When you're using power tools to complete a big project, battery life is a big problem. You probably don't want to find out you need a battery swap when you're in the middle of drilling. Thankfully, Black and Decker has a way to give you a heads-up: it's readying Bluetooth-connected Smartech batteries that talk to your smartphone. They'll let you know when they're running low, and there's a locate feature in case one of the packs gets lost in your workshop. They're useful even when you're not working, for that matter -- a USB port lets them double as mobile power packs.