put the old cells in his pocket thinking they were dead. One of the cells shorted across his car keys and set his pants on fire."

You shouldn't throw them into a fireplace either. Heat causes the chemicals inside the sealed cylinder to expand and form gases. Building pressure inside the metal case could cause it to explode.

It's also important to use the correct recharger for your specific batteries. "The hazards of using the improper charger range from premature battery failure to explosion," said Gray.

Protection tips

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