New submitter expert464 writes: I just purchased an external USB battery for the main purpose of charging smartphones. I've also thought of using it to power a USB lamp and charge a bluetooth speaker. What other things am I missing that would be useful and/or interesting to power when not near an electrical outlet?Have a question for Slashdot's readers? Take a look at other recent questions first to see if someone else has had a similar question. And if not, ask away! The more details and context you include, the more likely your question will be selected.