Right above where you type your message, click on the tiny little picture of a picture. It is between the filmstrip and "unlink" buttons. 3rd from the end or left.
Sounds like you have an ego-t but without seeing it, I can't say for sure. Assuming it is an ego-T, try taking a toothpick and running it all around the outside of the center post on the top of the battery. Kind of gently nudge that center post around & up a smidge. You may also see gunk/liquid in that area. Wet a corner of a napkin with alcohol or use an alcohol wipe if you have one and smoosh it down into the area around the contact pin and clean. The toothpick might come in handy for cleaning as well. That contact pin can get stuck down by screwing on a topper too tight or gunk build up. Do other tanks/clearos/cartos work on it? Does it appear to charge fully?