I have a Mintyboost, but have not used it extensively yet. Just tested it to make sure it works. I have a long ride this weekend, the Horribly Hilly Hundreds, where I will need more battery time. How do you use yours? Do you wait for the Edge battery to get low then plug it in? Or do you just plug it in from the get go and use the external power first? I guess the question could be answered by anyone who has used an external battery source for their Edge. Later.