Devices won't turn on unless plugged in.

Hi, I work in a school district that uses ASUS C203X-YS02-GR chromebooks (this model wasn't an option for this question). A substantial number of these models will not turn on normally. You have to plug in the chargers for them to boot, and when it does, the battery is almost always full. Any ideas on how to resolve this? It's inconvenient for our students.