Mobile computer users will tell you that the number one need they have is for sufficient battery power. That fancy notebook or netbook doesn’t do much good when it has no juice to run and there are no power outlets nearby to quench its thirst. The standard solution for this is to add bigger batteries to the notebook but as Kevin points out at some point the size/ weight penalty begins to make that solution less than viable. There is another solution however that will work for many that shouldn’t be overlooked.
External battery packs are nothing new, they’ve been around for years.They are nothing more than large battery packs that are not designed toattach to the notebook, rather they are separate gadgets that plug intothe notebook much like a power adapter. They can power most laptops for8-10 hours without a plug and that makes them viable solutions to thedry battery problem that road warriors often face. These externalpacks can be somewhat expensive with good ones running about $300 butwhen you need them you really need them.
I used such a solution for years and found it easy to implement. Theexternal battery pack stayed in a pocket in my bag and when I neededthe juice or to top off my internal notebook battery I simply ran thecable from the pack to the notebook without removing the pack from thebag. While I had to deal with the extra weight of the pack in the bagusing it this way didn’t add much inconvenience and that was important. I would also connect the notebook to thebattery pack in my car between meetings and could insure my notebookbattery would last all day as a result. That’s the other benefit theseexternal packs bring, they charge the notebook battery while runningthe notebook which is a double benefit.
Electrovaya is a company that is famous for their external batterypacks and I have heard nothing but good things about them. Their PowerPads come in assorted sizes depending on the size you are willing to carry around and the battery life you need. GearLog recently reviewed a relatively new battery pack called the Powergorillaand they seemed to be pretty impressed with it. All of these externalbattery packs are available with power tips that fit most notebooks sothey are a "one size fits all" approach that can be used with multipledevices if need be. They are not cheap but for the road warrior who isconstantly faced with the dreaded empty tank this method shouldcertainly be considered.