I recently bought an iPowerPro adapter to charge my laptop on a long plane ride to Asia. I even checked with seatguru.com to make sure my seat had access to the juice, but when I got on the plane, an outlet was nowhere to be found. I was stuck rereading a magazine for 10 hours while softly cursing the measly evolution of battery power.
What I came to realize is that I could have taken the about same amount of money I spent on the adapter and bought a sleek universal notebook battery from APC. Even when traveling, I'm rarely more than 10 hours away from the nearest power outlet; most reviews of this battery say that it will generally last twice as long as the internal one, so it seems to fit my needs perfectly.
The battery is about the size of a magazine, and most people simply place their laptops on top of it. As a reviewer on Amazon suggests, you should attach it to your laptop with Velcro so the two pieces don't move independently.
