The HP EliteBook 6930p as claimed by HP that the model can last the whole day … but of course with conditions.

It must be using specific HP hardware and software

You need to pay extra for the ultra-capacity battery, HP Illumi-Lite LED display and 80GB Intel SSD.

With these hardware specs, the laptops targetted at road warriors, they can use it the whole day from a single charge

It is good news for such users who need long battery life on the road, as the nearest competitors is 6 hour shy of this new HP 24-hours laptop

via source