@ addison

Disclaimer: I don't own an n800, a Lenmar battery or any other products mentioned in this post.

Lenmar also makes a BP-5L battery for the n800, google it.

You could also get an external battery pack such as http://www.amazon.com/I-Up-6400mAh-E.../dp/B002PIFLVS . Sure it will double the weight and size of your n800 but you'll get 4x the battery life per charge!

Just google "external battery pack nokia adapter" for more battery packs.