[Solved] Gamebuino Classic: Battery issues

Hello,

Recently I noticed a problem with my gamebuino Classic:

When I leave it  to charge for night the next day in the eaving the battery is almost dead eaven though gamebuino showed that it's fully charged up in the morning. I didn't use my gamebuino all day so there is now way I could drain the battery.

Is this a battery problem?

Maybe I overheated it (I carry my gamebuino in my pocket)

If so I would be happy to receive a battery model number so I can buy a replacement.

(Yes I know that the number is on the battery but one time while fixing the display I touched the text with my hands and the text is all messed up now)