Dell claims its can run for up to 19 hours, but only if you configure the notebook with the following: an optional nine-cell battery (a $69 upgrade to the standard six-cell battery); $300 optional add-on battery; and a solid-state drive (currently it's a 128GB option that adds about $309 to the laptop's).
Right off the bat, you're adding $678 to this system's cost to get the 19 hours Dell promises. Is it worth it? Read the before you decide. Granted, you have to take online customer feedback with a chunk of salt. But some of the comments (like "This is the worst thing [I've] ever seen from Dell," or "large and heavy") might give you pause.
HP EliteBook 6930p
According to HP, this business notebook can run for . You must to get the full 24 hours, though at the moment there's no additional charge for that. Also, you must buy the 12-cell ultra-capacity battery ($189), which reportedly lasts about 10 hours longer than the standard battery. You have to use this battery in tandem with a six-cell battery, which comes with the notebook.
HP says to get the 24-hour charge, your EliteBook 6930p must also have an as its main storage--which adds $574. That's a total of $763 added to the system's $850 price tag.