If a smartphone demands the power outlet every few hours or a notebook's battery is drained after just a few minutes, it's high time to install new batteries. A German computer magazine, c't, has been checking out if no-name batteries are a good answer.
Original-equipment battery replacements from the device manufacturers tend to be expensive. Online shops often offer cheap alternatives from obscure manufacturers. But are these bargain batteries worth buying? At least when new, some of the generic batteries can match the batteries that came with the device originally, c't concludes.
Some lasted even longer than the originals. However, there are downsides.
"We found that replacement batteries generally age faster than the originals, so they won't last as long overall," says c't editor Christian Woelbert
While after a year and a half of normal use, original batteries usually maintained 80 per cent of their performance when new, in the case of the cheaper replacement batteries this was significantly lower.
But for users who can live with a battery that ages faster, the replacements offer an affordable alternative, Woelbert says.
Juergen Ripperger of the German electrical association VDE says it's okay to use replacements if the manufacturer of the original hardware has approved them for use in the device. However, using unapproved batteries will void the manufacturer's product liability if something goes wrong.
However, the danger that a replacement might explode is low, c't found. Billions of replacement batteries are sold every year, yet there are fewer than 10 known cases of exploding batteries.
But how do you tell a good replacement battery from a bad one? That's not easy to judge.
"The quality varies greatly," says Woelbert. A battery that held a charge well the first time can perform less well the next time.
When buying batteries that look outwardly original but are retailing at half the price of the original manufacturer's part, caution should be exercised - c't found that 12 such batteries on a large mail order company website were all counterfeits.
When searching for an affordable original battery, "you should ask what does it cost to get the original battery from the smartphone manufacturer?" Woelbert says.
"If the alleged original battery is selling for something like a third of the recommended retail price, you should be sceptical."
But even if you find a good deal, stocking up on batteries is not a good idea. Since even unused batteries age, replacements should only be bought when they're actually needed, advises Germany's PC Welt magazine.
The lithium-ion batteries used in most modern devices such as smartphones, tablets, notebooks and cameras need a little care. For one thing they should be protected from extreme weather conditions.
"Too hot, too cold, too wet - these are things the battery doesn't like," says Ripperger. So leaving the smartphone in the sun in a hot car is not a good idea.
One way to delay the aging of a notebook battery is to remove it while the device is plugged into a power socket, advises Woelbert.
There's also no need to let lithium-ion batteries drain out completely before recharging them so that they'll last longer, Ripperger says. The so-called "memory effect" applies only to nickel-cadmium batteries.
So devices with lithium-ion batteries can be plugged in and charged up any time and with any level of charge remaining.