Wednesday 9 July 2014 7.00am
I need to power one computer and an internet connection.
These things are not intended to keep your hardware going for any sort of extended period. They (and the software associated with them) are there to let you to save everything and shut down elegantly before they run out of juice themselves. Typically, if you haven't shut down yourself, they trigger autosaves of documents and the like before either shutting everything down for you or hibernating the machine by saving the machine state to hard disk so it can be resumed.
If you need an ininteruptable working environment then you need a laptop with a reliably long battery life, like one of Apple's Macbooks, and a fully charged smart phone that has a hotspot function that allows you to use the phone as a wireless router for the laptop. That way you can keep going for hours.