Preparation - keeping a laptop charged on the move
Halfords Portable Powerpack 200
It's basically a 12 volt leisure battery with a lamp, 240 volt inverter and air compressor built in. I only got it because I inherited it with the car (the previous owner bought it to jump start the car when it had been in storage too long and the main battery had gone flat). It can charge from a 12 volt car socket or mains adapter, plus I am having some success charging it from a solar gorilla. The battery sais that it is 20ah, whatever that means in lamens terms.
Using the 240 volt inverter is incredibly inefficient, so only for "emergencies" really. More efficient is using the 12 volt output with the Trust DC-DC converter (below) that allows me to step up from 12 volts to the 16 volts required to run my macbook.
The obvious downside of this battery is that it is very heavy, only suitable for lugging around in the back of a car, so while it will be useful on a campsite with no mains hookup, i'm not exactly going to lug it into a cafe!
Trust 130W Multi Function Notebook Power Adapter
This is really useful - if I wasn't a mac user, there would probably be a charger tip included with this, but due to licensing there isn't. Therefore I had to take the DIY approach of snipping a section of cable from my spare apple power adapter (doesn't feel good doing that, knowing they are about £60 to replace!). I also modified one of the tips to allow me to fit a section of wire with spade clips, to make it easier to plug in other adapters if necessary.
Amazingly this works - charging and powering the macbook. I need to do some proper experiments to see how many charges I would get out of the leisure battery.
It also has a USB port so I can charge my iphone from it at the same time.
More details on the dealer's site.
This is a lightweight portable solar panel that will apparently charge a laptop. Covered in more detail here