We have always been fans of external batteries that provide much needed extended battery life to our mobile gear, especially on trips.  Judie of Gear Diary has reviewed such an external battery, the Proporta Laptop Battery, and she gives a typically detailed overview of using this battery with her gear.  I’ll let Judie tell you what she thinks about the Proporta:

If you have been looking for an external battery solution that willallow you to travel without worrying about where and when you’ll beable to recharge, the Proporta Laptop Battery may be exactly what youneed. I think it is definitely worth the extra pound of weight in mygear bag, but the price may give you pause when it’s compared head tohead with other external batteries.

Head over and read the review if you are thinking about an external battery solution.  I’ve used them in the past and they can make a huge difference when you’re away from an outlet for hours.