Never been real impressed with the battery life on my n800. Seems to be about what everyone says is good if I keep it off the chargers and leave wifi / bt on.

Very few open wifis or anything else for that matter around here so I generally have wireless off since 99.999999999% of what I do with it is read ebooks.

For the very largest part mine stays on the AC or DC chargers and if those aren't handy running off a NIMH pack I put together.