recently i noticed my camera wasn’t turning on. the last time it was on was on 4th of july flashing a low battery symbol and went dead. i didn’t charge the battery after that. a week ago i went to go charge my battery and it says that it is fully charged, even though i have never charged it. when i do put it back in the camera, it doesn’t turn on it’s just a blank screen. i had this battery for one year, do i need to get a new one?
How old is the battery? Is it a genuine Canon battery?
It sounds like the charger could be bad, to me. I would trust what the camera is telling you. The batteries may not actually be charging. I have had several LP-E6N batteries seem to die on me all at once recently, within several weeks of one another. I tried a new charger, problem solved.
You can't always trust the camera. I have a T7 and the battery indicator never goes above 1/2, even with a fully charged battery. I talked to cannon support and their response was to send me a new battery. No change. The camera has never stopped working but I always carry extra batteries.
If batteries are left for long periods in a camera they can go into a state known as deep discharge.
My first suggestion is to put the battery back in the camera and see if it shows any life: if not, then put it back on the charger again for an extended period - several hours. The fully-charged indicator may be an error from its deep discharge state.
Meanwhile, get a new, genuine Canon battery from a reputable resource. Charge that, and see if the camera works.
In future, when not using your camera, I suggest removing the battery and storing it separately. Don't fully charge it up beforehand, but do fully charge it just before you are going to use it.