Most likely your battery needs to be replaced.
It's probably doing a "false charge", it's like having a rechargeable D-cell but internally only the equivalent of a AAAA-cell is working, only a more extreme version of this situation.
It would charge up very quickly but also discharge very quickly and not really power anything.
The charger doesn't realize that it's only taking seconds to charge the battery, it's just checking if the voltage is up to a full charge level.