I am interested in using the Raspberry Pi in portable projects for data collection outdoors. How would I go about running the RPi on batteries? Have any software tools been developed to monitor battery power similar to a laptop?
Dave Akerman recently created a post on how to run a Raspberry Pi off of battery power. His methods will give you the longest battery life running off of regular batteries, but his methods also void the warranty...
Laptop batteries usually have a small chip installed to measure different battery statistics (battery life being one of them). Laptops then access the information from this chip and print out the information to the user when requested. If you run your Raspberry Pi off of standard consumer batteries (which don't have a chip to my knowledge), you can't calculate the information as easily.
I don't believe any software has been developed yet to calculate battery power for the Raspberry Pi. Because there is no "standard" way of providing portable power, OS developers cannot implement it; there may be software that some people have developed for their specific way of supplying power to the Raspberry Pi, but it is doubtful that it would be released.
This is certainly possible, as confirmed by the fact that at least one group of teenagers was able to successfully launch a weather balloon for a substantial amount of time using a Raspberry Pi as it's flight computer:
(Unfortunately I haven't been able to locate any specific specs on the project)
I would look into testing with some cheap off the shelf USB battery packs (typically used for charging mobile devices on the go). I would take a look at items like this one: