Ever been out and about with a cellphone or music player running short on power and you didn't bring the charger? Sony's new Energy Link may be the solution. Stick in any two AA batteries, even alkalines, and it provides power to a USB device, including an increasing number of cellphones. Stick in a pair of rechargeable NiMH batteries, plug Energy Link into a wall outlet, and it charges them. Sony wants you to use its Cycle Energy batteries. A variant of NiMH, these are sold charged (they hold 90% charge for a year) and last for more cycles, about 1,000 vs. 500 to 700. But these first-gen Cycle Energy batteries have only 2,000 mAh (milli-amp hours) of power vs. 2,500 mAh for good NiMH batteries. The adapter holds two batteries and will sell for $35 this summer; batteries are about $15 for four, $2 more than standard NiMH, Sony says.