I have an iPad to for the same reason...2Story is 100% correct. Put them on iTunes and sync the iPad at the office. Also all the manuals can sync to you iPhone too, hard to read but good in a pinch. Another way, at home, if you have wifi, turn your iPad's wifi on (instead of cellular), go find your manuals. When you open a pdf, tap near the top of the screen and small window pops up (open in iBooks?), click it, and its in your library.
Much recommend Google Docs to transfer these; e.g. create a Gmail account, email the files to it and access them from your ipad using cellular when available, or simply download them from Gmail to the ipad and save them. They are much less data-intense than manuals and such.