Alternative power source for laptop?

[Treesie]

Im looking at going on a walking holiday staying at Le Grand Tent! Does anyone have any idea for alternative power sources to keep the old laptop in juice?

 

[Treesie]

Anyone? :shake:

 

[gramps]

Something like THIS? :shrug:

 

[Treesie]

Something like THIS? :shrug:

Thanks gramps, looks like it, I'm off to research!