There are two problems with recharging things on Earth. One is finding a place to plug in, but the bigger problem is finding a connector that fits the gadget. We recently tried out the new PowerAid Mobile from US Modular, a backup battery that comes with five adapters that fit cell phones, iPods, Treo PDAs and many other devices designed to take their charge from a computer's USB port or a wall outlet. None of the adapters fit our Sony-Ericsson w800 cell phone, but that wasn't crucial since we can never remember to turn it on.

The PowerAid Mobile weighs about 10 ounces (283.5 grams) and fits in a shirt pocket. It can recharge your cell phone or PDA in an hour. It holds a charge for two to three hours of heavy use. (Five indicator lights tell you how much charge is left.) It comes with a transformer that allows recharging from a standard electrical outlet and a USB cable for charging it from a computer's USB port. If you recharge from a computer port, it takes about six hours.

Having the PowerAid in your pocket is one solution to a dead gizmo, but what if your devices aren't compatible with it?

Targus.com will sell you just the tip you need to plug into a portable device, but it doesn't have tips for every phone. (Once again, it didn't have one for our phone.) The tips run around US$10 each and charger to fit them sells for US$20. But that does not include a backup battery you can carry with you, like the package from US Modular. The PowerAid Mobile lists for US$50 at their own site: USModular.com, and it was the same price at TigerDirect.com.