The madvapes PCC operates similar to the Joye PCC in that you don't screw the batteries in. You just stick it in and close the lid. The lid forces the battery down into the connecter. You push the button on the front for about three or so seconds and the LED light will flash. If it turns red, it's charging. If not, then it's either a full battery or a dud. The light will shut off after a few seconds. If you push the button again for a second or less, it will re-light the LED. If red, its still charging. If green then its done. Display on front tells you the PCC battery status only.