Are titanium batteries really better than alkaline? Or is this some sort of new marketing ploy? –Beth Hanes, via e-mail
Best of Chicago voting is live now. Vote for your favorites »
It’s been a few years since I wrote about batteries, during which time the technology has made great strides and the hype has advanced even faster. Titanium batteries, for example, aren’t a miraculous breakthrough in energy storage, just an improvement in both disposable and rechargeable batteries. Basically, small amounts of a titanium-containing compound are added to a battery to improve performance–to judge from the patents, mostly by lowering internal resistance. Lower resistance means less juice is lost as heat, leaving more to operate the CD player, vibrator, etc. Tests comparing titanium-enhanced batteries with the ordinary kind generally show improved performance, although you still don’t get as much power as from lithium batteries. Then again, lithium batteries cost maybe two and a half to three times what standard alkalines do, whereas the titanium premium is on the order of 20 to 40 percent. For high-drain applications like digital cameras, or where you need exceptionally long life (computer memory backup, for example), lithium is the best choice. Otherwise, titanium batteries are worth a look.
On to rechargeable batteries. In 1999 I wrote about nickel-cadmium (nicad) battery memory, a common term for the seeming tendency of a nicad battery that’s been charged too many times without being entirely drained to remember where it was drained to and eventually not take a full charge. I pointed out that such cases aren’t examples of true battery memory, a real if rare phenomenon, but rather something called voltage depression–though the total energy stored in the battery is unchanged, it doesn’t come out with as much force as before. Admittedly this is something of a fine point, since the net effect is the same–you get less use out of the battery per charge than you once did. Voltage depression in nicad batteries stems from an unfortunate characteristic of the cadmium hydroxide crystals that normally form as the battery discharges. The crystals start out small when the battery is new, then grow over time, increasing internal resistance and reducing power output. Most practical solution I’ve heard: periodic deep discharge followed by normal charging to full power, breaking the big crystals into little ones.
Art accompanying story in printed newspaper (not available in this archive): illustration/Slug Signorino.
