You can see what your current Overall Charge Level is on the top right corner of your screen (default layout), where there is this yellowish ring that appears to be on fire. In case you need to enter an area with a CL-limit which is lower than your own, it's possible to "cap" your Overall CL through the option in the main menu. While you can lower your CL limit anywhere, you can only raise it again when you are in the Null Chamber.