Doug's answer:
Hi !
Sadly that can short both the charger and the battery as it is connected to the battery when it is charging. It will not overload the battery, it will short it, same thing as if you took the positive terminal and tied it to the negative one, that is what happened. This means it will take up to two days to recharge, if the chargers internal protection worked. Do you have a volt meter ? If so, please check the output of the charger, it should be around 13.5 volts, if close odds are the charger is fine and it will over time, fully recharge the internal battery.