This is my new attempt to kill two birds with one stone: add a voltmeter and 5v USB output to my bag.   Problem #1. I use a Hawkwoods DV-SQN4S battery distro in my bag. I power my gear (Maxx, 2x411a) from the switchable, regulated 12v outputs. For my meager power needs, I can usually get through a day with a single set of batteries. HOWEVER it would be reassuring to have some insight into remaining battery life.   Problem #2. The most frequent power issue I run into is.... my iPhone. Rarely