Many of us are in the habit of plugging our phones in to charge overnight so we start each day at 100%. However, you might not be doing yourself ― or your battery ― any favors in the long run. You might have heard that charging your cell phone battery and leaving it plugged in once it hits a full charge is bad for long-term battery life. According to Chao-Yang Wang , the director of the Electrochemical Engine Center at Penn State University, there is some truth behind this thought. Over time, “a battery will degrade faster if you charge it to 100% versus a little bit lower state of charge,” Wang said. Keeping your phone plugged in once it hits a full charge and consistently charging it to 100% keeps the battery at a high voltage, which causes chemical aging in the product, said Dibakar Datta , an associate professor of mechanical and industrial engineering at New Jersey Institute of Technology.…