Hi all - all I want to do is to use my laptop outside on a market stall all day where there is no electricity supply - the battery on the laptop will not last long enough especially when playing videos all day as I will be... can I plug my laptop into an external battery which will power it all day and not harm my laptop? If so, what kind should I get - my laptop is a new Acer Extensa 5630EZ using Vista. Thanks for any replies... 
